Groundwater contamination in China has been greatly concerned due to dramatically increasing fresh water demand accompanied by economic development. However, little is known about aquifer vulnerability to hazardous matters especially in previously contaminated site of rapidly urbanizing cities. Here, we collected 90 groundwater samples from Xiong'an New Area during wet and dry seasons of 2019 and characterized the composition and distribution of emerging organic contaminants (EOCs) in this strategically developing city. A total of 89 EOCs, assigned to organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and volatile organic compounds (VOCs), were detected with the frequencies ranging from 1.11 %-85.6 %. Methyl tert-butyl ether (16.3 μg/L), Epoxid A (6.15 μg/L), and α-Lindane (5.15 μg/L) could be identified as major contributors to groundwater organic pollution. Significant aggregation of groundwater EOCs along Tang River were found due to historical residue and accumulation from wastewater storage there before 2017. Significant seasonal variations (p < 0.05) in the types and concentrations of EOCs could be attributed to discrepant pollution sources between varying seasons. Human health effects from exposure to groundwater EOCs were further evaluated with negligible risk (<10-4) in most samples (97.8 %) and notable risk (10-6-10-4) in several monitored wells (2.20 %) located along Tanghe Sewage Reservoir. This study provides new evidences for aquifer vulnerability to hazardous matters in historically contaminated sites and is of significant to groundwater pollution controlling and drinking water safety for rapidly urbanizing cities.
Keywords: Groundwater; Health risk; Organochlorine pesticides; Polychlorinated biphenyls; Source identification; Volatile organic compounds.
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