Organochlorine and pyrethroid residues: Occurrence, potential sources, degradation path, ecological and health risk assessment in maize plantation – A pilot study from southwest Nigeria

Due to the ban on the use of organochlorines, resulting from environmental and public health concern, there has been a significant surge on the use of pyrethroid pesticides for agricultural purposes. This has necessitated a pilot study on organochlorine and pyrethroid residues in four maize plantations in southwest Nigeria. The composition distribution of pesticide residues in the sampling sites includes hexa-chlorocyclohexane, hexachlorobenzene, cyclodiene, methoxychlor, type I and II pyrethroids. The high concentration of total organochlorine pesticides (TOCPs) ranging from 22.082 to 28.370 µg/g, as well as type I and II pyrethroids ranging from 12.320 to 35.668 µg/g and 2.541 to 10.936 µg/g indicated the intense use of these pesticides for agricultural purpose. Additionally, health risk assessment revealed that the incremental life cancer risk for dermal, ingestion and inhalation according to age and gender followed a similar sequence of female seniors > female adults > male seniors > male adults > adolescents > children. Moreover, the non-carcinogenic hazard index for organochlorines and pyrethroids was less than 1, whereas the risk quotient for pyrethroids was higher than 1, except for deltamethrin in most of the sampling sites. Thus, assessment of organochlorine and pyrethroid residues is essential to facilitate pesticide control and promote sustainable soil management.