الفهرس 
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Abstract
The goal of this study is to determine the levels of organochlorine pesticide residues (OCPs) in water and fish of some irrigation and drainage systems in El-Behera Governorate as well as fish (tilapia and catfish) found in these waters. During the year (2016), three sampling times were conducted for irrigation and drainage water sampling from six sites and fish sampling from El-Khandak El sharqi, El-Mahmoudia canals and El- Khairy drain. Water quality of water samples was done to determine quality of water and to determine correlation to OCPs. The results of the present study can be summarized as follows:
1-Water quality of irrigated and drainage water
The physicochemical parameters were measured in irrigated and drainage water. The maximum pH value is in drainage system out of range of LAW 92/2013 modified from LAW48/ 1982, both of irrigated and drainage water have the same range. Also highest value of Turbidity and TDS are recorded in drainage sites, it was 48.3 and 808 mg /L, respectively. Electrical conductivity results have shown that there are large differences between irrigation and drainage systems, the highest value recorded was for drainage water, which was 1243 pmos/cm that could be correlated with water runoff from agricultural and sewage systems that increase conductivity due to additional ions such as chloride, phosphate and nitrate ions. DO exceeded the permissible limits almost all water samples collected from drainage water, it ranged between 5.53 and 7.48 mg /I in irrigated water, while it reached between 4.5 and 0 mg /I in draiage water, depletion in DO can suggest a high load of organic matter and nutrients. COD of drainage sites is higher than irrigation sites because of high load of organic matter. High levels of BOD measurements at all sites refer to the sampled water contain organic materials that can be degradable by different organisms and this may indicate that sewage or agriculture wastes. High ammonium value in nearly all locations can be correlated with sewage containing a significant volume of urea, agricultural runoff (ammonia in fertilizer) and/or phytoplankton execration of ammonia. Nitrate recorded high levels that are above the permissible limits in some irrigated water but not above level in drainage water, because the permissible limit in drainage water is greater than in irrigated water. Concentration of sulphate and Chloride in drainage water are higher than irrigated water. All samples exceed permissible limits of alkalinity at irrigated and drainage water except two samples in irrigatied water in Egypt standard.
2- Residual levels of organochlorine pesticides (OCPs) in irrigated and drainage waters
A- Residual levels in irrigated water
Almost the tested compounds of (OCPs) were quantified in all sites, except T-HCH in (Denshal in April, Zawyat Ghazal and Zarkon in April and December), Heptachlor Epoxide in (Denshal in December and Zawyat Ghazal in April and December), Endosulfanel in (Denshal in April, Zarkon in April and July while during three months in Zawyat Ghazal site), P-Endosulfane at all sites in April, 6-HCH, Aldrin and Dieldrin were found below its limit of quantitation in all the tested water sites. While rest of pesticides (a- HCH, p-HCH, T-HCH, Heptachlor, Heptachlor Epoxide, Endosulfanel, P-Endosulfane , p,p’-DDT and p,p’-DDE) were quantified. The highest average amounts of extractable a- HCH, P-HCH, P-Endosulfane and p,p’-DDE were in Denshal site, T-HCH and p,p’-DDT.