Terbuthylazine (TBA) has replaced atrazine in many EU countries, becoming one of the most frequently detected pesticides in natural waters. TBA is a compound of emerging concern, due to its persistence, toxicity and proven endocrine disruption activity to wildlife and humans. Techniques applied in water treatment plants remove only partially this herbicide and poor attention is given to the generation and fate of by-products, although some of them have demonstrated an estrogenic activity comparable to atrazine. This paper summarizes the environmental occurrence of TBA and its main metabolite desethylterbuthylazine and reports the performance of an innovative electrochemical cell equipped with a solid polymer electrolyte (SPE) sandwiched between a Ti/RuO₂ cathode and a Boron-Doped Diamond anode, operating at constant current, in the treatment of an aqueous solution of TBA. The herbicide removal in the first 30 min of treatment increases from 42% to 92% as the applied current is increased from 100 to 500 mA. The rate of degradation at 500 mA decreases between 30 and 60 min, with a final abatement of 97%. An 89% removal was reached at 100 mA when the initial TBA concentration was raised from 0.1 to 4 mg L⁻¹ and less than 1% of the herbicide was converted in desethylterbuthylazine and minor metabolites. No chemicals are needed, no sludge is produced. Further research is encouraged, as this technology may be promising for the achievement of a zero-discharge removal of different emerging pollutants as pesticides, pharmaceuticals and personal care products.

Release of fluoride from Quaternary sediments produces F-contaminated groundwater which threatens the health of millions of people worldwide. Despite the mechanisms of fluoride release from sediments are documented by numerous studies, it remains poorly understood that whether indigenous microbes participate in or not for the formation of F-rich groundwater by releasing fluoride from aquifer sediments. A microcosm-based approach, geochemistry and techniques of microbiology and molecular ecology were conducted together to investigate these mechanisms. Results show that microbes are abundant in high [F] groundwater containing at least 1129 operational taxonomic units (OTUs), and indigenous microbes can have an essential role in the mobilization of fluoride in sediments collected from aquifers in a typical fluorosis area in China. It also shows that for the sediments in this study, fluoride release (ca. 2 mg/L) is coupled with elevated concentrations of Ca (△ = 75 mg/L), Mg (△ = 33 mg/L), Al (△ = 0.2 mg/L) and Mn (△ = 1.4 mg/L). This suggests that the fluoride may source from the dissolution of F-bearing carbonate minerals and/or Al-Mn hydroxides in a local acidic environment. The findings provide additional insights into the biogeochemical circulation of fluoride in natural environment, especially in groundwater system and the development of effective strategies for the management of F-contaminated groundwater worldwide.

Understanding the chemical response and characteristics of bacterial communities in soil is critical to evaluate the effects of selenium (Se) supplement on plant growth and chromium (Cr)/Se uptake in Cr contaminated soil. The rhizosphere soil characteristics of pak choi (Brassica campestris L. ssp. Chinensis Makino) were investigated in soil contaminated with different levels and forms of Cr when supplemented with Se. Although inhibition of plant growth caused by Cr stress was not completely alleviated by Se, Cr content in plant tissues decreased in Cr(VI)120Se5 treatment (Cr(VI): 120 mg kg−1 soil; Se: 5 mg kg−1 soil) and its bioavailability in soil decreased in Cr(III)200Se5 (Cr(III): 200 mg kg−1 soil; Se: 5 mg kg−1 soil) treatment. Moreover, antagonism of Cr and Se on soil enzyme activities and bacterial communities were revealed. Notably, results of Cr(VI) reduction and Se metabolism functional profiles confirmed that bacterial communities play a critical role in regulating Cr/Se bioavailability. Additionally, the increases of Se bioavailability in Cr contaminated soil were ascribed to oxidation of Cr(VI) and reduction of Se reductases proportions, as well as the enhancing of pH in soil. These findings reveal that Se has the potential capacity to sustain the stability of microdomain in Cr contaminated soil.

For divalent metals, the Biotic Ligand Model (BLM) has been proven to be an effective tool to predict biological effects by taking into account speciation calculations and competitive interactions. Nonetheless, the BLM has only rarely been validated for trivalent metals (e.g. rare earth elements), and the potential competitive effects of protons has been understudied. In this paper, the short-term biouptake of indium (In), a trivalent metal that is a byproduct of zinc extraction and used in numerous applications including the semiconductor industry, was evaluated under controlled conditions. Short-term (i.e. 60 min) indium biouptake by Chlamydomonas reinhardtii was measured as a function of pH in order to verify the validity of the BLM. At a given pH, In biouptake could be well described by the Michaelis-Menten equation with conditional stability constants of KIn,pH=4.0 = 106.7 M-1, KIn,pH=5.0 = 108.6 M-1, KIn,pH=6.0 = 109.3 M-1 and maximum internalization fluxes of Jmax, pH=4.0 = 0.74 × 10−14 mol cm−2 s−1, Jmax, pH=5.0 = 1.60 × 10−14 mol cm−2 s−1, Jmax, pH=6.0 = 2.22 × 10−14 mol cm−2 s−1. Although several potential mechanisms for the role of pH were examined, the results were best explained by a competitive interaction of H+ with the In uptake sites using overall stability constants of logKIn = 9.76 M-1 and logKH = 15.66 M-1. Based on these results, pH will play a critical role in bioavailability measurements of the trivalent cations in natural waters.

Cadmium is one of the most serious metal pollutants in the Bohai Sea. Previous studies revealed that mitochondrion might be the target organelle of Cd toxicity. However, there is a lack of a global view on the mitochondrial responses in marine animals to Cd. In this work, the mitochondrial responses were characterized in clams Ruditapes philippinarum treated with two concentrations (5 and 50 μg/L) of Cd for 5 weeks using tetraethylbenzimidazolylcarbocyanine iodide (JC-1) staining, ultrastructural observation and quantitative proteomic analysis. Basically, a significant decrease of mitochondrial membrane potential (△Ψm) was observed in clams treated with the high concentration (50 μg/L) of Cd. Cd treatments also induced specific morphological changes indicated by elongated mitochondria. Furthermore, iTRAQ-based mitochondrial proteomics showed that a total of 97 proteins were significantly altered in response to Cd treatment. These proteins were closely associated with multiple biological processes in mitochondria, including tricarboxylic acid (TCA) cycle, oxidative phosphorylation, fatty acid β-oxidation, stress resistance and apoptosis, and mitochondrial fission. These findings confirmed that mitochondrion was one of the key targets of Cd toxicity. Moreover, dynamical regulations, such as reconstruction of energy homeostasis, induction of stress resistance and apoptosis, and morphological alterations, in mitochondria might play essential roles in Cd tolerance. Overall, this work provided a deep insight into the mitochondrial toxicity of Cd in clams based on a global mitochondrial proteomic analysis.

To differentiate the source of aeolian dust between the desert sources from Pan-third pole and high mountain glaciers, therefore, we investigated the spatial variability of aeolian dust sources in the Pan-third polar region. The question of whether such changes reflect variable transport pathways from a unique source in the western China area was addressed. That is, the SrNd radiogenic isotope composition of modern desert samples do not support the hypothesis of a single dust provenance at higher elevation mountain glaciers by long-distance transport; regional sources also play a significant role. Based on previous studies and the data from this study, the five isotopic regions were divided, which are controlled by the geological characteristics in western China. The results suggest that mineral dust deposited into the high-mountain glaciers originated from the free ice region because of glacier melting and the physical and chemical erosion of rocks from the surrounding mountains by local wind systems. The Pb isotopic data further demonstrated that natural dust is the source of Pb for the high-mountain glaciers of Pan-third pole. These results provide an exhaustive documentation of the isotopic signature of the regional dust reaching the glacier regions.

We conducted a meta-analysis to evaluate the association between prenatal cadmium (Cd) exposure and birth weight. PubMed, Embase, China National Knowledge Infrastructure (CNKI), and Wanfang databases were searched for studies published before March 2019. We used a model-based method, standardizing effect size from linear regression models to include a maximum number of studies during our quantitative evaluations. As a result, 11 articles from the general population, containing 10 birth cohorts and one cross-sectional study, were included. Our meta-analysis demonstrated that a 50% increase of maternal urine Cd (UCd) would be associated with a 6.15 g decrease in neonatal birth weight (β = −6.15 g, 95% CI: −10.81, −1.49) as well as a 50% increase of maternal blood Cd (BCd) would be associated with an 11.57 g decrease (β = −11.57 g; 95% CI: −18.85, −4.30). Stratified analysis of UCd data indicated that the results of female newborns were statistically significant (β = −8.92 g, 95% CI: −17.51, −0.34), as was the first trimester (β = −11.34 g, 95% CI: −19.54, −3.14). Furthermore, increased UCd levels were associated with a higher rate of low birth weight (LBW) risk (OR = 1.12, 95% CI: 1.03, 1.22). This meta-analysis demonstrated that elevated maternal Cd levels are associated with decreased birth weight and higher LBW risk.

Mercury-antimony (HgSb) mining activities are important anthropogenic sources of Hg and Sb to the local environment. The Xunyang HgSb mine situated in Shaanxi Province is an active Hg mine in China. To understand the emission, transportation, and deposition of Sb through HgSb mining activities, current study systematically monitored the Sb concentration in precipitation in the Xunyang HgSb mining district. Five groups of experimental pots were carefully designed to further investigate the influence of HgSb mining activities on the Sb contamination in the local surface soil. Based on the overtime increasing of the Sb concentrations in soil from experimental pots, for the first trial, we estimated the atmospheric deposition flux/mass of Sb in the Xunyang HgSb mining district. Our results showed that the concentrations of Sb in precipitation in the Xunyang HgSb mining district ranged from 0.71 μg L−1 to 19 μg L−1 (mean = 4.2 ± 4.5 μg L−1), which was orders of magnitude higher than that at the control site. As expected, the concentration of Sb in precipitation was highly elevated near of the HgSb smelter and gradually decreased with distance from the smelter. After 12 months exposure, Sb concentrations in soil of experimental pots were increased by 1.2–8.5 times. The average atmospheric wet and dry deposition flux of Sb in the Xunyang HgSb mining district were 7.2 ± 6.9 μg m−2 day−1 and 2.1 ± 4.7 mg m−2 day−1, respectively; the annual wet and dry deposition mass of Sb through HgSb mining activities were estimated to be 1.6 t y−1 and 158 t y−1, respectively, indicating that dry deposition was the dominant pathway (98 ± 1.2%) for the removal of Sb from the atmosphere. Our results confirmed that the ongoing HgSb mining activities resulted to serious Sb contamination to terrestrial ecosystems, posing a potential threat to local residents in the Xunyang HgSb mining district.

With the increased numbers of nuclear power plants constructed along the east coast of China, it is important to know radioactive sources and transport pathways between land and sea, in order to better understand the impact of these nuclear facilities to the marine environment. Two sediment cores collected from the East China Sea dated to 1959–2010 were analyzed for long-lived radioactive 129I and stable 127I. It was observed that 129I levels (129I/127I ratio of (15.0–75.0) × 10−12) were significantly increased compared to the pre-nuclear value (129I/127I = 1.5 × 10−12). Some 129I peaks were observed in layers of 1959, 1966, 1971 and 1976 (1977), corresponding to the atmospheric nuclear weapon tests at Pacific Proving Grounds and Lop Nor. The high values of 129I after the late 1970s are attributed to the releases from the European reprocessing plants. In addition to ocean current transport, the atmospheric dispersion through the interaction of the Westerlies with East Asia monsoon is the important pathway of large-scale transport of pollutants from high latitude West Europe to middle latitude East Asia. Riverine input is the main transport pathway of radioactive pollutants released from Lop Nor to the East China Sea through the atmospheric dispersion, deposition and runoff processes.

Polycyclic aromatic hydrocarbons containing at least 24 carbon atoms (≥C₂₄-PAH) are often associated with pyrogenic processes such as combustion of fuel, wood or coal, and occur in the environment in diesel particulate matter, black carbon and coal tar. Some of the ≥C₂₄-PAH, particularly the group of dibenzopyrenes (five isomers, six aromatic rings) are known to show high mutagenic and carcinogenic activita.Gas chromatography – mass spectrometry is a well-established method for the analysis of lower molecular weight PAH but is not optimally suited for the analysis of ≥C₂₄-PAH due to their low vapor pressures. Also, hundreds of ≥C₂₄-PAH isomers are possible but only a few compounds are commercially available as reference standards. Therefore, in this study, a combination of multidimensional liquid chromatography, UV–Vis diode array detection, PAH selective and highly sensitive atmospheric pressure laser ionization – mass spectrometry is used to detect and unequivocally identify PAH. For identification of PAH in two bituminous coals and one petrol coke sample, unique and compound specific UV–Vis spectra were acquired. It was possible to identify ten compounds (naphtho[1,2,3,4-ghi]perylene, dibenzo[b,ghi]perylene, dibenzo[e,ghi]perylene, dibenzo[cd,lm]perylene, benzo[a]coronene, phenanthrol[5,4,3,2-abcde]perylene, benzo[ghi]naphtho[8,1,2-bcd]perylene, benzo[pqr]naphtho[8,1,2-bcd]perylene, naphtho[8,1,2-abc]coronene and tribenzo[e,ghi,k]perylene) by comparison of acquired spectra with spectra from literature. Additionally, it was possible to detect similar distribution patterns in different samples and signals related to alkylated naphthopyrenes, naphthofluoranthenes or dibenzopyrenes. Subsequent effect-directed analysis of a bituminous coal sample using the microEROD (ethoxyresorufin-O-deethylase) bioassay showed high suitability and revealed lower EROD induction for the ≥C₂₄-PAH (TEQ range 0.67–10.07 ng/g) than for the allover < C₂₄-PAH containing fraction (TEQ 84.00 ng/g). Nevertheless, the toxicity of ≥C₂₄-PAH has a significant impact compared with <C₂₄-PAH and must be considered for risk assessment. The LC-DAD-APLI-MS method, presented in this study, is a powerful tool for the unequivocal identification of these ≥ C₂₄-PAH.