Baran Aşıkkutlu
Freshwater ecosystems are increasingly threatened by persistent organic pollutants, particularly organochlorine pesticides (OCPs), due to their persistence, bioaccumulation potential, and associated ecological and human health risks. This study investigated the occurrence, distribution, and human health risks of OCPs in water and sediments from Apa Dam Lake (Türkiye). Water and sediment samples were collected from three shoreline stations in April, July, and October 2024 and analyzed for 28 target OCPs using GC-ECD. Human health risks were evaluated through oral ingestion and dermal exposure pathways. Physicochemical parameters indicated good water quality during the study period. OCP concentrations in water were low and remained below regulatory limits, whereas sediments showed higher concentrations and detection frequencies, particularly for HCH isomers and DDT derivatives. Although average sediment concentrations remained generally low, HCH isomers and Σheptachlor epoxide exceeded sediment guideline values. Isodrin exhibited the highest concentrations among the detected compounds and was the major contributor to sediment contamination. Health risk assessment revealed negligible non-carcinogenic risks, with hazard quotient (HQ) and hazard index (HI) values below 1. Oral carcinogenic risks remained within acceptable limits (ILCR: 10⁻⁷-10⁻⁶), whereas dermal exposure produced higher carcinogenic risk estimates (up to 10⁻3), mainly associated with DDT-related compounds. Overall, OCP contamination in Apa Dam Lake was low compared with many aquatic ecosystems. However, the occurrence of OCP residues in sediments, exceedance of sediment guideline values for some OCPs, and potential dermal carcinogenic risks highlight the need for continuous monitoring to support effective OCP management in freshwater ecosystems.