Occurrence and distribution of Pharmaceuticals and Personal Care Products (PPCPs) in wastewater related riverbank groundwater

Pharmaceutical and personal care products (PPCPs) are among the most frequently reported groups of emerging contaminants in groundwater worldwide. PPCPs in rivers may infiltrate into groundwater through hydraulic exchange and potentially threaten drinking water safety and human health. In the present study, the occurrence and distribution of nine PPCPs in riverbank groundwater and adjacent rivers (distance up to 113 m) were investigated at four sites with different lithological features and permeabilities of aquifers in a city in North China. Seven of nine PPCPs were detectable in groundwater, ranging from <LOQ (limit of quantification) to 128 ng/L. N,N-diethyl-meta-toluamide (DEET), carbamazepine, and caffeine had the highest detection frequencies (>90%). The concentrations and major compounds in river water varied with the sampling location and water system distribution, resulting in distinct compositions of PPCPs in the groundwater at each site along with different lithology and hydrological conditions. The spatial distribution of PPCPs in riverbank groundwater was affected by the hydraulic connection between the groundwater and river and the lithology of aquifers. Direct hydraulic connection of a fine sand aquifer to the adjacent river caused a decrease in PPCPs with increasing distance. The results also suggested that sandy gravel aquifers had a lower capacity to attenuate PPCPs compared to that of fine sand. Significant correlations between PPCP concentrations and thirteen physicochemical factors of groundwater were discovered, including nitrate, potassium, and manganese. Overall, this study provides important evidence on the role of lithology and hydrological conditions on the composition, distribution, and influential physicochemical factors of PPCPs in riverbank groundwater.

Occurrence and spatial distribution of perfluorinated compounds in groundwater receiving reclaimed water through river bank infiltration

Perfluorinated compounds (PFCs) in groundwater are of widespread concern due to their potential toxicity to human health and ecological systems. PFCs in rivers can infiltrate into groundwater through riverbank infiltration, potentially endangering the safety of drinking water and causing a deterioration in the groundwater environment. This study investigated the occurrence of PFCs in rivers and riverside groundwater from 2014 to 2017 in a city in north China. PFCs were detected in most of the groundwater samples, ranging from not detected to 64.8 ng L^-1. The predominant PFCs in both river and groundwater samples were perfluorooctane sulfonate, perfluorooctanoic acid, perfluorobutane sulfonate and perfluorobutanoic acid. The PFC concentrations and major compounds were consistent in both the river and riverside groundwater samples at each site, suggesting that the adjacent river was the source of the PFCs in the riverside groundwater. The spatial distribution of the PFCs in the riverside groundwater was affected by the hydraulic connection between the groundwater and the river, the lithology of the aquifer and the properties of the compounds. The results indicated that PFCs were attenuated during riverbank infiltration and the ability of different riverbank lithologies to remove PFCs was in the order sandy clay > fine sand > sandy gravel. Perfluorooctane sulfonate concentrations decreased sharply with increasing distances from river, whereas perfluorooctanoic acid, perfluorobutane sulfonate and perfluorobutanoic acid could by transported for greater distances in riverside groundwater. This study provides valuable information on PFCs in riverside groundwater affected by riverbank infiltration.