THE EFFECT OF PESTICIDE RESIDUES AND HEAVY METALS ON THE WATER QUALITY IN GAZA STRIP AND THEIR IMPACTS ON HEALTH Amani Alfarra a and Mazen Hamadah b a Bank of Palestine Center Bldg. Gaza El Rimal, App.910/911, P.O.BOX:1388, Gaza - Palestine, Email: [email protected]b Al Azhar University Gaza, Faculty of Science – Chemistry Department, Gaza Strip -Palestine , Email: [email protected]Gaza Strip in Palestine is located on the southern shores of the Mediterranean Sea. It is like many arid and semi – arid countries water is becoming an increasingly scare resource. The groundwater quality of the Gaza Strip is generally very poor. Water quality of the coastal aquifer underlying the Gaza Strip has deteriorated severely for a number of reasons. The most important reasons are saline water intrusion, wrong solid waste disposal, the agricultural pollution of the groundwater by the use of fertilizers, pesticides and soil amendments and the uncontrolled discharge of the wastewater over the soil surface. The groundwater quality changes in both horizontal and vertical directions. Water sources also receive inputs of many different chemicals such as heavy metals, leaching form dumping the solid waste, and there is also concern about the impact of such heavy metals on the health of the Palestinian people in Gaza Strip. This paper has the following objectives: To demonstrate the occurrence of pesticide residues and heavy metals on the quality of water in Gaza Strip. To highlight the environmental and health impact of misuse of pesticides and heavy metals in drinking water. To describe how improvement of management usage of pesticide and solid waste lead to protect health of people and reduce related diseases. It is estimated that 96.6% of irrigated land is treated with pesticides. The total quantity of pesticides used in Gaza strip is almost equal to that in West Bank despite the difference in agricultural areas. People who formulate and apply pesticides are risking both acute and chronic diseases. Many severe poisoning cases have been registered at al Shifa and AlAhly Hospitals in Gaza caused by the misuse of the forbidden Pesticides. The number of cancer patients in Gaza Strip was increased drastically in the last years. There are no available data about the concentration of pesticides in the water systems of the Gaza Strip except the lonely analysis done in 1997 for some wells by Israelis laboratories. In this paper we will focus on the dangerous impact on health due to pesticide and heavy metals contaminations of drinking water. Key wards: Water Quality, Pesticide, Heavy metals, Environment, Health, Management Introduction : Gaza Strip is located on the southern shores of the Mediterranean Sea, between Israel and Egypt with a total area of 365 km 2 . Cultivated areas in the Gaza Strip are classified into two categories as: rainfed and irrigated area. The percentage of persons engaged in agricultural activities is estimated about 22.65% of the total population of the Strip. Gaza Strip like many arid and semi-arid countries water is becoming an increasingly scarce resource. At the same time, the high rate of population in Gaza Strip means increase in the water demand which force planners to consider any other sources of available water that might be used economically and effectively to promote future development. 1
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THE EFFECT OF PESTICIDE RESIDUES AND HEAVY METALS ON THE WATER QUALITY IN GAZA STRIP AND THEIR IMPACTS ON HEALTH
Amani Alfarraa and Mazen Hamadahb
aBank of Palestine Center Bldg. Gaza El Rimal, App.910/911, P.O.BOX:1388, Gaza - Palestine, Email: [email protected] bAl Azhar University Gaza, Faculty of Science – Chemistry Department, Gaza Strip -Palestine , Email: [email protected]
Gaza Strip in Palestine is located on the southern shores of the Mediterranean Sea. It is like many arid and semi – arid countries water is becoming an increasingly scare resource. The groundwater quality of the Gaza Strip is generally very poor. Water quality of the coastal aquifer underlying the Gaza Strip has deteriorated severely for a number of reasons. The most important reasons are saline water intrusion, wrong solid waste disposal, the agricultural pollution of the groundwater by the use of fertilizers, pesticides and soil amendments and the uncontrolled discharge of the wastewater over the soil surface. The groundwater quality changes in both horizontal and vertical directions. Water sources also receive inputs of many different chemicals such as heavy metals, leaching form dumping the solid waste, and there is also concern about the impact of such heavy metals on the health of the Palestinian people in Gaza Strip.
This paper has the following objectives:
To demonstrate the occurrence of pesticide residues and heavy metals on the quality of water in Gaza Strip.
To highlight the environmental and health impact of misuse of pesticides and heavy metals in drinking water.
To describe how improvement of management usage of pesticide and solid waste lead to protect health of people and reduce related diseases.
It is estimated that 96.6% of irrigated land is treated with pesticides. The total quantity of pesticides used in Gaza strip is almost equal to that in West Bank despite the difference in agricultural areas. People who formulate and apply pesticides are risking both acute and chronic diseases. Many severe poisoning cases have been registered at al Shifa and AlAhly Hospitals in Gaza caused by the misuse of the forbidden Pesticides. The number of cancer patients in Gaza Strip was increased drastically in the last years. There are no available data about the concentration of pesticides in the water systems of the Gaza Strip except the lonely analysis done in 1997 for some wells by Israelis laboratories.
In this paper we will focus on the dangerous impact on health due to pesticide and heavy metals contaminations of drinking water.
Key wards: Water Quality, Pesticide, Heavy metals, Environment, Health, Management
Introduction:Gaza Strip is located on the southern shores of the Mediterranean Sea, between Israel and Egypt with a total area of 365 km2. Cultivated areas in the Gaza Strip are classified into two categories as: rainfed and irrigated area. The percentage of persons engaged in agricultural activities is estimated about 22.65% of the total population of the Strip.Gaza Strip like many arid and semi-arid countries water is becoming an increasingly scarce resource. At the same time, the high rate of population in Gaza Strip means increase in the water demand which force planners to consider any other sources of available water that might be used economically and effectively to promote future development.
The deterioration of groundwater quality in Gaza Strip occurs for a number of reasons. on The most important reasons are the agricultural pollution by the use of fertilizers, pesticides and soil amendments, the uncontrolled discharge of the wastewater over the soil surface, the wrong solid waste disposal and water salinity.Three major sources of salinity can be documented based upon the existing water quality data from the Gaza coastal aquifer • Inflow of brackish water from the east. The primary source is believed to be water from rocks
of Eocene age (and possibly younger formations in the Saqiya Group) where these underlie the coastal aquifer. A natural source from water-rock interaction in the coastal aquifer is also probable, though the current database cannot distinguish the relative importance of each.
• Influx of deep Ca-chloride brines in the southern part of the Gaza Strip, especially near Khan Younis, induced by excessive municipal pumping. The brines may be of fossil origin (i.e., connate from within the coastal aquifer) or may originate in the formations underlying the coastal aquifer. This needs additional study and sampling.
• Seawater intrusion, both shallow and deep in the southern part of the Gaza Strip, and around the major pumping center of Gaza City/Jabalya. Shallow seawater intrusion in sub-aquifer A is localized. Confirmation of deeper seawater intrusion is required from sampling of new monitoring wells.
The fresh groundwater is not distributed evenly through out the whole area of the strip. It can be concluded that the problem of water quality is equally as important as water supply in the Gaza Strip. In the aquifer of the Gaza Strip, good quality water occurs only in two small pockets one in the north, and one in the southwest. Most wells in the middle district and southern district are brackish. Saline water upcoming is mainly observed in the middle district.In 1999, it was estimated that approximately 140 MCM/yr of water was pumped from about 4000 wells, of which about 90 MCM/year of water was used for irrigation a 50 MCM/year were pumped for domestic and industrial purposes from 90 municipal wells. The Coastal Aquifer Management Program established the 1998 water balance of Gaza Coastal Aquifer by estimating all water inputs and outputs.The total estimated inflow to Gaza aquifer of 123.1 million m 3 / year is composed of:
1. Recharge from precipitation 35 million m 3 / year , 2. Return flows from leakages, wastewater and irrigation 51.6 million m 3 / year , 3. Lateral inflow from Egypt and Israel 36.6 million m 3 / year .
The total estimated outflow of 154.1 million m 3 / year reflects:
1. Municipal abstraction 50.3 million m 3 /year , 2. Agricultural abstraction 90.3 million m 3 /year , 3. Agreed Mekorot abstraction 5 million m 3 / year , 4. Natural discharge to the sea 8.5 million m 3 / year .
The deficit of 31 million m3 / year between total input and output to Gaza aquifer, implying the following adverse consequences: lowering of the groundwater table, reduction in availability of fresh groundwater, and increased seawater intrusion and potential intrusion of deep brines.
The municipalities are responsible for distributing water for domestic and industrial consumption each municipality has its own water source and a separate distribution system. Water consumption averages 75 litres per capita per day. Due to the deteriorating distribution network, water losses are very high, in the range of 35 -50 %. Most municipalities use groundwater without any treatment except for disinfection. Some municipalities buy water from Mekorot
Occurrence of Pesticides in Gaza Strip:
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Pesticides by their nature are toxic and are designed to kill unwanted organisms. Most act by interfering with biochemical and physiological processes which are common to a wide range of living systems. This results in them being potentially harmful to non-target organisms and they can be serious pollutants even in low concentrations. The widespread use of pesticides inevitably leads to a mixture of pesticides being present in water sources.
The increasing use of synthetic chemical pesticides is causing world-wide pollution. Water is polluted in two ways, through the general application of dilute compounds (e.g. through spraying) which then find their way to water (diffuse pollution) or through a single source such as a chemical spill (point source pollution). Leaching of pesticides occurs when the substance is moved through the soil in solution, usually with rainwater, as it percolates down to the water table. Normally soil will act as a filter in this process leaving the water relatively free of pesticides by the time it reaches the water table. But differences in soil and pesticide properties influence this movement. Contamination resulting from leaching of pesticides is a common and growing problem in major agricultural regions (Flury, 1996; DaSilva et al., 2003). The method and rate of pesticide application, the use of tillage systems that modify soil conditions, and the amount and quality of water can also influence pesticide leaching (Hebb and Wheeler, 1978; Kolpin, 1997; Tomlin, 1997; Kubilius and Bushway, 1998; USGS, 1998).
Pesticides tend to break down better in warm, moist soil than in cool, dry soil. Weather too plays a part in how quickly pesticides move through soil. Heavy rainfall, particularly after a recent pesticide application, can drive the pesticide deep into the soil, where breakdown tends to be slower.
The more compounds that are released to the aquatic environment the more difficult it becomes to test water for all the possible compounds it may contain. Nor are all pesticide compounds easy to determine through analytical procedures. High levels of organic matter and heavy metals in water and soil can mask low concentrations of pesticides making them difficult to detect.
Pesticides can be degraded by light, hydrolysis and oxidation (although other mechanisms may also exist). Breakdown products may, however, be more toxic than the original compound. Table 1 provides a summary of degradation half-lives of a range of pesticides in surface and ground waters – the amount of time it takes for half the active ingredient to disappear .Table 1: Estimated degradation half-lives in water of a range of pesticides
The persistence of the chemical in water will depend on the acidity or alkalinity of the water, and the amount of light and oxygen. Generally pesticides will take longer to break down in groundwater, deprived of light and oxygen. Water treatment can be effective in removing pesticides from drinking water, but it is expensive; groundwater cannot be remediated.Gaza Strip depends mostly on agricultural activities beside some light industries and fishing activities. The use of pesticides in Palestine has been increased significantly since their introduction in the 1970s, in particular in irrigated farming. Unfortunately this increase has not been accompanied by a full understanding of the impacts of pesticides on human health, beneficial soil organisms and micro – organisms and the environment as a whole.
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Pesticides and herbicide are normally found in agricultural areas and are associated with high nitrate. In addition to the misuse of pesticides, Gaza Strip is also suffering from decline of agricultural areas. Due to the misuse of pesticides large agricultural areas have lost their fertility because the biological diverse in them are destroyed. It is expected that after some years some agricultural lands will be completely inadequate for planting. As a result of that the different kinds of pesticides are leaching through the soil and contaminate ground water.
Pesticides are considered priority pollutants in Gaza and, with the expanding use of greenhouses; Palestinian agriculture is becoming increasingly dependent on chemical pesticides and fertilizers. According to Safi (2002), Gaza Strip consumed more than 393.3 tons of pesticides in 1999. Pesticides are often misused by the non-professional, inexperienced farmers, who do not take into consideration the "safe period", which is identified as the period between spraying and gathering of crops, specified according to the type of pesticide (Abu Middain, 1994). It is ironic that pesticides that are banned or restricted in many countries are being marketed and used in Gaza because of lack proper assessment and monitoring programs (SCF, 1991; Haapala, 1993; UNRWA, 1993; Abu Middain, 1994; Richter and Safi, 1997; IARC, 1999). Also lack of awareness among shop owners, farmers and public increased the level of soil and water contamination across Gaza (Hulshof, 1991; Issa, 2000).
The amounts and kinds of pesticides entering the Strip through the bounders with Israel are unfortunately roughly controlled. Most of the pesticides come through Israel with only Hebrew labels, warnings and instruction and very few Palestinian farmers read Hebrew.
Table 2 represents the annual amount of pesticides used in Gaza Strip in the period between 1996 and 2004 (Ministry of Agriculture in PA).
Graph (1) illustrates the relationship between pesticides and the quantity of each type of pesticide used in the period between1996-2004. In 1997 large quantities of pesticides where used if compared with other years, which represents 18% of the total of pesticide used in the period between1996-2004%.Up to the year 2000 the average of pesticides usage began to decrease, 5.9% in 2001 and 8.6% in 2002 but it is returned to increase in 2003 and 2004. This variation could be related to different factors such as the Israeli occupation circumstances, the reduction of agricultural areas and the change to green housing, and the lacks in monitoring the pesticide usage. Fumigants present nearly 60% of the total amount of pesticides that have been used in Gaza strip in the period between1996-2004. Fungicides and insecticides come with 14% and 11.9% of the total respectively. The reason is that the fumigants are very important in intensive agriculture, and very effective in green housing enclosed systems.Insecticides represent 11.95% of the total percent of pesticides which have been used in the period between 1996-2004. After the year 1996 the quantity of insecticides decreased in a clear way and it became stable in the last five years. Although insecticides are the most important methods used to kill pests, their usage is reduced due to application of the I.P.M programs in insect control.The use of fungicides is related to the outbreak of the fungi diseases and so as to the climate circumstances which differ from one year to another. Due to these factors the quantity of fungicides was not stable and it represent nearly 14% from the total amount of pesticides used in the same period.Herbicides used in Gaza strip in very small amount when comparing with other types of pesticides, its percent considered to be 1.84% of the total pesticides quantity. Its usage wasn't stable and it decreased in the last years because of the involvement of large number of the working hands in a sufficient way, in the last period, in cleaning the farms from the weeds.Fumigants used in the period between1996-2000 in large quantities but from 2001 to 2004 these quantities were clearly decreased. The total percent of fumigants was 58.9%. The use of thermo sterilization in sterilizing the agricultural soil and the international agreements that identified the use of methyl bromide gas used every year was the reason in this decrease in fumigants quantities which stabilized in the last four years.
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Contrary to all the previous types of pesticides the quantity of nematocides was increased in a clear way during the period between 1996-2004. In 1996 the nematocides weren't in use, but after this year it began to increase gradually. By reduction the quantities of sterilization compounds which are used in sterilizing the soil, the farmers tended to use more quantities of nematocides to kill the snaky warms. In the years 1996 and 1997 the use of plant growth regulators was limited, but after that it increased highly. Due to the nonexistence of chemical fertilizer the farmers were forced to use larger amounts of plant growth regulators to decompose the organic compounds in soil and utilizing from it.During the years 1996-2000 the use of rodenticides wasn't stable, there was a high decrease in 1997 and in other hand a high increase in 2000, but after the year 2000 the amounts of rodenticides decreased clearly and become stable. It might be due to the care of cleanliness and the entrance of municipality (health department) in a sufficient way which lead to reduce the number of mice and hence to minimize the quantity of rodenticides used.
Table 2: Pesticides annually used in Gaza strip in the period between 1996-2004 (in kg) *
*Ministry of Agriculture, Department of plant protection, Gaza Strip
A total of 123 different pesticides are used in the region, including many illegally imported and obsolete substances. Pesticides detected in well-water samples include DDT, lindane, aldrin, dieldrin, endrin, endosulfan, endosulfan sulphate, methoxychlor, and heptachlorepoxide (CAMP, 2000a; CAMP, 2000d). While these were found in levels below the WHO guideline values for drinking water, the technical complexity and expense of comprehensive pesticide monitoring mean that the problem is likely to be more serious than currently available data suggest.
Nitrate is a major groundwater contaminant throughout Gaza. There are numerous sources of nitrate contamination, including agricultural fertilizers, waste dumping, and – especially – direct discharge of raw sewage to Wadis and soil. This has been shown by isotopic techniques to be the main source of nitrate contamination (Al-Yacubi, 2001; CAMP, 2000d; CAMP, 2000e; Vengosh et al., 2002). Nitrate concentrations have been shown to exceed WHO guideline values in 50 % of the samples collected from domestic municipal wells in Gaza (Al-Yacubi, 2001).
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It is estimated that 96.6% of irrigated land is treated with pesticides. 90% of the annually used pesticides in the Gaza Strip is imported from Israel while the other 10% is manufactured locally. Since there is no restriction on the sale and use of pesticides, farmers have easy access to all of them including the banned. The total quantity of pesticides used in Palestine is distributed approximately equally between Gaza Strip and West Bank despite the smaller area of the Gaza Strip.
There are around 55 pesticide shops in the Gaza Strip and there are no wholesalers; all pesticides come from Israel through Israeli Arab wholesalers, who usually get most of their products from Israeli pesticide companies and sometimes from agents for imported chemicals (UNRWA, 1993; SCF, 1991). Adulteration and fraudulent sale of pesticides are common practices (Abu Middain, 1994; Hulshof, 1991). There is no monitoring either on the sale of pesticides or on their chemical composition, even though that Alazhar University was donated full equipped laboratories at 1996. This refers to two main reasons; first the absent of coordination between institution and secondly the high expenses of sample analysis.
From the monitoring of pesticides in the groundwater and the topsoil done by Shomar in Gaza Strip in 2005, Table 3 illustrates a list of pesticides analyzed and the instruments used for the analysis.
Bromacil was 0.5 μg/l in Safa 1 and atrazine-desisopropyl was 0.1 μg/l in Safa 2 (R/25a). Most results of the GC/MS of other target pesticides were generally less than the detection limit. Several private wells in Rafah area showed traces of endrin, heptachlorepoxide, DDT, DDE, and DDD.
Atrazine was detected in 47% of groundwater samples, while atrazine-desisopropyl, propazine, simazine were detected in 40%, 24%, and 13% of water samples, respectively. All showed results above the instrumental detection limit. Two water samples showed 5 μg/l of triadimenol, the wells are private and located in the area of Gaza wastewater treatment plant.
Several soil samples of strawberry greenhouses in Beit Lahia showed detectable values of propazine, sebutylazine, terbutylazine, 4,4’-DDT, 4,4’-DDE, and 4,4’-DDD. The averages of propazine, sebutylazine and terbutylazine were 19, 13 and 39 μg/kg, respectively.
Shomar’s analyses showed that one soil sample collected from the northern area of Beit Lahia in a vegetable farm had high contents of 4,4'-DDE and 4,4'-DDT which were 1104 and 793 μg/kg, respectively.
The most important finding of his study was the detection of 12 pesticides in the groundwater and 6 pesticides in the topsoils.
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Table 3: List of pesticides analyzed and instrument used for analysis Pesticide Analysis LD (µg/l) Pesticide Analysis LD (µg/l) Alachlor HPLC/MS 0.025 Monolinuron HPLC/MS 0.05 Atrazine HPLC/MS 0.025 Monuron HPLC/MS 0.025 Atrazine-desethyl HPLC/MS 0.05 Pendimethalin HPLC/MS 0.025 Atrazine-desisopropyl HPLC/MS 0.055 Propazine HPLC/MS 0.025
There are a number of different regulatory regimes that protect different water sources and apply different standards. The main ones are World Health Organization (WHO), guidelines for Drinking-water Quality, EU drinking water standards, dangerous substances and groundwater standards. The WHO produces guidelines for drinking water quality which lists substances and gives guideline concentrations for that substance in drinking water, with the guideline value based on health criteria. The guidelines are intended to set a standard which national governments might wish to follow when setting up their own drinking water legislation. The problem, however, is that WHO - guidelines exist for very few pesticides. They are available for possibly only half of the pesticides that may get into water and they do not take into account the ecotoxic impacts of pesticides. The most recent WHO Guidelines included the most updated regulation .
The EU Drinking Water Directive (80/68/EC) has been the most important in driving regulatory standards for most water sources. The maximum permitted concentration is 0.1 µg/l (which means one-tenth of a part per billion) for any individual compound, and a maximum total concentration of 0.5 µg/l for any combination of substances (although this latter figure may be about to be changed). The limits are not toxicologically based but were set originally at the limit of current ability to detect pesticides in water. They are now regarded as an early application of what has come to be known as the precautionary principle. Table 4 illustrates the most dangerous pesticides used in Europe.
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Table 4: Pesticides included in the Dangerous Substances EC directive 76/464/ECList I (substances to be eliminated) List II (substances to be reduced)AldrinDDTDieldrinEndrinIsodrinHexachlorobenzeneHexachlorocyclohexane (HCH)Pentachlorophenol
Up to our knowledge and with reference to the concerned organizations involved in the Water Quality of the Gaza Strip (Palestinian Water Authority, Municipality of Gaza, Ministry of health and the Palestinian Environmental Quality Authority) no available data about the concentration of pesticides in the water systems of the Gaza Strip was found except the analysis done once in 1997 for some wells by Israelis laboratories and the one done by Showmar in 2005 in German laboratories.
Occurrence of Heavy Metals in Gaza Strip:
From a research funded by Bundesministerium fuer Bildung und Forschung-BMBF, Germany through a project called "Monitoring of Groundwater and Soil Pollution Levels in Gaza Strip", it was found that in the most used solid pesticides collected from many markets of the Gaza Strip they contain considerable amounts of heavy metals and they do not comply with the expected-theoretical structure of each species; even pesticides originally with no heavy metals in their chemical structure have impurities of such metals. This was due to mixing pesticides in local markets with minor inorganic species without a scientific basis; or they have been smuggled to Gaza with different impurities. Some heavy metals were also found with high amounts in other pesticides which do not have these metals in their structure (table 5). Based on the results, the collected samples can be classified into two categories: the ones that have one or more of the tested elements in their structures and showed positive results; and the ones that have none of the collected elements in the structure but showed them in the analysis.
For the first category of the tested pesticides, the calculated value of each element is much higher than the measured value. Al, for example, in fosetyl-aluminum was 4 times higher than the measured value and it was 3 times higher in the second sample of the same pesticide; Zn was 11, 6, 1 and 12 in propineb, mancozeb, metiram, and zineb respectively; Mn was 4 and 9 times higher than the measured value in mancozeb and maneb respectively; Br 3 times higher in the two samples of bromacil; while it is 6895 and 9480 times higher in the two samples of bromadiolone; and finally Cu was 2 times higher in both copper oxychloride and copper sulfate.
The second category of pesticides represents the species that have none of the tested elements in their structure but they showed high amounts of them ; a good example is copper oxychloride which has high amounts of Pb; copper sulfate showed high amounts of Ni; and maneb showed high amounts of Fe beside the Mn as well.
The results propose that pesticides should be considered as a source of certain heavy metals (Cu, Mn, and Zn) and other elements (Br, Sr and Ti) that may affect their mass balances in soil and groundwater as well as plant uptake; and different scenarios and calculation models of heavy metal transport in soil and groundwater of the Gaza Strip should include pesticides as an additional source of certain heavy metals
Effect of Immobilizing Substances and of NaCl Salinity on Speciation of Heavy Metals in Soil Solution
The irrigation with saline water (1600 mg L-1) will not affect the soil solution characteristics, such as pH, Ca, Mg, PO4, NO3, SO4, and HCO3, but it causes a significant increase of Na and Cl in soil solution and resulted in a significant increase in metal chloride species (MCl+ and MClO2). One of the many factors affecting the solubility and immobilization of heavy metals is complex formation with inorganic ligands in soil solution (Temminghoff et al., 1995; Hirsch et al., 1989; Mattigod and Sposito, 1977; Garcia-Miragaya and Page, 1976).
The presence of complexing ligands may increase metal retention or greatly increase metal mobility (McLean and Bledsoe, 1992). The common inorganic ligands, complexed with heavy metals, are SO2-
4, Cl-, OH-, PO3-4, NO-
3, and CO-23 (Scheffer and Schachtschabel, 2002). Among
these ligands, chlorides are highly mobile and therefore, under certain conditions, they could be an important factor in the distribution of heavy metals between binding fractions. The highest metal complexation with Cl occurred for Cd. The total concentration of Cd in soil solution increased by 1.6–2.8-fold due to saline water (Showmar). Therefore, in many arid regions, saline irrigation water containing high level of Cl- might aggravate heavy metal pollution problems and any technology to immobilize heavy metals (HV) may not be effective, as a result of the formation of HM-Chloride complexes.
Chloro-complexes are particularly strong with some heavy metals such as Cd, Hg, Pb, and Zn (Hahne and Kroontje, 1973). Doner (1978) reported that Cl- increased the mobility of Ni, Cu, and Cd in soil and attributed this phenomenon to the formation of HM-chloride complexes. Maas et al. (1972) studied the effects of NaCl salinity on the uptake of Fe, Mn, and Zn by plants grown in nutrient solution cultures. They observed increased leaf concentration of these metals, but not an actual increase in total uptake.
Cupper is known to have a high complexing nature with soluble organic matter (McLean and, 1992; Inskeep and Baham, 1983). In many studies, the speciation calculation for soil solution predicted that the high proportion of Cd, Zn and Pb in soil solution presents as free Cd2+ (80–90%), Zn2+ (78–97%), and Pb2+ (43–75%) (Holm et al., 1995; Percival et al., 1999). In soil solution Ni can also present mainly as free Ni2+ (Scheffer and Schachtschabel, 2002). It was observed that the small percentage of studied HM was found as MSO0
4, MCl+, M (NO3) 02, MNO+, M (OH)0
2, and MOH+ in soil solution, ranging from less than 1% to 12% of total concentration .
The chloride concentration of soil and irrigation water should be taken into account while assessing the risk of metal uptake by food plants. The addition of Novaphos caused a large reduction in Pb availability to wheat, as Pb is known to make stable minerals with phosphorus.
The added phosphate fertilizers, however, had no significant effect on the reduction of Cd and Ni concentrations. The addition of Novaphos decreased concentration of Pb by 65% compared to the control soil. The use of bentonites is most promising for the reduction of HM availability to plants
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The Effect of Certain Plant Strategies towards Heavy Metals:
The high level of organic matter and heavy metals in water and soil in Gaza can mask low concentrations of pesticides making them difficult to detect. However, there are plants which work as geopotanical indicators for heavy metals. They are Accumulating Heavy Metals.All plants take up heavy metals to varying degrees from the substrates in which they are rooted. The concentrations in plant parts depend both on genetic and environmental factors and vary greatly for different species and heavy metals. Table 6 illustrates different heavy metals’ plant accumulators.
Table 6: Hyperaccumulation of Metals by Different Plant Genera
Three basic strategies by which higher plants can tolerate the presence of large amounts of heavy metals in their environment are proposed as follows:
a) Excluders, whereby transport of metals is restricted, and low, relatively constant metal concentrations are maintained in the shoot over a wide range of soil concentrations.
b) Indicators, whereby uptake and transport of metals to the shoot are regulated so that internal concentration reflects external levels.
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c) Accumulators, whereby metals are accumulated in nontoxic form in the upper plant parts at both high and low soil concentrations.
Accumulators can be characterized by a leaf: root metal concentration ration of >1 because of the tendency to translocate metals from root to shoot, whereas in excluders the ratio is >1.
Plants that have an inordinately high concentration of heavy metals have been termed hyperaccumulators and are defined as plants containing more than 100 ppm dry mass of Cd, or more than 1000 ppm of Ni, Cu, Co, Pb, Cr or more than 10000 ppm of Zn or Mn.
Such hyperaccumulators of heavy metals could be used to clean up polluted areas with heavy metals in Gaza Strip.
Health Impact:
The health concerns associated with chemical constituents of drinking-water differ from those associated with microbial contamination and arise primarily from the ability of chemical constituents to cause adverse health effects after prolonged periods of exposure.
Risks of pesticides in water to wildlife and humansPesticides have effects on wildlife. The effect of DDT poisoning on bird reproduction is well known, but other pesticides too have direct and indirect effects on fish, birds, bees and other species, and on their habitats and food chains. Ecosystems are complex entities and dependent on many interactions among animal species. A minor problem low down on the food chain can have major repercussions for top predators. Alterations that do not directly affect the animals but do affect its habitat or metabolism may alter survival, population density, species diversity and reproduction.
The water solubility of a pesticide is one of the factors determining where it may be distributed the environment as well as within an animal or plant. Although terrestrial and aquatic effects on wildlife are often treated separately, in reality a continuum may exist at the transport and environmental levels as well as in bioconcentration and biomagnification in aquatic and terrestrial animals. The phenomenon of species variation in the toxicity of a pesticide is complex. Pollution of environmentally sensitive upland rivers by the new forms of sheep dip is increasing. The new dips are approximately 100 times more toxic to river life than were the former organ phosphorous (OP) dips. One teaspoon of the new synthetic pyrethroid dips can damage hundreds of meters of river by killing the aquatic insects that provide food for fish and other wildlife.
Water sources also receive inputs of many different chemicals, and there is also concern about the impact of chemicals in mixtures, particularly where some aquatic organisms will be exposed chemicals that can exert similar adverse impacts on the same target organs – such as organ phosphorus pesticides or endocrine disrupting pesticides. They can cause adverse effects by interfering with the body’s hormones or chemical messengers. These substances are therefore called hormone endocrine disruptors, as it is the endocrine glands that secrete the hormones. A number of different chemicals are implicated – some pesticides, and also chemicals used in the manufacture of plastics, and oestrogens.
In Gaza Strip the farmers are using very high and intensive amounts of pesticides in their farms; those farmers have a very low educational background which let them use these pesticides and fertilizers with high dosage without any control and care. Many severe poisoning cases have been registered at al Shifa and AlAhly Hospitals in Gaza for the misuse of the forbidden Pesticides.
Pesticides affect humans, either immediately or in the long run (Carbonell et al., 1995; Bain and LeBlanc, 1996; Ribas et al., 1997; Richer and Safi, 1997). As an example, methyl bromide, which is used extensively in Gaza, causes fetus deformations, eye infections and dermatitis (Safi, 2002).
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Organochlorine pesticides used in Gaza cause breast cancer (Aronson et al., 2000). Another study conducted by Safi (2002) showed that heavy misuse of pesticides in the Gaza environment correlated with the growing incidence of cancer.
People who formulate and apply pesticides are risking both acute and chronic diseases. Parallel to the increasingly quantities of pesticides used in Gaza Strip the number of cancer patients are raised, beside other diseases such as sexual, neurological, genetical, misborn, and abroch diseases. The number of cancer cases registered in the period of 1979 – 1983 was slightly over 1000 (i.e. 45.7 cases/100000/year). However, the rate of cancer cases in the period 1995 – 2000, obtained from the national cancer registry center of the Ministry of Health, reached about 68.8 cases/ 100.000/year in Gaza strip (table 7). That means; the rate of cancer cases increased by a factor of 1.5 within approximately a decay, which is an obvious indicator about the pollution of ground and drinking water in Gaza Strip.
Table 7: Cancer cases registered in Gaza Strip, Palestine in the periods of 1979-1983 and 1995-2000.(Safi. et all, (1993),and Ministry of Health).
Cancer Type No. of Cases (Safi, 1993) (1979-1983)
No. of Cases (National cancer registry center)(1995-2000)
Breast 152 573Lymphoma 253 B.M Lung & Bronchus 29 316Colorecta 73 Brian , nervous system
Most chemicals arising in drinking-water are of health concern only after extended exposure of years, rather than months which can be seen in the following table 8 as example of water borne diseases (http://www.absolute-water.com/faq/ ).
Table 8: Chemicals water contaminants and their health’s effects, in drinking waterSubstance Main source Health effects Main risk
group
Arsenic (heavy metal)
Geologic pesticide residue, industrial waste and smelter operations.
Dermal and nervous system toxity effects, spasms, cramps.
Anyone
Benzene* Fuel (leaking tanks), solvent used forindustrial chemicals, pharmaceuticals, pesticides, paints and plastics.
Associated with cancer, leukaemia, anaemia.
Anyone
Cadmium (heavy metal)
Geological, mining and smelting Kidney effects, anaemia, gastrointestinal upsets.
Anyone
Chlorine* Excessive residue of chlorination at water treatment plant. Forms carcenogenic byproducts.
Possibly cancer. Anyone
Copper* (heavy metal)
Unfiltered surface water. Stomach pains, vomiting and diarrhoea.
Children
Endrin* (insecticide) Geological, additive to drinking water, toothpaste.
Nervous system, kidney effects. Anyone
Fluoride* Water contaminated by mammal droppings. Stains on tooth enamel, skeletal damage.
Children
Iron, manganese* Groundwater, water standing in iron pipes. Objectionable taste, odour or appearance.
Anyone
Lead* (heavy metal) Soft or acidic water in lead pipes, copper pipes connected by lead solder, or brass faucets.
Damage to nervous system, kidneys, reproductive system, low birth weight.
Children, fetuses
Lindane (insecticide) Used on seed and soil treatments, foilage application, wood protection.
Chronic liver damage, anaemia, leukaemia.
Anyone
Mercury (heavy metal)
Used in manufacture of paint, paper, vinyl chloride, used infungicide, geological.
Central nervous system disorders, kidney effects, allergenic.
Anyone
Methoxychlore (insecticide)
Used on fruit trees and vegetables. Nervous system, kidney effects. Anyone
Nitrate* Wells in agriculturalareas. Methemoglobinemia (blue-baby disorder), brain damage, death.
Infants under 6 months.
Pesticides Runoff and seepage in agricultural areas. In high doses, liver, kidney, or nervous system damage – possibly cancer.
Anyone
Radon (radioactive gas)*
Groundwater Lung cancer. Anyone
Sulphate* Geological, deep wells. Laxative action. Children
Trichloroethylene Industrial effluents, hazardous-waste sites, dry cleaning, metal degreaser.
In high doses nervous system damage, possibly cancer.
Anyone
Trihalomethanes (THM’s)
Chlorination of surface water. Possibly cancer. Anyone
Vinyl chloride PVC-monomer Central nervous system. Anyone
* existing in Gaza Strip
15
CONCLUSIONS
The focus of this paper is on pesticides and heavy metals polluting aquifer and their impact on health.
Diseases are serious and main indicators for the unhealthy water in Gaza Strip. Activities in Palestine and mainly Gaza strip are considered as agricultural area not as
industrial area, so the existence of heavy metal is unexpected. Calculations models of heavy metals transport in soil and ground water of Gaza Strip
should include pesticides as an additional source of certain heavy metals. The only screening project for heavy metals was German project “Monitoring of
Groundwater and Soil Pollution Levels in Gaza Strip". The rate of cancer cases increases by a factor of 1.5 within approximately a decay
which is an indicator that there is some thing needed to be investigated. Local impacts from uncollected waste caused by inadequate available equipment and
by curfews and special restrictions in certain periods. Several pesticides were detected in the groundwater of Gaza and their concentrations
have exceeded their respective WHO maximum contaminant levels or health advisory levels for drinking water.
Private groundwater wells showed higher contents of pesticides than the municipal wells. The levels of pesticides found in the municipal wells were at levels well below the water quality guidelines, and many were at levels close to the detection limit.
Several factors affecting the occurrence of pesticides in the groundwater of Gaza; soil type, aquifer characteristics and meteorological conditions, wells’ location and depth and groundwater quality.
The irrigation with saline water is one of the many factors affecting the solubility and immobilization of heavy metals due to complex formation with inorganic ligands in soil solution.
RECOMMENDATIONS: Major stakeholders that could affect or be affected by decisions or activities of the
drinking-water supplier should be encouraged to coordinate their planning and management activities where appropriate.
It is important to strengthen cooperation between all parties that working on water issue in Palestine as the Water Authority, Environmental Quality Authority, Ministry of Health, Ministry of Agriculture, Municipalities, and water legislation research institution as Al Azhar University “ the water research center “. Also local and international NGO’s working in water field.
The shortage and the deficit of water turned the interest from qualitative aspect to quantities aspect in the current stage which leads to health impact on the area.
The needs for monitoring Heavy metals and pesticides in the groundwater specially at drinking and domestic use wells
The chloride concentration of soil and irrigation water should be taken into account while assessing the risk of metal uptake by food plants.
Looking for different solutions that can help in reducing the contamination of soil and water, such as encouraging the cultivation of accumulator plants.
16
Looking for new technologies that uses new techniques for better management of water resources such as soil treatment with hot air (Cultivit) as alternative to methyl bromide
REFERNCES:
Safi. J. M., Y. El Nahal, S. A. Soliman and A.H. ElSebae; The Science of the Total Environment, 132 (1993) 371.
National cancer registry center of the Ministry of Health in Palestine
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