Evaluation of water pollution by insecticides in the Gharb plain (Morocco)

Abstract

Agriculture intensification relies on the use of enormous quantities of phytosanitary agents, resulting in contamination of the air, soil, and water, as well as a risk to human life. The purpose of this study was to evaluate the contamination of groundwater by insecticides using liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography tandem mass spectrometry (GC-MS/MS) analyses in the Gharb plain, which is part of the Sebou watershed in Morocco's northwestern region. The analysis of 20 samples from 20 different wells, which cover a 250,000 ha irrigated perimeter, revealed the presence of an intense insecticide contamination, which is concentrated in the southern part of the study area, where the contamination level in 50% of the water samples exceeds the WHO standard (0.5 g/l). The data that exceed the detection threshold (0.01 g /l) range from 0.21 g / l in well P7 to 6.71 g / l in well P12. The presence of 22 active components of insecticides, such as malathion, methomyl alderine, dieldrin, and fenthion, is also detected, indicating that pesticides are widely used in this location and that there is a high danger of contamination.