Pesticide residues in water, sediments, and fish from some agro-aquaculture farms of the Moungo Division - Cameroon: levels, variability, and associated risks

Abstract

This study focuses on the detection of plant protection products (PPPs) in 30 samples taken from ten agro-fish farms in the Moungo Division of the Littoral Region (Cameroon). The analyses covered three types of matrices: fish tissue, sediments, and farm water. Pesticide residues were extracted using the QuEChERS method, standardized by AOAC (2007), which allows for rapid and efficient extraction of compounds in complex matrices. Only two pesticides, Ametryn and Benalaxyl, were detected above the analytical detection limits. They are present in environmental matrices such as water and sediments. The concentrations of pesticide residues in the farming water ranged from 463 to 737 µg/L, which is higher than the QL of 0.05 µg/L, indicating a definite presence and a very high concentration of the contaminant in the sample. There is no universal standard, but it should be noted that the concentrations found in sediments of ametryn (ranging from 321 to 1067 µg/kg) and benalaxyl (ranging from 1053 to 1742 µg/kg) exceed the ecological risk levels suggested by EFSA for triazines (0.05 to 0.1 mg/kg in sediments). These observations highlight the transfer of pollutants to aquaculture systems via external sources (runoff, agricultural practices) and emphasize the importance of regular monitoring of water and sediments. It is also essential to improve input management techniques in order to prevent future contamination of products derived from this sector.