Abhatoo - Centre Nationale de Documentation

Levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in sediment samples collected at 5 sites along Oualidia lagoon (Morocco) from spring 2015 to winter 2016. A total of 13 organochlorine compounds (OCs), namely 7 OCPs and 6 PCBs markers were searched. Target analytes include p,p’-DDT (2,2,-bis(4-chlorophenyl)-1,1,1-trichloroethane) and its metabolites (DDE and DDD), aldrin, heptachlor, lindan, hexachlorobenzene (HCB) as well as following PCBs congeners : PCB28, PCB52, PCB101, PCB138, PCB153, and PCB180. The highest levels of the total concentrations of OCPs (ΣOCPs) were 31.19 ng/g dry weight (d.w.) and that of the 6 PCBs (ΣPCBs) 9.44 ng/g d.w. In addition to spatial variation, these organochlorine compounds showed seasonal variations, with an increase of OCPs, in particular DDE compared to its metabolites, from spring to a maximum in autumn. For PCBs, the highest levels were observed in spring, with dominance of PCB153 compared to other congeners. Furthermore, a significant correlation was observed between the accumulation of DDT and DDE on the one hand and between DDT and aldrin on the other. According to the Sediment Quality Guidelines, the risk of adverse biological effects from such levels of PCBs as recorded at most of the study sites was insignificant. However, DDT levels at two sites could cause biological damage.