Pesticide pollution status in cocoa plantation soil

Abstract

Management of cocoa plantation field relied on the use of pesticides over the years; hence, the fate of such chemicals is one of the most debated issues among the stakeholders. Young and old cocoa plantation fields from 4 major cocoa producing States in Nigeria were selected as the study area. Eight composites soil samples collected from 3 portions of 6 transect measured area (100 x 50m) of the field were transported to the laboratory in sterile glass jar for analysis. A total of 19 organochlorine pesticides residues; (aldrin, α-hexachlorohexane, β-hexachlorohexane, γ-hexachlorohexane, δ-hexachlorohexane, α-chlordane, γ-chlordane, p,p’-dichlorodiphenyldichloroethane, p,p’-dichlorodiphenyldichloroethylene, p,p’-dichlorodiphenyltrichloroethane, dieldrin, endosulfan I, endosulfan-II, endosulfan sulfate, endrin, endrin aldehydes, heptachlor, heptachlor epoxide and metoxychlor) were analyzed with gas chromatography equipped with electron capture detector. The results revealed the variation in the number of residues detected among the study fields. Endosulfan-I had the highest value g organochlorine pesticides residue detected. Most of the residue concentrations were within the European Union regulatory standard of Czech Republic. Other-cyclodine group had the highest concentration value among the evaluated organochlorine pesticides groups. The significant (P < 0.05) higher concentration of total organochlorine pesticides were observed in old fields. Composition quotients values indicate that most of the observed organochlorine pesticides residues were products of historical usage. There were strong correlations among the total organic carbon contents of soils and the total organochlorine pesticides compounds. Government regulatory agencies are encouraged to vigorously embark in further monitoring and ensuring the safety compliance of farmers towards the use of pesticides in Nigeria farms.