Risk posed by chlorinated organic compounds in Abu Qir Bay, East Alexandria, Egypt

In Egypt, the picture of threats to humans and the environment from the exposure to organic pollutants is still incomplete. Thus the objectives of this study were to assess the occurrence and distribution of polychlorinated biphenyls (PCBs), organochlorine pesticides, and chlorpyrifos in sediments and mussels of Abu Qir Bay and their risks for environment and human health.

Twenty-three different compounds organochlorines were determined in 20 surfacial sediment and 10 mussel samples by gas chromatography-electron capture detector. A Screening Level Ecological Risk Assessment (SLERA) and a Human Health Risk Assessment (HHRA) were performed with the data.

ΣDDT (DDT, DDE, DDD) (average concentration 27 µg/kg dw) dominated the detected organic pollutants in the sediments, followed by CHLs (chlordane, heptachlor, heptachloro epoxide), hexachlorocyclohexane, chlorpyrifos, endosulfane, dieldrine, Σ6 PCBs, aldrine, hexachlorobenzene, pentachlorobenzene, methoxychlor, and mirex. In general, concentrations of Σ6 PCBs in mussels were higher than their corresponding sediment concentrations reflecting their relatively high bioavailability and bioaccumulative potential. However, concentrations of the organochlorine pesticides in mussels were lower than their corresponding sediment samples. Nevertheless, the SLERA on the bay sediments revealed that adverse ecological effects to benthic species are expected to occur whereas the HHRA showed that adverse health effects are not expected to occur from the consumption of the mussels.

With the help of a SLERA, it was possible to indicate which class of chlorinated organic compounds is of highest concern to assess and to improve the environmental quality of the bay. Monitoring of organochlorines and chlorpyrifos would be needed to control the future trend of pollution.