Spatial distribution of pesticide residues in the groundwater of a condensed agricultural area

Pesticide residues in groundwater have caused health and environmental concerns in regions in which the water is used for drinking and irrigation purposes. In this study, seven pesticide residues were studied in groundwater of a condensed agricultural area in the Al-Qassim region, Kingdom of Saudi Arabia using multiresidue gas chromatography coupled with mass spectrometry. Diazinon followed by chlorpyrifos and carbofuran was the most frequently detected pesticide in the collected water samples. In most locations, pesticide residues detected in groundwater samples were above the maximum acceptable levels of total and individual pesticide contamination of 0.5 and 0.1 μg L−1, respectively. The spatial distribution of the detected pesticides showed extremely high concentrations in intensified agricultural areas 55 km southwest of Buraydah. The results of the present study are expected to provide adequate information to enable the formulation of guidelines for permissible pesticide residues in water. Additionally, a regular monitoring program for pesticide residues in water is suggested based on the strict guidelines for pesticidal use.