الفهرس 
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Abstract
The increasing demand of pesticides for agricultural pu~oses and other purposes of disinfection and preventive medicine require an early attentive control of waste water and polluted river water. Especially here in Egypt where these compounds are .used on a large scale, consequently they affect the environ ment very badly, since pesticides are toxic to human health and cause diseases, tnerefore determination of pesticides in drinking water is essential. . ’. Mahmoudia,canal is the only source of drinking water in Alexandria. The increase of industrial waste ~ischarge, as well as the discharge of the agricultural drains to the canal had lead to study the quality of Alexandria public water supply through determination of pesticides and trace metals concentrations in the inffluent and effluent of the water treatment plants (El-Seouf, Bab Sharky, El-Manshia El pidida and Forn El-Aeraia) during the period from September 1980 to Agust 1981. , Ten stations were fixed for regular sampling (stations I.II,IV,V,VII and IX) for raw water and stations III,VI,VITI , and X for treated water to determine pesticide residues, some of heavy metals and some chemical tests were carried out for these samples. The samples had been collected every three .months for pesticides~determination and the techniques of sampl i~, isolation, concentration, identification and quanti fication of pesticides in water fo~lowed in this study had ! been carried according to EPA/pesticide Analytical Manual , (Thompson,1974). Samples were co~lected every month for trace metals ~ I and’ chemical analys.is. . ... The techniques of sampling, isolation, concentration, identification and quantification of trace metals (~, Cd, Cu, Ni, Pb, Fe, Zn and Mn) .followed in this study are generally those recommended by the standard methods(APHA v 1971) for examination of water and waste water. The chemical tests were carried out to determine pH value, total, fixed and volatile solids, Ammonia nitrogen, Nitrites, Dissolved oxygen, Biochemical oxygen demand, Chlorides, total alkalinity, Hardness, Sulfates and Phos phates. All these chemical tests were carried out according f i to the standard methods (1965, 1971 and 1974). The i results were analyzed and conclusions were summarized f as follows: 7.1. Pesticides: Lindane, DDE and DDT wer~ the chlorinated hydrocarbon pesticides which had been detected in the raw and treated water samples. In the Mahmoudia canal at Khourshid their concentrations were 0..91’, 2.32, 1.97 ppb respectively and ~ DDT was 4.56 pp b. None of these pesticides had been I dete~ted during the winter. At El-Seouf water treatment plant inffluent the mean values were 2.23, 0.67, 1.95 ppb respectively and Z DDT was 2.06 ppb. For the effluent the means decreased with values 0.9, 0.65, 0.9 ppb respective ly and ~ DDT was 1.63 ppb. These pesticides had not been detected during winter at all., El-Seouf W.T.P. showefficiency in reducing pesticide residues where the percentage removals ranged from 60, 3, 54 and 21 for Lindane, DDE, DDT and <f. DDT respectively. In the influent of EI-Manshia W.T.P. the concentra tions were 0.6, 1.99, 0.42 ppb respectively and ~DDT was 2.63 ppb. In effluent they were 0.69 , 2.2, 0.49 and .... LDDT was 2.49 ppb respectively. The results indicated El-Manshia El-qidida W.T.P. has no efficiency in reduc i~ pesticide residues and this is may be due to lack of periodic washing of the sand beds at filters. At Bab-Sharky W.T.P. the concentrations in the inffluent were 0.43, 1.02, 3.96 pyb respectively and ~DDT was 5.1 ppb. In the effluent the mean values were zero, 0.68, 0.97 ppb respectiv~ly and~DDT was 1.73 ppb and ” None of”tftese pesticides had been detected during the autumn. So Bab ”Sharky W.T.~ has a great efficiency in reducing p~s~icide residueswith maximum percentage re moval of 100 for L;lndane, 76 for DDT, 66 for 2PDT .. and DDEwith 3~ percent removal. At Forn EI-Geraia W.T.P inffluent the mean values of these pesticides were 1.04, 3.75, 0.9 ppb respectively . ” and ~DDT was 5.07 ppb, but in the effluent they were ,” 1.04, 1.15, 1.25 ppb respectively and:!E.. DDT was 2.53 ppb. The results indicated that Forn El-Aeraia W.T.P has not any efficiency in reducing the residues of L~ndane and DDT, while it helped in reducing the residu~s of DDE ~ith 69 and ~ DDT percentage removal was 50. So the fore mentioned results proved that El-Seouf and Bab-Sharky ~ #’ water treatment plan~are the best among the water treatment plants in reducing pesticide, residues. 7.2. Trace Metals: 7.2’..1. Trace metals in raw water: The results showed that the observed concentrations \ of the trace metals ( Cu, Pb, Zn, Mn ’and Fe ) in the raw water were less than the maximum intern~tional recommend ed limits (WHO, 1970). While cadmium, chromium and Nickel were not detected in~the measured water samples. , .. 7.2.1.1. Copper:. Copper was detected at all intake sites on Mahmoudia . , canal, it ranged from 15.0 ug/l at Khourshid to 11.0 ug/l at Forn EI-Geraia W. T.P ” the results have shown also that the recorded copper concentration was the lowest concentration of trace metals in raw water 4etected in this study. 7.2.1.2. Lead: Lead had been observed in raw water at all sample, . . sites, the maximum value of 43 ug/l was reported at Khourshid, then the concentration was decreased at El-Seouf intake with a.mean value of 33 ug/l, followed with a slight decrease at . ,.J the up stream of EI-Mountaza canal with mean value of 28ug/l The concentration increased again at Bab~Sharky where a mean value of 36 ug/l was obtained, while at Forn El -Geraia the concentration was 35.ug/l. 7.2.1.3. Zinc. Zinc had been detected in th~ water at all sample sites. At Khourshid the mean value was 57 ug/l, then . slightly decreased to 53 ug/l at El-Seouf intake}was almost the same at the up stream of the MOuntaza canal . . with mean value of 52 ug/l, then the concentration decreased to 49 ug/l at Bab~Sharky intake follo~ed by 39 ug/l at Fo:t’n -EI-Qeraia intake. .. 7.2.1.4. Manganese: - ” The mean values of manganese were~igher than those of copper and lead while they are lower than those of zinc.’ The concentrations were 62 ug/l.at Khourshid, 56 ug/l at El-Seouf intake, 52 ug/l at the up’ stream of , the Mountaza canal, 45 ug/l at Bab Sharky intake and 28 ug/l at Forn EI-Geraia intake. 7 . 2 .1. 5 ’. Iro n: Iron concentrations were the highest among the test ed trace metals, where it had been reported at Khourshid .. with mean values of 168 ug/l,’ and 131 ug/l of El~Seouf , intake. Then it’s concentratiOIT decreased ’to 112 ug/l at”Mountaza canal and increased t~ 183 ug/l at Bab Sharky and 238 ug/l at Forn El.~eraia. ’7.2.2. Efficiency of water treatment plants in removinp: metals: The highest concentrations of Cu and. Fe were reported for the raw and treated water of El-Yanshia water treatment plant. Lead was slightly higher in both raw and treated water at Bab-Sharky W.T.P ,. but zinc and manganese were found at .the~r highest concentration in the raw ~nd trefted w~ter of El-Seouf water treatment plant. . .. So it could be concluded that, El-Seouf W.T.P the greatest efficiency among the studivd plants in , had removing Zn, while EI-Manshia El-Gidida had the greatest efficiency in removing manganese. ]’orn EI-Geraia demons trated the greatest efficiency among the plants in remov ing iron, lead and copper. But Bab-Sharky had modest efficiency in removing the five metals in comparison with the other water treatment plants. . 7.3. The chemical analysis of the raw and treated water: The concentrations of total,fixed and volatile solids, chlorides, alkalinity, total ~ardness and sulfates .are ” within the limits of the Egyptian law, 1975. It was noticed that introputed discharge of sewage, and indus-’ trial wastes or ground water has affected the water qual i ty go ing to different ’plants.