Obsolete pesticide residue level analysis and toxicological risk evaluation from Hadya Zone dump site, Ethiopia

Abstract

ABSTRACT. Hadya Zone (HZ) obsolete pesticide dump site was selected for determinations of OCPs from soil and assessing the toxicological risks to environment and human health. Composite soil samples were collected and extracted using Soxhlet (SOX) extraction method and analyzed for p,p’-DDT, p,p’-DDE, p,p’-DDD, α-BHC, β-BHC, g-BHC, d-BHC, g-chlordane, α-chlordane, and endosulfan sulfate using GC-MS. The total average concentrations of SDDTs, SBHCs, chlordanes, endosulfans were 41.92, 5.91, 11.47, 0.44 ng/g, respectively. DDTs, chlordanes and BHCs were categorized as causing potential risks to the eco-environment exceeding the threshold value (2.5 ng/g) set by Netherlands’ soil quality standards. However, endosulfans residual concentrations were below the threshold value. Carcinogenic risk assessments to humans were evaluated using incremental lifetime cancer risks (ILCRs) via three exposure routes (ingestion, dermal contact; inhalation). The average ILCRs values were 2.54 x 10^-8, 1.68 x 10^-8, and 2.71 x 10^-8 for the three age groups: childhood, adolescence, and adulthood, respectively. The result shows the cancer risk to humans from the soil matrix in the study site was acceptable. However, since the dumping site is at high elevation, there is high probability to be transported via runoff to different environmental matrices: river water, sediment and biota. Thus, if the residue analyses of all these environmental matrices are considered, the risk might be increasing.

KEY WORDS: Obsolete pesticide, Dump site, Toxicological risk assessment, OCPs

Bull. Chem. Soc. Ethiop. 2022, 36(2), 329-337.                                                               

DOI: https://dx.doi.org/10.4314/bcse.v36i2.7