Pesticide contamination pattern of surface water in an urban–agricultural mediterranean watershed (Wadi Guenniche, Bizerte Lagoon, Northern Tunisia)

Urban Farm DB summary

Two years of monthly water sampling and hydrological monitoring at the outlet of the Wadi Guenniche watershed (86 km², with rainfed cereal, legume and orchard cultivation and irrigated market gardening) in northern Tunisia, a tributary of the Bizerte coastal lagoon, tested for 469 pesticide active ingredients and metabolites. Twenty-nine pesticide active ingredients and 2 metabolites were detected in the water, 24 of which are authorized for use in Tunisia; 14 of the authorized substances had never before been mentioned in farmer surveys. The five most frequently detected herbicides and metabolites were AMPA (100%), glyphosate (94%), simazine (94%), 2,4-D (70%) and deisopropylatrazine (DIA, 47%). The detection frequency and concentration range suggest phytosanitary pressure and water contamination comparable to the northern Mediterranean shore, indicating a need for further study of pesticide use and fate on the southern shore, particularly in Tunisia.