Perfluoroalkyl acids (PFAAs) in urban surface water of Shijiazhuang, China: Occurrence, distribution, sources and ecological risks

Plant species dominance over PFAAs in structuring bacterial communities and their functional profiles in treatment wetlands

This study investigates the impact of different plant species (Iris pseudacorus L., Phragmites australis (Cav.) Trin. Ex Steud., Typha latifolia L.) and solutions containing increasing perfluoroalkyl acids (PFAAs) concentrations (11 perfluorocarboxylic acids and three perfluorosulfonic acids, 500, 2500, and 5000 ng L-1, each) on bacterial communities in treatment wetland (TW) mesocosm systems. The aim was to rank the respective importance of plant species and pollutant concentration in shaping the structure of the selected bacterial communities. While microbial community structure was mainly a function of plant species, PFAAs had some effect on the predictable bacterial functional profiles. Among the tested species, Typha demonstrated exceptional versatility in supporting bacterial communities with enhanced nitrogen, sulfur, and organic compound metabolism, outperforming Iris and Phragmites. Different PFAA concentrations did not modify the overall taxonomical community structure, although they significantly altered the relative abundances of single functional groups. The observed variations in taxonomy-predictable functional groups highlighted the impact of PFAAs on specific plant bacteria, with potential implications also for the metabolism of other specific compounds. The study also identified distinct bacterial functional profiles associated with specific plant species, revealing that bacteria linked to Typha exhibited more specialized functions, while those associated with Phragmites qualified more within the generalist category. This suggests that Typha may be particularly suitable for TWs under PFAA-rich wastewaters, due to its ability to support the metabolism of organic compounds. Additionally, results indicated that phylum diversity may be used as a reliable proxy of functional diversity patterns. Overall, this study contributes to cast light on the intricate relationships between plant species, PFAA concentrations, and bacterial communities and their catabolic functions, which provides an exploitable advancement of knowledge for the optimization of treatment wetlands.

Integrated environmental assessment of a diversion-project-type urban water source considering the risks of novel and legacy contaminants

The water diversion project is an effective engineering approach to overcome water scarcity as a water source for the area. However, the complex environmental conditions of long-distance water diversion bring many uncertainties for water security. In this study, we assessed the pollution condition and risk levels of emerging contaminants and traditional contaminants in the water and soil along a water diversion project in Tianjin. Then, we assessed the influence of eco-economic characteristics on environmental conditions and established a comprehensive assessment framework of water source sustainability by analytic hierarchy process (AHP). The results showed that excessive nutrient elements and heavy metal pollution mainly contributed to environmental problems in the water source area. Contrary to pollution assessment, the soil ecosystem was more subject to environmental pressure due to atmospheric deposition. The health risk assessment indicated that all contaminants had negligible non-carcinogenic risks for adults, with arsenic being considered a priority pollutant. The statistical analysis results indicated land use allocation was the most important factor in the environmental management of the water source area. According to the result of the integrated environmental assessment, the main characteristics of pressure zones were high pollution levels and human activity intensity. It is urgent to control agricultural pollution and allocate land use rationally for water source pressure zones. By considering the risks of traditional and emerging contaminants in water and soil, this study could support urban water source management and the sustainable development of the water diversion project.

Association between per- and poly-fluoroalkyl substances and nonalcoholic fatty liver disease: A nested case-control study in northwest China

Per- and poly-fluoroalkyl substances (PFAS) have been reported to have hepatotoxic effects. However, it is unclear whether they are linked to non-alcoholic fatty liver disease (NAFLD). This nested case-control study focused on the epidemiological links between PFAS and the prevalence of NAFLD. We selected 476 new cases of NAFLD and 952 age- and sex-matched controls from the Jinchang cohort population between 2014 and 2019. Serum concentrations of PFAS were measured using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Only PFAS with a detection rate of ≥90 % were included for analysis, which included PFPeA, PFOA, PFNA, PFHxS, PFOS, and 9Cl-PF3ONS. The relationship between single and co-exposure to PFAS and the occurrence of NAFLD was evaluated using conditional logistic regression, Quantile g-computation (QgC), and Bayesian kernel machine regression (BKMR) model. Logistic regression indicated that PFPeA, PFOA, and 9Cl-PF3ONS were positive correlation with the incidence of NAFLD after adjusting for confounders, with odds ratios (OR) and 95 % confidence interval (CI) of 3.13 (95 % CI: 2.53, 3.86), 1.39 (95 % CI: 1.12, 1.73), and 1.41 (95 % CI: 1.20, 1.66), respectively. PFNA, PFHxS, and PFOS were nonlinearly and negatively associated with the incidence of NAFLD, with OR (95 % CI) of 0.53 (0.46, 0.62), 0.83 (0.73, 0.95), and 0.52 (0.44, 0.61), respectively. QgC showed a significant joint effect of PFAS mixture on NAFLD onset (OR: 1.52, 95 % CI: 1.24, 1.88). BKMR showed a weak positive trend between PFAS mixtures and NAFLD incidence. Positive correlations were primarily driven by PFPeA and 9Cl-PF3ONS, while negative correlations were mainly influenced by PFNA and PFOS. The BKMR model also suggested that there was an interaction between PFOS and PFNA and other four PFAS compounds. In conclusion, our findings suggest that individual and co-exposure to PFAS is associated with a risk of NAFLD onset.

Occurrence and Fate of Per- and Polyfluoroalkyl Substances (PFAS) in Atmosphere: Size-Dependent Gas-Particle Partitioning, Precipitation Scavenging, and Amplification

The concerns about the fate of per- and polyfluoroalkyl substances (PFAS) in the atmosphere are continuously growing. In this study, size-fractionated particles, gas, and rainwater samples were simultaneously collected in Shijiazhuang, China, to investigate the multiphase distribution of PFAS in the atmosphere. Perfluoroalkyl carboxylic acids (PFCAs) dominated the total concentration of PFAS in atmospheric media. A strong positive relationship (0.79 < R2 < 0.99) was observed between the concentration of PFCAs and organic matter fraction (fOM) in different particle size fractions, while no such relationship for perfluoroalkyl sulfonic acids (PFSAs) and fOM, suggesting fOM may be an important factor influencing the size-dependent distribution of PFCAs. Temperature played a key role in the gas-particle partitioning of PFAS, while it did not significantly affect their particle-size-dependent distribution. The associative concentration fluctuation of particle and particle-bound PFAS during precipitation suggested that precipitation scavenging was an important mechanism for the removal of PFAS from the atmosphere. Furthermore, temporary increases in atmospheric PFAS concentrations were observed during the precipitation. Fugacity ratios of PFAS in rainwater and gas phase (log fR/fG ranged between 2.0 and 6.6) indicated a strong trend for PFAS to diffuse from the rainwater to the gas phase during the precipitation, which may explain that the concentration of PFAS in the gas phase continued to increase even at the end of the precipitation.

Per- and polyfluoroalkyl substances (PFASs) in Chinese surface water: Temporal trends and geographical distribution

PFAS, recognized as persistent organic pollutants, present risks to both the ecological environment and human health. Studying PFASs in surface water yields insights into pollution dynamics. However, existing research on PFASs surface water pollution in China often focuses on specific regions, lacking comprehensive nationwide analyses. This study examined 48 research papers covering PFAS pollution in Chinese surface water, involving 49 regions and 1338 sampling sites. The results indicate widespread PFAS contamination, even in regions like Tibet. Predominant PFAS types include PFOA and PFOS, and pollution is associated with the relocation of industries from developed to developing countries post-2010. The shift from long-chain to short-chain PFASs aligns with recent environmental policy proposals. Geographic concentration of PFAS pollution correlates with industry distribution and economic development levels. Addressing point source pollution, especially from wastewater plant tailwater, is crucial for combating PFAS contamination. Greater emphasis should be placed on addressing short-chain PFASs.

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in water and edible fish species of Karun River, Ahvaz, Iran: spatial distribution, human health, and ecological risk assessment

Per- and polyfluoroalkyl substances (PFASs) such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are environmental contaminants with unfavorable impacts on human health and nature. This study aimed to determine the PFOA and PFOS concentration in water and fish samples from Karun, the largest river in Iran. According to the results, the PFOA and PFOS in water samples were 5.81-69.26 ng/L and not detected (n.d.)-35.12 ng/L, respectively. The dry season displayed higher concentrations in water samples than in the wet season. The maximum PFOS concentration measured was related to Barbus barbules sp. (27.89 ng/g). The human health risk assessment indicated minor risks (hazard ratio, HR < 1) from PFOA and PFOS through consuming contaminated drinking water and fish. Only HR value of PFOS in downstream area exceeded slightly 1.0, indicating potential health risk due to consumption of the river fish. Considering the average PFASs concentration, the risk quotients (RQs) showed low ecological risk.

Occurrence, mass loading, and post-control temporal trend of legacy perfluoroalkyl substances (PFASs) in the middle and lower Yangtze River

Present study focused on per- and polyfluoroalkyl substances (PFASs) occurrence in dry and wet seasons in the middle and lower Yangtze River (YZR) and changing temporal trends after years of control. Results revealed that perfluorooctanoic acid (PFOA) was 75 % of total PFAS concentrations (∑11PFASs). ∑11PFASs were ranged 0.20-28.49 ng/L and 1.17-112.84 μg/kg in water and sediment. The logKoc of perfluoroalkyl carboxylic acids was positive with the carbon chain length (p < 0.05, r2 = 0.78). A meta-analysis of results from 16 peer-reviewed publications about PFASs in the YZR showed that fluorochemical industries strongly influenced the high PFAS levels in the detected scenes. PFOA was still the primary pollutant. Individual PFAS in the lower reach was higher than those in the middle reach. The mass loading of PFASs imported into the sea was 10.80 t/y. This study will help develop effective approaches for controlling emerging pollutants in the YZR.

Distribution, sources and ecological risks of per- and polyfluoroalkyl substances in overlying water and sediment from the mangrove ecosystem in Hainan Island, China

Since data on Per- and polyfluoroalkyl substances (PFASs) in mangrove ecosystems are very limited. This study investigated the occurrence, distribution, sources, and ecological risk of 24 PFASs in the overlying waters and sediments of mangrove systems in Hainan Island, China. The concentration levels of PFASs in water and sediment ranged from 6.3 to 35.3 ng/L and from 0.33 to 10.2 ng/g dw, respectively. In terms of spatial distribution, firstly, the mangrove forests in Haikou and Sanya contained higher levels of PFASs; secondly, the eastern region contained higher levels of PFASs than the western region. The reasons for this may be related to the population size and development level of the region. For the organic carbon normalized sediment-water partition coefficient (log Koc), the results showed that log Koc decreased with increasing carbon chains for short-chain PFASs (with ≤6 CF2 units) and increased with increasing carbon chains for long-chain PFASs (with ˃6 CF2 units). Principal Component Analysis (PCA) and correlation analysis were employed to pinpoint specific origins of PFASs, namely firefighting, metal plating, food packaging, textiles, and fluoropolymer manufacturing. The risk quotient (RQ) values of PFASs in mangrove ecosystems on Hainan Island were all <1, but the existence of potential risks cannot be excluded. Hence, further investigations related to the bioaccumulation effects of PFASs in organisms in mangrove forests should be conducted to gain a more comprehensive understanding of their environmental behavior.

Advances in identifying and managing emerging contaminants in aquatic ecosystems: Analytical approaches, toxicity assessment, transformation pathways, environmental fate, and remediation strategies

Emerging contaminants (ECs) are increasingly recognized as threats to human health and ecosystems. This review evaluates advanced analytical methods, particularly mass spectrometry, for detecting ECs and understanding their toxicity, transformation pathways, and environmental distribution. Our findings underscore the reliability of current techniques and the potential of upcoming methods. The adverse effects of ECs on aquatic life necessitate both in vitro and in vivo toxicity assessments. Evaluating the distribution and degradation of ECs reveals that they undergo physical, chemical, and biological transformations. Remediation strategies such as advanced oxidation, adsorption, and membrane bioreactors effectively treat EC-contaminated waters, with combinations of these techniques showing the highest efficacy. To minimize the impact of ECs, a proactive approach involving monitoring, regulations, and public education is vital. Future research should prioritize the refining of detection methods and formulation of robust policies for EC management.

Spatiotemporal variations and bioaccumulation of per- and polyfluoroalkyl substances and oxidative conversion of precursors in shallow lake water

Per- and polyfluoroalkyl substances (PFAS) in water and fish from Nansi Lake, Chian and in inflowing tributaries and nearby sewage treatment plants (STPs) were determined to evaluate their distribution and bioaccumulation. The potential precursors of perfluoroalkyl acid (PFAA) present in the water were converted via hydroxyl radical oxidation. Over 3 seasons, the average concentration ranges of the 15 PFAA (∑₁₅PFAA) concentrations in Nansi Lake, inflowing tributaries, and STPs were 22.8-70.3, 19.5-43.5, and 84.1-129 ng L^-1, respectively. Perfluorooctanoic acid, perfluorooctane sulfonate (PFOS), and short-chain PFAA (perfluorocarboxlate acid <8, perfluorosulfonate acids <6) were present in high concentrations in the lake and tributaries. PFAA concentration was the lowest during the wet season and the highest during the dry season. Moreover, PFAA precursors were converted to perfluorocarboxlate acid. The concentration of C8-based precursors was higher than that of the C6-based precursors in the lake and tributaries. The concentration of PFAA in the fish liver was higher than that in fish muscles, and PFOS was the dominant chemical present in fish. Potential risk assessment based on Environment Quality Standard revealed heavy PFOS contamination in the fish. Thus, the water of Nansi Lake was heavily polluted by PFAS.