Search of Organochlorine Pesticide Residues (Pocs) in Bodies of Water in Cotton-Growing Area of Benin by GC-ECD

ABSTRACT:

Despite their incontestable services in agriculture, the use of pesticides is not without consequences on the environment. So, in an attempt to access the impacts of pesticides usage in agriculture in Benin, research of some residual organochloride pesticides have been conducted both in rainy and dry seasons in two cotton growing areas: the northern and central part of Benin. The analytical technique used is GC-ECD. During the dry season we notice that the DDT and its metabolites (DDE and DDD) represent 36% of all organochlorine pesticides (POCs) against 64 % of cyclodiens. Endosulfan comes first representing 57% of all organochlorine pesticides (POCs), then follows DDT with 17 %. During the rainy season these two types of organochlorine pesticides (POCs) represent 73% for cyclodiens and 23% for DDT and its by-products. Endosulfan comes first by representing 47% of all organochlorine pesticides (POCs) followed by DDT representing 12%. In the sediments and regardless of the season, the cyclodiens come first by representing 70% of all organochlorine pesticides (POCs) and then follows the DDT and its by-products which represent 30%. Since in the water column, the sediments are more contaminated in rainy season than in dry season (25273 ppb of all organochlorine pesticide (POCs) in rainy season against 2.256 ppb in dry season), it is derived from this study that northern areas are more contaminated than the central areas. Also a strong correlation has been established between the content of different moleculars of organochlorine pesticide (POCs). This means that the famers still use prohibited pesticides in the two areas despite existing laws like “Stockholm convention” which strictly ban the usage of those moleculars.