Abstrato

Residues of some organic pollutants, their bioaccumulation, and risk assessments profile in Lake Temsah, Ismailia, Egypt

Tawfic Ahmed M, Almatari, MS, Yousry M Ahmed, Laila Reda and Naglaa Loutfy

Residues of polycyclic aromatic hydrocarbons (pahs), polychlorinated biphenyls (pcbs) and organochlorine pesticides (ocps) were monitored in Lake Temsah ecosystem including fish and bivalve species, water and sediment. The concentration of these organic pollutants were in the order of pahs>ocps> pcbs. The mean total concentrations of pcbs (Σ 11 pcbs) were in the order of sediment (49.8 ng/g), biota (29.7- 44.7 ng/g), water (16.1 ng/ml. PCB118, a dioxin -like congener is detected in almost all samples, at concentrations not exceeding 4.5-24% of Σ 11 pcbs. Concentration of pcbs in sediment samples (49.8 ng/g) exceeded the Canadian pcbs threshold effect level (TEL) of 21.5 ng/g, but were below pcbs probable effect level (PEL) of 189 ng/g. The ocps concentration reported in biota were below FDA Regulatory Action Levels of 0.3 μg/g in Fish. For biota, bioaccumulation factors (BAF) of ocps (23.7-560) were much higher than those of pcbs (0.1-12.9) and pahs (0.1-1.2), with heptachlor epoxide showing the highest mean bioaccumulation factor (BAF). Similar trend was reported for the biota−sediment accumulation factor (bsafs) with values of 0.33 to 5.57 for ocps, 0.11 to 4.53 for pcbs, and 0.16 to 4.47 for pahs. The greatest BSAF values were for DDT metabolites.