Research Highlights

(1995 - 2000)

National Science Foundation

CONTENTS

Agriculture & Forestry 1 - 16

Biological Sciences 17 - 22

Biotechnology 23 - 37

Chemical and Earth Sciences 39 - 50

Health Sciences 51 - 59

Natural Resources 61 - 66

Physical Sciences 67 - 69

Science Education and Popularization 71 - 73

Social Sciences 75 - 82

Buffalo Research Programme 83 - 88

Agriculture A Forestry

I m p r o v e m e n t o f in tegra ted pest m a n a g e m e n t in rice through a

study of biology and populat ion ecology of paddy bug, Leptocorisa oratorius (Hemiptera.Alydidae)

Gram No: RGAtf/AG/VI Grantees: DrL Nugatiaddc'. Prof. J. Edirisinghe Institution: 'Rice Research and Development Institute. Batalagoda

'Faculty of Science. I Iniversity of Peradenixu

Paddy bug, Leptocorisa oratorius, the predominant grain-sucking pest of rice, has been the focus ot crop protection research on rice in Sri Lanka, due to the

increasing awareness of the economic importance of its damage. Furthermore, there is a growing concern about the environmental hazards caused by the extensive use of insecticides against paddy bug. during the reproductive stage ot the crop. This has lead to the destruction of the beneficial fauna including the pollinators and natural enemies

The paddy bug, Leptocorisa oratorius, feeding on rice grains

Objectives: The objective of this study was to determine the population dynamics of paddy bug and identify its natural enemies(egg-predators/egg-parasites) in rice and non-rice habitats in order to develop improved management methods tor paddy bug.

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Research Highlights

Methodology:

Bi-weekly sweep net samples were taken from 4 selected locations, (Kurunegala in the

intermediate zone, Polonnaruwa in the dry zone, Matale and Gampaha in the wet zone), to

determine the population dynamics of paddy bug and its natural enemies(predators

and parasites) in rice and non-rice habitats. The sampling was done over a period of two

years. Using field collected paddy bug eggs, egg parasitoids were identified and percent­

age egg parasitism was determined. In order to identify alternate host plants that could

sustain the total community structure of the insect, paddy bug adults were introduced

into field cages containing flower bearing Echinochloa colonum, E.glabrescens, Panicum repens.Cyperus iria and rice separately. In each cage the number of eggs laid, nymphs

hatched, and adults emerged were monitored.

Results and Discussion: The percentage mature females and nymph/adult composition of paddy bug was found to

synchronise with the crop growth. The highest proportion of mature females was re­

corded at milky stage and the nymphal stages were confined to the heading through soft-

dough stages of rice. During the fallow period and vegetative stage of rice, paddy bugs

rest and feed on the inflorescence of a number of weed species found commonly in rice

and non-rice habitats. Paddy bug eggs were not observed in the field on these weeds.

Under non-rice situation paddy bugs laid significantly lower number of eggs (eggs/

female) on panicle bearing Echinochloa sp., Panicum sp. & Cyperus sp. than panicle bearing rice. However, the first generation adults thus developed could not reach matu­

rity and lay eggs on the same weed host. This makes clear that availability of rice (espe­

cially at flowering stage) is essential for survival of paddy bug.

Conclusions and Recommendations: It was found that rice is the only host plant that could sustain populations of paddy bug

though the insect could be found in some weeds. This is a new finding.

It can be concluded that through proper management practices, the paddy bug can be

successfully controlled. Suggested recommendations for the management of paddy bug

are:

* Plan crop establishment (varieties with similar or different maturity) in a paddy tract

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Agriculture & Forestry

in such a way that flowering will be completed within a shorter period.

Monitor rice and adjacent non-rice areas for paddy bugs from late vegetative stage

rice (first monitor the non-rice border areas of the paddy tract).

Weed the rice and adjacent non-rice areas to keep the populations of flower bearing

weeds low.

Apply insecticides if the paddy bug population exceed economic threshold level

before the flowering stage of rice. (This would reduce the population of mature female

paddy bugs before they lay eggs, and thus help reduce the population size of the next

generation.)

Since paddy bug is a migratory pest, management methods should be undertaken at

community level.

Research Highlights

E n v i r o n m e n t a l manipu la t ion: A s tra tegy to assure yield

stability and e x p o r t quality of t o m a t o grown dur ing the rainy

s e a s o n

Grant No: RG/95/AG/03 Grantees: Dr W.A.P. Weerakkody. Dr B.C.N. Peiris Institution: Faculty of Agriculture. University of Peradeniya

Protected culture is predominantly used in the temperate region where the cultivation of perishable crops is restricted due to seasonal weather changes. Because of the

intensive environmental control, it leads to greater yield and quality of produce compared with the conventional open-field culture. This technique has been successfully intro­duced to the tropical region in order to avoid the problems of excessive rain and drought. Therefore, this study was conducted to investigate the potential of expanding protected culture technology in Sri Lankan vegetable production with special reference to tomato.

Tomato grown under protected culture

Objectives: A two year study was conducted commencing from 1996, to assess the effect ol protected culture conditions on the yield stability and the quality of tomato under rainy conditions and also to study the feasibility of protected culture to upgrade the conventional vegeta­ble farming in the mid and up country areas.

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Agriculture & Forestry

Methodology: This investigation was carried out in two phases. In the first phase, two types of indoor structures and a package of improved technology were compared with the conventional open field cultivation of tomato during Yala & Maha seasons in the mid country wet zone, to study the growth, yield and fruit quality. In the second phase, the treatments that showed comparative success over the others were further modified and employed in a field experiment to examine the stability of earlier results.

Results and Discussion: Protected culture showed a superiority over open field culture in terms of plant dry weight, flowering and fruit development. The polythene house lead to more flowering branches, earlier flower initiation, more fruits and higher yield than the shed house. The improved technology showed a profuse leaf and stem growth, early flowering and high number of flowers and fruits but did not influence the marketable fruit number, yield, and most quality parameters compared with the conventional technology. The repeated trial in Maha season assured comparatively high leaf and stem growth, flowering, fruit devel­opment and yield by protected culture even under dry weather. - Although polythene house assured greater vegetable growth under dry conditions, it resulted in a lower marketable fruit number and yield than the shed house. The improved technology ap­peared to be favourable for most vegetable parameters, flowing and fruit formation regardless of the changes in weather or treatment conditions.

From the experiments in Phase 2 it was revealed that the agro-ecological conditions at 'Rahangala appeared to be more conducive for tomato than that of Peradeniya. Each variety showed superiority in terms of plant growth, fruit formation and fruit quality over the other. The variety Caribio showed better results at Rahangala while others performed better at Peradeniya.

Conclusions and Recommendations: Protected culture, especially the polythene house was favourable for tomato cultivation during rainy weather. This improved technology contributed mainly for plant growth and fruit quality of tomato. In general, the modified polythene house with improved technology gave better growth and yield of tomato in the upcountry intermediate zone, and improved fruit quality in the mid country wet zone.

Dr W.A.P. Weerakkody was awarded a PhD for this work by the University of Peradeniya..

Research Highlights

H H | Future direction of rubber wood industry in Sri Lanka: Supply and demand, technology, constraints and investment opportunities

Grant No: RG/95/AGAM

Grantees: Dr I.N. Samarappuli, Dr LM.K. Tilakaratne, Dr K.G.K. de Silva Institution: Rubber Research Institute, Agalawatte.

Rubber wood is found in abundance in the Natural Rubber producing coun­tries including Sri Lanka. It is a light hard wood and has strength proper­

ties comparable to those of other reputed timber species. Rubber wood contains a relatively higher percentage of starch than conventional timber species and is therefore susceptible to attack by the fungi and borer insects. But effective treatment can totally prevent insect and borer attack and such treated wood has a life of more than 25 years. The biggest outlet for rubber wood timber is the furniture industry. Natural Rubber producing countries have been able to compete favourably in the expanding interna­tional market for rubber based wooden household furniture.

With the continuous depletion of forest woods in the country the demand for treated rubber wood is growing steadily. Nevertheless, it is assumed that about 80% of rubber wood is still being used as a major fuel source in Sri Lanka. Therefore at the macro level, the loss of valuable foreign exchange is considerable. At the micro level too, the farm gate price hardly exceeds Rs 300/tree compared to an equivalent of Rs 1000/= reported in most natural rubber producing countries, with a well developed rubber wood industry. Despite the global importance of the rubber wood industry, surprisingly very little re­search has been done or documented in Sri Lanka.

Objectives: The general objective of this study was to investigate the Sri Lankan rubber wood industry and to identify the changes required to produce quality timber from rubber wood with a view of achieving a higher net profit margin at each stage of production process. In order to achieve the above, it was decided to analyse the supply and demand potential, technology, constraints and investment opportunities of the rubber wood industry and to develop a conceptual and analytical model of the existing rubber wood industry.

Aftrn ulture A forestry

Methodology: The supply potential of rubberwood in the smallholder sector w j s estimated trom a ran dom sample ol rubber smallholders using a pretested questionnaire. The sample con­sisted of 1200 rubber smallholders selected trom eight major rubber growing districts viz, Kegalle, Kalutara. Rainapura. Galle, Matara. Gampaha, Colombo and Kandy. Similar data pertaining to the estate sector was gathered from 18 Plantation Management Companies using a combination of procedures such as a mailed questionnaire, personal visits to management companies/estates and through records available al Plantation Reconstruc­tion Unit of the Ministry of Plantation Industries. A field census on rubberwood based processing/manufacturing units was conducted to collect information on plant capacity,

% present output levels, status of technology, recovery rates, employment generation, con straints, product types and marketing.

Transportation of rubber toifsjor mJmirial usa/ie

Results and Discussion: The results indicate that potential yearly production ol sawable rubber logs is around 325.000 m 1 Yet 4 0 % of sawable rubber logs end up as tuel wood and the balance 60'/< is converted into sawn timber and veneer products. However. 3.V,< of the sawn limber is wasted as untreated low valued planks for shuttering and pallets.

Around 200 wood processing/manufacturing unils use rubberwood as a raw material to produce a range of semifinished and finished products such as sawn wood, furniture, toys, kitchen utensils, plywood, brush handles. & broom sticks and parquet tlooring.

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Research Highlights

About 70 units of dipping plants and 17 pressure impregnation treatment plants are in operation. The latter type effectively treats 20,000 m 3 of sawn wood per year. Only 65-70% of the available drying capacities have been utilized by the rubberwood industry. Nearly, 70% of the raw material used by the plywood and veneer industry consists of rubberwood. More than 90% of the total saw dust generated from rubberwood based processing units is not utilized industrially. Rubberwood based industries provide direct and indirect employment for over 42,000 people.

Conclusions and Recommendations:

* Rubber wood can be regarded as an under-utilized, non-conventional timber resource in Sri Lanka with a huge potential for further expansion

* Distribution of processing units is unsatisfactory and therefore it is important to set up mobile processing units

* Recovery rates are relatively low and therefore, improved technology is necessary

* In order to utilize small diameter logs and saw dust, and to convert short/small diameter logs into products with sufficient length/width/thickness, it is important to set up factories to manufacture M D F boards, particle boards, joinery products and briquettes

* The floor price imposed on the export of rubber wood based sawn timber needs to be reduced to a realistic level and the import duty on face veneer has to be removed to improve the performance of the rubber wood industry.

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Agriculture A Forestry

Modified a t m o s p h e r i c s t o r a g e and its effect on b iochemica l

c h a n g e s of b a n a n a , m a n g o and a v o c a d o

Grant No: RG/V6/AG/U2 Grantees: Dr D.C.K lUeperuma'. Dr B.C.N. Feins'. Dr D.B.T. Wijeratne Institution: 'Faculty of Agriculture. University of Peradeniya

'Horticultural Research and Development Institute tHORDI). Peradeniya

Kolikuttu' banana and 'Karu thaco lomban ' mango receive a higher price al the market than other cultivars due to their pleasing taste. 'Pollock' avocado is

also a popular fruit cultivar grown in Sn Lanka. The perishable nature of these fruits has limited their export volume, and post harvest losses of these fruits are reported to be 4()'/f

or more.

Avocado kept under modified atmospheric storage al l.fCfor 21 days.

Objectives: The objective of this study was to carry out an investigation on modified atmospheric-storage (MA) and its effect on biochemical changes of banana, avocado and mango in order to extend their storage life.

Methodology: Mature 'Kolikuttu' banana, 'Karuthacolomban' mango and 'Pollock' avocado fruits were enclosed in low density polyethylene (LDPK) bags to create modified atmospheres and

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Research Highlights

stored at 14°C and 25±2 °C(banana), 12°C(avodaco) and 13°C(mango). The effect of potassium permanganate impregnated bricks as ethylene scavengers and/or granular charcoal as carbon dioxide scavengers on storage life was studied. The in-package concentrations of carbon dioxide, oxygen and ethylene were measured during storage. Percentage weight loss, changes in total soluble solids (TSS), pH, titratable acidity(TA), sugar-acid ratio, peel or flesh colour and firmness were also determind. The packages were opened after the optimum storage period determined based on the in-package gas­eous composition, and the fruits were allowed to ripen naturally under ambient condi­tions. Firmness, TA, TSS, pH , sugar-acid ratio and peel or flesh colour of the ripened fruits were analysed.

Results and Discussion: The modified atmosphere created inside LDPE bags was effective in extending the stor­age life of banana, mango and avocado. Inclusions of scavengers were effective in decreasing the in-package carbon dioxide and ethylene concentrations, thereby further extending the storage life. No significant changes were observed in most of the physico-chemical properties of the fruits during storage. Percentage weight loss of the fruits was lower than 3% during MA storage. The MA conditions did not alter the ripening process as indicated by non significant differences in physico-chemical properties between rip­ened fruits after MA storage and the control fruits.

Conclusions and Recommendations: Packaging of 'Kolikuttu' banana as individual hands inLPDE(0.075 mm) with potassium permanganate impregnated bricks could extend the storage life up to 3 0 days at 13°C and 9 4 % RH, and 2 0 days at 25±2°C and 85± 1 % RH. 'Karuthacolomban' mango and 'Pollock avocado could be stored at 9 4 % RH in LDPE (0.05 mm) with ethylene and carbon dioxide scavengers for 21 days at 13°C and 2 9 days at 12°C respectively.

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Agriculture & Forestry

Identifying optimum agrowell dimension for sustainable irrigation in Anuradhapura district

Grant No: RG/97/AGA11 Grantee: Dr C. Shanthi de Silva Institution: Faculty of Engineering Technology. The Open University of Sri Lanka

Water shortage is the major problem for agricultural activities in the intermediate and dry zones, of Sri Lanka. In most years, precipitation is insufficient to meet the

crop water requirements from February to August. Therefore, farmers in these zones depend on seasonal rainfall and storage in several thousands of small and medium village tanks to sustain their traditional way of cultivation including rainfed paddy. Over the years, these small and medium village tanks have not been maintained properly and they store water, hardly sufficient to meet the needs of rural poor. Therefore, it is imperative that supplementary sources of irrigation are found. Unlike in the Jaffna peninsula, groundwater in the dry and intermediate zones is limited due to the underlying hard rock aquifers, with low transmissivity and storage coefficient. This limited resource is used when there is no alternative. Large diameter wells (agrowells) are ideally suited for hard rock aquifers because they act as a short-term storage reservoir, as well as a groundwater abstraction point. However, the development of agrowells has taken place in a rather haphazard way, without a general assessment of the hydrogeological properties of the aquifer, the possible yield and a rational siting of wells. According to previous studies, in most of the small tank cascade systems, the densities of these agrowells have been increased drastically. This development threatens the limited groundwater resources.

Objectives: A three year study was conducted to identify the optimum well dimensions (well radius, depth and spacing) and sustainable irrigated land area under a typical cropping pattern based on aquifer properties and recharge characteristics.

Methodology: A case study was conducted in the Meegassagama lower command area o f the Thirappane Tank Cascade system in Anuradhapura District. Study area was fully equipped with twenty observation boreholes covering seven agrowells, rain gauge, parshall flumes and evaporation pan. Daily monitoring was done on the groundwater

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Research Highlights

levels at twenty observation boreholes and seven agrowells before and alter purnping, rainfall, evaporation, tank water level, tank water issue and outflows at the drainage. In addition crop information such as type of crop, cultivation extent, time of planting. 20'/r cover (ground cover by the forest), time of harvesting etc was recorded periodically. Soil infiltration rate, permanent wilting point and field capacity were also measured during the study period. Several pumping tests were conducted during the study period in all seven wells during early and late dry seasons. Analysis was mainly based on the radial flow model (RFM) developed by the principal investigator in her Ph. D. study. Pumping tests were analysed by the RFM to identify the horizontal hydraulic conductivity and specific-yield. The same model was used to study the long term behaviour of the agrowell and to develop the nomograph. A soil moisture balance based compuler model was used to estimate the annual average recharge to the aquifer.

An agrowell in a small cascade system

Results and Discussion: Average horizontal hydraulic conductivity and snecific yield of the study area were 5m/ day and 0.025 respectively. The average annual recharge to the aquifer was 170 mm. Groundwater balance was developed with components such as recharge, change in groundwater storage, tank water issue, and seepage losses from the tank, abstraction, outflow and big tree evaporation. It is extremely difficult to perform a perfect balance due to the errors in several of the components. Nevertheless, groundwater balance indicates valuable information such as the groundwater flow under the tank bed even during the dry season, which connects the tanks in the system.

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Agriculture <5 Forestry

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Conclusions and Recommendations: A nomograph was developed using the RFM and the results obtained on the aquifer parameters, recharge and groundwater balance to identify the optimum well dimension such as optimum well radius, well depth and spacing in a new agrowell system. These parameters may be used when developing agrowell systems in future in the Anuradhapura district.

Research Highlights

Development of swinging lugs reversible cage wheels for small and medium power tractors

Grant No: RG/97/AG/02 Grantee: Dr P.LA.G. Alwis Institution: Faculty of Agriculture, University of Ruhuna, Kamburupitiya

H istorically the agricultural systems of the country are based on rice based cropping systems, which make Sri Lanka one of the most experienced rice growing

nations. A considerable area, 7 300 0 0 0 ha (11.3% from total land area of the country), has been used to cultivate paddy in 1997. But, due to the poor productivity, paddy farmers have not been able to supply the demand of the country.

Machinery application for land preparation is one possible solution to improve timeli­ness in operation and land and labour productivity. Application of small and medium power tractors for paddy land preparation has become increasingly popular in Sri Lanka and the use of small and medium power tractors has increased exponentially over the past decade.

The performance of a tractor depends on a number of parameters, but the soil surface on which the tractor operates is the main factor affecting efficiency of operations. It is already well understood that a tractor with ordinary high lugged rubber tyres performs poorly in wetland operations due to slip and sinkage. To overcome this problem, different types of traction aids have been introduced including chains, tracks and cage wheels.

Objectives: This study was conducted to design and develop a suitable mechanism for a folding type cage wheel for small and medium power tractors, in order to improve the performance of the currently available cage wheels.

Methodology: A folding type cage wheel for small and medium power tractors was designed and devel­oped to provide facility for road transportation and to improve performance in wet land operations. Two pairs of cage wheels were constructed for small and medium power tractors after testing the first wheel and implementing necessary modifications.

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Agriculture & Forestry

Two experiments were conducted in two locations (on the experimental station and on tanner's field) to compare the performance of above designed cage wheel with conven­tional cage wheels. Effective field capacity, time per hectare, travelling speed . travel reduction and the cost for construction criteria were considered.

The designed cage wheel Jor Jour wheel tractor {expanded position)

Results and Discussion: The results of the farmer trial showed that the effective field capacity and travelling speed of designed cage wheels were 0.36 ha/hr and 2.05 m/s respectively. Above observations of the conventional cage wheel were 0.23 ha/hr and 1.6 m/s respectively. Therefore the effective field capacity and travelling speed of the four wheel tractor equipped with the designed cage wheel were greater by 60.8 9} and 28.08'/ , respectively.

Time per hectare to plough the field with designed cage wheels and conventional cage-wheels were 2.74 hours and 4.72 hours respectively ; a decrease of 41.68'/} with the designed cage wheel.

According to the test results of the "on station" trial, it was observed that the travel reduction of designed cage wheel was significantly different from conventional cage wheel. Mean travel reduction of designed cage wheel was 9.79} and that of conventional cage wheel was 249} . Hence travel reduction of designed cage wheel was lower than conventional cage wheel.

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Research Highlights

Cost of production o f conventional cage wheel and designed cage wheel was Rs. 5846/ and Rs. 6020/- for two wheel tractor, and Rs. 5846/- and 6020/- for four wheel tractor respectively. Considering the benefits of the designed cage wheel, this difference is negligible. Considering the test results obtained, it is concluded that the performance of the designed cage wheels were significantly higher than conventional cage wheel.

The main advantage of the designed cage wheels was its capability of road transporta­tion since the cage wheel diameter was smaller than the tyre in the retracted situation, and an improved traction while puddling as the cage wheel diameter was greater than the tyre in the expanded situation, so that the lugs can touch the hard pan before the tyre.

Conclusions and Recommendations: The developed folding type cage wheel performed efficiently when compared with the conventional cage wheel. But it should be still further developed to improve its perform­ance and use under more difficult soil conditions. The developed cage wheel is low cost and simple with a quick mounting and dismounting system to facilitate road transporta­tion. It also has a high floating ability.

The designed cage wheel for two wheel tractor

Therefore it can be recommended that this "multipurpose cage wheel" is a new, suitable traction aid for small and medium power tractors which can be used in both high and wet land conditions.

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Biological Sciences

A study of the diversity of some wetlands in the Colombo and greater Colombo area

Grant No: RGAM/B/OI Grantee: Prof. Kanlhi Abeynayake Institution: Faculty of Science, University of Colombo

M arshlands have been defined as wetlands according to the Ramsar Convention in 1987. These are not wastelands but productive ecosystems on

which man has depended on for farming practices, fishing, herding of livestock and for obtaining firewood, fodder and vegetables. In addition to the above uses, marshlands in and around Colombo play a vital role as 'Flood Buffers' into which the storm water is discharged and detained in time of heavy rains which otherwise would cause serious flooding problems.

With the acceleration of development processes and due to population pressures, the need might arise for some of these marshes to be released for various purposes including reclamation, wetland cultivation etc. In such an event the documentation of biodiversity of these marshlands would be useful to evaluate the marshlands in order to develop a land use zoning plan for sustainable utilization or management of these marshes.

Objectives: The objectives of this study were to determine (a) the floral and faunal composition of the study sites to demarcate plant communities

and associations that are visible in each site (b) the characteristics of the habitat and human interferences on these sites (c) the feasibility of using the data obtained for selection of a marsh for development

if the need arises in the future.

The sites selected for the study were Yakbedda marsh, Heen marsh, Bloemendhal marsh, Sri Jayewardenepura marsh, Pagoda-Kotte marsh, and Bellanwila-Attidiya marsh. All plant species occurring in the selected study sites (except algae & fungi) were identified. Cover/ abundance of herbaceous vegetation was determined using lm x Im quadrates using Braun-Blanquette scale. A preliminary survey on the fauna was also conducted at the above sites.

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Research Highlights

Conclusions: The species lists for plants and animals for different marshlands revealed that marshlands contain a rich biodiversity and provide excelleni habitats tor wildlife. I.andtillmg either legally or illegally seems to be the main threat to the study sites as they continuously reduce the extent of the marsh area. Although all study sites have been given a protective status by the S L L R D C and the Department of Wildlife Conservation, new reclamation of land in most areas were observed during the period of field data collection. Therefore a strict control on this action is immediately required.

Association dominated with grasses as seen at lleen marsh

The dumping of wastes has also become a way ol encroachment of marsh areas. This creates an unhygienic condition for human habitats and also a threat for the survival of fish and other aquatic organisms. A suitable way of demarcation of the marshland bor­ders by the responsible authority is needed to prevent the problem of using these sites as dumping grounds to a certain extent.

This study could be employed as a preliminary survey for the preparation of a detailed land suitability/land use zoning plan for the management of Colombo flood Detention Areas (CFDA) and taken into consideration for future work.

The results of this study indicate that, if there is pressure lor release ol a marshland al a future date for development the choice should be made between either Heen marsh or areas of Sri Jayewardenepura marsh out of the sites studied However future work should look into hydrological aspects of the marshlands.

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Biological Sciences

A survey on the existing turtle hatcheries and mapping of the nesting beaches of turtles along the North West, West, South-West, South and South-Eastern coasts of Sri Lanka

Grant No: RG/95/B/02 Grantees: DrfMs) P. Dayarame, Mr D. Amarasooriya Institution: National Aquatic Resources Research A Development Agency, Colombo

S ri Lanka's beaches serve as the nesting sites for many turtles. As a signatory to the Convention of International Trade on Endangered Species (CITES) Sri Lanka

has an obligation to assist in the conservation of these endangered species.

Therefore it is necessary to identify, record and map the existing nesting sites along the coastal belt of Sri Lanka.

Objectives: 1. To determine the impact of the hatcheries on the natural process of the ecosystem 2 To study the hatching requirement of eggs in an artificial hatchery and in the

natural conditions 3. To assess the pros and cons of the hatcheries 4. To survey nesting beaches and to determine the human impacts to these beaches. 5. To identify possible conservation measures that can be applied under the

existing conditions.

Results: This study showed that the current practices observed in the hatcheries in egg collection, transportation of eggs, burying of eggs, handling and rearing of hatchlings and releasing them in to the sea could have serious effects on the complex life cycle of turtles. Under the existing rate of excavation of turtle nests along the coastal belt from Karai ti vu to Yala the concept of hatcheries cannot be totally neglected. Therefore, introduction of proper scientific hatchery procedures is immediately required.

The entire coastline from Karaiti vu (in Puttalam District) to Yala (in Hambantota district) was surveyed to identify turtle nesting beaches within the study area. According to the findings no turtle nesting beaches remain in the Puttalam and Gampaha districts. Some beaches in the Colombo, Kalutara and Matara districts are still occasionally nested by turtles. The good nesting beaches are mainly located in the districts of Galle and -

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Research Highlights

Hambantota. Kosgoda- Induruwaarea (in I ialle district i and Rekawa beach i m llambantoia district) have been identified as turtle rookeries. I hree beaches, kosgoda-lnduruwa. Rekawa and Bundala are still being regularly visited bv all the live species i»f turtles inhabiting Sri Lankan waters.

Recommendations: Based on the survey of the existing turtle Hatcheries of Sri Lanka the following recom­mendations were made.

* Introduction of Sea Turtle Hatchery Guidelines * Introduction of Hatchery License Scheme. * Establishment of Hatchery monitoring scheme * Improvement of the current hatchery practices to promote research, education

and coastal tourism * Not to permit any more hatcheries for the Kosgoda - lnduruwa area. * Encourage tourists to watch the sea turtle in the wild.

Based on the survey of nesting beaches the main recommendations proposed under the above study are:

* Declaration of Kosgoda-Induruwa beach and Rekawa beach as protected areas * Strict implementation of the law regarding the offenses related to the turtles. * Research and educational programmes should be established al the major nesting

beaches. * The concept of turtle based eco-tounsm should be implemented at ihe major

nesting beaches.

55 Hawksbill luriU awaiting removal ' si nie\

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Biological Sciences

In t roduct ion of w i ld flora to the floriculture industry

Gram No: Grantees: Institution:

RG/95/B/I2 Mr D.M.U.B. Dhanasekera, Ms S.A. Krishnarajah Royal Botanic Gardens, Peradeniya

he floriculture industry in Sri Lanka is a vibrant, expanding sector, which A brings in substantial foreign exchange and employment generation, foreign

exchange earned for the year 2000 alone was 650 million rupees.

One of its important aspects is the introduction of new plants to maintain a competitive edge in world markets. Identification of naturally available indigenous plants in the wild and their subsequent adaptation to suit consumer preferences is one method of introduc­ing new plants. Identification and introduction ol native plants would not only help to overcome the problem of finding new ornamental plants for the floriculture industry, n would also help prevent the loss of these plants from the wild. Once cultivated ami I n c h available, these indigenous plants would not be over collected and exploited tor short-term financial gains. This project was aimed to identify and introduce native plants from the wild to the floriculture industry.

Different stages of growth in culture Jor Osbeckia oclandra

Research Highlights

Objectives:

The objectives of this project were; to select potential plants of ornamental value; Value addition and identification of methods for easy propagation; to introduce plants to the public for cultivation; and re-introduction of very rare plants to the wild.

Conclusions: The following plants selected under the above project showed a positive response to regeneration under in vitro conditions.

1. Didymocarpus humboldtianus Gardn 2. Osbeckia octandra (L) DL 3. Exacum petiolare Griseb 4. Anoectochilus setaceus Blume 5. Impatieus acaulis Arn 6. Kendrickia walteri (wight ex Gardn Triana)

An initial stock of plants could be produced through tissue culture, as this would reduce the number o f plants being collected from the wild. These could then be used as starter material for conventional methods of propagation by growers as well as for studies in value addition and flower induction.The induction of flowering has been achieved in Didymocarpus humboldtianus which has shown profuse flowering, and Osbeckia octandra in which one year old plants have shown flowering.

The findings of the above project would be useful for the development of the floriculture industry in Sri Lanka.

Osbeckia octandra (L) DL

22

Biotechnology

mnm Development of DNA probes for the identification of WKM Anopheles culicifacies species complex

Grant No: RG/93/BT/02 Grantee: Dr. Maya B. Gunasekera Institution: Faculty of Science, University of Colombo

M alaria is a major health problem in Sri Lanka. The malaria parasite is transmitted to humans through a bite of an infected mosquito vector. The mosquito species

known as Anopheles culicifacies is considered to be mainly responsible for the trans­mission of malaria in Sri Lanka. It is also found to be an important vector of malaria in many regions of the Indo-Pakistan subcontinent. Studies in India have shown that A. culicifacies mosquito is present as a species complex comprising five sibling species designated as A, B , C, D and E (a more recent addition to the complex). Sibling species of a complex do not cross mate with each other and cannot be distinguished by their external features as they all look identical to each other. Hence, the usual taxonomic keys cannot be used for their identification. Accurate identification of the sibling species of the A. culicifacies complex is very important for any mosquito vector control programme of malaria. This is because the siblings, despite their similarity in looks, may play a different role in transmission of malaria as they show differences in their behaviour, their ability to infect humans, their competence as vectors as well as their response to insecti­cides.

All studies done previously in Sri Lanka on sibling species identification of this mosquito species used a technique called polytene chromosome analysis. This is a very tedious technique and only certain stages of the life cycle can be identified. A mosquito has several life cycle stages - the larvae, pupae and the adult. Only fresh semi-gravid adult or mature larvae can be used for this technique and many field samples are lost during the analysis due to unsuitable preparations. Therefore, a project was initiated to look at the differences in their DNA, and the genetic material of organisms, with the intention of developing DNA probes to identify the sibling species of the complex.

DNA probes have several advantages over the conventional techniques of mosquito species identification: they are accurate, rapid, highly sensitive, and all life cycle stages can be identified by a single technique.

First, a DNA library of the mosquito was constructed and repetitive sequences were isolated. These sequences were labelled with a radioisotope and used as DNA probes

23

Research Highlights

to detect and distinguish the DNA of A. culcifacies from the DNA of other mosquito species. The three DNA probes developed in this study (Rp36, Rp217 & Rp234) can distinguish all life cycle stages of A. culicifacies from those of other mosquito species. In addition, a DNA probe to distinguish sibling species A from B and C species of A. culicifacies was also developed (Figure below).

<aj DNA from individual An.c. mosquitoes

P r o b e Rp36

- . ion

( b ) DNA from individual mosquitoes

P r o b e Rp.16

10 n 12 s p e c i e s

Dot-blot hybridization of DNA extractedfrom individual mosquitoes to show specificity of DNA probes:(a) total DNA (T),approximately 600ng and diluted DNA samples of Anoph­eles culicifacies species A, B and C hybridized with probes Rp 234, Rp 36 and Rp217. The filters were washed in 0.1 x SSC at 30PC; (b) total DNA samples of Aedes aegypti (I), A. togoi (2), Anopheles aconitus(3), A. culicifacies species B, female (4), A. culicifacies species B.male (5), A.jamesi (6), A. kaweri (7), A. nigerrimus (8), A. subpictus (9), A. lessellatus (10), A. vagus (11) and Culex quinquefaciatus (12) probed with Rp 36. An identical pattern ofhybridization is also given with probe Rp 234. The filter was washed in 0.1 x SSC at 50PC.

2 4

Biotechnology

Using this method 9 6 mosquito DNA samples can be analyzed at once. Furthermore, to screen for A. culicifacies sibling species A in the field itself, a simple and a safe tech­nique was developed. It only needs to squash a part of the mosquito on to a filter paper, and sibling species A is distinguished from other mosquito species by the non-radioac­tive DNA probes. A mass scale field survey involving more than 2000 mosquito samples from various regions of the country to find out the presence /absence of sibling species A of A. culicifacies was also conducted. Sibling species A in Sri Lanka was not detected. The DNA probes developed in this study can also be used for field larval surveys on A. culicifacies for vector surveillance studies. The grantee has completely characterized the DNA probes developed in this study by DNA sequence analysis. These probes were requested by scientists in India (Malaria Research Centre), and were sent for their field surveys on sibling species A .

This was the first and the only published DNA probe developed to date in the world to detect members of the A. culicifacies species complex.

Research Output of the project: No. of publications: 5 No. of research communications: 9 PkD. thesis: I

25

Research Highlights

DNA finger printing of M. tuberculosis using RFLP : its use in the study of epidemiology of tuberculosis with special reference

H I to the prison population

Grant No: RG/95/BTA)8

Grantee: Prof. JenniferPerera

Institution: Faculty of Medicine, University of Colombo

Restriction Fragment Length Polymorphism (RFLP) analysis has become a very important tool in the epidemiology of tuberculosis (TB) . The repetitive Insertion

Sequence (IS 6 1 1 0 is the most frequently used genetic marker for strain differentiation of M. tuberculosis (Mtb).

The aim of this study was to determine the transmission of pulmonary TB among prison­ers and their effect on the epidemiology of T B in Sri Lanka, by studying R F L P patterns of DNA extracted from Mtb strains. Mtb strains were isolated from prisoners and chest clinic attendees.

Prisoners, ex-prisoners and tuberculosis patients attending the Central Chest Clinic were used as the study population. Dendogram was created by feeding the data to a computer software package. This was used to study the R F L P patterns of Mtb strains, which is a method of visualization of the degree of relatedness between strains.

Of the 2 0 strains isolated from prisoners, none displayed identical fingerprints. Among the M. tuberculosis isolates tested, one strain lacked the IS 6 1 1 0 element. There were 6 strains of M. tuberculosis among the prisoners that had only a single IS copy, while among the isolates from the general population there were 25 strains which had single IS copy.

This study showed that the majority of circulating Mtb strains in Sri Lanka belong to a limited number of families, but the degree of IS 6 1 1 0 DNA polymorphism among strains were high. The high degree of DNA polymorphism among the Sri Lankan strains permit us to study the epidemiological aspects of T B transmission with a high degree of accu­racy.

No difference in clustering was found between susceptible and resistant strains. Typing of Mtb isolates is of great potential value for basic and epidemiological studies on tuber­culosis.

26

Biotechnology

Among bacterial isolates of prisoners and ex-prisoners from the general population, there were 2 strains that had identical banding patterns, while there were clear similarities between several isolates. Analysis of the RFLP patterns among chest clinic attendees showed 5 pairs of identical banding patterns. Analysis of the data showed that ex-prisoners contributed to a substantial propotion of TB patients in the general population.

In conclusion, high degree of polymorphism was observed in the ONA fingerprinting patterns of M.tuberculosis isolates, with low copy number. However, for the unambigu­ous confirmation of the identities of strains, additional genetic markers should be em­ployed in strain typing. Therefore, establishment of this method of analysis in Sri Lanka will be useful to study strain variations in epidemiological analysis.

Research output of the project: No. of research communications: 7 PhD. thesis: The project has contributed to a part of a PhD thesis submitted in January 2001.

27

Research Highlights

JEM Histamine in fish and fish products: contamination, control and effects of processing

Grant No.: RG/95/BT/I0 Grantees: Prof. U. Samarajeewa and Dr. T.S.G.Fonseka Institution: Faculty of Agriculture, University ofPeradeniya

Consumption of fish contaminated with histamine is of concern as it causes irritating body reactions such as redness in eyes, tingling and burning sensations

around the mouth and gastrointestinal complaints in sensitive individuals. Although these symptoms are similar to symptoms of food allergies, they are not described clinically as allergies. In this project histamine concentrations of market fish and fish products in Sri Lanka were determined to assess the extent of contamination. The histamine-producing bacteria were isolated and the effects of processing fish on histamine were examined.

Two methods for estimation of histamine in fish, namely thin layer chromatography and fluorometry were compared. The results showed a correlation coefficient of 0.88 when applied to market fish, indicating that the thin layer chromatographic method could be used for screening of samples. Of the five solvent systems compared for thin layer chro­matography, chloroform: methanol: concentrated ammonia (2:2:1) was the most suitable and gave a minimum detection limit of 2 0 ppm. Spots of tyramine were also observed in the extracts of most histamine-contaminated fish samples examined by thin layer chroma­tography.

Of the 27 species of marine and inland water varieties offish tested, fresh skipjack con­tained the highest histamine concentration o f478 ± 9 1 ppm. Among the other market fish products fresh tuna [kelawalla], fresh or dried herring [hurulla], dried skipjack [balayaj and maldive-fish [umbalakada] contained histamine concentrations higher than 100 ppm. Fresh inland fish and "jadi" contained less than SO ppm. Innermost portions of maldive-fish contained histamine concentration of 190 ± 11 ppm compared to 9 0 ± 10 ppm in the outer layer of about 2 mm depth. Canned mackerel [Kumbalawa] contained histamine concentration of 132 ± 127 ppm. Canned fish manufactured for Sri Lanka contained higher histamine concentrations than those manufactured for other countries.

Sri Lanka Standards Specifications for fresh, dried and canned fish do not stipulate toler­ance limits for histamine. Standards for maldive-fish and canned fish- curry stipulate the tolerance limit as 2 0 0 and 100 ppm respectively. The United States Food and Drugs

28

Biotechnology

Administration and the European Economic Community directives specify tolerance limits of SO ppm histamine in fish. Most of the fresh, dried, canned or maldive-fish collected from retail markets carried unacceptable concentrations of histamine.

Nine species of histamine producing bacteria were isolated from more than 100 samples of fish. Of the isolated species, Hajhia sp. produced the highest concentrations of hista­mine under laboratory conditions. Two species of bacteria. Micrococcus and Flavobac-terium sp., which were not reported as histamine producers before, produced histamine under the experimental conditions. The other histamine-producing species isolated included Klebsiella pneumoniae, Klebsiella sp., Hafnia alvei, Enterobacter sp, Proteus sp. and Morganella sp.

Comparison of the methods of preparing dried-fish under different conditions showed that beheading, gutting, washing and salting of fish prior to sun drying inhibits the histamine production. Maldive-fish prepared from the dorsal loins of skipjack contained more histamine than those from the ventral loins did. The dorsal loins contain much higher proportion of dark tissues than ventral loins.

Cooking fish with aqueous extracts of "goraka", "siyambala" and "biling" reduced the histamine percentages by 9 2 , 7 8 and 68 respectively. Tartaric acid in "goraka" appeared to be the component responsible for reduction of histamine in fish. Cooking fish with aque­ous extracts of "kathurumurunga" and "murunga" leaves reduced histamine by 57 and 59 percent respectively. The use of these ingredients brings down the concentrations of histamine in cooked fish below tolerance limit of 100 ppm.

Exposure of Niven's agar medium inoculated with histamine-producing bacteria to sunlight or storage in nitrogen atmosphere did not suppress bacterial growth. The histamine producing bacteria did not grow at temperatures below 10°C and above 70°C or at sodium chloride concentrations higher than 14% or at pH range outside 4 - 9 when tested in Niven's agar medium. Incorporation of extracts o f "murunga" or "kathurumurunga" leaves at concentrations higher than 80% to Niven's agar medium also prevented growth of histamine producers. Petroleum ether extracts of "goraka", "siyambala" or "biling" caused a slightly higher inhibition of histamine-producing bacte­ria in Niven's medium, when compared with aqueous extracts. Zesti™ liquid smoke, a commercial food preservative and a flavouring agent, suppressed the growth of hista­mine-producing bacteria when incorporated to Niven's medium at concentrations higher than 3%.

Frying in coconut or soya oil for more than 4 min. reduced histamine concentrations in fish by 50%. Immersing fish in coconut water prior to cooking did not remove or reduce

29

Research Highlights

3 0

histamine. However, it is not known whether this treatment reduces other amines or compounds that may be responsible for "heaty" effects described to be associated with tuna.

A spectrophotometric method was developed to estimate histamine in culture media. The method was extended to estimate histamine in fish by measuring absorbency at 585 nm. The industry could use this method for rapid testing of fish for histamine. The method is less expensive and more convenient than the other methods based on HPLC or fluorometry.

Research output of the project: No. of publications: 3 No. of research communications: 4 PhD. thesis: 1 Awards: 3

Biotechnology

W^m To develop DNA probes to detect the presence of fungal pathogens in propagation material and plant tissue

Grant No.: RG/96/BTA32 Grantees: Prof. R.LC. Wijesundera and Dr. N.V. Chandrasekharan Institution: Faculty of Science, University of Colombo

TTyhizoctonia solani is the causative fungus of sheath blight disease of rice. The disease is characterized by greyish green lesions starting on the sheath of plants

at the water level. Severe attacks can affect the yield considerably. In tropical countries including Sri Lanka, the disease has become increasingly important in recent years with the introduction of high yielding cultivars having short stature and large number of tillers, which provide suitable microclimate for the pathogen. In addition to rice R. solani infects a large number of other important crop plants all over the world. Early detection of the pathogen is useful in controlling and prevention of these diseases. Presently, the most common method of identification of the pathogen is based on morphology which is time consuming and laborious. To overcome these disadvantages, a repetitive DNA sequence from the genome of R. solani was cloned with a view to develop a DNA based diagnostic assay.

The isolate of the fungus was grown in modified Czapeck Dox broth. The fungal mat was harvested and total genomic DNA was extracted form the freeze dried fungal mat. To construct a genomic DNA library, partial digestion of genomic DNA was carried out using the restriction enzyme Sau3AI. The digested DNA fragments were ligated with BamHl cleaved Zap vector arms (Strategene) and packaged in vitro. The library was then amplified with E. coli strain X L 1 Blue MRF. To isolate recombinant clones containing repetitive'sequences, the library was screened with 3 2 P labeled total genomic DNA of R. solani. Of the clones giving strong hybridiza­tion signals, the clone designated as L R Z 1 0 was selected and in vivo excised to yield a recombinant plasmid pRZlO. Restriction analysis of pRZIO revealed that the clone contains l.S kb DNA insert of R. solani. Southern blot analysis was performed by using 5 2 P labeled pRZIO as the probe. Based on the restriction pattern, the cloned sequence appears to be interspersed within the genome of R. solani.

Thereafter the 3 2 P labeled clone pRZIO was used as a hybridization probe to detect R. solani. A dot blot analysis for serial dilutions of R. solani genomic DNA probed with "P labled pRZIO showed that it was capable of detecting as little as lOOpg of R. solani genomic DNA. The cloned fragment in pRZIO was completely sequenced and a Polymer-

31

Research Highlights

32

ase Chain Reaction (PCR) based diagnostic assay was developed by designing sequence specific primers from the cloned sequence.

This diagnostic assay could be used to detect Rhizoctonia solani in the soil. It will also enable planning of strategies in disease management programmes.

Research output of the project: No. of publications: I PhD. thesis: Submitted

Biotechnology

Wwm l s c of biotechnology for conservat ion and susta inable use of

medicinal plants in Sri L a n k a

Grant No.: RGAWBT/07 Grantees: Mr Gunaratna de Silva1 and Dr A. Hirimbureganw Institution: ''Bandaranayake Memorial Ayurvedic Research Institute. ,V;» inna

'Faculty of Science. University of I olombt>

T^auvolfia serpentina (Ekaveriya) and Munronia pinnata (Binkohomha) are ± \ very valuable and widely used plants in Ayurveda system of medicine in Sri Lanka. Ekaveriya is mainly used for treatment of hypertension, skin disorders and it has the property of lowering blood pressure. The entire plant of Binkohomba is used especially in the treatment of malarial fever, fever, dysentery and purification of blood.

At present there is no cultivation of these two plant species, probably due to the poor seed production and their low viability. The use of stem cuttings to produce plantlets is also not practiced for M. pinnata.

Presently, plants are mainly collected from the wild. But this is insufficient to meet the demand, which is met by imports. Removal of the plants from the forest has been very rapid, and as a result of continuous clearing ot forest cover both plants have become endangered and are now listed as threatened or rare plants.

This study was carried out with the main objective of developing techniques tor mass propagation of planting material of the two medicinal plants using micropropagation techniques. A phytochemical screening for compounds of economic value was also car­ried out.

Callus regenerated rooted M. Pinnata

3 3

Research Highlights

Tissue cultured R. serpentina plant with roots

The results obtained indicate that mass production of R. serpentina is possible through shoot tip culture and in vitro propagation of M. pinnata is possible through leat callus culture. It was also concluded that there was no significant difference between major groups of chemical compounds present in tissue cultured and normal R. serpentina plants.

Research output of the project: No. of publications: 2 (submitted) No. of research communications : 2 Ph.D. thesis: submitted

34

Biotechnology

Screen ing black p e p p e r vines aga ins t P i p e r yellow mott le v irus

by P C R and adopt ion o f dot-blot hybridizat ion technique for m a s s scale screen ing o f b lack p e p p e r plants

Grant No.; RG/97/BT/01 Grantees: Dr Padmini de Silva and Mr M. Dharmadasa Institution: Export Agriculture Research Station, Malale

B lack pepper (Piper nigrum L.) cultivations in Sri Lanka are affected by Piper yellow mottle virus (PYMV) . disease. The symptoms include mottling and mosaic on

leaves, small brittle leaves, short spikes and badly filled spikes and yield reduction. Since affected pepper vines show significant yield reductions, control of this disease is very important.

Mossaic and mottling symptoms and small brittle leaves oj injected plants

Commercially, black pepper is propagated by vegetative methods. The most effective method of disease transmission occurs through rooted cuttings. Therefore, one objec­tive of this project was to show the importance of using healthy planting material in controlling the P Y M V disease. Studies conducted in Matale, Walpita and Vennoruwa nurseries showed a very high risk of P Y M V disease spread. The distribution of infected plants (symptomatic and asymptomatic black pepper mother vines) were within a range of 7.6% - 1 2 % . The results confirmed the possibility of disease spread through rooted

35

Research Highlights

cuttings. The transmission of the disease by infected planting material from above nurs­eries was controlled by testing mother vines by Polymerase Chain Reaction (PCR) and roguing all PCR positive mother vines as well as destroying symptomatic mother vines.

Electron micrograph showing PYMV parasites

The second objective was to find out whether the alternate hosts or carriers of P Y M V as alternate hosts can act as the sources of the inoculum, which may be a cause of the disease spread. This was done by graft inoculation and confirming the susceptibility by PCR. Results showed Piper chuvya, P. longum and P. Sylvester as susceptible hosts, and P. sriboa resistant to infection. Natural infections of P Y M V on weeds were checked by PCR and found to be negative. The results confirmed that there was no risk of weeds acting as alternate hosts of PYMV.

Positive PCR reactions showing 600bp bands of virus origin

36

Biotechnology

Vector transmission studies confirmed aphids (Aphis gossypii) leaf hoppers (Amrasca devastans) and thrips (Liothrips karnyi) as non-vectors of PYMV.

According to the results, the following recommendations were made: * Use certified virus free planting material to control the disease spread and reduce

the-losses due to P Y M V infection. * Remove susceptible wild Piper spp. from black pepper gardens especially from

newly planted fields. * Maintain the weed cover as recommended by the Department of Export

Agriculture. * Suggestions were made to include P. sriboa in the breeding programme to find out

the possibility of developing a resistant line for PYMV disease.

As aphids and other two insect species are non-vectors of PYMV, spraying chemicals were not recommended to control P Y M V disease.

Research output of the project: No. of publications: I (submitted) No. of research communications: 2

Chemical & Earth Sciences

Mttm Investigations on the field use of natural attractants for Rhynchophorus ferrugineus.

Grant No: RG/92/C/2 Grantees: Prof. N. E. Gunawardena Institution: Faculty of Science, University of Kelaniya

"jnhynchophorus ferrugineus F. (Coleoptera: Curculionidae), commonly known /V as the red weevil is a devastating pest on young coconut palms (Cocos nucifera, L ) in coconut growing countries while it is amongst the five major pests on coconut in Sri Lanka. Despite attempts to control this pest through male sterilization and electronic detection of feeding larvae inside the trunk, the present control measures still rely on old techniques which are sometimes dangerous and environmentally harmful.

Several natural attractants of the red weevil have been investigated as potent lure in a number of previous studies. These include the coconut bark-steam volatiles, a mixture of attractants from the coconut bark, 4-hydroxy 3-methoxystyrene (S) and (Y nonanoic acid lactone (1: l,v/v), short chain alcohols and the weevil's aggregation pheromone, 4-methyl S-nonanol.

Objectives: The objective of this study was to examine the above natural compounds or their combi­nations as lure for the red weevil and to develop a suitable attractant baited trap to control R. ferrugineus populations.

Methodology : A laboratory activity comparison of the above attractants, viz the steam distillate of young coconut bark, 1:1 (v/v) mixture of synthesized 4-hydroxy 3-methoxystyrene (S) and (Y nonanoic acid lactone ( L ) , n-pentanol, n-propanol and synthesized racemic 4-methyl-S-nonanol (ferrugineol) was conducted using a Y-shaped glass olfactometer.

A field assay was carried out using the above attractants as baits, dispensed at a uniform rate through glass capillary tubes. A bucket (SL) containing soap water (2L) was used as the trapping device. Each capillary tube was suspended inside the bucket just above the water level. Traps, 30 m apart were attached, at 1.6m height to coconut palms in a random

39

Research Highlights

manner. Six fields in two different districts were used and six replicates ot each lure were run in each field. Empty capillaries were used in blank runs. Trap catch was counted weekly.

In a final field assay three binary combinations ( 1 : 1 , v/vi of ferrugineol with pentanol. propanol and the bark attractant mixture (S+L) were also field tested similarly.

Allractanl baited soap water trap

Results: The olfactometer bioassay revealed prominent short range attractant properties of the coconut bark-steam distillate, pentanol and propanol with 7 5 - 8 9 $ weevils responding. In contrast, the mixture S+L and ferrugineol showed only moderate activity having 60 -75 ' '< weevils selecting the baited arm.

In the field assay however, only ferrugineol and the mixture S+L lured weevils into the bucket with a mean number of 0.23 and 0.01 weevils /trap/day respectively while traps baited with the bark-steam distillate, pentanol, propanol or the blank did not catch anv weevils.

In the final field assay the combination, ferrugineol and pentanol ( l : l ,w/w) gave the highest trap catch of 0.40 weevils/trap/ day. This combination was field active for a period of 6 0 days.

40

Chemical & Earth Sciences

Conclusions : Ferrugineol-pentanol batted soap-water trap offers a simple and safe method to reduce

the adult R. ferrugineus population in Sri Lanka. An average trap catch of 0.4 weevils/ trap/day is found steadily over a period of 6 0 days. This method has the following advantages over conventional methods such as burning palms and pouring insecticides into infested trunks.

Simplicity - the trap is simple to operate. Economy - approximately Rs SO for the baited trap Long life time - activity over 2 months without maintenance. Safety - no insecticides and therefore no hazards to environment or users. Selectivity - highly specific for/?, ferrugineus.

The above trap was subjected to extensive field tests (1995-96) for its efficiency and after effects by the Coconut Research Institute, Sri Lanka and was recommended as suitable for the control of adult red weevil population.

* Commercial production of the above trap commenced in 1999and it is marketed by Serendib Natural Products, Sri Lanka. (Address: 227, Castle Street, Colombo 08)

41

Research Highlights

m^m Investigation on adulteration of essential oils with special reference to oil of Ceylon citronella

Grant No: RG/95/C/12 Grantee: Mr. KRDayananda

Institution: Industrial Technology Institute, Colombo

Adulteration of Sri Lankan essential oils have been reported' in many instances. It was reported that Ceylon citronella oil is being adulterated with kerosene from the

time of early 1940s; cinnamon bark oil is suspected to be adulterated with synthetic cinnamic aldehyde, which is cheap compared to cinnamon bark oil. Local dealers as well as export buyers have made numerous inquiries on genuineness and authenticity of essential oils produced in Sri Lanka.

Low quality terpene fractions isolated from the various essential oils, petroleum based hydrocarbons or synthetic chemicals are commonly used in the other manufacturing countries for adulteration. In Sri Lanka, products such as kerosene, coconut oil, sesame oil and synthetic compounds (cinnamic aldehyde) are being used for this purpose. In early 1970s it was reported that the method used to detect kerosene in citronella oil is giving false positive results.

To confirm the authenticity of Sri Lankan essential oils ITI(CISIR) launched a program to establish proper test methods for the identification of adulterants and its level in cit­ronella oil.

Methodology: Citronella grass (Cymbopogon nardus) obtained from Katuwana, Hambantota was distilled at the Process and Plant Engineering Division of the ITI to obtain authentic samples of citronella oil. Physical parameters such as specific gravity, refractive index, optical rotation, solubility and chemical composition of samples were determined using classical methods of analysis and Gas Chromatography. Citronella oil samples drawn from the Colombo Pettah market in January 9 6 were analysed for kerosene; it was revealed that all 25 samples of Grade TJ citronella oil which was selling at a lower price were adulterated at a level of 10-25%. However among the Grade I oil, only one sample was found to be adulterated at the level of 5%. These consignments of citronella oil were prepared for local sales. In the consignments for exports, Only 2 samples were found to be adulterated with kerosene among the 138 samples analysed, and the level was less than 2%.

42

Chemical & Earth Sciences

Conclusion and Recommendations: Adulteration of Ceylon citronella oil with kerosene is common in low-grade retail lots available in the Colombo market. However, it was observed that the export consignments are free from adulterants. Physical methods of analysis such as specific gravity, optical rotation, refractive index may not be sufficient to confirm the adulteration; solubility in ethanol is found to be by far the best field test method for the detection of above adulter­ants in Sri Lankan essential oils. However for Ceylon citronella oil Sep-pak silica cartridge separation followed by GLC analysis proved to be successful for the detection of kero­sene up to 1%. All the analysed (25 samples) Grade II citronella oil, which was selling at a lower price, was adulterated at a level of 10-25%. However among the Grade I oil adul­teration was rare. These consignments of citronella oil were prepared in bottles of capaci­ties ranging from 175 ml-750 ml to be sold for local use.

Sep-pak cartridge clean up followed by GLC analysis can be recommended for the detec­tion of kerosene in citronella oil (minimum detectable level 1%). Solubility with 80% ethanol is recommended for the detection of petroleum hydrocarbon or fatty oils in other essential oils such as cinnamon leaf oil, bark oil, nutmeg oil, pepper oil, cardamom oil etc., which permits detection even up to 0.1%.

Adulteration of cinnamon bark oil with synthetic cinnamic aldehyde was not completely ruled out, as test methods available are still the classical methods of analysis which do not permit the detection below 5%. Analysis for the presence of traces of phenyl pentadienal, a by-product formed during the preparation of synthetic cinnamic aldehyde is proposed for the detection of synthetic cinnamic aldehyde in cinnamon bark oil.

43

Research Highlights

Design and construction of a low-cost colorimeter suitable H | for the use in GCE Advanced Level Teaching

Grant No: RG/97/C/7 Grantee: Dr. S.A. Fernando Institution: Faculty of Science, University of Colombo

Construction of relatively inexpensive equipment for education is o f utmost importance to upgrade the status of teaching activities. Education on chemical in­

strumentation is not well developed in Sri Lanka as compared to other developing coun­tries. The main reason for this may be the lack of interaction between the chemist and other relevant disciplines.

Objectives: The aim of this project is to construct chemical equipment to be used in G.C.E. Advanced Level Teaching. To initiate such a programme three model colorimeters have been con­structed. These colorimeters consist of three major compartments: radiation source(s), cell holder and detector/display unit.

Radiation Source(s) Locally available Light Emitting Diodes (LED's) were used as the radiation source and options are available to fabricate any additional LED's. LED's emit a fairly narrow band­width of visible radiation (red, orange, yellow, and green). Hence the use of LED's elimi­nate the need for a tungsten lamp and filters, generally used in conventional colorimeters. The emission characteristics of locally available LED's were studied and the following table represents the calculated peak wavelength (nm) and bandwidth (nm) respectively.

L E D colour Peak wavelength (nm) Bandwidth (nm)

Blue 475.0 65 .0 Green 570.0 25 .0 Yellow 580.0 30 .0 Orange 620.0 15.0 Red 640.0 35.0

44

Chemical & Earth Sciences

Cell Holder Cell compartment has been designed using PVC tubes or plastic sheets to accommodate 1-cm square type cells.

Detector/Display Unit Locally available photodiodes were used as the radiation detector. The light intensity^,) incident on the photodiode surface is proportional to the output voltage (R.) of the signal amplifier.

Three model colorimeters have been designed with different display units. Model I colo­rimeter consists of a Digital multimeter as the display unit. An analog display unit has been used in the Model II colorimeter. Model III consists of a digital display unit.

The components and necessary options used for the construction of the three colorimeters are shown below:

Components Colorimeter

Model-I Model-II Model-Ill

Power supply Radiation source and detector + + + Cell compartment + + +

Signal amplifier + + + Display unit + + +

Digital multimeter + - -Analog meter - + -Locally fabricated 4-digit display - - +

Log converter +

As the model III consists of a log converter, absorbance measurements can be made directly.

The principle of operation of Models II and III are similar to colorimeters available in the market. The principle of the operation of Model I colorimeter is illustrated in the figure.

45

Research Highlights

Meter Response - Ri

Principle oj operation (Model 11

Model I

The light intensity (Ii) incident on the photodiode surface is proportional to the output voltage (Ri) of the signal amplifier and it can be represented by

R = k l i i

The response corresponding to a reagent blank (consists of all reagents except the anal s te i could be adjusted to a fixed value (R^) using zero adjustment.

4(>

Chemical & Earth Sciences

Model HI

47

A standard curve can be developed using variable concentrations o f the selected analyte to find an unknown concentration. These hypothetical standard curves can be repre­sented by Absorbance vs. Concentration and Response vs. Concentration. These re­sponse values are used to calculate the nominal transmittance ( P ) for each concentra­tion using the following equation which can be applied to any given concentration.

T 1 = R. / R d i r o

Where T 1 is the nominal transmittance for a kiiven concentration ( ( ' ) . the absorb?nee values (A ) for each calculated T 1 can be calculated.

y r n

Research Highlights

The cost of the three colorimeters developed (at current prices) is estimated as follows:

Conclusion: This study shows that simple colorimeters can be fabricated at a reasonable cost. The performances of these colorimeters were comparatively the same as the conventional colorimeters, and these can be effectively used for secondary and tertiary education at a minimum cost

Model I Model II Model III

6000/-6200/-8000/-

4 8

Chemical & Earth Sciences

Pesticide Residue Trials on Selected Vegetable Crops

Grant No: RG05/OO5 Grantees: Dr. A.M. Mubarak Institution: Industrial Technology Institute, Colombo

Pesticides are used for the protection of crops against pests and diseases. Application of pesticides on crops will also leave residues, which pose a potential

threat to the health of the consumer. It has been reported that there is wide misuse of pesticides in the country, particularly among the vegetable growers, majority of who apply excessive dose of insecticides on vegetables and send them to market immediately after spraying.

Few residue studies on food crops in Sri Lanka are reported in the literature but none of them are supervised trials.

Objectives: This research programme was therefore aimed at monitoring the residue levels in some common vegetables, (i) 2 hrs and (ii) 14 days after spraying with insecticides at recom­mended and double the recommended dosage. The effectiveness of simple cooking proc­esses such as washing in cold and hot water in removing any residues present in these vegetables was also evaluated.

Methodology: The familiar leafy vegetables, Kankun (Ipomoea aquatica), Sarana (Boerhavia diffusa), Mukunuwenna (Alternanthera sessilis) and Gotukola (Centella asiatica) were treated with different classes of common insecticides in the country- endosulfan (chlorinated hydrocarbon), carbofuran (systemic carbamate), Chloropyriphos, quinalphos and profenofos (organophosphates). These insecticides were mixed and sprayed at normal and double the normal dose. Carbofuran, a granular formulation, was however mixed with soil before planting. Crops were harvested (i) 2 h and (ii) 14 days after the final spraying. In the case of Sarana an additional harvest was done 3 days after the final spraying to monitor the rate of disappearance of residues.

4 9

Research Highlights

From each experiment three samples were analysed - one without any processing, one after washing with water twice, and the other after washing with water twice and then heated to 80° C in water. Gas chromatography with ECD and NPD was used for the determination of residues.

Conclusions and Recommendations: Soil applied Carbofuran was not detected in any of the vegetables studied. All the other insecticides monitored were detected at high levels (19-82 mg/kg) in all vegetables when applied at normal dose and analysed immediately after spraying (after 2 h). In three of the vegetables Sarana, Mukunwenna and Kankun residue levels dropped to 0.01-0.5 mg/kg, 14 days after spraying. In Gotukola however, the residue levels remained notably high, 5-11 mg/kg, even after 14 days. Field trials with Sarana indicated that more than 85% of the residues present immediately after spraying dissipated within 3 days. At double the normal dose, alarmingly high levels (35-173 mg/kg) of residues were detected in all veg­etables at 2 h after spraying but reduced to 0.05-1.2 mg/kg in Kankun, Mukunwenna and Sarana after 14 days. Gotukola once again retained significant levels of residues, 6-11 mg/ kg for endosulfan, chloropyrifos and quinalphos while for profenfos it was as high as 33 mg/kg..

Our field trials results suggest that if vegetables are sent to the market immediately after spraying, especially with high dosage, the residue levels of the insecticides studied will be well above the FAO recommended Maximum Residue Limits (MRL) for fruits & vegeta­bles, which ranges from 0.1-2 mg/kg, depending on the insecticide-vegetable combina­tion. Further, simple cooking process such as washing and heating in water can induce only a marginal reduction in residue levels from vegetables studied.

On the other hand if farmers harvest the vegetables 14 days after spraying, even with excessive dosage of insecticides, a significant reduction in residue levels can be expected (except Gotukola), which will greatly reduce the health risk to consumers. Our studies also suggest that even a delay of 3 days in harvesting after last spray can reduce the toxic residues considerably. Since Gotukola retains a significant amount of insecticides, di­etary intake studies should be done to make a realistic estimate of the health risk associ­ated with consuming contaminated Gotukola.

Since pesticide residues adhere to the surfaces of fruits & vegetables due to surface active agents present in the formulations, adding detergent to water during washing of vegetables will be more effective in removing toxic residues.

Similar studies in other fruits & vegetables should be carried out as they will provide useful information on health risks associated with vegetables sprayed with pesticides.

SO

Health Sciences

UmM Nosocomial infections in the Intensive Care Units in the National Hospital of Sri Lanka

Grant No: RG/95/M/17 Grantees: Dr. J. K. P. Wanigasuriya', Prof. R. Sheriff Institutions: 'Faculty of Medicine, University of Sri Jayawardenepura

'Faculty of Medicine, University of Colombo

Infectious diseases remain a major health problem in many countries and ac­count for a major portion of hospital care. Improved techniques in prevention and

treatment of these infections have become a great challenge in modern medicine.

Infections can be divided into two broad groups: (a) nosocomial infections and (b) community acquired infections. Infections produced by micro-organisms acquired dur­ing hospitalization are called nosocomial infections or hospital-acquired infections. In­creasing awareness and demands on quality assurance in medical care has brought the topic of nosocomial infections into sharp focus.

Intensive care units (ICU) have become an absolute necessity in modern medical manage­ment and today, most general hospitals in Sri Lanka have acquired this facility. The National Hospital of Sri Lanka is equipped with several ICUs and a specially trained staff in these units manages patients with various medical and surgical conditions.

The nosocomial infections play a significant role in morbidity and mortality patterns of critically ill patients. Several factors account for the high incidence of nosocomial infection in the intensive care unit patient. The principal contributory factor is the severity of the underlying illness. The host defences in these patients are considerably more impaired than in the average hospital patient, and the ICU patients undergo more invasive procedures which predispose them to hospital-acquired infections. There are many studies conducted in developed countries on nosocomial infections in the ICUs. But to date there are only a very few studies on this aspect carried out in intensive care units in Sri Lanka. Even those are short-term studies.

Objectives: The objectives of this research project were to study the incidence, pattern, risk factors and outcome of nosocomial infections in the ICUs of the National Hospital of Sri Lanka with a special reference to Dialysis Unit and to formulate strategies for the prevention of nosocomial infection in the ICUs.

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Research Highlights

Results and Discussion: One hundred and eighty five patients were followed up during their stay in the intensive care units. Lower respiratory tract infections occurred in 24.4%, urinary tract infections in 2 0 % and infection of intravenous cannula site in 19.2% of patients admitted to ICUs. The incidence of peritonitis in patients undergoing peritoneal dialysis was 65.5%. The perito­neal infection rate was alarmingly high for this simple life saving procedure. Surgical wound infections were not a major problem in this group of patients. Gram negative bacteria were the commonest aetiological agents. Staphylococcus aureus was isolated in small number of patients.

Urinary tract infection occurred in 2 0 % of patients managed in intensive care units. Blad­der catheterization in ICU patients has been shown to be a major source of nosocomial urinary tract infection. Positive urine cultures from catheterized patients in the absence of symptoms does not warrant antibiotic therapy as most cases are due to colonization. In routine practice regular urine cultures from catheterized patients are often requested and the antibiotics are prescribed according to these results.

There was evidence of emergence of drug resistant strains among the bacteria causing urinary tract infections. This is probably related to the use of antibiotics in the inten­sive care unit. The outcome of nosocomial urinary tract infections was good. All of them responded to antibiotic therapy and removal of the catheter in suitable patients. However, the emergence of drug resistance in colifoms is a matter for concern.

One of the most commonly used medical devices in the hospitals is the intravenous cannula. Intravenous fluids, drugs, blood and blood products are administered through these lines to most of the patients treated in the intensive care units. This study showed 19% of infections associated with intravenous cannula and in two patients it proceeded to abscess formation. Acute peritoneal dialysis is a life saving procedure in patients with advanced renal failure. The incidence of peritonitis during acute perito­neal dialysis was 65 .5%. In the majority, the peritoneal fluid cultures became positive on the 4 t h day of dialysis. The gram negative bacteria was the major causative agent in peritonitis. This study also highlighted the deficiencies in hygienic measures in the dialysis unit.

Conclusions and Recommendations: Nosocomial infections are a significant problem with patients treated in our intensive care units. Regular surveillance by the infection control team is essential to identify these infections and to prevent the spread to other patients. It is vital to have access to the microbiology laboratory rto isolate organisms, monitor antibiotic sensitivity patterns and

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Health Sciences

to identify organisms with antibiotic resistance. The infection control measures that are documented in the hospital infection control manual should be strictly followed in high-risk units such as the intensive care unit.

The diagnosis of nosocomial pneumonia is not always easy in the ICU patient. As shown in this study, lack of definite diagnostic criteria led to the over diagnosis of nosocomial pneumonia and over treatment in the ICU.patient. Therefore, development of protocols for the diagnosis of pneumonia in the ICU setting is useful in limiting the costs and the hazards of antibiotic therapy.

Although antibiotics are highly effective in treating bacterial infections they should not be perceived as the only answer to the infection. Antibiotics not only cause serious side effects but also they are expensive and lead to evolution of microorganisms with high level of resistance to antibiotics. Rational use of antibiotics should be encouraged in the intensive care units to prevent the emergence of resistant organisms.

Simple infection control measures such as isolation, hand washing, barrier nursing and use of disinfectants should be-encouraged in the ICU setting. Regular surveillance for antibiotic resistant strains and isolation of patients with highly resistant strains are nec­essary requirements in the control of these infections. Aseptic techniques should be strictly adhered to while performing invasive procedures. Maintenance of medical equip­ment according to the accepted criteria will minimize the spread of nosocomial infections.

Attempts should be made to minimize the use of Foley catheters and protocols for closed system drainage and sterile insertion of catheters should be strictly enforced. Routine cultures are time consuming and expensive. Treatment should be started only when there is evidence of infection as suggested by the presence of fever or leucocytosis. Catheters should be inserted with care, using disinfectant on the skin and should be changed frequently.

Dialysis unit should be regarded as a high-risk environment and procedures in infection control should be strictly adhered to. The hospital infection control team should take a renewed interest in this respect.

Although community-acquired infections account for the majority of illnesses treated in our hospitals, it seems clear that nosocomial infections are emerging as a major national health problem. They contribute greatly to the morbidity and increase the burden on the hospital cost. Improved methodologies in diagnosis, treatment and prevention of noso­comial infections should be addressed in the national health policy.

53

Research Highlights

Identification and characterization of viruses causing economically important poultry diseases

Grant No: Grantee:

RG/95/V/02 Dr. G.S.P. de S. Gunawardena

Institution: Veterinary Research Institute, Peradeniya

The poultry industry in Sri Lanka has developed rapidly in recent years. Several factors are economically important for this industry, among which, poultry

diseases have acquired a significant place. Despite the use of imported vaccines, out­breaks of certain viral diseases are still reported. To produce local vaccines or to evaluate the efficacy of imported vaccines, the existing local field virus strains must be isolated and characterized. Furthermore, the increased knowledge on the causative viruses will help to plan more effective vaccination programmes and other disease control measures.

Methodology: Clinical and pathological studies were carried out on chickens affected with viral diseases found in different parts of the country. Attempts were made to isolate the causative viruses using culture techniques. The viruses isolated from chickens affected with clini­cal diseases are as below.

(a) IB - Infectious Bronchitis virus (b) AE - Avian Encephalomyelitis virus (c) RED - Reo virus

All the virus isolates were tested for the presence of other virus contaminants and were purified by the serial dilution technique. These purified samples were subsequently used for further virus propagation. Each isolate was tested using a flock of SO birds comprised of 21 day - old chickens. During the experiment, hajf of the flock was inoculated with a virus isolate and the other half was kept as the control group. The birds of both treatment and control groups were examined daily for the clinical manifestations of the disease. Pathological manifestations, viz., gross-pathologica!,histological and serological changes were also studied.

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Health Sciences

Conclusions & Recommendations: Infectious Bronchitis virus, Reo virus and Avian Encephalomyelitis virus that cause disease and death in poultry are found in Sri Lanka. IB virus infection leads to respiratory disease and growth retardation in affected birds, though it does not cause high mortality. This in turn may result in substantial economic losses to the farmer.

Virulent Field IB virus isolates (13 DB, 10 IB and 48 IB) found in this study can be used to assess the efficacy of commercial IB vaccines. Since all these vaccines are imported to our country, their efficacy against local virus strains should be evaluated before use.

Possibility of using the field IB virus isolates as seed cultures should be studied with the objective of producing poultry IB vaccines locally.

55

Results: Chickens infected with IB virus isolates developed clinical signs characteristic of a respi­ratory disease. The main clinical signs observed were: depression, coughing, sneezing, nasal discharge and decreased food intake. They recovered from the clinical disease within a period of 2-3 weeks after infection. However, all the affected birds appeared weak and showed a markedly reduced growth rate after recovering from the infection. Chickens infected with Reo and A E virus isolates remained clinically normal throughout the experi­ment.

Research Highlights

MEM The effectiveness of a new restorative material for use in outreach dental clinics in Sri Lanka

Grant No: RG/98/D/0I Grantee: Dr. S. Usgoda Arachchi Institution: Postgraduate Institute of Medicine, Colombo

Dental caries is the most common oral disease among children. In 1986, the government implemented an outreach strategy in the School Dental Service (SDS) to

improve its service. Here School Dental Therapists (SDTT) have to move from their base clinics to provide oral health care to children of schools situated in remote peripheries by setting up mobile dental clinics.

When 'Amalgam* is used as a filling material, the tooth needs special preparation and it is a complex procedure requiring a longer time to perform a restoration. Therefore, SDTT are incapable of providing treatment to higher number of children during the course of one day. This problem is more acute in outreach dental clinics, where usually a higher attend­ance of children is observed in a day.

Therefore, introduction of a new permanent restorative material with qualities of quick and easy manipulation may be a solution to enhance the work performance of SDTT at outreach dental clinics.

Objectives : Glass Ionomer Cement (GIC) is a permanent restorative material used by developed coun­tries. Studies show that it can be used in both anterior and posterior teeth using quick and easy manipulative techniques.

The purpose of this study was to test the effectiveness of the use of GIC in outreach dental clinics with a view to enhancing the work output of these clinics.

Methodology: Three School Dental Therapists (SDTT) were randomly selected according to their work­ing experience and they were given a training on the use of GIC. Following this, they were instructed to conduct outreach clinics. One group of children were treated with GIC and the other group was treated with Amalgam. The treated children were followed up for a

5 6

Health Sciences

period of six months, and re-examinations were made in one, three and six monthly inter­vals. The quality, the durability, the occurrence of post-operative complications of these restorations, and the work outputs of two restorative interventions were taken as measurements. Moreover, the cost for restorations, the assessment of logistic difficulties and the fulfillment of the operators expectations by the use of GIC were used as indica­tors to test the effectiveness.

Observations and Conclusions: SDTT were able to place GIC restorations as effectively as Amalgam restorations in terms of the quality, durability, and the absence of post-operative complications. Further, with the use of GIC, they were able to produce more work output than the use of Amalgam. Accordingly, GIC seems to be the more efficient restorative material. The cost for a GIC filling was lower than that of an Amalgam restoration, hence it was cost effective too. Moreover, there were no apparent logistic difficulties concerning the introduction of GIC in outreach dental clinics.

The use of GIC in outreach dental clinics would be a more effective method of provision of restorative care rather than the use of Amalgam. Moreover, with the other advantages of the GIC, its introduction to the school dental service would be a better strategy for the provision of restorative care.

57

Research Highlights

^^^9 Periodontal status of pregnant women and women using hormonal contraceptives

Grant No: RG/95/D/V1 Grantees: Dr (Ms) A T. Tilakaratna, Dr. A. W. Ranasinghe Institution: Faculty of Dental Science, University of Peradeniya

Periodontal tissues are the supporting structures of teeth: the gingiva, periodon­tal ligament, the alveolar bone and the cementum. Periodontal disease is an in­

flammatory disease affecting these supporting structures of teeth and it is the most prevalent oral health problem in Sri Lanka. Gingival inflammation (GI) with an accompany­ing increase in the gingival exudate is known to be the most common oral manifestation of elevated levels of ovarian hormones in the female. Therefore, pregnant women and those who use hormonal contraceptives may be considered as two "risk groups" for periodon­tal disease. Birth control pills utilize synthetic gestational hormones, progesterone and synthetic oestrogen. Less dramatic but similar effects are observed in the gingivae of oral contraceptive users, compared with pregnant women.

Previous studies have shown that during pregnancy, gingival inflammation increases significantly from the first to the third trimester with a maximum increase in the second trimester and a decrease at the end of 3 months post-partum. Similarly, oral contraceptive users showed higher levels of gingival inflammation than non-users, despite a lower mean oral debris index. Women who were using hormonal contraceptives for more than 1.S years exhibited greater periodontal destruction compared to the control group of comparable age and oral hygiene.

The critical predisposing factor for periodontal disease in these groups is thought to be the elevated levels of sex hormones. If such a predisposition occurs in these two groups of women, it is important that dental health personnel be integral members of antenatal and family planning teams to identify periodontal problems in these risk groups, and to educate them in prevention and treatment.

Objectives: The main objectives of this study were to investigate and to determine the severity of

periodontal disease (a) during pregnancy and 3 months post-partum, and (b) in hormonal. contraceptive users, compared to a matched control group.

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Health Sciences

Results: Despite similar scores for plaque levels in both pregnant and non-pregnant women, the GI of pregnant women significantly increased, during 1st and the 2nd trimesters of pregnancy compared to the controls. During the 3"* trimesters of pregnancy GI was further increased, but dropped at 3-months post-partum. However, values for loss of periodontal attachment (LA) did not show significant differences from that of controls, during any of the stages of pregnancy.

Contraceptive users of less than 2 years and 2- 4 years duration and non-users had similar oral hygiene levels; yet the contraceptive users had a significantly higher level of gingival inflammation, compared to the non-users. Usage of hormonal contraceptives for 2 - 4 years caused a significantly higher LA compared to that of controls.

Conclusions : The results of this study show that pregnancy had an effect only on the gingivae and not on the periodontal attachment levels. The effects of oestrogen and progesterone could give rise to a more florid response to the irritant effects of plaque, resulting in severe gingivitis. Severity of gingivitis increases throughout pregnancy from the first trimester to the third trimester, followed by a drop during the last month.

Usage of contraceptive preparations containing oestrogen and progesterone resulted in hormonal changes similar to those seen in pregnancy, associated with increased prevalence of gingivitis. The significant loss of attachments detected with the usage of progesterone injections for a longer duration 2 - 4 years, could be attributed to its effects in promoting tissue catabolism resulting in increased periodontal attachment loss.

* The work related to this project is included in a PhD thesis (Tilakaratne A; in 1999), and in two international publications:

59

Methodology: The study was conducted on women (in the age range 17-36 years) selected form Yatinuwara Divisional Secretarial area of the District of Kandy in Sri Lanka, being a local population of same ethnicity, socio-economic background and oral habits (never chewed betel or smoked). They were target selected using pre-determined selection criteria for the investigation. They were all informed of the scope of study and their consent was obtained prior to clinical examination. During clinical examination, all the subjects underwent a comprehensive peri­odontal examination, which included examination for the plaque levels, assessment of gingival condition and measurement of loss of periodontal attachment. Examinations were repeated for a period of one year during which they were examined four times at three monthly inter­vals.

Natural Resources

WSM Developing new techniques for gem exploration .'application of Rb/Sr ratio

Grant No RG//96/NR/01 Grantee: Prof. M.S. Rupasinghe Institution: Institute of Fundamental Studies, Kandy and University of Sabaragamuwa. Buttala

Recent scientific investigations have revealed that about 2 5 % of the total land area of Sri Lanka is gem bearing. However the gem industry in Sri Lanka is still based

on traditional mining methods. Development and application of scientific tools in gem exploration as well as mining and processing is therefore nationally important.

Objectives: This research project was mainly focused on studying the behaviour of major and trace elements in stream sediments of Sri Lanka and the use of geochemical ratios in identifying gem bearing areas.

Results and Discussion : For this study stream sediment samples were collected mainly from Kotmale Oya and Menik Ganga basin and Walawe Ganga basin. Data of previous surveys were used, for statistical analysis. Gem bearing sediment samples and samples from gem source rocks such as skarn and pegmatites were also collected. Samples were analyzed using the X-ray fluorescence technique.

The results of the study revealed that different elements are concentrated in different size fractions of sediments. K, Al, Mn, Rb, Ni and Sr concentrate in the -63M m fraction and concentration decreases towards higher grain sizes. Nb and Cr are found in the +125-17^1 m fraction while the highest concentration of Si was found in the +177-250urn fraction. Zr accumulates in the +63- 125ft m fraction. The accumuation of clays, and heavy minerals, which contain these elements, in different fractions may be the factor behind this distribution pattern.

It was also noted that major elements have been depleted with reference to upper crustal levels while trace elements have been enriched in all the studied river basins. High leach­ing rates of major elements and accumulation of trace elements during the sedimentation process may account for this result.

61

Research Highlights

Conclusions and Recommendations : Both factor analysis and correlation coefficients show that major and trace elements behave according to their ionic potential.

Studying the relationship with element ratios and gem potential reveal that ratios between elements of similar ionic potentials have good relationships with gem potential. Among the studied ratios Rb/Sr x Ba/Sr ratio can be used in discriminating areas according to their gem potential more effectively. The predicted potentials by this newly identified ratio are comparable with field observations. This new ratio can therefore be applied for gem exploration after field trials.

62

Natural Resources

H 9 Risk assessment and environmental protection in landslide prone HNfl areas of Sri Lanka

Grant No: RGW/NM1 Grantee: Mr N M SIA rambepola Institution: National Building Research Organization, Colombo

Landslides are one o f the most pressing environmental problems of he hill country areas of Sri Lanka. They are likely to have a greater economic impact

in the urban and semi-urban environment when there is a possibility of damage and losses to investments on various development projects, infrastructure and more importantly to lives.

Despite repeated occurrences of natural disasters due to landslides in Sri Lanka, inflicting losses in terms of life and property, very little has been done towards introducing scien­tific practice of delineating the degrees of hazard, identifying elements at risk and risk assessment. The present practice in Sri Lanka is merely to relocate disaster driven homeless to other locations, even without the prior knowledge about the safety or other­wise of these sites. Therefore, a need was felt for the development of a scientific method to know the landslide prone areas. National Building Research Organisation (NBRO) has already produced a set of landslide hazard maps covering 2680 km 2 of area for the districts of Badulla, Nuwara Eliya, Ratnapura and Kegalle. These maps could provide an essential input to the risk assessment.

Objectives: The overall aim of the study was to introduce for the first time in Sri Lanka scientific

approaches to risk assessment and environmental protection in landslide prone areas. The specific objectives of the research were to develop the scientific methodology of risk assessment by utilizing landslide hazard maps already produced by NBRO, and by addi­tionally developing human settlement and infrastructure maps for the corresponding areas; to advance mapping methodology to accommodate scale effects (e.g. the currently available hazard maps of 1:10,000 would be enlarged and sufficiently detailed by input of additional information to render them fit for utilization in assessing risks in location spe­cific situations); to test risk assessment methodology developed under the programme against a specific problematic site; to produce a manual detailing scientific principles involved in the suggested methodology, and a case study demonstrating an example of risk assessment in a real ground situation; and to develop guidelines for environmental

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Research Highlights

protection and sustainable development particularly with respect to the location specific problematic situations considered above.

Damaged house due to landslide al Yatiyantota

Methodology: The methodology adopted for risk assessment and environmental protection in landslide prone areas of Sri Lanka was mainly divided into live stages. They are, development ol landslide risk assessment methods, site selection and base map preparation, desk study, field surveys, data analysis, interpretation and presentation. The methodology adopted in the development of landslide risk assessment methods is the risk assessment for land­slide prone areas of Sri Lanka based on the data and experience gained through the Landslide Hazard Mapping Programme (LHMP) executed by NBRO. The quantitative landslide risk assessment, including detailed probability analysis may be appropriate for slopes with detailed engineering investigations, whereas qualitative landslide risk anal) sis using geomorphology, geology, hydrology, land use and expert judgement may be appropriate for simple risk assessment of natural slopes. Site selection and base map preparation was based on the studies of landslides carried out by NBRO. The most recent (September 1997) landslide event at Yatiyantota in Kegalle district of Sri Lanka was se­lected as the representative site for field testing. A topography map of Yatiyantota unsta­ble area was prepared at 1:5000 scale using existing 1:10,000 scale ABMP map (60/24) of the area. It is one o f the major landslide prone districts in the Central Highlands ol Sri Lanka.

64

Natural Resources

The desk study including air photo interpretation lead to production of the state-of-nature maps i.e. slope range and category and land use and management were done. Geotechnical and geological, environmental and socio-economic, surveys were also done. Through the field work on geotechnical and geological survey, the state-of-nature maps in the study area were produced; i.e. bedrock geology and structure, former landslide and overburden deposits, location and hydrology. Laboratory investigations were done on selected representative soil samples which were collected during the field work. The field work on socio-economic survey gave input to the state-of-nature map and data for risk analysis. The environmental survey helped to identify environmental risk of the area and preparation of guidelines for environmental protection.

Development of holes due to springs and minor earth movements

Results and Discussion: All data obtained from desk studies and field work were subsequently analyzed, corre­lated and interpreted. Finally these findings have been presented as tables, figures, cross sections, maps, photographs etc. in order to achieve the objectives of the research study. State-of-nature maps of the study were prepared in 1:50,000 scale, i.e. bedrock geology and structure, former landslide and overburden deposits, location and hydrology, slope range and category, land use and management. Landslide hazard zonation map of the study area was prepared with sufficient details to enable risk assessments. The infra­structure map showing housing, agriculture, plantation and other public utilities was prepared simultaneously for the corresponding areas through air photo interpretation

65

Research Highlights

and field survey. Guidelines on landslide risk assessment and environmental protection were also developed.

.Conclusions and Recommendations: The graded landslide hazard maps will play an important role in site selection and devel­opment planning within the hill country districts of Sri Lanka. The risk assessment methodology developed by NBRO will facilitate determination of risk and scientific analy­sis of landslide risk. Development of a culture for risk analysis before commencement of major infrastructure development projects and establishment of human settlements in landslide prone areas based on the risk criterion will be essential for sustainable develop­ment of the hill country. In addition, awareness creation on appropriate mitigatory meas­ures and cost effective solutions to reduce the impact of landslide hazard, will also be necessary.

The methodology proposed in this report may assist in the designing of cost effective solutions and mitigatory actions for the area in which the study was carried out (Yatiyantota) and can be developed for the other landslide prone areas. The method has to be field tested to assess the applicability under different conditions, to suit the events of different degrees of severity, depending on the changes of physical and socio-eco­nomic structures. The methodology proposed by NBRO for risk assessment essentially will have a wide range of applicability in improved land use and urban planning for regulated development. It should transfer the benefits to the whole population, residing in the hill country districts of Sri Lanka, eventually, minimizing the loss of life and property due to the occurrence of landslides.

66

Physical Sciences

Kfif l Continuous flow photochemical reactor for B decontamination of water using sunlight

Grant No: RG/95/P/04 Grantee: Prof. K. Tennakone Institution: Institute of Fundamental Studies. Kandy

Drinking water used in many localities is contaminated with organic pollutants. Agrochemicals, industrial effluents, diffusion and leaching of sewage into ground

water are common sources of contamination. Some organic contaminants escape con­ventional methods of water treatment. In this project a simple device (photochemical reactor) for decontamination of water with sunlight was constructed.

The method of decontamination, depends on the photocatalytic property of titanium dioxide ( T i 0 2 ) which is an inert nontoxic white powder commonly used in the paint indus­try. T i 0 2 has semiconducting properties and when it is exposed to light, electrons and positive charges (referred to as holes) are generated. Electrons and holes react with water and oxygen molecules to produce hydroxyl and superoxide free radicals. Both these species are powerful oxidants that readily reacts with trie-organic compounds. In this process carbon and oxygen gets converted to carbon dioxide and water respectively. If there is chlorine, chloride ion is produced and organic phosphorus (which is very toxic) transforms to the phosphate ion. These substances in small Quantities do not cause any problems.

In order to avoid separation of the catalyst from water it has to be immobilized in an inert substrate such as glass. Commercially available Degussa P25 titanium dioxide can be used without any purification. Titanium dioxide powder is converted into a colloidal dispersion by agitation in water in the presences of acetic acid (mixing ratio of about 10 g per litre). Titanium dioxide is coated on a glass plate by the following method.

An aluminium foil cut into the shape shown in the shaded portion of the Figure (page 64) is placed on a sheet of glass (26 * 12 cm 2 , thickness =0.23 cm). This is laid on a horizontal heated surface (~150°C) and the Ti0 2suspension is sprayed onto the surface of glass until a film - 1 0 um is deposited (thicker films tends to crack and peal during sintering). The plate is then sintered in an oven at 450°C for 45 minutes and allowed to cool slowly. The above procedure results in deposition of a porous film of T i 0 2 firmly affixed to the glass surface.

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Research Highlights

Thin strips of glass (width = 0.5 cm, thickness = 0.25 cm) are pasted (silicone gum was used) onto those portions of the glass plate uncoated with T i 0 2 as shown in the Figure (the gaps at A and B are left to insert the water inlet and the outlet). The upper surface of the glass strips are coated with silicone gum and a sheet of glass, same size as the plate on which T i 0 2 is coated, is pressed into the plate fixed with the strips. Two pieces of glass tubing (outer diameter ~Q.25 cm, thickness ~0.15 cm) are attached to inlet and outlet vents at A and B . With this construction, water introduced into the module through the inlet A is circulated along the path marked with arrows (Figure below). The circulation ensures the exposure of almost all fluid volume to the T i 0 2 surface.

2 c m

Inlet OJcm ( b ) ELEVATION ° u , l e «

Construction (plan) of a reactor module: (a) For spraying Ti02 .shaded portion is covered with aluminium foil After spraying glass strips are pasted onto the shaded portion and the second glass sheet is placed on top of the first one after applying silicon gum on the upper surface of the glass strips, (b) Elevation of the module showing the inlet and the outlet.

Reactor modules can be connected in series or parallel. When the modules are in series, the rate can be increased proportionately while maintaining complete degradation. The limitation in series connection is the viscous resistance of the reactor. Desired flow rates can be obtained with parallel and series connections.

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Physical Sciences

6 9

Conclusions: This device seems to be ideal for purification of contaminated drinking water. Suitably connected modules placed on a roof could be connected to the water supply. The system can be further optimized to meet the practical requirements. Dimensions of the modules constructed here depended on the size of the oven available for sintering the T i 0 2 film. Silicone gum and teflon tubing connections were used to avoid chemical contamination of water from materials used to construct the modules. In principle, the process of coating can be incorporated into the glass sheet manufacturing process and necessity of sealing with silicone gum could also be avoided. Preliminary laboratory experiments suggest that the catalyst will remain active indefinitely in the absence of iron and manganese in water. However, in practical use, deposition of fine mineral particles (that escape a filter) in the porous Ti0 2 f i lm could inactivate the catalyst. Loosening of the film due to uneven expansion during temperature changes could also be a problem. Experiments are under way to examine above issues and devise remedial measures.

Science Education

•nH Development of a suitable teaching method on evironmental •|H pollution for tertiary level education

Grant No: RG/9.VSEA)2 Grantee: DrSA Fernando Institution: Faculty of Science, University of Colombo

The project was aimed at developing a teaching method on environmental pollution for tertiary level education. The present state of Environment education at

undergraduate and postgraduate level at Sri Lankan Universities were reviewed. Various environmental related courses conducted by universities have also been compiled for reference. This survey revealed that the present system required a restructuring and a new integrated approach. As an integrated approach, a teaching method with the concept of 3 A's (Awareness, Attitude and Ability) and 3 R's (Recycle, Reduce and Render) has been designed as an innovative method for structuring laboratory experiments for teach­ing programme.

The learning process with these six major principles has been introduced to students within the classroom or the laboratory. Through this method of education, it is expected to create awareness about environmental and industrial aspects among students. As a result an attitudinal change of students could be achieved. Resource management is also an important aspect, which could be achieved through this education process.

Apart from the above, a modified laboratory arrangement to achieve cleaner and safer laboratory has been demonstrated successfully. A teaching laboratory needs to be ar­ranged to demonstrate cost minimization on chemicals, and other raw materials, replace­ment of toxic materials, reduction of waste and creation of a cleaner laboratory environ­ment for the students. Major steps for a modified arrangement are given in Step 1, Step 2, Step 3 and Step 4 in brief.

Step 1: All the chemicals stored at the student working areas need to be removed. A set of glassware and other necessary tools should be allocated for each work ing station. No reagent bottles should be supplied to students in any experi ments; required chemicals for experiments were provided on the relevant day.

Step 2: Provide safe storage conditions for all the chemicals available within the labo ratory.

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Research Highlights

EDUCATION EDUCATION

FORMAL EDUCATION NONFORMAL EDUCATION

Awareness

Attitude

Ability

Reduce

Recycle

Render

Environmentally literate citizens including science and non science graduates

CONSERVATION OF NATURE AND SUSTAINABLE DEVELOPMENT

OFTHE COUNTRY

Concept of six objects

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Science Education

Step3: Excess glassware should not be stored in the vacant cupboards of students since it would cause the unnecessary breakage of glassware in the laboratory.

Step 4: In order to provide a green environment, flowerpots must be kept at vacant places in the laboratory. This would make the environment cool and pleasant for working.

Further it is suggested to have a wastewater collection tank and a small wastewater treatment plant to treat waste water generated in laboratories to minimize the pollution caused by chemicals.

Leaflets and safety manuals were prepared under the project to be used for dissemination of information on safety aspects, good laboratory practices, safe disposal methods of chemicals etc.

These new teaching methods can be easily linked with laboratory courses in the univer­sity and schools laboratory experiments and directly applied in science learning programs to achieve a sustainable education system suitable for the country.

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Social Sciences

R e c r e a t i o n a l potential o f the Beliholova - I ' a m b a h i n n a a r e a : a s tudy o f the ra t iona l a l locat ion o f g e o g r a p h i c a l r e s o u r c e s for t o u r i s m d e v e l o p m e n t

Grant No: RG/92/SS/13 Grantee: Ms K.V.D. Edirisooriya Institution: Faculty of Arts, University of Sabaragamuwa, Belihuloya

Travelling to engage in recreational activities is part of tourism and is an integral part of the modern lifestyle. Recreation has become a major national concern in

developed countries as a prime source of foreign exchange earnings. Similarly, in less developed countries, pristine natural resources and anthropogenic resources are steadily opening out to the international recreation market.

There is a dearth of research and studies on the recreational potential of Sri Lanka in general and more specifically on the potential inherent in certain regions such as the Belihuloya-Pambahinna area. This study which was undertaken w ith the idea of reducing this paucity to some extent, reveals a considerable amount of interesting and useful information on the potential for the exploitation ot the recreational resources in this picturesque part of the island.

Panoramic view <>/ the area

7 5

Research Highlights

Belihuloya-Pambahinna, situated between 80° 4 3 ' - 80° 4 9 ' along the Eastern longitude and 60° 40 ' - 60° 47' on Northern latitude within the Ratnapura District of the Sabaragamuwa Province has a beautiful terrain and a comfortable climate conducive to many recreational and health recuperative activities. It is located close to the border of the recreational region identified by the Sri Lanka Tourist Board (1992) as the Hill Country.

The area abounds in picturesque mountain peaks, waterfalls and waterways, and beauti­ful natural settings. The current study has identified the potential in the area to be developed for recreational activities such as hiking, camping, mountain trekking, moun­tain climbing, cycling, sightseeing, fishing, rafting, swimming, boating, hiking along wa­ter courses, bird watching, and study of flora and fauna.

The possibility of developing these recreational activities has been explored during the study through direct self assessment of the status of the infra-structure facilities such as transportation, accommodation, trading establishments, industries, communication, medi­cal facilities, water and electricity etc. Representative demographic features were estab­lished through questionnaire surveys. The researchers have visited natural and manmade sites and made their observations while secondary data has been used relating to land use patterns, roadways, trekking routes, hiking camping, sightseeing sites in the area and places of tourist attractions in the vicinity of the study area.

The study provides profiles of the mountain peaks, relating to which these activities could be developed. Hawagala, Paraviyangala, Papulagala, Gomalee, Apalagala, Ellamana and Ettric are the main peaks examined for this purpose in the study.

Water falls such as the Galagama Fall, Surathalee Fall, Brumpton Fall, Apalagala Fall and other attractive water falls have been dealt within the study. A large number of rivers and streams also flow through these hills and valleys. The main rivers found in this area are Kiriketi Oya, Belihuloya, Dandugam Oya, Walawe Ganga and the Welioya. These rivers

and streams have been identified as being suitable for rafting, boating, bathing, fishing etc. Although the Samanala wewa reservoir is suitable for many a water sport its use is restricted due to security reasons.

In addition, there are in this area, locations at which beautiful parks and gardens can be built. It is also famed for certain traditional cultural activities. The climate is extremely conducive to health and outdoor activities.

The area could also be an important transit zone for domestic and foreign tourists who travel to the hill country and the South coast area. This could prove to be an ideal stop­over district or could accommodate short holidays, while it could also be used as a point from which to travel to the more attractive major recreation areas in the vicinity.

7 6

Social Sciences

However, facilities for visitors to the area are available only at the Belihuloya Resthousc. Pearl Inn Rest, River Garden Restaurant and the Guest-house of the Sabaragamuwa Uni­versity.

Mam mountain peak in the urea

While thus indicating the potential for development, the study also highlights the inher­ent drawbacks. Although there is no scarcity of water and electricity, (being located in the vicinity of the Samanalawcwa Hydropower project) the area in general has poor infra structure facilities and the economy is at a low level. Correspondingly, the human re­sources available are of a low level and would not be upto management or even middle management levels.

Therefore, there is a possibility for highly enterprising investors to develop projects for the provision of recreation facilities identified by the study.

* This work has resulted in the award of a Master of Arts Degree to Ms. K. V. D. S. Edirisooriya.

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Research Highlights

HMH The geomorphology of the wetlands of the South west coast Hfl of Sri Lanka and their ecological and socio-economic problems

Grant No: RG/98/SS/03 Grantee: Mr. S.LJ. Fernando Institution: Faculty of Arts, University of Ruhuna,Matara

A lthough there have been several geomorphological studies on the wetlands of Sri Lanka there are only a few such studies related to the Southern coastal belt. The

present study was undertaken considering its current relevance and significance, with the objectives of mapping the geomorphological spread of the wetlands in the South­western coastal zone of Sri Lanka; studying the origins of its geomorphology, its process of evolution, the present geomorphology; estimating the potential value and uses of the wetlands and examining its plant community. In this way, the study is not restricted to the geomorphology of the area, but also includes other environmental factors related to wetlands.

Methodology: The map titled the geomorphological map of the Southwestern coastal area of Sri Lanka was constructed using aerial photographs and one inch maps and the TOPCON mirror stereoscope. To test the accuracy of the map constructed, the geomorphological features identified were examined in the field using a 4 0 percent sample and errors minimised through pantographic projection. Samples of sediments were collected at four locations and analysed at the University of Colombo. Laboratory tests were also used in determin­ing clay content. The transect method and quadrate method were used in measuring the plant community. Chi Square tests were used to examine the relations between plant distribution and micro variation and the value of potential resources were measured by using data collected through questionnaires and interviews.

Results: The area investigated is the coastal belt between 80,35'. 10 and 80,03'. 12 longitudinal and latitudinal area. A representative sample comprising the wetland areas of Ambalangoda, Rathgama, Hikkaduwa and Koggala have been studied. The results indicate that the evolution o f the wetlands has a long history and that it is closely bound to the geomorphological processes of the area. Two main facets of the geomorphlogical

78

Social Sciences

evolution i.e. shrinkage of wetlands and expansion of wetlands, were observed. The three processes that contribute to this activity have been identified as sedimentation, segmen­tation and plant encroachment. By examining the correlated operation of these processes, it has become possible to understand the likely trend in the future evolution of the wetlands.

The outstanding geomorphological process found in the coastal wetland area examined was sedimentation. Therefore the prominent feature observed was the contraction of the wetlands. In the Southwestern coastal wetlands the area of contraction exceeds the area of expansion. This situation has been intensified by human activities.

Conclusions and Recommendations: To minimize the process of contraction of the wetlands, the following course of action is recommended * Exercise control over the human influences which obstruct the natural process of the

wetlands - under this measure, the excavations in the wetlands should either be prevented or controlled.

* Preserve the plant community in the area instead of removing it haphazardly - this could be facilitated by taking steps to conserve the geo-environment around the wetlands - abstaining from destroying the plants and trees in the area, which in turn would prevent sedimentation, and soil erosion.

* Prevent the disposal of waste into the wetland areas and implement an effective programme to remove from the wetlands, waste material generated by the coconut fibre industry - this could be achieved by heaping the fibre dust, coconut husks etc resulting from the manufacture of fibre products, outside the limits of the wetlands and arranging for it to be disposed as a fertilizer to other areas.

* Introduce modern technology required for the development of the fishing industry -under this programme, the use of modern techniques could be introduced in place of the brush-park fishery now practised in the wetlands.

Out of the resources available in the coastal wetlands of Sri Lanka, fishery resources and resources for coir production could be utilized more efficiently. This could be facilitated by removing the present obstacles to the development of these two industries. The use of modern technology in place of the elementary systems, and improving markets, will rein­force these industries.

79

Research Highlights

Out of the man made wetland areas, the Akurala wetlands, which extends over an area of around 6 0 0 acres is important. The use of this area, in which the factors required for the production of ftsh are found well integrated, to develop fisheries, will help to enhance economic productivity. The export of ornamental fish could be developed in the coastal wetlands. This would yield valuable foreign exchange.

8 0

Social Sciences

A study on the Agriculture curriculum implemented in 1996, H I in year 10 & 11 in Sri Lankan schools and its relevance to the Hjjfl professional agriculture courses provided by institutions

Grant No: RG/98/SS/04 Grantee: Mrs. Priyanthi Samaraweera Institution: Faculty of Education, University of Colombo

Agriculture is an important subject in the educational curriculum of a country with a traditionally agricultural economy. The objective of the revised G.C.E. (G7L) Agricul­

ture syllabus introduced to Sri Lankan Schools in 1996 was to give a practical and profes­sional orientation to the subject. It was considered relevant to examine the extent to which this syllabus helped to prepare students for the professional Diploma course of­fered by the Schools of Agriculture and the examination conducted by the Department of Agriculture. During this study, the G.C.E. (O/L) Agriculture syllabus has been analysed in detail, and the attitude of students to the profession and professionals in agriculture have been examined while at the same time problems faced by teachers of agriculture too have been identified.

Methodology: Curriculum development formats in general and the agriculture curricula in other coun­tries were examined to acquire the basic knowledge required for the study. In this study, the sample examined comprised 4 0 0 students and 2 0 teachers from 20 schools randomly selected from three Education Districts, 5 0 students and 15 teachers from 4 Schools of Agriculture, and 15 subject specialists. Data collection was through curriculum material, questionnaires and interviews. The curriculum has been analysed using the data col­lected. The data was interpreted through tables , percentages and graphs and through correlation.

Results: The study revealed that the syllabus provides a knowledge base that adequately pre­pares a student to follow a professional course in Agriculture. However, it was also found that practical activities under the syllabus are not being appropriately conducted; the teachers face various difficulties in implementing the teaching programme; the evaluation of the practical aspects is not satisfactory from the perspective of the students; and that it does not generate a positive attitude towards agriculture as a subject, despite the fact that in comparison to the earlier syllabus, the syllabus introduced in 1996 was more successful.

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Research Highlights

Conclusions and Recommendations: Technical subjects should be learnt only by students who have a liking for the subject concerned. It is recommended that the selection of Agriculture as a subject should also be based solely on the student's liking for the subject.

Some students who had a liking -for Agriculture have had to make a choice between agriculture and other technical subjects as only one technical subject could be selected. It is recommended that students should be allowed to offer more than one technical subject and also that agriculture be made a core subject instead of an optional one. ,

It is also recommended that the time allocated in the school timetable for Agriculture be given in double periods considering the practical nature of the subject. »

Although the content of the syllabus was found to be adequate, a heavy orientation towards traditional agriculture and a lack of modern elements was observed. By overcom­ing this deficiency, agriculture could be turned into a more attractive subject for students.

Teachers with diverse qualifications were engaged in teaching Agriculture. There was a serious need to update their knowledge by constantly providing them with training in agriculture, which is a continuously developing technological area. There is a need to establish a training college to train teachers of Agriculture. A change in practical evalua­tion has been suggested.

Since it is difficult to provide the required resources to all schools it has been proposed that schools with adequate facilities and resources be turned into Resource Centres. Going beyond the stated objectives of the study some suggestions relating to the School of Agriculture curriculum have also been made.

* Mrs. Priyanthi Samaraweera has been awarded an M. Phil. Degree in Education based on this study, by the University of Colombo.

3

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Buffalo Research Programme

Buffalo R e s e a r c h a n d Deve lopment: In format ion Dissemination P r o g r a m m e

Grant No.: Ill-/Phase III Grantees: Prof. II. Abeygunawardena, Dr. D.II.A. Subasinghe.

Dr. J.A. tie S. Siriwardene and Dr.N II. Ilorudagoda Institution: Faculty of Veterinary Medicine and Animal Scient e. I niversit) oj Peradeniya

L ivestock (cattle and buffalo) played a vital role in the agrarian economy of Sri Lanka from ancient times. The buffalo was used particularly in land preparation and post-

harvest processing (threshing) of paddy, while the milk was consumed usually in the form of curd and other by-products. Traditionally buffaloes were maintained as large herds under a free grazing system of management, popularly known as "extensive system". They grazed mostly on communal pastures/scrub lands, post-harvest paddy fields etc. The quality of stock, their management and productivity were generally low. Lven recent studies have shown the importance of the buffalo as a source ol draught power in nee production in Sri Lanka, where a third of the farm power is met through animal diaugM.

Research Highlights

With the rapid expansion in the human population of Sri Lanka, vast extents of state lands, which were mostly traditional grazing lands, were brought under crop production and human settlement schemes. This posed a challenge to the sustainability of the exten­sive system of livestock farming. Therefore, there was an urgent need for livestock farmers to deviate from the traditional methods of management and adopt new systems of farming in keeping with the limitations in land and fodder availability. The requirement was to develop a low cost smallholder model for intensive dairy / buffalo production, with improved nutrition and management with the optimal use of farm resources and idle farming labour. Despite the great potential of the buffaloes as a dairy /draught animal that could perform relatively well under harsh environment and poor quality forage ironically, it has been neglected as a subject of active research, until the situation changed about two decades back when international donor agencies came forward with financial assist­ance tor research and development on this subject, having recognized the importance of the water buffalo in the rural agrarian economy of Sri Lanka. Some of the international agencies that supported were the International Atomic Energy Authority (IAEA), Food and Agriculture Organization (FAO), and the Swedish Agency for Research Cooperation (SAREC). The latter provided substantial technical and financial assistance for Sri Lankan research and development on the water buffalo for over one and half decades.

The Buffalo Research Programme The SAREC funded programme was coordinated and administered by the National Sci­ence Foundation (NSF). Funding came in three phases. The first two phases were focussed on research into fundamental aspects of buffalo breeding and reproduction, physiology and nutrition, production and management, diseases, socio-economics which included field surveys on productivity and management. Livestock scientists of the University of Peradeniya, University of Ruhuna and those of Vterinary Research institute (VRI) partici­pated actively in this research programme.

The Buffalo Information Dissemination The third phase of the programme commenced in 1994 with the objective of taking the knowledge gained through research (during the early phases) and transfer those new technologies to the end-users (rural farmers). Scientists of the University of Peradeniya carried out this programme in collaboration with other state and private sector organiza­tions involved in livestock production.

84

Buffalo Research Programme

Approach to information dissemination The university scientists developed a new approach to technology generation and trans­fer by working with farmers in the process of technology development, adaptive research and information dissemination. This model includes the following steps.

a) Selection of the target group of farmers. b) Diagnosis of farming system, family constraints etc. c) On-station and on-farm trials for appropriate technology generation (TG) with

feedback loops for continuous refinement. d) Lateral dissemination of farmer approved technologies (FAT) to a wider group of

beneficiaries.

The working model on buffalo management was the smallholder intensively managed buffalo unit (SIMBU) model constructed with low cost material but with appropriate built-in features to ensure the welfare of the animals and hygienic milk production. Activities of the farm were managed by family labour. The management package included preventive healthcare, feeding and reproductive management. The feeding system was based on the utilization of natural grass, tree legumes and crop-residues supplemented with the use of urea-molasses-multi nutrient mixture (UMMM) and other supplements. In this programme, the research scientists working with the farmers demonstrated the feasibility, cost effec­tiveness and benefits of the intensive system, to overcome problems associated with land limitation, poverty and other constraints experienced in livestock (buffalo) produc­tion and farming.

Following activities were successfully completed under the above programme in order to achieve the stated objectives.

a) Field programme to demonstrate the feasibility and profitability of the intesive man agement system through technology transfer via the Demonstration Farms (DF) in three regional locations of the country, namely the Coconut Triangle and Mahawali Systems H and C. Twenty eight SIMBU models were established with the farmers in the two Mahawali systems while 14 such DFs were established in the Coconut Trian­gle. Those models have eventually served as training and demonstration farms for other farmers in the region.

b) Popularization of urea-molasses-multi nutrient (UMMM or UMMB) feed formulations for catalytic feed supplements for dairy cattle and buffalos. One of the major feeding components in the SIMBU model was the use of UMMM/ UMMB as a catalytic feed supplement along with crop residues (e.g. rice straw),to overcome seasonal feed shortages and nutritional deficiencies experienced often

85

Research Highlights

by farmers. To implement this activity, three U M M B feed manufacturing plants were established in 3 of the State farms in the 3 locations mentioned above, namely MASL farms at Niraviya and Girandurukotte and NLDB farm at Horakele, Chilaw. Farmer cooperatives and private sector organizations were also encouraged to venture on the production of U M M B to meet the increase in demand for the product in the future.

c ) Continuing Education Programme: This was undertaken to train veterinarians, extension workers and farmers. A series of such programmes were conducted in selected locations at different times. They were implemented in collaboration with the Institute of Continuing Education of the Department of Animal Production and Health (ICE/APH), Provincial Directors of APH and Milk Producer Cooperative Societies in the target areas. The objective of this effort was to update the knowedge and skills of veterinarians, extension workers, management staff in the farms and the farmers in appropriate technologies.

d) Buffalo Information Centre: A special information unit was established in the library of the Department of Animal Production and Health located at the ICE/APH, Peradeniya. Several books, journals, essential items of furniture and a computer were purchased through project funds. This Centre will serve as a depository and a resource base for information on research and development on the water buffalo for students and researchers. It is already being used by the scientific community.

e) Scientific publications: A series of information leaflets and books on relevant technical subjects published by this project are listed below. 1. Report on Planning Workshop - Workshop on Assessment of Training Needs of

Farmers and Extension workers on Buffalo Development in the Coconut Triangle, 5 August 1995, Kuliyapitiya, Sri Lanka.

2. Programme and Abstracts of papers - SAREC/NARESA Regional Symposium on the Role of the Buffalo in Rural Development in Asia 15 December 1995, Peradeniya, Sri Lanka..

3. The Role of the Buffalo in Rural Development in Asia. (1995) Ed. B.M. A.O. Perera, J.A. de S. Siriwardene, N.U. Horadogoda and M.N.M. Ibrahim. Proceedings of the SAREC/NARESA Regional Symposium. NARESA Press, Colombo.

4. Series of ten Information Leaflets on the following topics were published in all 3 languages (English, Sinhala and Tamil) for distribution among extension workers

8 6

Buffalo Research Programme

and farmers to disseminate technical information in the following subjects. a) Fibrous Feeds and their Utilisation (1998) Ed.

A.N.F.Perera, H. Abeygunawardena, J . A. de S. Siriwardene and D.H. A. Subasinghe

b) Urea Molasses Mineral Multi nutrient (UMMM) feed supplement (1998) Ed. B.M.A.O. Perera, H. Abeygunawardena and J.A. de S. Siriwardene

c) Body condition Scoring System for Assessing the nutritional status of cattle and buffalo (1998) Ed. BM.A.O. Perera, H. Abeygunawardena and J.A. de S. Siriwardene

d) Reproduction in the Buffaloes and Cattle (1998) Ed. H. Abeygunawardena, B.M.A.O. Perera and J.A. de S. Siriwardene.

e) Breeding of Bufaloes and Cattle (1998) Ed. H. Abeygunawardena, J.A de S. Siriwardene and B.M.A.O. Pereia.

f) Health and Diseases of Buffaloes and Cattle (1998) Ed. M.C.L de Alwis, H. Abeygunawardena, J.A. de S. Siriwardene and D.H.A.Subasinghe.

g) Use of Tree Fodder for Ruminant Feeding (1998) Ed. A.N.F.Perera, E.R.K.Perera, H. Abeygunawardena, D.H.A. Subasinghe andG.G.C.Premalal

h) Management of Bufaloes and Dairy Cattle (1998) Ed. D.H.A. Subasinghe, H. Abeygunawardena, A.N.F. Perera and E.R.K. Perera

i) Feed Formulation for Cattle and Buffaloes (1998) Ed. M.N.M. Ibrahim, H. Abeygunawardena and D.H.A. Subasinghe.

j) Crop-livestock integration for maximising smallholder farm income (1998) Ed. D.H.A. Subasinghe, H. Abeygunawardena and G.G.C. Premalal.

5. Cattle and Buffalo Farming - A training manual for Extension Workers (1998) Ed. H. Abeygunawardena, J.A. de S. Siriwardene and D.H.A. Subasinghe

6. Water Buffalo - Improved utilization through new technologies (1998) Ed. D.H.A.Subasinghe, N.U.Horadagoda, H.Abeygunawardena and J.A.de S. Siriwardene. NARESA Press, Colombo, Sri Lanka.

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Research Highlights

7. Water Buffalo Research in Sri Lanka - Compendium of Research Information (1999) Ed. J . A. de S. Siriwardene, NU Horadagoda, H. Abeygunawardena and D.H. A. Subasinghe.

8. Cattle and Bufalo Fanning - Handbook for Veterianarians (1999) Ed. H. Abeygunawardena, and J.A. de S. Siriwardene

9. Water Buffalo in Asia - Volumes I, II, III and IV (I) Nutrition of the Buffalo. (Under preparation) Ed.

K.K. Pathirana, M.N.M. Ibrahim and J.A. de S. Siriwardene (II) Buffalo Production and Management (ID) Genetics and Reproduction (TV) Diseases of the Buffalo. Ed.

M.C.L. de Alwis, D.H.A.Subasinghe and N.U.Horadagoda Volumes II and III will also be printed during the course of this year.

10. Changing Role of the Buffalo in the New Millennium in Asia (2000) Proceedings of the 3 r d Asian Buffalo Congress, March 2000 , Kandy Sri Lanka. (2000) Ed. J . A. de S. Siriwardene, D.H. A.Subasinghe, N.U-Horadagoda and H. Abeygunawardena.

88