Persistent organochlorine pesticide and PCB residues in surface sediments of Lake Qarun, a protected area of Egypt

► High levels of OCs were found at sites near wastewater discharges. ► Ubiquitous contaminants were endrin, γ-HCH, aldrin, CHLs, and endosulfan. ► The composition of DDT and its metabolites suggest old input of DDT. ► Levels of OCs were low to moderate compared to other locations worldwide. ► Areas of expected potential ecotoxicological risk were identified.