Polybrominated diphenyl ethers (PBDEs) undergo debromination when they were exposed in zerovalent metal or bimetallic systems. Yet their debromination pathways and mechanisms in these systems were not well understood. Here we reported the debromination pathways of three BDE congeners (BDE-21, 25 and 29) by nano-zerovalent iron (n-ZVI). All these BDE congeners have three bromine substituents that were located in ortho-, meta- and para-positions. Results demonstrated that BDE-21, 25 and 29 preferentially debrominate meta-, ortho- and para-bromines, respectively, suggesting that bromine substituent at each position (i.e. ortho-, meta- or para-) of PBDEs can be preferentially removed. Singly occupied molecular orbitals of BDE anions are well correlated with their actual debromination pathways, which successfully explain why these BDE congeners exhibit certain debromination pathways in n-ZVI system. In addition, microscale zerovalent zinc (m-ZVZ), iron-based bimetals (Fe/Ag and Fe/Pd) were also used to debrominate PBDEs, with BDE-21 as target pollutant. We found that the debromination pathways of BDE-21 in m-ZVZ and Fe/Ag systems are the same to those in n-ZVI system, but were partially different from those in Fe/Pd systems. The debromination of BDE-21 in Pd-H2 system as well as the solvent kinetic isotope effect in single metal and bimetallic systems suggests that H atom transfer is the dominant mechanism in Fe/Pd system, while e-transfer is still the dominant mechanism in Fe/Ag system.

Perfluorooctane sulfonate (PFOS) and related substances are widely used in various industrial and commercial applications in China that ultimately discharge sufficient quantities of PFOS to the environment. It remains unclear how emissions of PFOS ultimately affect its concentrations as well as its fate in the environment. In this study, an improved Berkeley-Trent (BETR) multimedia model is developed to predict the PFOS levels with spatial and temporal distributions on unsteady state mode from 1981 to 2050, by taking the Bohai Rim of China as a case. The results showed that the modeled concentrations agreed well with the measured data. According to the model, PFOS concentrations in fresh water peaked in some months after the peak emission (2008 or 2009), whereas in urban soil the concentrations increased to peak slightly later (around 2014). Among the selected regions, Beijing and Tianjin were simulated with higher PFOS levels in the past and present because of their higher urbanization and industrialization since the 1980s, while in the future, Shandong and Liaoning are expected to have higher concentrations of PFOS than those in Beijing. The water system including coastal water, fresh water and sediment was the biggest sink for PFOS for coastal regions. Among the chemical inputs, direct primary emissions played a more important role, whereas for chemical removal processes, inter-regional advection and background outflow were the predominant pathways. The results would be useful to control the PFOS releases in China and will help the management agencies to implement the “Stockholm Convention” effectively.

With the rapid development of urbanization and industrialization, the peri-urban areas are often the sites for waste dumps, which may exacerbate the occurrence and spread of antibiotic resistance from waste to soil bacteria. However, the profiles of antibiotic resistomes and the associated factors influencing their dissemination in peri-urban areas have not been fully explored. Here, we characterized the antibiotic resistance genes (ARGs) in peri-urban arable and pristine soils in four seasons at the watershed scale, by using high-throughput qPCR. ARGs in peri-urban soils were diverse and abundant, with a total of 222 genes were detected in the peri-urban soil samples. The arable soil harbored more diverse ARGs compared to the pristine soils, and nearly all the ARGs detected in the pristine soils were also detected in the farmlands. A random forest prediction showed that the overall patterns of ARGs clustered closely with the landuse type. Mantel test and partial redundancy analysis indicated that bacterial community variation is a major contributor to antibiotic resistome alteration. Significant positive correlation was found between the abundance of ARGs and mobile genetic elements (MGEs), suggesting potential mobility of ARGs in peri-urban areas. Our results extend knowledge of the resistomes compositions in peri-urban areas, and suggest that anthropogenic activities driving its spatial and temporal distribution.

In this study, a pilot combined sewer system was constructed to characterize the pollutant transformation in sewer sediment. The results showed that particulate contaminants deposited from sewage could be transformed into dissolved matter by distinct pollutant transformation pathways. Although the oxidation-reduction potential (ORP) was varied from −80 mV to −340 mV in different region of the sediment, the fermentation was the dominant process in all regions of the sediment, which induced hydrolysis and decomposition of particulate contaminants. As a result, the accumulation of dissolved organic matter and the variation of ORP values along the sediment depth led to the depth-dependent reproduction characteristics of methanogens and sulfate-reducing bacteria, which were existed in the middle and deep layer of the sediment respectively. However, the diversity of nitrifying and polyphosphate-accumulating bacteria was low in sewer sediment and those microbial communities showed a non-significant correlation with nitrogen and phosphorus contaminants, which indicated that the enrichment of nitrogen and phosphorus contaminants was mainly caused by physical deposition process. Thus, this study proposed a promising pathway to evaluate pollutant transformation and can help provide theoretical foundation for urban sewer improvement.

Dinotefuran, as the latest generation of neonicotinoid insecticide, has broad application prospects around the world. However, dinotefuran is easily metabolized and the two main metabolites are 1-methyl-3-(tetrahydro-3-furylmethyl) urea (UF) and 1-methyl-3-(tetrahydro-3-furylmethyl) guanidium dihydrogen (DN). In the present study, the risks of UF and DN in soil on typical non-target species earthworm were investigated. In the same time, the degradation in soil and accumulation in earthworms of UF and DN were monitored. The present results showed that the toxicities of UF and DN were similar in their effect on earthworms and they were supertoxic pollutants to earthworms. The degradation trend in soil and accumulation trend in earthworms of UF and DN were consistent throughout the whole exposure period. At 1.0 mg/kg and 2.0 mg/kg, UF and DN could induce the excess production of ROS, resulting in oxidative stress effects in earthworm cells. The excess ROS induce changes in antioxidant enzyme activities, damage in biomacromolecules, and abnormal expression of function genes. The present results showed that UF and DN may have high risks for earthworms.

During the last years, declines in honey bee colonies are being registered worldwide. Cholinergic pesticides and their extensive use have been correlated to the decline of pollinators and there is evidence that pesticides act as neuroendocrine disruptors affecting the metabolism of neuropeptides. However, there is a big absence of studies with quantitative results correlating the effect of pesticide exposure with changes on neuropeptides insects, and most of them are conducted under laboratory conditions, typically with individual active ingredients. In this study, we present an analytical workflow to evaluate pesticide effects on honey bees through the analysis of (neuro)peptides. The workflow consists of a rapid extraction method and liquid chromatography with triple quadrupole for preselected neuropeptides. For non-target analysis, high resolution mass spectrometry, multivariate analysis and automatic identification of discriminated peptides using a specific software and protein sequence databases. The analytical method was applied to the analysis of target and non-target (neuro)peptides in honey bees with low and high content of a wide range of pesticides to which have been exposed in field conditions. Our findings show that the identification frequency of target neuropeptides decreases significantly in honey bees with high concentration of pesticides (pesticide concentrations ≥ 500 μg kg⁻¹) in comparison with the honey bees with low content of pesticides (pesticide concentrations ≤ 20 μg kg⁻¹). Moreover, the principal component analysis in non-target search shows a clear distinction between peptide concentration in honey bees with high level of pesticides and honey bees with low level. The use of high resolution mass spectrometry has allowed the identification of 25 non-redundant peptides responsible for discrimination between the two groups, derived from 18 precursor proteins.

The main objective of the present study was to investigate possible links between sub-individual and supra-individual levels (i.e. population level) biomarkers in D. magna exposed to sublethal concentrations of the insecticide chlorpyrifos (CPF). To achieve the aim, 8-day old individuals were exposed for 96 h to two environmentally relevant concentrations of CPF (50 and 250 ng/L). Sub-individual level effects were investigated by measuring the activity of antioxidant (SOD, CAT, and GPx) and detoxifying (GST) enzymes, as well as by measuring the acetylcholinesterase (AChE) inhibition. In addition, the effects at supra-individual level were assessed by using a video-tracking system and analyzing changes in swimming capabilities (i.e. percentage of activity time, distance moved, and velocity). Our data have shown that daphnids exposed to both CPF concentrations were in a condition of stress which was highlighted by changes in both sub- and supra-individual biomarkers. Moreover, our results highlighted that the lowest tested CPF concentration did not modulate the antioxidant and detoxifying enzymes, whereas, an inhibition of AChE and a decrease of some parameters related to swimming behaviour (distance moved and velocity) were noted. On the contrary, significant changes in all the sub-individual biomarkers were measured at the highest tested concentration. In addition, organisms recovered the movement capability (distance moved) and also activate a mechanism of avoidance (increased swimming velocity). On the other hand, a reduction in the percent of active time was measured and this was attributed to the energy spent by organisms to activate antioxidant and detoxifying enzymes and the mechanism of avoidance. Based on these results, our study suggests the existence of a link between sub- and supra-individual levels, as the activation or non-activation in the antioxidant and detoxifying enzymes activities can led to different modifications of the swimming behaviour in D. magna.

Exposure to pesticides results in DNA damage and genomic instability. We previously predicted that endosulfan might be associated with leukemia, but the role of endosulfan in leukemia cells has been unexplored. The aim of this study is to elucidate molecular mechanism of endosulfan-induced DNA damage response in human leukemia cells. We performed endosulfan exposure experiments in K562 cells with varying concentrations of endosulfan for 48 h and found that endosulfan lowered cell viability in a dose-dependent manner. We observed the dramatic DNA damage using comet assay and the increase of micronucleus in 75 μM endosulfan-exposed cells. Endosulfan at 75 μM caused the expression alterations of ATM and DNA repair genes such as FANCD2, and BRCA1/2 at different exposure time points (12, 24, 48 h), which was reversed by ATM inhibitor KU-55933. Endosulfan significantly increased the mRNA expression levels of p53 and GADD45A, and decreased PCNA and XRCC2 at 48 h after exposure. Flow cytometric analysis showed that endosulfan at 50 and 75 μM induced cell cycle G1 arrest, a response attributed to down-regulation of CDK6 and up-regulation of p21. We also observed that endosulfan at 50 and 75 μM induced a considerable percentage of cells to undergo apoptosis, as detected by Annexin-V binding assays. Endosulfan resulted in the activation of caspase-3, and elevated the expression levels of PUMA and the ratio of BAX/Bcl-2. These findings suggest that endosulfan caused DNA damage response throughATM-p53 signaling pathway, implicating the potential correlation between endosulfan and leukemia.

This article comments on the current reality of particulate matter (PM) concentrations breathed by commuters on subway train platforms and considers what can be done to improve air quality underground. We propose the introduction of a targeted, color-coded approach to the problem, based on the methodology of the World Health Organisation and designed to encourage transport authorities to aim for progressive PM reductions. The method defines thresholds that cascade down through bands of decreasing PM concentrations towards the ideal WHO Air Quality Guideline of PM₂.₅ annual mean level of 10 μg m⁻³, where negative health effects of long term particle inhalation are minimal.

Triclosan (TCS) is a suspected endocrine disrupting chemical which is widely used in consumer products as an antibacterial agent. But findings in human studies focusing on the fetal developmental effects of prenatal TCS exposure were rare and inconsistent. This study aimed to determine maternal urinary TCS and investigate its association with birth outcomes. Pregnant women (n = 1006) were randomly selected from the prospective Healthy Baby Cohort (HBC) enrolled in 2014. TCS levels were determined in maternal urine samples collected at delivery and recorded birth outcomes were obtained from the medical records. Multiple linear regressions were applied to evaluate associations of maternal urinary TCS levels with birth outcomes including birth weight, birth length, and gestational age. Logistic regressions were used to evaluate associations with preterm birth, late term birth, and low birth weight. The geometric mean concentrations for TCS and specific gravity (SG) adjusted TCS in maternal urines were 0.73, 0.78 ng/mL, respectively. In the crude model, one ln-unit increase of urinary SG-adjusted TCS concentration was associated with a 0.30-day [95% confidence interval (CI): 0.00, 0.60] increase in gestational age; however, the associations were not statistically significant after adjustment for covariates. No significant associations of SG-adjusted TCS concentrations with birth weight and birth length were observed. Maternal SG-adjusted TCS concentrations were not related to preterm birth, late term birth, and low birth weight (all p > 0.10). Our findings reported a relatively low level of TCS among Chinese pregnant women. With such exposure level, we did not find strong evidence for associations between maternal TCS exposure and birth outcomes. Longitudinal studies concerning about different potential effects of TCS on perinatal health are necessary.