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Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in eight sampling sites collected from El-Mex Bay sediments during the period of 2013–2015. Concentrations of PCBs, Hexachlorocyclohexanes (HCHs), Dichloro Diphenyl Trichloroethanes (DDTs), and cyclodienes ranged from 0.148 to 23.99, ND to 0.089, ND to 4.64, and 0.005 to 0.581 ng g−1dry wt, respectively. Total organic carbon (TOC) was relatively low, ranging from 0.09% to 1.42%. Total carbonate content ranged from 38% to 58%. The negative correlation of TOC with total pesticides (r  =  −0.18) suggested that TOC does not have a role binding with pesticides. On the other hand, a positive correlation between PCBs and TOC (r  =  0.254 atp > 0.01) was observed probably due to the low solubility of PCBs in the seawater. So, it will continue to precipitate until it reaches the bottom water and contaminates the sediment. The data obtained in the present work compared well with the counterpart data reported internationally. In general, the results of PCBs and OCP concentrations in El-Mex Bay sediments were much lower than the permissible levels recorded by sediment quality guidelines (SQGs). Interestingly, the organochlorines in sediments of El-Mex Bay were below the respective SQG values and were not likely to pose potential biological adverse impact. [ABSTRACT FROM AUTHOR]

Lake Burullus is one of the Delta lakes, connected with the Mediterranean Sea through El Boughaz opening. Concentrations of organochlorine contaminants were measured in water, sediments and biota of the lake because of concerns about their effects on its productivity. The concentrations of chlorinated hydrocarbons decreased in the order of PCBs > DDTs > TC > HCHs for all water samples collected from Lake Burullus during 2006. Higher concentrations were recorded during summer season, this clearly affected by higher agricultural and sewage activities. The concentrations of DDTs in water were ranged from 0.07 to 221.9 ng L−1; 46.3–656.5 ng L−1; 94.3–882.6 ng L−1 and 24.8–233 ng L−1 during winter, spring, summer and autumn, respectively. Among DDTs metabolites p,p-DDE was the most dominant with a maximum of 520.13 ng L−1 recorded at station 10 (El Boughaz opening). In sediment samples, PCBs concentrations were ranged from 4.6 to 213.9 ng g−1 with an average 47.2 ng g−1; dry weight. Total pesticides were higher than PCBs for mostly all sediment samples of Lake Burullus. Concentrations of DDTs in fish tissues were ranged from 2.76 to 24.23 ng g−1 and from 14.16 to 45.13 ng g−1; wet weight for Oresochromus niloticus and Clarries sp., respectively. [ABSTRACT FROM AUTHOR]