Batch sorption of metformin hydrochloride (MET) onto a specially designed biochar mix consisting of both macro (MAC) and micro (MIC) algae, rice husk and pine sawdust was conducted. Pyrolysis of both MAC and MIC algae mixture was done followed by chemical activation with hydrogen-peroxide. Additionally, sorption of MET under the influence of pH was separately investigated. Batch studies of isotherms were well described by Freundlich model with high non-linearity and Freundlich exponent values ranged anywhere from 0.12 to 1.54. Heterogeneity of MET adsorption to the bonding sites was attributed to the surface functional groups of the modified biochar. Amongst the four biochars, the activated macroalgae biochar (MACAC) and microalgae biochar (MICAC) depicted favourable adsorption of MET with maximum adsorption at pH 7. Up to 76% of MET removal from the environment was obatained using the MACAC biochar. Scanning electron micrographs coupled with energy dispersive X-ray, as well as elemental analyses confirmed formation of oxygen containing surface functional groups due to activation strengthening chemisorption as the main sorption mechanism. Further, Fourier transform infra-red spectroscopy and other surface functional group analyses along with Zeta potential measurements reinforced our proposed sorption mechanism. Lowest zeta potential observed at pH 7 enhanced the electrostatic force of attraction for both the biochars. Negative zeta potential value of the biochars under different pH indicated potential of the biochars to adsorb other positively charged contaminants. From a techno-economic perspective, capital expenditure cost is not readily available, however, it is envisaged that production of pyrolyzed biochar from algal biomass could make the process economically attractive especially when the biochar could be utilised for high-end applications.

Per- and polyfluoroalkyl substances (PFAS) have become a target of rigorous scientific research due to their ubiquitous nature and adverse health effects. However, there are still gaps in knowledge about their environmental fate and health implications. More attention is needed for remote locations with source exposures. This study focuses on assessing PFAS exposure in Gustavus, a small Alaska community, located near a significant PFAS source from airport operations and fire training sites. Residential water (n = 25) and serum (n = 40) samples were collected from Gustavus residents and analyzed for 39 PFAS compounds. In addition, two water samples were collected from the previously identified PFAS source near the community. Fourteen distinct PFAS were detected in Gustavus water samples, including 6 perfluorinated carboxylic acids (PFCAs), 7 perfluorosulfonic acids (PFSAs), and 1 fluorotelomer sulfonate (FTS). ΣPFAS concentrations in residential drinking water ranged from not detected to 120 ng/L. High ΣPFAS levels were detected in two source samples collected from the Gustavus Department of Transportation (14,600 ng/L) and the Gustavus Airport (228 ng/L), confirming these two locations as a nearby major source of PFAS contamination. Seventeen PFAS were detected in serum and ΣPFAS concentrations ranged from 0.0170 to 13.1 ng/mL (median 0.0823 ng/mL). Perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) were the most abundant PFAS in both water and serum samples and comprised up to 70% of ΣPFAS concentrations in these samples. Spearman's correlation analysis revealed PFAS concentrations in water and sera were significantly and positively correlated (r = 0.495; p = 0.0192). Our results confirm a presence of a significant PFAS source near Gustavus, Alaska and suggest that contaminated drinking water from private wells contributes to the overall PFAS body burden in Gustavus residents.

Although road traffic noise is the most important source of environmental noise emission in large cities, little is known about health burden. The present study was conducted to estimate the burden of diseases attributed to traffic noise in the metropolis of Tehran in 2017. Using noise maps provided by the municipality of Tehran, we calculated population exposure distribution in term of Ldₙ and Lₙᵢgₕₜ and the number of DALYs lost due to ischemic heart disease, hypertension, high sleep disturbance, annoyance and stroke endpoints based on the World Health Organization Environmental Noise Guidelines for the European Region. We applied published dose-response functions to estimate the traffic noise burden for high sleep disturbance and annoyance. We estimated 61,284 DALYs or 697 DALYs per 100,000 population attributed to traffic noise in Tehran for the reference year 2017. Highly sleep disturbance with a share of 58.74% of the DALYs was recognized as the most important contributor of disease burden, and noise annoyance with a share of 23.12% was ranked next. Ischemic heart disease (11.71%), stroke (5.12%), and hypertension (1.31%) were ranked third to fourth, respectively, in terms of the burden of disease caused by environmental noise. A considerable fraction of the population of Tehran lives in areas with an environmental noise higher than the standard level. The findings showed that traffic noise pollution is an important environmental risk factor in Tehran imposes the greatest burden on the community, mainly through highly sleep disturbance and noise annoyance endpoints.

Although the hazards of microplastics (MPs) have been quite well explored, the aberrant metabolism and the involvement of the autophagy pathway as an adverse response to environmental MPs in benthic organisms are still unclear. The present work aims to assess the impact of different environmental MPs collected from the south coast of the Mediterranean Sea, composed by polyethylene (PE), polyethylene vinyl acetate (PEVA), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP) and polyamide (PA) on the metabolome and proteome of the marine polychaete Hediste diversicolor. As a result, all the microplastic types were detected with Raman microspectroscopy in polychaetes tissues, causing cytoskeleton damage and induced autophagy pathway manifested by immunohistochemical labeling of specific targeted proteins, through Tubulin (Tub), Microtubule-associated protein light chain 3 (LC3), and p62 (also named Sequestosome 1). Metabolomics was conducted to further investigate the metabolic alterations induced by the environmental MPs-mixture in polychaetes. A total of 28 metabolites were differentially expressed between control and MPs-treated polychaetes, which showed elevated levels of amino acids, glucose, ATP/ADP, osmolytes, glutathione, choline and phosphocholine, and reduced concentration of aspartate. These novel findings extend our understanding given the toxicity of environmental microplastics and unravel their underlying mechanisms.

Long-term change and shorter-term variability in the atmospheric deposition of pollutants and marine salts can have major effects on the biogeochemistry and ecology of soils and surface water ecosystems. In the 1980s, at the time of peak acid deposition in the UK, deposition loads were highly dependent on prevailing weather types, and it was postulated that future pollution recovery trajectories would be partly dependent on any climate change-driven shifts in weather systems. Following three decades of substantial acidic emission reductions, we used monitoring data collected between 1992 and 2015 from four UK Environmental Change Network (ECN) sites in contrasting parts of Great Britain to examine the trends in precipitation chemistry in relation to prevailing weather conditions. Weather systems were classified on the basis of Lamb weather type (LWT) groupings, while emissions inventories and clustering of air mass trajectories were used to interpret the observed patterns. Concentrations of ions showed clear differences between cyclonic-westerly-dominated periods and others, reflecting higher marine and lower anthropogenic contributions in Atlantic air masses. Westerlies were associated with higher rainfall, higher sea salt concentrations, and lower pollutant concentrations at all sites, while air mass paths exerted additional controls. Westerlies therefore have continued to favour higher sea salt fluxes, whereas emission reductions are increasingly leading to positive correlations between westerlies and pollutant fluxes. Our results also suggest a shift from the influence of anthropogenic emissions to natural emissions (e.g., sea salt) and climate forcing as they are transported under relatively cleaner conditions to the UK. Westerlies have been relatively frequent over the ECN monitoring period, but longer-term cyclicity in these weather types suggests that current contributions to precipitation may not be sustained over coming years.

Water quality forecasting can provide useful information for public health protection and support water resources management. In order to forecast water quality more accurately, this paper proposes a novel hybrid model by combining data decomposition, fuzzy C-means clustering and bidirectional gated recurrent unit. Firstly, the original water quality data is decomposed into several subseries by empirical wavelet transform, and then, the decomposed subseries are recombined by fuzzy C-means clustering. Next, for each clustered series, bidirectional gated recurrent unit is applied to develop prediction model. Finally, the forecast result is obtained by the summation of the predictions for the subseries. The proposed forecast model is evaluated by the water quality data of Poyang Lake, China. Results show that the proposed forecast model provides highly accurate forecast result for all of the six water quality data: the average of MAPE of the forecast results for the six water quality datasets is 4.59% for 7 day ahead prediction. Furthermore, our model shows better forecast performance than the other models. Particularly, compared with the single BiGRU model, MAPE decreased by 32.86% in average. Results demonstrate that the proposed forecast model can be used effectively for water quality forecasting.

Survivorship of early life stages is key for the well-being of sea turtle populations, yet studies on animals that distribute around oceanic areas are very challenging. So far, the information on green turtles (Chelonia mydas) that use the open NE Atlantic as feeding grounds is scarce. Strandings occurring in oceanic archipelagos can provide relevant information about the biology, ecology and current anthropogenic pressures for megafauna inhabiting the open ocean. In this study, we analysed stranding events of green turtles found in the Azores archipelago to investigate interactions with marine litter. In addition, we quantified and characterized litter items stranded on beaches to provide a direct comparison between the ingested items with the debris found in the environment. A total of 21 juvenile green turtles were found stranded in the region between 2000 and 2020 (size range: 12–49 cm, CCL). Overall, 14% of the animals were entangled in marine litter and 86% of the turtles necropsied had ingested plastic. The mean abundance of items ingested was 27.86 ± 23.40 and 98% were white/transparent. Hard plastic fragments between 1 and 25 mm were the most common shape recovered in the turtles, similarly to what was found on the coastline. All of the litter items analysed with pyrolysis GC-MS revealed to be polyethylene (PE). This study provides the first baseline assessment of interactions of plastic litter with juvenile green turtles found at the east edge of the North Atlantic Subtropical Gyre. The combination of these results supports the hypothesis that migratory megafauna that use remote oceanic islands as a feeding ground are exposed to anthropogenic litter contamination dominated by plastics, even when these regions are located far away from big industrial centers or populated cities.

Bisphenol A (BPA) is a ubiquitous environmental pollutant, mainly from the manufacture and use of plastics. The use of BPA is restricted, and its new analogs (including bisphenol AF, BPAF) are being produced to replace it. However, the effect of BPAF on the male reproductive system remains unclear. Here, we report the effect of BPAF on Leydig cell regeneration in rats. Leydig cells were eliminated by ethane dimethane sulfonate (EDS, i.p., 75 mg/kg) and the regeneration began 14 days after its treatment. We gavaged 0, 10, 100, and 200 mg/kg BPAF to rats on post-EDS day 7–28. BPAF significantly reduced serum testosterone and progesterone levels at ≧10 mg/kg. It markedly reduced serum levels of estradiol, luteinizing hormone, and follicle-stimulating hormone at 100 and 200 mg/kg. BPAF significantly reduced Leydig cell number at 200 mg/kg. BPAF significantly down-regulated the expression of Cyp17a1 at doses of 10 mg/kg and higher and the expression of Insl3, Star, Hsd17b3, Hsd11b1 in Leydig cells at 100 and 200 mg/kg, while it induced a significant up-regulation of Fshr, Dhh, and Sox9 in Sertoli cells at 200 mg/kg. BPAF induced oxidative stress and reduced the level of SOD2 at 200 mg/kg. It induced apoptosis and autophagy by increasing the levels of BAX, LC3B, and BECLIN1 and lowering the levels of BCL2 and p62 at 100 and 200 mg/kg. It induced autophagy possibly via decreasing the phosphorylation of AKT1 and mTOR. BPAF also significantly induced ROS production and apoptosis at a concentration of 10 μM, and reduced testosterone synthesis in rat R2C Leydig cells at a concentration of 10 μM in vitro, but did not affect cell viability after 24 h of treatment. In conclusion, BPAF is a novel endocrine disruptor, inhibiting the regeneration of Leydig cells.

To improve the accuracy of dietary risk assessment of arsenic (As) from aquatic products, toxic As species (As(III), As(V), monomethylarsonic acid [MMA], and dimethylarsinic acid [DMA]) and total As were analyzed in 124 marketed aquatic products from eight coastal cities in China. Distribution characteristics of Toxic As (the sum of the four toxic As species) in the samples and associated risk of human dietary exposure were emphatically investigated. The impact of cooccurrence of As and other chemical elements in the aquatic products was assessed based on our former results of mercury (Hg) and selenium (Se). Toxic As contents (maximum value 0.358 mg kg⁻¹ wet weight) in the samples accounted for at most 14.1% of total As. DMA was the major component (mean proportion 50.8% for shellfish, 100% for fish) of Toxic As in aquatic products. Shellfish contained more Toxic As than fish did. Mean estimated daily intakes of Toxic As for the residents with aquatic product consumption rates of 46.1–235 g day⁻¹ ranged from 0.034 to 0.290 μg kg⁻¹ day⁻¹. Potential health risk was indicated among those who greatly consumed aquatic products, as their target hazard quotient (THQ) and target cancer risk (TR) values exceeded safety thresholds (1 for THQ, 10⁻⁴ for TR). DMA and MMA exposure contributed to 3.42–7.72% of the THQTₒₓᵢc Aₛ. Positive correlations between concentrations of As and Hg (Fish: r = 0.47, p < 0.01; Shellfish: r = 0.60, p < 0.01), as well as between that of As and Se (Fish: r = 0.69, p < 0.01; Shellfish: r = 0.37, p < 0.01) were found in the samples. It requires attentions urgently that As and Hg coexposure through aquatic product consumption rose the sum THQ of Toxic As and methylmercury (MeHg) to approximately two to eight times as high as the THQTₒₓᵢc Aₛ.

Wastewater and stormwater are both considered as critical pathways contributing microplastics (MPs) to the aquatic environment. However, there is little information in the literature about the potential influence of constructed wetlands (CWs), a commonly used wastewater and stormwater treatment system. This study was conducted to investigate the abundance and distribution of MPs in water and sediment at five CWs with different influent sources, namely stormwater and wastewater. The MP abundance in the water samples ranged between 0.4 ± 0.3 and 3.8 ± 2.3 MP/L at the inlet and from 0.1 ± 0.0 to 1.3 ± 1.0 MP/L at the outlet. In the sediment, abundance of MPs was generally higher at the inlet, ranging from 736 ± 335 to 3480 ± 4330 MP/kg dry sediment and decreased to between 19.0 ± 16.4 and 1060 ± 326 MP/kg dry sediment at the outlet. Although no significant differences were observed in sediment cores at different depth across the five CWs, more MPs were recorded in silt compared to sandy sediment which indicated sediment grain size could be an environmental factor contributing to the distribution of MPs. Polyethylene terephthalate (PET) fibres were the dominant polymer type found in the water samples while polyethylene (PE) and polypropylene (PP) fragments were predominantly recorded in the sediment. While the size of MPs in water varied across the studied CWs, between 51% and 64% of MPs in the sediment were smaller than 300 μm, which raises concerns about the bioavailability of MPs to a wider range of wetland biota and their potential ecotoxicological effects. This study shows that CWs can not only retain MPs in the treated water, but also become sinks accumulating MPs over time.