Pesticides, Heavy Metals and Plasticizers: Contamination and Risk Assessment of Drinking-Water Quality

This study highlights the impact of formal agricultural practices and their adverse effect on the deterioration of underground water quality, with special emphasis on toxic elements, including pesticides, herbicides, fungicides, plasticizer accumulation and heavy-metal contamination. A comprehensive study was conducted at various recently developed societies of Sadiqabad that were formerly used for agricultural purposes. Ten various societies were selected, and three samples from each society were collected from different regions of these areas. Data regarding the physicochemical properties, metal contamination and accumulation of pesticide residues were determined using standard protocols. The results revealed that almost all the physicochemical properties of water samples selected from these sites were close to the WHO’s recommended limits. The range for physicochemical properties was pH (6.4–7.7), electrical conductivity (168–766 µ S cm−1), turbidity (6–17 NTU), total hardness (218–1030 mg L−1), chloride contents (130–870 mg L−1) and phosphate contents (2.55–5.11 mg L−1). Among heavy metals, lead and arsenic concentrations in all sampling sites were found to be above the recommended limits. The decreasing pattern in terms of water-quality deterioration with respect to physicochemical properties was FFT > USM > CRH > UCS > CHS > MAH > FFC > CGA > GIH > AGS. Overall, 95 different kinds of toxic elements, including pesticides, herbicides, plasticizer, etc., were detected in the groundwater samples. The toxic compounds in the groundwater were categorized into pesticides, herbicides, plasticizer, plant growth regulators, fungicides, acaricides and insecticides. Most of these parameters showed peak values at the Fatima Fertilizer Company area and Chief Residencia Housing Society. Pesticide contamination showed that water-filtration plants have a big positive impact on the drinking quality of water. Proper monitoring of the pesticides must be performed, as the majority of the pesticides showed low priority. The monitoring method of the pesticides needs to be updated so that the occurrence of recently authorized pesticides is demonstrated.