A comprehensive analysis of organochlorine pesticides in Egyptian waters: distribution, ecological impacts, and health risks

Organochlorine pesticides (OCPs) are a pressing global issue, particularly in developing countries like Egypt. These pervasive pesticides pose an environmental and public health concern in Egypt due to their historical use and frequent identification in soils, water bodies, and food products. These present a potential long-term risk to human health and ecosystems. We collected water and Nile tilapia (Oreochromis Niloticus) samples in four Egyptian governorates: Alexandria, Port Said, Ismailia, and Faiyum. Our analysis, through using gas chromatography/mass spectrometry, spans 17 OCPs in depth. Our study revealed that certain OCPs, such as Heptachlor, Aldrin, Pentachloronitrobenzene, Heptachlor epoxide, and β-Endosulfan, are consistently found in higher concentrations among the 17 pesticides tested. Seasonal spikes were identified, particularly in Ismailia, Faiyum, and Alexandria, marking them as environmental risk hotspots. Certain OCPs demonstrated distinctive seasonal variations, such as 4,4′-DDE in Faiyum. Heptachlor, β-HCH, Endrin, and α-Endosulfan exhibited significant changes solely in Ismailia, while α-HCH, Heptachlor epoxide, and γ-HCH showed unique seasonal patterns only in Alexandria. The risk quotient (RQ) analysis highlighted that Aldrin, Heptachlor, 4,4′-Dichlorodiphenyltrichloroethane, and 2,4′-Dichlorodiphenyltrichloroethane pose a high environmental risk in all governorates, while 4,4′- Dichlorodiphenyltrichloroethane showed high risk only in Port Said (RQ > 1). Several OCPs posed an ecological risk with an RQ > 1. In addition, our results emphasized that there is negligible non-carcinogenic risk associated with dermal water exposure or the consumption of Nile tilapia. There is, however, a minor risk of cancer associated with consuming Nile tilapia or dermal exposure. Therefore, we recommend advocating for strict regulations, implementing monitoring programs, initiating public health initiatives, adopting effective alternatives, developing new remediation approaches, conducting long-term and association studies, and examining the consequences of climate change on the persistence of OCPs in the environment.