Evaluation and risk assessment of organochlorine pesticide residues in some fish species in south-south Nigeria

Abstract

This study reports the presence, distribution pattern, concentration levels and health risk assessment of organochlorine pesticide residues in fresh and cured fish species in South-South Nigeria. The concentrations of organochlorine pesticides in fresh and cured fish were analysed with Gas Chromatography/ Mass Spectrophotometry (GC-MS) after Soxhlet extraction of the fish species. The study revealed that no organochlorine pesticide was present in fresh fish. However, cured fish species from all the markets sampled had at least two organochlorine pesticide residues which ranged from endosulfan (0.252±0.0022–748±0.004ug/g), lindane (0.386±0.010–0.443±0.009 ug/g), heptachlor-epoxide (0.328±0.005–3.162±0.010ug/g), ortho-para-dichloro-diphenyl-trichloro-ethane (o,p’-DDT) (0.021±0.001–0.180±0.030ug/g) and aldrin (0.140±0.040–2.770±0.020ug/g). These levels are far higher than the maximum residual limit and allowable daily intake values recommended by World Health Organization (WHO) and Food and Agricultural Organization (FAO). There were no pesticide residues in fresh fish probably because the fisher folks in the study area may have abolished the use of obnoxious fishing methods due to the awareness of threats to the aquatic ecosystem. The high percentage occurrences, amounts and distribution of organochlorine pesticides in cured-fish from markets sampled could be as a result of the fact that these organochlorine pesticides were consistently used in the study area by fish processors, distributors and sellers. Human risk assessment of this study revealed a potential danger in the consumption of cured-fish containing the organochlorine pesticides seen in the study