Abstract:
Nine pesticide residues were detected in soil and water samples from the Waanpu Dam in the
Bimbilla District of Ghana at varying mean concentrations using Gas Chromatography. The
pesticide residues detected in the soil and water samples were chlorpyrifos, beta-endosulfan,
cypermethrin, aldrin, heptachlor, beta-BHC, heptachlor-epoxide, dieldrin, and methoxychlor.
The concentration of beta-endosulfan was the highest among all the pesticides detected. It ranged
from 0.001 – 0.070 μg/g for soil samples and 0.001 – 0.036 μg/g for water samples. The mean
concentrations of pesticide residues in the soil samples analysed from the study sites were
generally below WHO 2017 maximum residue levels, MRLs, for agricultural soils except for
beta-endosulfan in all soil samples and chlorpyrifos at AS1, AS2, AS3, BS1, BS2, and BS3. The
mean concentrations of beta-endosulfan and chlorpyrifos at the above mentioned sites were
found to be above the respective WHO 2017 MRLs for agricultural soils. All pesticide residues
recorded in the water samples from the various zones were below the respective WHO 2017
MRLs for potable water except for beta-endosulfan at W1, W2, W3, E1, E2, and E3 which exceeded the WHO 2017 MRLs of 0.03 μg/g. Pesticide residues of beta-BHC, Dieldrin,
Heptachlor, Heptachlor-epoxide, Methoxychlor, cypermethrin, chlorpyrifos, and beta-endosulfan
showed significant differences at p<0.05.
The presence of pesticide residues in the samples analysed was an indication of the use of the
pesticides by farmers in the study area to control pests and diseases.
