MASS LIVESTOCK DEATHS FROM NITRATE POISONING IN EL-HADI VILLAGE, MARSABIT COUNTY IN KENYA

Gitao1 Chege Gitao

1Department of Veterinary Pathology, Microbiology and Parasitology, University of Nairobi, P.O. Box 29053 code 00625, Uthiru. Kenya

Abstract

Nitrate poisoning of animals in Africa is rare and hardly documented, a situation which is even more pronounced for camels which are reared in the Semi-arid and arid areas. A previous incidence of Nitrate poisoning was reported in Kargi, Marsabit county in 2000 when 7000 livestock heads were reported dead although there was no categorization of the livestock species involved. In the recent outbreak, there was a reported mass death of 115 camels, 8 cattle and several sheep and goats in El hadi situated in North Horr Sub-county, Marsabit County between 6-7 January, 2019. Samples of water and dead camels were submitted for analysis. A visit was undertaken on 24 Jan 2017 by a Kenya Camel Association team to determine the detailed community perspective and well environment. Community members confirmed consistent occurrence of sporadic deaths of small stock for the last fifteen years after drinking water from some of the wells. This was especially true during the dry season when such water would be foamy, salty to taste and would flocculate milk when making tea. Use of the water by humans to bath would result in skin cracks and dryness. Animals drinking such water would be weak, exhibit trembling, dehydration and pregnant animals would abort while some would recover after a week. A recent influx of Gabbra from Forole, and inability to seek for water along the Ethiopian border had overtaxed the El Hadi wells. The current mass deaths of livestock is the first time that camels are involved. A herd of about 140 camels from Yaa Gaara, a community that recently came from Forole was brought for watering and waited a whole day in the scorching sun as they waited their turn while the pump broke down and were eventually taken to the Tula well which had been abandoned for sometime. Two hours after drinking, these camels died along the way as they went back to the manyatta and 20 carcasses could be identified over a 5km distance. According to the elders, these camels on slaughter remained red and had peeling of rumen pili. The lungs of these camel as well as the heart apex were black and there was no frank blood in the carcass. There was no bloating or decomposition even after 5 days. Petechial haemorrage in abomasal mucosa and distended urinary bladder were noted by veterinarians. The reports from Kephis and Intertek indicated a level of230, and 780 mg/L of Nitrates which is way above the normal 10 mg/L. It was concluded that the high level of nitrates contributed to the deaths of the livestock. Ruminants are especially vulnerable because the ruminal flora reduces nitrate to nitrites and then to ammonia but this process is overwhelmed when excess nitrates are consumed leading to accumulation of excess nitrite which is very toxic. While local animals may have had cumulative exposure to nitrates, the camels from Yaa Gaara were relatively new and thus very susceptible. Acute intoxication is manifested primarily by methemoglobin formation (nitrite ion in contact with RBCs oxidizes ferrous iron in Hgb to the ferric state, forming stable methemoglobin incapable of oxygen transport) and resultant anoxia which in post mortem was identified as myocardial necrosis. This explains the black lungs, lack of blood and sudden death of camels and cattle. In the short term, it is recommended that pastoralists are trained on how to ensure fecal wastes does not accumulate at the well head and the use of nitrate filters when water is suspicious. In the long term, pastoralists are trained on sustainable use of animal manure and enough well designed wells are constructed to cope with surging human and animal population. Despite the more than 1.8 million camels reared in North Eastern region, the only two cases of nitrate poisoning have been reported in Kargi and Elhadi

Introduction

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Nitrate poisoning is rare in camelids but has been reported to have killed four Alpacas and induced abortion of a full‐term fetus after access to oaten hay (Avena sativa) containing 3.2% KNO3 equivalent in dry matter. Necropsy findings were cyanosis, dark‐coloured blood, and pulmonary congestion and oedema.(Gordon et al, 2009)

In January in the year 2000, sudden deaths of an estimated 7,000 heads of livestock occurred

following drinking of water from a Government managed borehole in Kargi settlement, Marsabit

District. Informal interviews from a cross-section of community leaders and affected pastoralists were conducted, samples of water from the borehole was collected for toxicological analyses, clinical examinations of surviving animals and autopsies of dead ones were carried out. Key clinical observations included acute muscular weakness, ataxia, brown mucous membranes and

abortions. Major autopsy observations were methamoglobinaemia, gastrointestinal corrosion,

cooked appearance of internal organ, swelling, and rapid decomposition of carcasses. Chemical

analyses showed that both nitrates were five to (450 & 950 mg/1) ten times higher than WHO recommended levels in drinking water, while the levels of other normally toxic chemicals like arsenic, selenium, lead and fluoride were within acceptable ranges. The clinical picture, autopsy and chemical analyses led to a high probability of nitrate poisoning (Shivairo et al 2014 )

Nitrate poisoning in camels not documented especially in pastoral areas –gap

In the current case, it was reported that a herd of over 115 camels, goats, cattle and a few donkeys had died a few hours after drinking from a well at El Hadi village, in Marsabit. It was important to investigate the camel deaths and understand the dynamics in this extensive pastoral production system in Africa

1. Materials and methods

Marsabit County is one of the forty seven counties of the Republic of Kenya created under the 2010 Constitution.   The County covers an area of 70,961.2 Km2 and occupies the extreme part of northern part of Kenya. Marsabit county is divided into seven sub-counties: Marsabit Central, Marsabit South (Laisamis), Marsabit North (Chalbi), Loiyangalani, North Horr, Moyale and Sololo. The three sub-counties of Marsabit North, Loiyangalani and North Horr form 72% of the total county area, but lie in Chalbi desert, where large rocky and unutilised pieces of land are found.  It is in El hadi a location within Durkana ward of North Horr Sub-county that a report of mass deaths of camels was reported on 8th of Jan 2019 (Fig I). The residents are entirely pastoralists and their population is estimated at 1151 households. The areas are semi-desert, receiving annual rainfall of less than 200mm with frequent drought occurrences and mean monthly temperatures of 27oc -29oc. Rainfall follows a bimodal pattern where long rains are received in March-April and short rains in October-December. Vegetation in the areas is mainly dwarf shrubs interspersed with trees or annual grasses and used for communal grazing. Soils are either volcanic or metamorphic in nature. The Gabra community living here is largely pastoralists and keep livestock species comprising of camels, goats, sheep and cattle. The livestock domestic species reared in this region include camels (23000), Sheep& goats (92,0000), cattle(10,000) and donkeysA visit by the team from Nairobi was conducted from 24/1/2019 where a meeting with Dr Wario and his staff was held and a field visit conducted. During the field visit, a focus group discussion was held with 50 pastoralist members. The team visited the wells and made observations. The proper case history was obtained from discussions with Dr Wario and his official report at the county livestock office. Tissue samples from a dead camel (liver, lung, intestines, Kidney) were submitted to the Dept Veterinary Medicine. Other samples submitted included intestinal contents, serum, whole blood samples and water samples from five wells: Tulla, Golo, Malacha. The tissue samples were processed for histopathology and stained with haematoxylin and eosin; Deliberate mixing done for stagnate water.  Samples were collected in 1-litre plastic containers. The containers were rinsed twice with water to be sampled prior to sampling. Sample containers were filled to the brim leaving little or no air space and seal tightly with the cap. Sample containers were then labelled with name of water source, location, type of water source, season of sampling and date. Labelled sample containers were taken to laboratory for analysis The water samples were submitted to KEPHIS, Intertek, vet labs and Government chemists. Spectrometric techniques were used for the determination of nitrate in water.

Fig 1. ELHadi location in Marsabit county

2. RESULTSFocus group discussion

Sporadic Cases: According to the elders (Fig 7), sporadic cases of animals suffering after drinking water from these wells have been reported since 15 years ago initially affecting goats before affecting sheep and, cattle and donkeys. The sporadic incidences would normally happen in extremely hot periods when water levels in the well goes down, before the well re-charges. During these times, the water would be foamy, and taste “salty” or“ bitter. When human beings use the water for bathing or drinking, they get would ‘cracks’ on their dry skin. They have used the water for tea, after removing foam but milk flocculates. Pregnant animals abort after showing weakness and some animals recover. The current mass deaths was the first time that camels were affected. It is important to note that the elders also felt that the current wells are overwhelmed by huge human and livestock population influx. The current wells were have been there for several generations and there have been no new wells. About four wells in this region have a history of livestock death after taking water from them. These are: Tula (Fig 2,3), Falama, Gollo Guyo Boku’s, and Barile Sora’s. which are all situated in one line along the eastern bank of the river. There has been no complain from the wells situated along the Western bank of the river.

Deaths

The Yaa Gara is a cultural village belonging to Gara Phratery of the five Phrateries of Gabbra Community. The village is composed of about 174 households. The village is situated 27 KM East of El-hadi Trading Centre along El-Hadi –Forole Road. The villagers are pure nomads and recently relocated from Forole to a better pasture on the Northern Slopes of Hurri Hills where they can also easily access source of water at El-Hadi.

In 2019, there has been a huge water constraint in the entire location after one of the borehole that used to support the livestock reportedly broke down on 26th December 2018.

On 7th January 2019, A herd of about 140 lactating camels from Yaa Gara were taken to the Marime Borehole which is solar powered at El hadi because the other borehole was not yet fixed. Unfortunately, the Marime borehole was reportedly overwhelmed by huge number of animals that turned up for watering. The camels from Yaa Gara waited for their turn at the site the whole day in the scorching sun until it was dark and by then, the solar powered borehole lost energy and could not provide water for the waiting herd. This was the first time that this herd was taking water here after the surface water from the short rains dried up a week earlier. The herd comprised of the dams who were barely a week old since calving. They could not stay another day and night without feeding their calves. Out of desperation, the herders took their animals to the Tulla well

On 6th of Jan 2019, from among several herds that were watered at Tula well, 6 cattle (4:2, Female: Male) died from one herd. The particular herd was the first one watered at the well that morning.

On 7th of Jan, 2019, from among several herds that were watered at this well, 2 cattle (2:0, Female: male) and 115 camels died after taking water. 95 of these camels were lactating dams from Yaa Gara village while 20 of the other camels were a mixed gender/age belonging to Abudho Huqa Banchale’s village. These camels dropped dead 3-4 hours after drinking the water all along the road on their way home (Fig 4)

On 10th of Jan, 2019 the response team received report of sheep and goats having died. The number for that particular day was estimated at 94 sheep and goats.

The camels from Yaa Gara started to die after walking 20 km back towards their manyatta and carcasses were strewn along the route. Some camels jumped up and down before dying, while others jumped and recovered. However, those that lay down never recovered. Some camels which urinated survived but only one male camel survived.

According to the pastoralists, when the camels were slaughtered and on cooking, all remained red after boiling for many hours. There was ‘Peeling of’ ruminal pili in dead animals; Lungs were completely black, the apex of heart was also black ;After death, the carcasses were ‘not bloated’ even after 5 nights; After slaughter, there was no blood at all. The veterinarians talked of Staggering, hind limb weakness, Urine retention, Dehydration Petechial haemorrage in abomasal mucosa and distension of the urinary bladder

Lab Reports: Reports from Kephis (Appendix 5) indicate there were extremely high levels of Nitrates in the Tula and Gollos well(130,230mg/L) and Intertekhad levels reading 873mg/L from Tula. Normal levels are in the range of 10mg/L. The water from all wells had no pesticides from the Kephis reports. Strontium levels were also very high (Table 1, Fig 1). Reports from Vet Labs were difficult to interpret since there was no quantification of the identified compounds (Appendix 3). Reports from University of Nairobi indicated there was Proteus and E coli spp in the foecal sample which form part of normal microbial flora. The pathology reports indicated mycocardial necrosis and hepatopathy. These are consistent with nitrate poisoning. The government chemist is yet to present results on water, intestinal contents and blood

Table 1 Lab reports from KEPHIS(Kenya Plant health and Inspectorate service) using Photo multi-parameter and ICP/MS

KEPHIS

Intertek

Chemical

Normal

Tula

Gollos

 

 

 

 

 

 

conductivity(µmhos/cm)

 

2283

5130

 

Chlorides (mg/L)

<250

0.31

1.11

 

Phosphates(mg/L)

 

0.8

1.4

 

Nitrates(mg/L)

10

133

230

873

Sulphates(mg/L)

<250

46.23

124.5

 

Cadmium (Cd) µg/L

 

0.32

0.32

 

Mercury (Hg)µg/L

2

0.51

0.74

 

Selenium(Se)µg/L

 

3.15

7.93

 

Rubidium(Rb)µg/L

 

10.24

9.21

 

Strontium( Se)µg/L

10

1722.76

3360.81

 

Uranium(U)µg/L

30

2.65

6.99

 

Magnesium(Mg) µg/L

100

62.8

133.65

 

Calcium(Ca)µg/L

 

7.73

13.45

 

Vanadium(V)µg/L

140

79.41

66.68

 

Thallium(TI) µg/L

0.0005 mg/L

0.11

0.11

 

Arsenic(As)µg/L

 

1.26

1.39

 

Fig 2. High levels of nitrates and Strontium as depicted from Intertek and Kephis

Fig 3 Tula well-note rocky surfaceFig 4 Note concentric rings of salt deposits

. Fig 5 Camels drop dead at intervals 3-4 hrs later

z

Fig 6 Focus Group Discussion

Discussion

Nitrate poisoning is rarely reported in pastoral livestock production systems and even more rarely in camels from Africa. A report in the year 2000 indicated that 7000 herds died from nitrate poisoning although no details were given on which livestock were involved. Although nitrate poisoning is rare in camelids, it has been reported in Alpacas in Australia( )The current case of acute nitrate poisoning occurred when animals started dying three hours after drinking water and continued until about 115 camels died in about two days. The animals dropped dead along the road home at varying intervals between a few metres and 20 or more metres (Fig 5). These high nitrate levels were confirmed in the water samples obtained (Table 1, Fig 1). Acute poisoning usually occurs within 1–4 h after ingestion of high nitrate feed or water. Animals that do not have usual exposure to low levels of nitrate are frequently more susceptible to nitrate poisoning (Burrows et al. 1987). In this case, the camels were from Yaa Gara and had waited for a whole day for an opportunity to water. These camels from Yaa Gara migrated recently from Forore and were therefore not exposed to low levels of nitrates. Many species are susceptible to nitrate and nitrite poisoning, but cattle are affected most frequently. Ruminants are especially vulnerable because the ruminal flora reduces nitrate to ammonia, with nitrite (~10 times more toxic than nitrate) as an intermediate product. Nitrate reduction (and nitrite production) occurs in the cecum of equids but not to the same extent as in ruminants. Nitrite toxicity occurs when the intake of nitrates and conversion to nitrite is faster than the conversion to ammonia in the natural microbial reduction process. A few donkeys were also reported to have succumbed to the poisoning. Methemoglobinemia may result when hemoglobin is exposed to oxidizing agents such as nitrate or nitrite; these compounds cause the iron in the hemoglobin to be oxidized, producing MtHb and a reduction in oxygen-carrying capacity (Gupta et al. 2000). The MtHb in some affected animals ranged from 28 to 50%. Kemp, Guerink, and Malestein (1977) reported that when over 30 to 40% of hemoglobin is converted to MtHb clinical signs of poisoning become apparent, with death occuring as MtHb levels approach 80%. Acute intoxication nitrite leads to anoxia and this is consistent with myocardial necrosis(Appendix 2). The nitrite ion may also alter metabolic protein enzymes. Ingested nitrates may directly irritate the GI mucosa as pastoralists noted. Blood that contains methemoglobin usually has a chocolate-brown color as noted by pastoralists who said the lungs were black or chocolate brown. In the history of the well, sporadic cases of poisoning with abortion had been observed especially when water levels were low as nitrates were concentrated and thus local animals were exposed. The area has an environment strewn with lave rocks (Fig 4). Abortion may occur due to methemoglobinemia in the dam, resulting in fetal death from hypoxia or its interference with other essential iron containing proteins. This is in agreement with abortions as cited by pastoralists. It is known that in animals with MtHb, 40–50% recovery can occur spontaneously through the activity of a red blood cell, NADPH-dependent reductase which slowly reduces MtHb to Hb (Osweiler et al. 1987). This explains why the sporadic cases described by pastoralists frequently recovered and were somehow ‘resistant’ to future intoxications

One of the clear observations is that all the wells were constructed more than twenty years ago and no news wells have been constructed recently although there has been an influx of pastoralists and their animals in search of water and pasture as typified by the Yaa Gaara community

The water used by livestock and humans in ASALs generally has high mineral content (especially nitrates and copper) and bacteria such as Salmonella spp. and Escherichia coli which are evidence of faecal contamination [18, 20, 21, 22]. For those who treat the water, the main water treatment methods included boiling, using chlorine-based chemicals (such as pur and water guard), traditional herbs and water filters promoted by NGOs [2]. Nitrates occur naturally in plants, for which it is a key nutrient. Nitrate and nitrite are also formed endogenously in mammals, including humans. Nitrate is secreted in saliva and then converted to nitrite by oral microflora. Nitrate can reach both surface water and groundwater as a consequence of agricultural activity (including excess application of inorganic nitrogenous fertilizers and manures), from wastewater treatment and from oxidation of nitrogenous waste products in human and animal excreta, including septic tanks. Nitrite can also be formed chemically in distribution pipes by Nitrosomonas bacteria during stagnation of nitrate-containing and oxygen-poor drinking-water

Nitrate -NO3 ) comes into water supplies through the nitrogen cycle rather than via dissolved minerals. It is one of the major ions in natural waters. Most nitrate that occurs in drinking water is the result of contamination of ground water supplies by septic systems, feed lots, and agricultural fertilizers. Nitrate is reduced to nitrite in the body. The source of Nitrate poisoning is yet to be determined but it is highly suspected that holding camels at the well head enclosure meant there was an accumulation of feacal deposits and this may have contributed to high nitrate concentration especially during the dry season. It is noted that the wells have rocky background (Fig 2,3) which is impervious and thus allowing concentration of minerals which can be seen as concentric rings along the edges of the well. There is also very little vegetation to utilize the nitrates as the area is at the edges of the Chalbi desert (Fig 6). The area is completely arid and there is no agriculture taking place within 200-300 km radius hence no danger of fertilizer or pesticides as confirmed by Kephis(Appendix 6.) Under aerobic conditions, nitrate can percolate in relatively large quantities into the aquifer when there is no growing plant material to take up the nitrate and when the net movement of soil water is downward to the aquifer. Degradation or denitrification occurs only to a small extent in the soil and in the rocks forming the aquifer. In this case, there was no growth of vegetation and the movement of water is downward

Cf KARGI

Treatment of animals

Treatment of affected animals are normally treated by the intravenous administration of 20 mg of 1% methylene blue per kg body weight (Blood and Radostits 1989). All treated animals normally recover promptly although some severely affected animals with severe clinical signs may requires a repeat dose after 2–3 h. Orphan camel calves: The orphan camels seemed to have succeeded through a combination of surrogate mothers and milk replacement

Implications for humans

Most humans over one year of age have the ability to rapidly convert methemoglobin back to oxyhemoglobin; hence, the total amount of methemoglobin within red blood cells remains low in spite of relatively high levels of nitrate/nitrite uptake. However in infants under six months of age, the enzyme systems for reducing methemoglobin to oxyhemoglobin are incompletely developed and methemoglobinemia can occur. This also may happen in older individuals who have genetically impaired enzyme systems for metabolizing methemoglobin.

Recommendations

The most appropriate means of controlling high nitrate concentrations, particularly in groundwater, is the prevention of contamination. Boiling water does not help because it actually concentrates the nitrate. Charcoal filters, water softeners, or use of chlorine do nothing to remove nitrate from water

Nitrate in water is undetectable without testing because it is colorless, odorless, and tasteless. Activities near the well can potentially contaminate the water supply. In this case, livestock foecal contamination of the water is highly suspected. Steps to be taken include: 

· The wells near potential point sources of contamination, should be tested at least once a year to monitor changes in nitrate concentration.

· Capacity building- There should be regular training on how to avoid nitrate poisoning by pastoralists especially in high risk areas. This could include awareness creation on signs of poisoning, actions to be taken, types of animals and ages affected and effects on the livestock. Ready to use Methylene Blue concentrations could be provided to the local animal health workers in case of emergency

Long term strategies

· There is need to develop a strategy for sustainable use of animal waste not just in El hadi but in the county generally. Some of the proposals could include development of Small and medium enterprises for production and sale of biological fertilizers, and biogas production for cooking or energy source.

· There is need to develop more wells and design them in a way to avoid nitrate poisoning. This would entail planning on how fecal waste will not drain into the wells. Considering the increase in human and livestock population, the County Government and other donors could establish more wells along densely populated routes

Aknowledgement: The author wishes to express gratitude to all who contributed in various ways to data collection laboratory analyses at the University of Nairobi, the Community Leaders, the

.RPLP-logistics, Dr Toroitich, Kenya Camel Association; Dr Wario, County

References

Blood, D., and O. Radostits. 1989. Veterinary medicine. 8th ed. London: Baillaire Tindall.

Burrows, G., G. Horn, R. McNew, L. Croy, R. Keeton, and J. Kyle. 1987. The prophylactic effect of

corn supplementation on experimental nitrate intoxication in cattle. Journal of Animal Science 64,

no. 6: 1682–9.

FAO/WHO (2003) Nitrite (and potential endogenous formation of N-nitroso compounds). In: Safety evaluation of certain food additives and contaminants. Geneva, World Health Organization, Joint FAO/WHO Expert Committee on Food Additives (WHO Food Additives Series No. 50; http://www.inchem.org/documents/jecfa/jecmono/v50je05.htm).

Revised WHO Guidelines for Drinking-water Quality (GDWQ)

Gupta, S., R. Gupta, A. Seth, A. Gupta, J. Bassin, and A. Gupta. 2000. Methemoglobinemia in

areas with high nitrate concentration in drinking water. National Medical Journal of India 13,

no. 2: 58–61.

Kemp, A., J. Guerink, and A. Malestein. 1977. Nitrate poisoning in cattle. 2. Changes in nitrate in

rumen fluid and methemoglobin formation in blood after high nitrate intake. Netherlands Journal

Agricultural Science 25: 51–62.

Osweiler, G., T. Carson, W. Buck, and G. Van Gelder. 1987. Clinical and diagnostic veterinary

toxicology. 3rd ed. Bubuque, Iowa: Kendall/hunt publishing company.

Shivairo, R. S.Shivoga, W. A. Mbaria, J. M. Kumba, J. K (2014). Acute Borehole Poisoning in Livestock in Kargi, Marsabit, Kenya:A Case Report Advances in Life Science and Technology Vol.24, 2014 ISSN 2225-062X (Online)

Kenya national Bureau of statistics 2009 census

Wayua FO 2017 Nutritional and Health Challenges of pastoralist populations in Kenya Afr. J. Food Agric. Nutr. Dev.; 17(1): 11592-11602 DOI: 10.18697/ajfand.77.16810

RA McKenzie 

 

Gordon AN, Burren BG, Gibson JA,  Gardner MP (2009) Alpaca plant poisonings: nitrate–nitrite and possible cyanide Australian Veterinary Journal 87, (3) 113-115 https://doi.org/10.1111/j.1751-0813.2009.00400.x

 

 

 

Mineral content in El Hadi wells

Normalconductivity(µmhos/cm)Chlorides (mg/L)Phosphates(mg/L)Nitrates(mg/L)Sulphates(mg/L)Cadmium (Cd) µg/LMercury (Hg)µg/LSelenium(Se)µg/LRubidium(Rb)µg/LStrontium( Se)µg/LUranium(U)µg/LMagnesium(Mg) µg/LCalcium(Ca)µg/LVanadium(V)µg/LThallium(TI) µg/LArsenic(As)µg/L0100210301001400KEPHISTulaconductivity(µmhos/cm)Chlorides (mg/L)Phosphates(mg/L)Nitrates(mg/L)Sulphates(mg/L)Cadmium (Cd) µg/LMercury (Hg)µg/LSelenium(Se)µg/LRubidium(Rb)µg/LStrontium( Se)µg/LUranium(U)µg/LMagnesium(Mg) µg/LCalcium(Ca)µg/LVanadium(V)µg/LThallium(TI) µg/LArsenic(As)µg/L22830.310.813346.230.320.513.1510.241722.762.6562.87.7379.410.111.26KEPHISGollosconductivity(µmhos/cm)Chlorides (mg/L)Phosphates(mg/L)Nitrates(mg/L)Sulphates(mg/L)Cadmium (Cd) µg/LMercury (Hg)µg/LSelenium(Se)µg/LRubidium(Rb)µg/LStrontium( Se)µg/LUranium(U)µg/LMagnesium(Mg) µg/LCalcium(Ca)µg/LVanadium(V)µg/LThallium(TI) µg/LArsenic(As)µg/L51301.11000000000000011.4230124.50.320.747.939.21000000000000093360.816.99133.6513.4566.6800000000000070.111.39intertekconductivity(µmhos/cm)Chlorides (mg/L)Phosphates(mg/L)Nitrates(mg/L)Sulphates(mg/L)Cadmium (Cd) µg/LMercury (Hg)µg/LSelenium(Se)µg/LRubidium(Rb)µg/LStrontium( Se)µg/LUranium(U)µg/LMagnesium(Mg) µg/LCalcium(Ca)µg/LVanadium(V)µg/LThallium(TI) µg/LArsenic(As)µg/L873

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