Once released into the environment, engineered nanomaterials can significantly influence the transformation and fate of organic contaminants. To date, the abilities of composite nanomaterials to catalyze environmentally relevant abiotic transformation reactions of organic contaminants are largely unknown. Herein, we investigated the effects of two nanocomposites – consisting of anatase titanium dioxide (TiO2) with different predominantly exposed crystal facets (i.e., {101} or {001} facets) anchored to hydroxylated multi-walled carbon nanotubes (OH-MWCNT) – on the hydrolysis of 1,1,2,2-tetrachloroethane (TeCA), a common groundwater contaminant, at ambient pH (6, 7 and 8). Both OH-MWCNT/TiO2 nanocomposites were more effective in catalyzing the dehydrochlorination of TeCA than the respective component materials (i.e., bare OH-MWCNT and bare TiO2). Moreover, the synergistic effect of the two components was evident, in that the incorporation of OH-MWCNT increased the TeCA adsorption capacity of the nanocomposites, significantly enhancing the catalytic effect of the deprotonated hydroxyl and carboxyl groups on nanocomposite surfaces, which served as the main catalytic sites for TeCA hydrolysis. The findings may have important implications for the understanding of the environmental implications of composite nanomaterials and may shed light on the design of high-performance nanocomposites for enhanced contaminant removal.

Modeling for the toxicity of ionic liquids (ILs) is necessary to fill data gaps for untested chemicals and to understand the relevant mechanisms at the molecular level. In order for many researchers to easily predict toxicity and/or develop some prediction model, simple method(s) based on a single parameter should be proposed. Therefore, previously our group developed a comprehensive toxicity prediction model with unified linear free-energy relationship descriptors to address the single parameter for predicting the toxicities, as follows (Cho et al., 2016b).Log 1/toxicity in the unit of mM= (2.254 Ec – 2.545 Sc + 0.646 Ac – 1.471 Bc + 1.650 Vc + 2.917 J+ – 0.201 Ea + 0.418 Va + 0.131 J−) – 0.709.It is considered that the model can calculate the general toxicological effect of ILs in parenthesis, as it was developed on the basis of numerous toxic effects i.e., 58 toxicity testing methods and about 1600 data points. In order to check the hypothesis, the values calculated by the model were correlated with four different datasets from insect cell line (Spodoptera frugiperda 9), earthworm (Eisenia fetida), nematode (Caenorhabditis elegans), and fish (Danio rerio). The results clearly showed that the calculated values are in good agreement with each dataset. In the case of S. frugiperda 9 cells, the calculated parameters were correlated with log1/LC50 values, measured after 24 h and 48 h incubation, in R2 of 0.67 and 0.88, respectively. The R2 values for the earthworm, nematode, and fish were 0.88, 0.96, and 0.94–0.95, respectively. This study confirmed that the comprehensive model can be simply and accurately used to predict toxicity of ILs.

Herein, we investigated the effects of di-n-butyl phthalate (DBP) on photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) content, oxidative damage, and biomass accumulation of different tissues in wheat (Triticum aestivum L) planted in cinnamon soils. The photosynthetic or fluorescence parameters (except for the intercellular carbon dioxide concentration), chlorophyll content, RuBisCO content, and biomass of roots, stems, and leaves decreased at the seedling, jointing, and booting stages under the stress of DBP. Compared with the control, the content of superoxide anions and hydrogen peroxide in the roots, stems, and leaves increased with increasing DBP concentrations at the seedling, jointing, and booting stages. The activities of superoxide dismutase (SOD) and catalase (CAT) in the roots, stems, and leaves increased under the 10 and 20 mg kg−1 DBP treatments; however, no significant changes were observed under the 40 mg kg−1 DBP treatment at the seedling stage (except for the SOD activity in roots). The increase in SOD and CAT activities in the roots, stems, and leaves with increasing DBP concentration at the jointing and booting stages suggested that an increase in the activities of these antioxidant enzymes may play an important role in defending against excess reactive oxygen species under DBP stress. The biomass of wheat roots, stems, and leaves decreased with an increase in DBP concentration, which was presumably caused by a decrease in photosynthesis and RuBisCO. The effect of DBP on wheat roots, stems, and leaves decreased with wheat growth.

Organic pollutants in the Arctic seas have been of concern to many researchers; however, the vast dynamic marine water poses challenges to their comprehensive monitoring within appropriate spatial and temporal scales in the Arctic. In this study, on-board passive sampling of organic pollutants using a self-developed device coupled with triolein-embedded cellulose acetate membranes (TECAMs) was performed during an Arctic cruise. The TECAM extracts were used for target analysis of organophosphorus flame retardants (PFRs), and non-target screening of persistent, bioaccumulative, and toxic (PBT) contaminants using two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC-TOFMS). Sixteen chemicals were screened out as PBT contaminants from the 1500 features in the non-target analysis and further identified. Consequently, two chlorinated PFRs (tris(chloroisopropyl)phosphate and tris(1,3-dichloroisopropyl)phosphate) and four PBT contaminants (4-tert-butylphenol, 2-isopropylnaphthalene, 1,1,3-trimethyl-3-phenylindane, and 1-phenylnonan-1-one) were accurately quantified, with the temporally and spatially integrated concentrations ranging from 0.83 ng L⁻¹ to 20.82 ng L⁻¹ in the seawaters. Sources and transport of the contaminants were studied, and ocean current transport (West Spitsbergen Current, WSC) and local sources (human settlement, Arctic oil exploitation, and petroleum fuel emissions) were found to contribute to the presence of the different contaminants. Finally, annual transport fluxes of the contaminants from the North Atlantic to the Arctic Ocean by WSC were estimated, and the results indicate that their hazard to the Arctic should be concerned.

Bisphenol A (BPA) is widely used in consumer products and is a potential endocrine disruptor linked with abnormal development of male reproductive tract. However, its action and its effects on the pathways in the development of male gonad are still unclear. Here we report that effects of BPA exposure during gestation on male gonad development. Sprague-Dawley rats were gavaged daily with BPA (0, 4, 40, and 400 mg/kg body weight) from gestational day 12 to day 21. BPA dose-dependently decreased serum testosterone levels (0.45 ± 0.08 ng/ml and 0.32 ± 0.08 ng/ml for 40 and 400 mg/kg BPA, respectively) versus the control level (1.11 ± 0.22 ng/ml, Mean ± SE). BPA lowered Leydig cell Insl3 and Hsd17b3 mRNA and their protein levels at doses of 40 and 400 mg/kg. BPA also lowered Leydig cell (Lhcgr, Cyp11a1, and Cyp17a1) and Sertoli cell (Amh) mRNA and their protein levels at 400 mg/kg. BPA decreased fetal Leydig cell number via inhibiting their proliferation, but it did not affect fetal Sertoli cell number. In conclusion, the current study shows that in utero exposure to BPA inhibits fetal Leydig and Sertoli cell differentiation, possibly disrupting the development of male reproductive tract.

Melatonin (Mel) serves as an important signalling molecule in various aspects of stress tolerance in plants. However, the function of Mel in pesticide metabolism remains unknown. Here, selecting the widely used fungicide carbendazim (MBC) as the model, we found that exogenous Mel had the ability to alleviate pesticide phytotoxicity and residues in tomato as well as in some other vegetables. Additionally, overexpression of the Mel biosynthetic gene caffeic acid O-methyltransferase 1 (COMT1) significantly enhanced the capacity of the tomato to reduce MBC phytotoxicity and residue. This outcome was mainly because of the Mel-induced antioxidant capability, as well as the key detoxification process. Indeed, levels of reactive oxygen species (ROS) and lipid peroxides significantly decreased after applying exogenous Mel or overexpressing COMT1, which resulted from direct ROS scavenging, and increased Mel levels significantly enhanced antioxidant enzymatic activity. More importantly, Mel activated the ascorbate-glutathione cycle to participate in glutathione S-transferase-mediated pesticide detoxification. A grafting experiment showed that rootstocks from COMT1 transgenic plants increased the Mel accumulation of wild-type scions, resulting in MBC metabolism in the scions. To our knowledge, this is the first report providing evidence of Mel-induced pesticide metabolism, which provides a novel approach for minimizing pesticide residues in crops by exploiting plant self-detoxification mechanisms.

MicroRNAs (miRNAs) are a class of small non-coding RNA that control multiple biological processes through negative post-transcriptional regulation of gene expression. Recently a role of miRNAs in the response of aquatic organisms to environmental toxicants emerged. Toxicant-induced changes in miRNA expression might then represent novel biomarkers to evaluate the health status of these organisms. In this study, we aimed to identify the miRNA repertoire in the liver of the European eel Anguilla anguilla and to compare their differential expression between a polluted site located in the Gironde Estuary and a pristine site in Arcachon Bay (France).A total of 299 mature miRNAs were identified. In polluted water, 19 miRNAs were up-regulated and 22 were down-regulated. We predicted that these differentially expressed miRNAs could target 490 genes that were involved in ribosome biogenesis, response to hormones, response to chemical and chromatin modification. Moreover, we observed only few examples (29) of negative correlation between the expression levels of miRNAs and their targets suggesting that, in the system studied, miRNAs might not only regulate gene expression directly by degrading mRNA but also by inhibiting protein translation or by regulating other epigenetic processes.This study is the first example of in situ investigation of the role of miRNAs in the response of a fish species to water quality. Our findings provide new insights into the involvement of epigenetic mechanisms in the response of animals chronically exposed to pollution and pave the way for the utilization of miRNAs in aquatic ecotoxicology.

Feammox is a newly discovered and important anaerobic nitrogen (N) loss pathway, and its variation and role in removing N following the application of N fertilizer and its migration from paddies to other land use types and from surface soils to deep soils have not been thoroughly elucidated to date. In this study, field sampling and slurry incubation experiments were performed to evaluate the Feammox rate between different land use types (paddy, irrigation ditch, riparian zone and lake, 0–10 cm) and different paddy soil depths (0–70 cm) in a wheat-rice rotation area in China. Based on a ¹⁵N-labelled isotope-tracing technique and analysis of microbial communities, it was estimated that the potential Feammox rate ranged from 0.031 to 0.42 mg N kg⁻¹ d⁻¹ in this area. In the soil profile of the paddy, the depth of 20–30 cm was the active region of Feammox, with a value of 0.37 ± 0.057 mg N kg⁻¹ d⁻¹. Compared with the surface soil (0–10 cm) of the paddy (0.18 ± 0.031 mg N kg⁻¹ d⁻¹), the potential Feammox rate of the irrigation ditch soil was not significantly different, but that of the lake riparian soil and lake sediment were decreased by 27.27% and 32.11%, respectively (p < 0.01). Fe(III) content was the best predictor of the Feammox rate and explained the variation of the Feammox rate by 36.00% in the surface soil. At the genus level, the paddy soil at a depth of 20–30 cm had the greatest abundance of the genera in which the Fe reduction bacteria were distributed; and where Bacillus, Geobacter and Anaeromyxobacter had higher proportions. It was estimated that the potential N loss by Feammox was in the range of 7.36 (the lake) ∼43.35 (the paddy) kg N ha⁻¹ year⁻¹ in the surface soil of this area. Considering denitrification and the Feammox rate as a whole, we found that denitrification remained to be the main contributor to N loss in the surface soil (94.72–96.89% of N loss), although Feammox dominated N loss in the deep soil (below 0–10 cm).

Little information is available about effect of particle size and crystal structure of nTiO₂ on their trophic transfer. In this study, 5 nm anatase, 10 nm anatase, 100 nm anatase, 20 nm P25 (80% anatase and 20% rutile), and 25 nm rutile nTiO₂ were selected to investigate the effects of size and crystal structure on the toxicity, bioconcentration, and trophic transfer of nTiO₂ to algae and daphnia. In the exposed daphnids, metabolic pathways affected by nTiO₂ and nTiO₂-exposed algae (nTiO₂-algae) were also explored. The 96 h IC₅₀ values of algae and the 48 h LC₅₀ values of daphnia were 10.3, 18.9, 43.9, 33.6, 65.4 mg/L and 10.5, 13.2, 37.0, 28.4, 60.7 mg/L, respectively, after exposed to nTiO₂-5A, nTiO₂-10A, nTiO₂-100A, nTiO₂-P25, and nTiO₂-25R, respectively. The bioconcentration factors (BCFs) for 0.1, 1, and 10 mg/L nTiO₂ in daphnia ranged from 21,220 L/kg to 145,350 L/kg. The nTiO₂ biomagnification factors (BMFs) of daphnia fed with 1 and 10 mg/L nTiO₂-exposed algae were consistently greater than 1.0 (5.7–122). The results show that the acute toxicity, BCF, and BMF all decreased with increasing size or rutile content of nTiO₂. All types of nTiO₂ were largely accumulated in the daphnia gut and were not completely depurated within 24 h. At the molecular level, 22 Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways of daphnia were impacted by the nTiO₂ and nTiO₂-algae treatments, including glutathione metabolism, aminoacyl-tRNA biosynthesis, among others. Six and four KEGG metabolic pathways were significantly disturbed in daphnids exposed to nTiO₂ and nTiO₂-algae, respectively, indicating the presence of algae partially alleviated the negative impact of nTiO₂ on metabolism. These findings increase understanding of the impacts of physicochemical properties of nTiO₂ on the food chain from molecular scale to that of the whole organism, and provide new insight into the ecological effect of nanomaterials.

Maternal exposure to phthalates may cause some adverse health effects on both mother and fetus, but variations of phthalate exposure and metabolism during pregnancy have not been thoroughly characterized. A total of 946 participants were selected from a cohort study conducted in Wuhan between 2014 and 2015 through which they had provided a complete set of urine samples at three trimesters. Eight phthalate metabolites were analyzed in 2838 urine samples. Based on urinary concentrations, various parameters (i.e. phthalate metabolite concentrations, ratios of metabolites of bis(2-ethylhexyl) phthalate (DEHP) in DEHP, and percentages of individual metabolites in total phthalates) were compared over three visits. We observed that levels of phthalate metabolites showed a U-shaped trend across three trimesters. The significant variations in the ratios of DEHP metabolites indicated that the efficiency in metabolizing DEHP declined during pregnancy and less recent exposure occurred in mid-pregnancy. The changes of percentages of individual compound in total phthalates suggested the inconsistent pattern over trimesters. This longitudinal study found that the exposure pattern, exposure timing and metabolic susceptibility varied by trimesters, which suggests that urine samples should be collected at multiple time points and mothers should be especially careful in the early pregnancy.