Spatial Distribution and Ecological Risk of OCPs and PCBs in Sediments from Lake Edku, Egypt

Lake Edku represents one of the important sites for the environment and wildlife in Egypt. Persistent organic pollutants (POPs) hurt the environment and human health. All the samples were analyzed using gas chromatography coupled with a flame ionization detector. Hexachloro cyclohexanes (HCHs) recorded 1.83 -3.68 µg/kg and 6.27–7.03 µg/kg with an average 4.69 ±0.84 and 4.30 ±2.01 µg/kg during spring and summer, respectively. Total cyclodienes (TC) ranged between 1.02 - 2.70 µg/kg and 12.96–16.03 µg/kg, with an average 8.58 ±3.50 and 9.55 ±5.10 µg/kg during spring and summer, respectively. 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane DDTs ranged between 16.79–1.00 µg/kg and 19.15–16.79 µg/kg with an average 17.69 ±0.84 and 10.46 ±5.26 µg/kg during spring and summer, respectively. α-HCH/γ-HCH ratio suggested the use of pure lindane for agricultural purposes. β-/(α+γ)-HCH ratio suggests recent HCH input and past usage. o,p′-DDT/p,p′-DDT, suggesting that technical DDTs were the main source, except stations IV, V, and VIII during summer that indicated dicofol-type of DDT. DDE + DDD)/∑DDTs ratio indicating past input of DDT. DDE/DDD ratios refer to anaerobic and anaerobic degradation. Sediment quality and ecological risk assessments: γ-HCH, Dieldrin, and Endrin do not represent any danger or actual threat to the environment. The concentrations of ∑DDE, ∑DDDE, and ∑PCBs are indicated as safe values for the ecosystem. The results obtained from principal component analysis (PCA) showed that the studied compounds could migrate into the lake from drains, leading to their accumulation and deposition in the lake.