Bioaccumulation of PFASs in cabbage collected near a landfill site in China: Laboratory and field investigations

Family-based exposure assessment of legacy and alternative poly- and perfluoroalkyl substances (PFASs) by multiple pathways

PFASs are persistent, amphiphilic chemicals that bioaccumulate and cause adverse health effects. Restrictions on major PFASs have increased exposure to precursors and alternatives, requiring examination of contamination from major sources and internal levels. We collected house dust (n = 45), dietary (n = 124), and serum (n = 123) from 48 families and analyzed 30 PFASs. Three PFCAs (PFOA, PFDA, and PFUnDA) and one precursor (6:2diPAP) showed detection rates >90 % in house dust. Among these compounds, 6:2diPAP showed the highest level, with median of 4.71 ng/g dry weight. In dietary, PFPeA (1.43 ng/g) and 6:2FTS (0.61 ng/g) had the highest medians and were detected in all samples. In serum, the highest median was PFOA (4.50 ng/mL), followed by linear (L)-PFOS (3.90 ng/mL), L-PFHxS (1.79 ng/mL), and PFNA (1.15 ng/mL) across all family groups. The study identified diet as a significant exposure pathway, underscoring the importance of dietary habits in PFASs intake. The estimated daily intake from PFOA for all family members exceeded the USEPA's threshold. Compared to the EFSA's threshold for a mixture of four PFASs, exceedances ranged from 18 % to 38 %. This study highlights the need for continuous monitoring and regulation of PFASs and their alternatives to mitigate health risks.

Co-occurrence of microplastics, PFASs, antibiotics, and antibiotic resistance genes in groundwater and their composite impacts on indigenous microbial communities: A field study

There is a major gap in the occurrence of mixed emerging contaminants, which hinders our efforts in exploring their behaviors and transport in environmental media, as well as their toxicity to human and ecosystem. This study assessed the occurrence and their correlations of mixed contamination by microplastics (MPs), per- and polyfluoroalkyl substances (PFASs), antibiotics, and antibiotic resistance genes (ARGs) in groundwater collected from a pharmaceutical and chemical industrial park. MPs, PFASs, antibiotics and ARGs were detected at all monitoring wells. The total concentration range of MPs and 20 PFASs were 693-1032 pieces/L and 577.47-2982.45 ng/L, respectively, with perfluorooctanoic acid (PFOA) being the most prevalent compound among PFASs in groundwater. The abundance of detected target antibiotics and ARGs ranged from 1.97 to 30.65 ng/L and from 2.65 × 102 to 7.53 × 105 copies/mL, respectively. MPs and PFASs have a significant positive correlation, yet interestingly, no correlation was found between antibiotics and ARGs. In addition, the relatively high abundance of integron intI1 detected in the study area illustrated the potential horizontal transfer risk of ARGs in the subsurface. Furthermore, the effects of these mixed emerging contaminants on the indigenous microbial communities were elucidated. The coexistence of MPs, PFASs, antibiotics, and ARGs led to the enrichment of species that were tolerant to pollutants. Specifically, MPs, PFASs and ARGs were found to be positively correlated with Acinetobacter, unclassified_f__Comamonadaceae, Pseudomonas, Simplicispira and Proteiniphilum, while antibiotics were positively associated with Paenisporosarcina and Arthrobacter. Moreover, geochemical parameters such as oxidation-reduction potential and nitrate also played a key role in shaping the microbial community structure. The co-occurrence of mixed emerging contaminants highlighted in this study underscores the urgent need for comprehensive environmental monitoring, systematic toxicity assessments, and stricter regulatory frameworks. In addition, it offers insights in the development of effective bioremediation strategies to mitigate their impacts on both ecosystems and public health.

Migration characteristics and toxic effects of perfluorooctane sulfonate and perfluorobutane sulfonate in tobacco

Perfluorooctane sulfonate (PFOS) and its new substitute, perfluorobutane sulfonate (PFBS), are increasing in concentration in the environment annually, and their toxicity cannot be ignored. With an increasing amount of PFOS and PFBS entering the environment, especially into farmland soil, it is very likely to pollute tobacco-planting soil. Therefore, we chose tobacco (Nicotiana tabacum L.) as the test organism. Through the analysis of migration characteristics, we found that PFOS (0.82) is more likely to migrate within tobacco plants than PFBS (0.42). Pot experiments showed that PFOS has a more obvious inhibitory effect on the growth of tobacco. Further investigations revealed that PFOS induces oxidative stress reactions in tobacco and stimulates the increase in the activities of enzymes such as superoxide dismutase (SOD) and catalase (CAT). In addition, both PFOS and PFBS inhibit the expression of genes related to the synthesis of auxin and aroma substances in tobacco. In particular, under the exposure of 10 mg/kg PFOS, the inhibition rates are as high as 88.53 % and 92.32 % respectively. The results of this study compared the differences in toxicity between PFOS and PFBS, and provided a theoretical reference for the behavioral characteristics of new per-polyfluoroalkyl substances (PFASs) in the environment and their potential risks to the ecological environment.

From wastewater to feed: Understanding per- and polyfluoroalkyl substances occurrence in wastewater-irrigated crops

Reusing treated wastewater for irrigation is a sustainable way to recycle nutrients and reduce freshwater use. However, wastewater irrigation inadvertently introduces per- and polyfluoroalkyl substances (PFAS) into agroecosystems, causing concerns regarding potential adverse effects to ecosystem, animal, and human health. Therefore, a better understanding of the pathways by which PFAS accumulate in forage crops is needed. A greenhouse study was conducted to (1) quantify the contribution of root uptake versus foliar sorption of PFAS in corn (Zea mays) and orchard grass (Dactylis glomerata), (2) assess effects of PFAS-impacted wastewater irrigation on plant health, and (3) determine the potential implications for bioaccumulation. The greenhouse study was composed of four treatments for each forage crop to isolate the relative contribution of two uptake pathways. Results suggested that foliar sorption was an unlikely contributor to PFAS concentrations observed in crop tissue. Root uptake was identified as the predominant uptake pathway. PFAS were detected more frequently in orchard grass samples compared to corn silage samples. Additionally, corn exhibited a lower uptake of long-chain PFAS compared to grass. Overall, no plant health effects on growth attributable to PFAS concentrations were observed. Forage data suggest cattle exposure to PFAS would be largely short-chain PFAS or long-chain "replacement" compounds (>50%). However, cattle may still be exposed to potentially harmful long-chain PFAS; levels in the forage crops exceeded the tolerable weekly intake set by the European Food Safety Authority. This study provides insights on PFAS entry into the food chain and potential implications for livestock and human health.

Comparative uptake, translocation and metabolism of phenamacril in crops under hydroponic and soil cultivation conditions

Many studies investigate the plant uptake and metabolism of xenobiotics by hydroponic experiments, however, plants grown in different conditions (hydroponic vs. soil) may result in different behaviors. To explore the potential differences, a comparative study on the uptake, translocation and metabolism of the fungicide phenamacril in crops (wheat/rice) under hydroponic and soil cultivation conditions was conducted. During 7-14 days of exposure, the translocation factors (TFs) of phenamacril were greatly overestimated in hydroponic-wheat (3.6-5.2) than those in soil-wheat systems (1.1-2.0), with up to 3.3 times of difference between the two cultivation systems, implying it should be cautious to extrapolate the results obtained from hydroponic to field conditions. M-144 was formed in soil pore water (19.1-29.9 μg/L) in soil-wheat systems but not in the hydroponic solution in hydroponics; M-232 was only formed in wheat shoots (89.7-103.0 μg/kg) under soil cultivation conditions, however, it was detected in hydroponic solution (20.1-21.2 μg/L), wheat roots (146.8-166.0 μg/kg), and shoots (239.2-348.1 μg/kg) under hydroponic conditions. The root concentration factors (RCFs) and TFs of phenamacril in rice were up to 2.4 and 3.6 times higher than that in wheat for 28 days of the hydroponic exposure, respectively. These results highlighted that cultivation conditions and plant species could influence the fate of pesticides in crops, which should be considered to better assess the potential accumulation and transformation of pesticides in crops.

Crop Contamination and Human Exposure to Per- and Polyfluoroalkyl Substances around a Fluorochemical Industrial Park in China

Due to their significant environmental impact, there has been a gradual restriction of the production and utilization of legacy per- and polyfluoroalkyl substances (PFAS), leading to continuous development and adoption of novel alternatives. To effectively identify the potential environmental risks from crop consumption, the levels of 25 PFAS, including fourteen perfluoroalkyl acids (PFAAs), two precursor substances and nine novel alternatives, in agricultural soils and edible parts of various crops around a fluoride industrial park (FIP) in Changshu city, China, were measured. The concentration of ΣPFAS in the edible parts of all crops ranged from 11.64 to 299.5 ng/g, with perfluorobutanoic acid (PFBA) being the dominant compound, accounting for an average of 71% of ΣPFAS. The precursor substance, N-methylperfluoro-octanesulfonamidoacetic acid (N-MeFOSAA), was detected in all crop samples. Different types of crops showed distinguishing accumulation profiles for the PFAS. Solanaceae and leafy vegetables showed higher levels of PFAS contamination, with the highest ΣPFAS concentrations reaching 190.91 and 175.29 ng/g, respectively. The highest ΣAlternative was detected in leafy vegetables at 15.21 ng/g. The levels of human exposure to PFAS through crop consumption for various aged groups were also evaluated. The maximum exposure to PFOA for urban toddlers reached 109.8% of the standard value set by the European Food Safety Authority (EFSA). In addition, short-chained PFAAs and novel alternatives may pose potential risks to human health via crop consumption.