The increasing prevalence of short-chain per- and polyfluoroalkyl substances (PFASs) poses significant challenges for urban water systems (UWS) due to their persistence, high mobility, and widespread occurrence. This study provides a comprehensive assessment of the occurrence, environmental transport, influencing factors, removal efficiency, and human health risks of PFASs across UWS impacted by industrial activities. Regulatory restrictions on long-chain PFASs have led to their replacement with short-chain analogues, resulting in their dominance in effluents from manufacturing plant parks (MPPs), with concentrations ranging from 30.28 to 3738.51 ng/L (mean: 557.68 ± 1072.03 ng/L). Wastewater treatment plant (WWTP) serve as both sources and sinks of PFASs, with a negative average removal efficiency (-47.4 %) and an estimated annual discharge of 12.29 kg of PFASs into the environment. Downstream of WWTP, PFASs concentrations in rivers decrease exponentially due to dilution and sediment partitioning; however, short-chain PFASs persist over long distances due to their high aqueous mobility. While the detected PFAS levels in rivers pose low health risks to humans, they present low to medium ecological risks to aquatic organisms, particularly algae, invertebrates, and fish. Advanced statistical analyses using piecewise structural equation modeling (piecewiseSEM) and co-occurrence network analysis (CNA) identified key environmental drivers of PFASs behavior, including heavy metals (effect size: 0.70), nutrient levels (0.36), and physicochemical parameters (-0.52). Furthermore, drinking water treatment plants (DWTPs) demonstrated limited removal efficiency, with tap water concentrations ranging from 27.95 to 84.72 ng/L, exceeding the regulatory limits set by the US EPA (2022) (PFOA: 0.004 ng/L, PFOS: 0.02 ng/L) and Health Canada (Σ₂₅PFAS: 30 ng/L). These findings underscore the urgent need for enhanced regulations, the development of sustainable alternatives, and the implementation of advanced treatment technologies to mitigate the environmental and public health risks associated with short-chain PFASs.

Background: Antibiotics and antibiotic resistance genes (ARGs) threaten ecological sustainability and human health, especially the drinking water sources of the Douhe Reservoir, which have critical significance amid their direct use by people and the ecological hub of flora and fauna. Although antibiotics and ARGs pollution in reservoirs have been reported, it is of no practical significance to only study the changes (increase or decrease) of the abundance and diversity of ARGs, and it is more important to explore the mechanisms of the changes affecting ARGs. Thus, the occurrence and prevalence characterizations of the spatial and seasonal of the ARGs, mobile genetic elements (MGEs) and bacterial communities were comprehensively studied in present study. Results: 263 ARG (nine types of ARGs) and 51 MGE subtypes were detected in 56 samples, and the characteristics of the temporal and spatial distribution of ARGs, MGEs and the composition of bacterial communities were significantly different. Moreover, the correlation among the ARGs, bacterial communities, MGEs and environmental factors were defined, and the co-occurrence patterns associated with ARG subtypes, bacterial genera, and MGE subtypes between water and sediment of the Douhe Reservoir were different. Conclusions: In summary, ARGs were ubiquitous presence in water and sediment of the Douhe Reservoir, and the multidrug, aminoglycoside and macrolide–lincosamide–streptogramin B (MLSB) were main types of ARGs. Bacterial genera and the environmental factors [such as temperature (T), nitrate–nitrogen (NO– 3–N), total dissolved nitrogen (TDN), and total phosphorus (TP)] significantly affected the distribution pattern of ARGs. Overall, this research revealed the spatiotemporal change and transmission mechanisms of ARGs in the typical drinking water sources of reservoirs, which will supply clues to ensure the safety of water sources.