The environmental behavior of microplastics (MPs) in estuaries with saline and freshwater intersections is extremely complex. This increases the chance of MP ingestion by fishery resources, posing potentially tremendous health risks for humans. Herein, a total of 105 fishes from 14 different species, and 86 crustaceans (including shrimps and crabs) from five different species were sampled in the Yangtze River estuary and offshore, and MP bioaccumulation, accumulative organ, and the influencing factors were comprehensively studied. The results elucidated that MP accumulation in benthos was significantly higher than that in pelagic animals due to the lower acceptance threshold, assimilation efficiency and egestion rate for benthos. The MP content in crustaceans with the burrowing favoring the MP retention was significantly higher than that in fishes. MPs ingested by fish can accumulate in skin, gills and viscera rather than muscles. Most MPs accumulated in fishery resources were cellulose and polyethylene terephthalate characterized by black and gray fibrous and lengths ranging from 0.1 mm to 1 mm. The gill retention capacity of pelagic fish to smaller-size (<0.1 mm) MPs was pronouncedly stronger than that of benthic fish. It was more accurate to assess the ecological risk of MPs in terms of the maximum size of MPs accumulated in organisms. Compared with the offshore area, the incidence of MP uptake was higher in the estuary owing to anthropogenic impacts. This study helps understand the transfer of MPs in aquatic food webs and offers a foundation for assessing the risk of human exposure to MPs.

In arid inland irrigated areas, the role of human activities on fluoride enrichment in groundwater is not fully understood. There is an extremely arid climate, high-intensity irrigation, and severe soil salinization in the Hotan Oasis within the Tarim Basin, Northwestern China. In this study, hydrogeochemistry and environmental isotope methods were combined to explore the distribution characteristics and controlling processes of fluoride enrichment in groundwater. The F⁻ concentration in groundwater had a range of 1.12–9.4 mg/L. F⁻ concentrations of all the groundwater samples were higher than 1.0 mg/L (Chinese Standards for Drinking Water Quality), and about 89% were higher than 1.5 mg/L (WHO Guidelines for Drinking Water Quality). High fluoride groundwater was mainly distributed downstream of the river and in the middle of the interfluvial zone. Vertically, the fluoride concentration was higher when the sampling depth was less than 15 m. There was a significant positive correlation between F⁻ concentration and salinity in groundwater. F⁻ in groundwater was mainly derived from river water fluoride, which could be imported to groundwater with infiltration of rivers and irrigation canals as well as irrigation return flow. Anthropogenic inputs may be partly responsible for fluoride enrichment in groundwater. Fluoride accumulated in the vadose zone by strong evapotranspiration and then leached into groundwater with irrigation return flow was the main mechanism of F⁻ enrichment in groundwater in the study area. This work is a clear example of how human activities together with natural processes can affect the chemical quality of groundwater, which is essential to safeguard the sustainable management of water and soil resources inland arid oasis areas.

In this study, a novel approach was employed for the remediation of cationic and anionic metals/metalloids co-contaminated soil by tetrapolyphosphate enhanced soil washing coupled with ferrous sulfide treatment. Tetrapolyphosphate could simultaneously enhance the desorption of cationic metals (Pb and Zn) and anionic metal/metalloid (Cr and As) from the contaminated soil in the whole tested pH range of 2–10. With addition of 0.15 mol/L tetrapolyphosphate at pH 7.0, the removal ratio of Pb, Zn, As and Cr could achieve 83.1%, 70.4%, 75.7% and 66.4% respectively. The fractionation analysis of heavy metals/metalloids demonstrated the release of exchangeable and Fe/Mn bound forms contributed to most desorption of Pb and Zn. The decreases of non-specifically sorbed form and amorphous and poorly-crystalline hydrous oxides of Fe and Al bound form were responsible for most removal of As. The comparison with other common washing agents (EDTA, oxalate and phosphate) under their respective optimal dosage could confirm that tetrapolyphosphate was superior to simultaneously desorb the cationic and anionic metals/metalloids with higher efficiency. After 12 h, applying 150 mg/L FeS at pH 3.5 could totally remove Pb, Zn, As and Cr from the washing effluent by sulfide precipitation, reduction and adsorption processes. Higher pH would inhibit the removal of As and Cr by FeS. Meanwhile, the residual of tetrapolyphosphate could be totally recovered from the washing effluent by employing anion exchange resin. This study suggests tetrapolyphosphate enhanced soil washing coupled with ferrous sulfide treatment is a promising approach for remediation of cationic and anionic metals/metalloids co-contaminated soil in view of its high efficiency and simple operation.

To date, knowledge of internal human exposure to BPA and its analogues (particularly bisphenol S and bisphenol F, etc.) remains limited. In the present study, a method involving dispersive solid-phase extraction and LC/MS was proposed to investigate the contamination levels of 28 precursor bisphenols and 9 major metabolites in serum. The critical variables of preparation method were screened out by Plackett-Burman design and further optimized by central composite design. Left in optimal conditions, a total of 286 samples consisting of 153 males and 133 females were analyzed. The results showed that BPA dominated over all the cases with the highest positive rate (82.2% of all the surveyed people), and totally four metabolites (BPA β-D-glucuronide, BPA monosulfate, BPA bis-(β-D-glucuronide) and BPS monosulfate) were detectable. The occurrence of BPA bis-(β-D-glucuronide) in serum is reported for the first time and its higher positive rate and contamination concentrations suggested that it may be a more important metabolite of BPA than others. Negligible potential risk of health effects to blood donors was observed, since the estimated exposure levels (mean 32.1 ng/kg bw/day, 95th 123.2 ng/kg bw/day) were well below far less than the temporary tolerable reference dose of BPA that recommended by the European Food Safety Authority (4 μg/kg bw/day by). The reference level of BPA for healthy population was determined to be 4.09 μg/L via the percentile method.

The increasing microplastics (MPs) pollution and continuous acid rain coincide in many areas of the world. However, how MPs interact with acid rain is still unclear. Herein, we conducted a microcosm experiment to decipher the combined effect of polyethylene (PE) MPs (1%, 5%, and 10%) and acid rain (pH 4.0) on the agricultural soil ecosystem of Southern China, in which edaphic property, microbial community, enzymatic activity and CO₂ emission were investigated. The results showed that PE MPs significantly decreased soil water retention and nitrate nitrogen content regardless of acid rain. Soil total nitrogen significantly decreased under the co-exposure of 10% PE MPs and acid rain. However, PE MPs did not alter soil microbial biomass, i.e., the content of microbial biomass carbon, total phospholipid fatty acids, with or without acid rain. 10% PE MPs and acid rain treatment significantly increased the activity of catalase and soil CO₂ emission. PE MPs addition did not affect the temperature sensitivity (Q₁₀) of soil CO₂ emission regardless of acid rain. These findings suggest that MPs may interact with acid rain to affect soil ecosystems, thus underscoring the necessity to consider the interaction between MPs and ambient environmental factors when exploring the impact of MPs on the soil biodiversity and function.

Lead-zinc slag (LZS) is a solid waste product that is rich in silicon and aluminum and has enormous resource potential for functional environmental functional geopolymer materials. Unfortunately, the solidification mechanism of heavy metals in geopolymers is still unclear, which is detrimental to the heavy metal solidification of LZS. In this study, we comprehensively studied and demonstrated the solidification mechanisms of Pb and Zn in geopolymers, based on the preparation of high-performance LZS-based geopolymers (compressive strength up to 89.3 MPa, and Pb and Zn solidification efficiency up to 93.1% and 90.0%, respectively). Thereafter, the solidification mechanism differences between Pb and Zn were explained by electronegativity and ion potential. Due to the ionic potential order of Zn²⁺> Pb²⁺> Na⁺, both Zn²⁺ and Pb²⁺ could exchange with Na⁺ in the geopolymer. In addition, due to the electronegativity order of Pb > Si > Zn, Pb could attack the [SiO₄] structure and form covalent bonds in the Pb–O structure, while Zn did not (shown by Raman spectroscopy). As a result, Pb simultaneously solidified in the geopolymer through covalent bonding and ion exchange, while Zn was solidified mainly by ion exchange. Thus, this work provides new perspectives and ideas for the solidification mechanisms of heavy metals in geopolymers.

Wastewater treatment plants (WWTPs) are considered one of the important sources of aquatic/terrestrial microplastic (MP) pollution. Therefore, the abundance and properties of MPs in the wastewater and sludge of an urban WWTP in Bursa Turkey were investigated. The amount, properties, and removal of MPs were evaluated. The results showed that the average abundance of MPs was 135.3 ± 28.0 n/L in the influent and 8.5 ± 4.7 n/L in the effluent, with a 93.7% removal rate, MP was removed and transferred to the sludge. The daily MP amount released in the aquatic environment is calculated as 525 million MPs, and the annual amount is 1.9 × 10¹¹ MPs. The abundance of MPs in the sludge thickening and sludge filter cake is 17.9 ± 2.3 and 9.5 ± 2.3 n/g dry weight (dw), respectively. The sludge disposal amount of WWTP is 81.5 tons/day and the approximate amount of MP accumulated in the sludge per year is calculated as 2.8 × 10¹¹ MPs. In wastewater and sludge samples, fragment dominant shape, black main colour, and 500–1000 μm sizes are the most common size. The main MP types in wastewater samples at the influent are polypropylene (PP, 36.8%), polyethylene (PE, 31.0%), polystyrene (PS, 11.8%), polyethylene terephthalate (PET, 8.0%), and polyamide (PA, 7.1%), at the effluent (PE, 33.0%), (PP, 52.5%), and (PS, 8.2%). In the sludge cake, the distribution is (PE, 40.8%), (PP, 27.6%), (PS, 18.7%) and (PET, 8.0%). The results of this study show that MPs are removed from wastewater with high efficiency by treatment processes and a significant amount accumulates in the sludge. Therefore, it is suggested that to integrate advanced treatment processes into urban WWTPs and use effective sludge disposal management practices to reduce the amount of MP released into the environment with effluent and sludge.

To investigate tissue distribution, spatial difference, temperature variation, and potential health risks of PAEs in vegetables, celery was used as a model plant. Celery samples were collected from open fields and greenhouses from two provinces in China over four seasons. Celery tissues were analyzed for 16 PAE compounds by gas chromatography–tandem mass spectrometry. The total content of PAEs was 89.0–1130.3 μg kg⁻¹ dry weight (dw) in stems and 155.0–2730.8 μg kg⁻¹ dw in leaves. Concentrations of PAEs in celeries showed notable spatial differences (P < 0.05), and the levels in samples from open fields were lower than those in samples from plastic greenhouses. In celeries from greenhouses, higher PAE concentrations were observed for plants grown at high temperatures than in plants grown at low temperatures. Discrepancies in tissue distribution indicated different uptake pathways of PAE contaminants. Risk assessments to humans found that both carcinogenic risks and non-carcinogenic risks of PAEs via celery consumption were at an acceptable level. Further research should consider other exposure pathways of PAEs and pay special attention to reducing PAE contents in vegetables.

Increasing levels of artificial light at night (ALAN) are a major threat to global biodiversity and can have negative impacts on a wide variety of organisms and their ecosystems. Nocturnal species such as bats are highly vulnerable to the detrimental effects of ALAN. A variety of lighting management strategies have been adopted to minimise the impacts of ALAN on wildlife, however relatively little is known about their effectiveness. Using an experimental approach, we provide the first evidence of negative impacts of part-night lighting (PNL) strategies on bats. Feeding activity of Myotis spp. was reduced along rivers exposed to PNL despite no reduction in overall bat activity. We also provide the first evidence of negative effects of PNL on both feeding and activity for Pipistrellus pipistrellus which has previously been recorded feeding under artificial light. Despite having considerable energy-saving benefits, we outline the potential negative impacts of PNL schemes for bats in riparian habitats. PNL are unlikely to provide desired conservation outcomes for bats, and can potentially fragment important foraging habitats leading to a breakdown of functional connectivity across the landscape. We highlight the potential dichotomy for strategies which attempt to simultaneously address climate change and biodiversity loss and recommend alternative management strategies to limit the impacts of ALAN on biodiversity.

The contamination of paddy soils is of great concern since it links to human health via food supply. Limited knowledge is available on PCB residue characteristics and the associated health risks in paddy soils under various environmental conditions. In this study, a soil sampling campaign was conducted in three typical paddy fields, i.e., Sanjiang Plain (SP), Taihu Plain (TP) and Hani Terrace (HT), crossing a transect of 4000 km in China. The concentrations of 29 quantified PCBs varied from 58.6 to 1930 pg/g in paddy soils, with samples at TP showing the highest burden. Tri-CBs were the major homologue group at SP and HT, whereas hexa-CBs at TP. Altitude, temperature, soil organic matter content and soil conductivity well explained the variations in PCB concentrations among sites. The homologue profiles of soil PCBs followed the fractionation theory. In addition, soil conductivity was found to be negatively correlated to low-chlorinated PCBs and positively to high-chlorinated congeners. Furthermore, the toxicities of soil PCBs and the exposure risks through rice intake were estimated. Higher toxicity equivalent quantities and hazard indexes were found at SP than TP and HT, with over one third of the samples displaying health risks. The results of this work highlight the necessity to better understand the occurrence characteristics and the associated health risks of PCBs in soils of rice-growing regions.