Effects of mining and metals production have been reported in freshwater lake sediments from around the world but are rarely quantified in saline lake sediments, despite the importance of these lake ecosystems. Here we used dated sediment cores from Great Salt Lake, Utah, USA, a large saline lake adjacent to one of the world’s largest copper mines, to measure historical changes in the deposition of 22 metals. Metal concentrations were low prior to the onset of mining in the catchment in 1860 CE. Concentrations of copper, lead, zinc, cadmium, mercury, and other metals began increasing in the late 1800s, with peaks in the 1950s, concomitant with enhanced mining and smelting activities. Sedimentary metal concentrations in the 1950s were 20-40-fold above background levels for copper, lead, silver, and molybdenum. Concentrations of most metals in surficial sediments have decreased 2-5-fold, reflecting: 1) storage and mineralization of sedimenting materials in a deep brine layer, thereby reducing metal transport to the sediments; 2) improved pollution control technologies, and; 3) reduction in mining activity beginning in the 1970s and 1980s. Despite reductions, concentrations of many metals in surficial sediments remain above acceptable contamination thresholds for aquatic ecosystems with migratory birds, and consumption advisories for mercury have been placed on three waterfowl species. The research also highlights that metal deposition in saline lakes is complicated by effects of hypersaline brines and deep-water anoxia in regulating sediment redox and release of metals to surface waters. Given the importance of saline lakes to migratory birds, metals contamination from mining and metals production should be a focus of saline lake remediation.

Efficient extracellular electron transport is a key for sufficient bioremediation of organoarsenic pollutants such as 4-hydroxy-3-nitrobenzenearsonic acid (roxarsone). The related apparent kinetics characteristics are essential for engineering practice of bioremediation activities and for full understanding the environmental fate of roxarsone, yet remains poorly understood. We report, to our knowledge, the first study of the electron transfer characteristics between roxarsone and participating S. oneidensis MR-1. The electron transfer rate during roxarsone biotransformation was estimated up to 3.1 × 10⁶ electrons/cell/s, with its value being clearly associated with the apparent roxarsone concentration. Lowing roxarsone concentration extended the average separation distance between cells and neighboring roxarsone molecules and thereby augmented electric resistance as well as extended cell movement for foraging, thus reduced electron transfer rate. In addition, the presence of roxarsone significantly stimulated population growth of S. oneidensis MR-1 with nearly doubled maximum specific growth rate, albeit with clearly increased lag time, as compared with that of none-roxarsone scenario. These findings provide, at the first time, basic biostoichiometry of S. oneidensis MR-1 induced roxarsone biotransformation, which may shed lights for full understanding of roxarsone transformation process in waste treatment systems that are necessary for engineering practice and/or environmental risks assessment.

To compare the health risks of multiple metal(loid)s in groundwater, and discuss the feasibility of drinking water standards, 66 groundwater samples were collected from the Hetao Plain in October 2017. Eighteen metal(loid) species (boron (B), manganese (Mn), iron (Fe), strontium (Sr), barium (Ba), lithium (Li), scandium (Sc), titanium (Ti), vanadium (V), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), rubidium (Rb), molybdenum (Mo), uranium (U)) were analyzed, and the related non-carcinogenic risks were assessed. The results showed that 83.3% of the groundwater samples had As and Fe contents above the maximum allowed contaminant levels (MCLs) in drinking water standards, followed by Mn (70.2%), B (65.2%), Se (60.6%), U (18.2%), Ni (18.2%) and Mo (1.50%). Compared with the dermal exposure pathway, oral ingestion made a risk contribution of more than 99% for all target metal(loid)s. Site-specific hazard quotient (HQ) values ranged from 2.30E+00 to 1.75E+02, indicating that multiple metal(loid)s in the drinking groundwater cause a serious non-carcinogenic risk to the local people. The risk contributions (mean value) were ranked as As (55.2%) > U (25.5%) > Li (10.8%) > other total metal(loid)s (8.60%), and the contributions of U and Li could reach 91.7% (site 20) and 69.8% (site 56), respectively. The calculation of specific health risks further indicated that the MCLs of metal(loid)s do not match the corresponding health risk well. Some metal(loid)s such as Li that showed high exposure risks in this study, still have no MCL values until now. Therefore, current drinking water standards need to be updated.

Inorganic particulate nitrate (p-NO3−), gaseous nitric acid (HNO₃₍g₎) and nitrogen oxides (NOₓ = NO + NO₂), as main atmospheric pollutants, have detrimental effects on human health and aquatic/terrestrial ecosystems. Referred to as the ‘Third Pole’ and the ‘Water Tower of Asia’, the Tibetan Plateau (TP) has attracted wide attention on its environmental changes. Here, we evaluated the oxidation processes of atmospheric nitrate as well as traced its potential sources by analyzing the isotopic compositions of nitrate (δ¹⁵N, δ¹⁸O, and Δ¹⁷O) in the aerosols collected from the Mt. Everest region during April to September 2018. Over the entire sampling campaigns, the average of δ¹⁵N(NO3−), δ¹⁸O(NO3−), and Δ¹⁷O(NO3−) was −5.1 ± 2.3‰, 66.7 ± 10.2‰, and 24.1 ± 3.9‰, respectively. The seasonal variation in Δ¹⁷O(NO3−) indicates the relative importance of O₃ and HO₂/RO₂/OH in NOₓ oxidation processes among different seasons. A significant correlation between NO3− and Ca²⁺ and frequent dust storms in the Mt. Everest region indicate that initially, the atmospheric nitrate in this region might have undergone a process of settling; subsequently, it got re-suspended in the dust. Compared with the Δ¹⁷O(NO3−) values in the northern TP, our observed significantly higher values suggest that spatial variations in atmospheric Δ¹⁷O(NO3−) exist within the TP, and this might result from the spatial variations of the atmospheric O₃ levels, especially the stratospheric O₃, over the TP. The observed δ¹⁵N(NO3−) values predicted remarkably low δ¹⁵N values in the NOₓ of the sources and the N isotopic fractionation plays a crucial role in the seasonal changes of δ¹⁵N(NO3−). Combined with the results from the backward trajectory analysis of air mass, we suggest that the vehicle exhausts and agricultural activities in South Asia play a dominant role in determining the nitrate levels in the Mt. Everest region.

The comparison of fly ash generated from lignite combustion in a thermal power plant Kolubara A (Veliki Crljeni) and bottom and fly ash from coal waste combustion in a semi-industrial fluidized bed boiler (Vinča) was performed as the function of particle size. The average total concentrations of the 16 EPA priority PAHs in ash fractions are 0.49 mg kg⁻¹ of ash (thermal power plant) and 17.48 mg kg⁻¹ of ash (fluidized bed boiler). The sum of 3- and 4-ring PAHs accounts for more than 93% of overall PAHs concentration, and the most abundant among them is fluoranthene.The portions of PAHs groups defined based on their physico-chemical properties, as obtained from quantitative structure-activity relationship (QSAR) models included in the Vega platform, were determined. These portions, emission factors, and benzo[a]pyrene equivalence concentrations were further on used to estimate the potential environmental impact of ash disposal. The PAHs emission factors are higher compared to values in the air pollutant emission inventory guidebook of the cooperative program for monitoring and evaluation of the long-range transmission of air pollutants in Europe (EMEP/EEA). The overall emission factors of 16 PAHs for combustion of lignite and coal waste are determined to be 0.15 and 249.97 mg kg⁻¹ of fuel, respectively. Based on the ratios of benzo[a]pyrene equivalence concentrations of each ash and correspondent fuel, the disposal of fly ash from the cyclone of fluidized bed boiler represents the highest risk to the environment among tested ashes.

Microplastics are ubiquitous in natural waters and affect the environmental fate of hydrophobic organic micropollutants. This study evaluated the impacts of four microplastics, polypropylene (PP), polyethylene (PE), polystyrene (PS) and polymethyl methacrylate (PMMA), on the photodegradation of organotin compounds (OTCs) under UV₃₆₅ irradiation (2.3 ± 0.1 W m⁻²). The experiments were performed by mixing PP, PE, PS or PMMA microparticles with tri-organotins in artificial seawater. The photodegradation of OTCs in microplastic suspensions was influenced by the absorptivity onto microplastics. The decomposition rate of tributyltin (TBT) in UV-irradiated PP suspensions was greater than trimethyltin (TMT) and triphenyltin (TPhT) (p < 0.01). The adsorption capacities of OTCs (e.g., TBT) on PP particle surfaces were significantly lower than those on PE surfaces (p < 0.05) but similar with those on PMMA due to the different surface areas, shapes, and surface hydrophobicity of microplastics. TBT degraded faster (9.1%) in PS than in PMMA suspension (11.2%) within 240 min, respectively. However, only less than 5.4% was photodegraded in PP suspension due to the light scattering or absorption of the large sized PP particles. This study provided new insight into the impacts of microplastics on photodegradation of micropollutants in natural waters.

Carbon disulfide (CS₂) is seen an odor-toxic organic sulfur compound, which presents a major impact on global climate change. Therefore, the conversion of CS₂ into valuable chemicals is the key to reduce the concentration of CS₂ in the atmosphere. On the basis of a CS₂ fixation strategy, CS₂-storage materials (CS₂SMs) are firstly synthesized by the reaction of CS₂ with a binary ion-like liquid systems of ethylenediamine (EDA) and ethylene glycol derivatives (EGs) under mild condition. In view of the serious shortage of sulfur fertilizer and its important position in global agricultural production, it is a promising choice to use the CS₂SMs as a new type of green sulfur fertilizer to promote the growth of eggplant, tomato, sweet pepper and cucumber. In this work, the influence of CS₂SMs on the growth of plants were studied by taking plants irrigated by using various aqueous CS₂SMs solutions as experimental groups, and those irrigated by using water and NH₄HCO₃ as control groups. The experimental results showed that all CS₂SMs could promote plant height, stem diameter, root weight, flower bud number and leaf size. Especially, several CS₂SMs presented significant influence on fluorescence and fruit number. Further studies showed that the CS₂SMs as new energy resources sulfur-containing boosted leaf area, improved root development, enhanced photosynthesis and soil nutrient uptake, and promoted vegetative and reproductive growth of these four types of plants. Thus, this work provided a new strategy for the use of CS₂ as an indirect energy source for the experimental four plants.

Infections caused by carbapenem-resistant Enterobacteriaceae are a growing concern worldwide. Raoultella ornithinolytica is a species in the Enterobacteriaceae family which can cause hospital-acquired infections and is sporadically reported as carbapenem-resistant from human and environmental sources. In this study, we firstly report on an NDM-1-producing R. ornithinolytica, Rao166, isolated from drinking water in an animal cultivation area in China. In addition to carbapenem-resistance, Rao166 was resistant to several other antibiotics including gentamicin, sulfamethoxazole-trimethoprim, tetracycline and fosfomycin. Rao166 carried a novel IncFIC-type megaplasmid, 382,325 bp in length (pRAO166a). A multidrug resistance region, 60,600 bp in length, was identified in the plasmid containing an aac(3)-IId-like gene, aac(6′)-Ib-cr, blaDHA₋₁, blaTEM₋₁B, blaCTX₋M₋₃, blaOXA₋₁, blaNDM₋₁, qnrB4, catB3, arr-3, sul1, and tet(D). Results from virulence assays implied that Rao166 has considerable pathogenic potential. Although pRAO166a was found to be non-transmissible, dissemination of the NDM-1 producing strain may occur from well water to humans or animals through cross-contamination during food preparation or directly via drinking water, and potentially lead to difficult-to-treat infections. Thus, contamination of well water by this carbapenem-resistant and presumptively virulent strain of R. ornithinolytica should be considered a potential public health risk.

Bisphenol A (BPA), a monomer used for polycarbonate manufacture, has been widely reported as an endocrine-disrupting chemical (EDC). Among other alterations, BPA induces reproductive dysfunctionalities. Changes in the endocannabinoid system (ECS) have been recently shown to be associated with reproductive disorders. The ECS is a lipid-based signaling system (cannabinoid receptors, endocannabinoids and enzymatic machinery) involved in several physiological functions. The main goal of the present study was to assess the effects of two environmental concentrations of BPA (10 and 20 μg/L) on the ECS in 1-year old zebrafish gonads. In males, BPA increased the gonadosomatic index (GSI) and altered testicular levels of endocannabinoids as well as reduced the testicular area occupied by spermatogonia. In male liver, exposure to 20 μg/L BPA significantly increased vitellogenin (vtg) transcript levels. In female zebrafish, BPA altered ovarian endocannabinoid levels, elevated hepatic vtg mRNA levels as well as increased the percentage of vitellogenic oocytes in the ovaries. In conclusion, exposure to two environmentally relevant concentrations of BPA altered the ECS and consequently, gonadal function in both male and female zebrafish.

Arsenic, a class I human carcinogen, is ubiquitously found throughout the environment and around the globe, posing a great public health concern. Notably, Bangladesh and regions of West Bengal have been found to have high levels (0.5–4600 μg/L) of arsenic drinking water contamination, and approximately 50 million of the world’s 200 million people chronically exposed to arsenic in Bangladesh alone. This study was carried out to examine genome-wide gene expression changes in individuals chronically exposed to arsenic-contaminated drinking water. Our study population includes twenty-nine Bangladeshi female participants with urinary arsenic levels ranging from 22.32 to 1828.12 μg/g creatinine. RNA extracted from peripheral blood mononuclear cells (PBMCs) were evaluated using RNA-Sequencing analysis. Our results indicate that a total of 1,054 genes were significantly associated with increasing urinary arsenic levels (FDR p < 0.05), which include 418 down-regulated and 636 up-regulated genes. Further Ingenuity Pathway Analysis revealed potential target genes (DAPK1, EGR2, APP), microRNAs (miR-155, -338, −210) and pathways (NOTCH signaling pathway) related to arsenic carcinogenesis. The selection of female-only participants provides a homogenous study population since arsenic has significant sex dependent effects, and the wide exposure range provides new insight for key gene expression changes that correlate with increasing urinary arsenic levels.