The accidental leakage of industrial wastewater containing heavy metals from enterprises poses great risks to resident health, social instability, and ecological safety. During 2005–2018, heavy metal mixed pollution accidents comprised approximately 33% of the major environmental ones in China. A Bayesian Networks-based probabilistic approach is developed to quantitatively predict ecological and human health risks for heavy metal mixed pollution accidents at the watershed scale. To estimate the probability distributions of joint ecological exposure once a heavy metal mixed pollution accident occurs, a Copula-based joint exposure calculation method, comprised of a hydro-dynamic model, emergent heavy metal pollution transport model, and the Copula functions, is embedded. This approach was applied to the risk assessment of acute Cr⁶⁺-Hg²⁺ mixed pollution accidents at 76 electroplating enterprises in 24 risk sub-watersheds of the Dongjiang River downstream watershed. The results indicated that nine sub-watersheds created high ecological risks, while only five created high human health risks. In addition, the ecological and human health risk levels were highest in the tributary (the Xizhijiang River), while the ecological risk was more critical in the river network, and the human health risk was more serious in the mainstream of the Dongjiang River. The quantitative risk assessment provides a substantial support to incident prevention and control, risk management, as well as regulatory decision making for electroplating enterprises.

Herein, the first evidence of the ability of melatonin (MLT) to counteract cadmium (Cd) toxic effects on the rat ovary is reported. Cd treatment, enhancing oxidative stress, provoked clear morphological, histological and biomolecular alterations, i.e. in the estrous cycle duration, in the ovarian and serum E₂ concentration other than in the steroidogenic and folliculogenic genes expression. Results demonstrated that the use of MLT, in combination with Cd, avoided the changes, strongly suggesting that it is an efficient antioxidant for preventing oxidative stress in the rat ovary. Moreover, to explore the underlying mechanism involved, at molecular level, in the effects of Cd-MLT interaction, the study focused on the mTOR and ERK1/2 pathways. Interestingly, data showed that Cd influenced the phosphorylation status of mTOR, of its downstream effectors and of ERK1/2, inducing autophagy and apoptosis, while cotreatment with MLT nullified these changes. This work highlights the beneficial role exerted by MLT in preventing Cd-induced toxicity in the rat ovary, encouraging further studies to confirm its action on human ovarian health with the aim to use this indolamine to ameliorate oocyte quality in women with fertility disorders.

Soil samples were collected at 61 sites of the national monitoring network for persistent organic pollutants (POPs) in South Korea. The target compounds were brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), hexabromocyclododecanes (HBCDDs), and tetrabromobisphenol A (TBBPA). The mean concentrations of Σ₂₇ PBDEs, Σ₃ HBCDDs, and TBBPA in soil were 222, 17.2, and 4.4 ng/g, respectively, but PBBs were not detected. Industrial sites had statistically higher BFR concentrations than suburban sites but no significant difference compared with urban sites. The commercial deca-BDE mixtures were the most likely source of PBDE contamination in the soil samples, with the minor influence of commercial penta-BDE and octa-BDE mixtures. The profiles of HBCDDs in most soil samples differed from those in the powder types of technical HBCDD mixtures, indicating that they are affected by the HBCDDs contained in commercial products and the conversion of HBCDD diastereoisomers (γ-HBCDD to α-HBCDD) in the environment. The concentrations of Σ₂₇ PBDEs, Σ₃ HBCDDs, and TBBPA were significantly correlated with population density, gross domestic product, and the number of companies (p < 0.01), indicating a direct impact of anthropogenic activities. Significant correlations among BFRs were determined (0.63 < r < 0.74, p < 0.01), suggesting that these pollutants had similar sources. Relatively good correlations (0.44 < r < 0.98, p < 0.01) between BDE-209 and other light BDEs (except for BDE-71, -77, −126, −156, and −205) might result from the degradation of heavy BDEs under anaerobic and natural sunlight conditions. To the best of our knowledge, this study provides the most comprehensive soil monitoring data for various BFRs in South Korea. Furthermore, it is the first report on soil contamination by deca-BDE, HBCDDs, and TBBPA in South Korea.

This study aimed to examine whether and how third-hand smoke (THS) exposure would influence serum melatonin level. 1083 participants with or without exposure to THS were enrolled. Serum ROS, SOD, GSH-Px, and melatonin were measured by ELISA. Methylation microarrays detection and WGCNA were performed to identify hub methylated-sites. The methylation levels of hub-sites were validated in addtional samples. Moreover, mice were exposed to THS for 6 months mimicking exposure of human and the serum, liver, and pineal were collected. Oxidative stress-related indicators in serum, pineal, and liver were measured by ELISA. The expressions of mRNA and protein and methylation levels of hub-gene discovered in human data were further explored by RT-PCR, western-blot, and TBS. The results showed the participants exposed to THS had lower melatonin-level. 820 differentially methylated sites associated with THS were identified. And the hub-site located on the CYP1A2 promoter was identified, which mediated the association between THS and decreased melatonin-level. Decreased peak of serum melatonin, increased ROS and reduced SOD and GSH-Px in pineal and liver, and elevated CYP1A2 expression in liver was also found in the THS-exposed mice. Hypo-methylation of 7 CPG sites on the CYP1A2 promoter was identified, which accelerated the catabolism of melatonin. Overall, THS exposure is associated with abnormal melatonin catabolism through hypo-methylation of CYP1A2-promoter.

Despite the broad use of lichens as biomonitors of airborne trace elements, the surface chemistry and metal adsorption parameters of these organisms are still poorly known. The current investigation is aimed at (i) quantifying the acid-base surface properties and the first-order physical-chemical parameters of Cu²⁺ and Zn²⁺ adsorption of devitalized Pseudevernia furfuracea, a lichen commonly used in biomonitoring of airborne trace elements, and (ii) comparing the results with those available for moss biomonitors. Equilibrium constants and metal-binding site concentrations were calculated with a thermodynamic model by taking into account the presence/absence of ancillary extracellular cell wall compounds, namely melanin and acetone-soluble lichen substances. An acid–base titration experiment performed in the pH range of 3–10 showed that melanised and non-melanised P. furfuracea samples have lower pHPZC (3.53–3.99) and higher metal-binding site concentrations (0.96–1.20 mmol g⁻¹) compared to that of the mosses investigated so far at the same experimental conditions. Melanin biosynthesis increased the content of carboxyl and phosphoryl groups and reduces that of amine/polyphenols. Cu²⁺ and Zn²⁺ adsorption was unaffected by the degree of melanisation while the removal of extracellular lichen substances slightly decreased Zn²⁺ adsorption. Although Cu²⁺ and Zn²⁺ adsorption parameters related to P. furfuracea surfaces were 3 times lower than in the mosses, lichen samples adsorbed the same amount of Cu²⁺ and 30% more Zn²⁺. The present study contributes in understanding the role of ancillary cell wall compounds in Cu²⁺ and Zn²⁺ adsorption in a model lichen. It also provides a first comparison between the surface physico-chemical characteristics of lichens and mosses frequently used as biomonitors of trace elements.

Excessive Cd accumulation in cereals, especially in high-consumption staple crops, such as rice, is of major concern. Therefore, elucidation of cultivar-specific variation in rice grain Cd bioaccessibility and toxicity in humans would help the development of remedial strategies for Cd accumulation and toxicity. The present study combined an in vitro gastrointestinal digestion model with a human HL-7702 cell and assessed Cd bioaccessibility and toxicity to humans from the grains of 30 rice cultivars of different types harvested from Cd-contaminated paddy soil. The mean grain Cd content of cultivars within the type exceeded acceptable national standards. Cadmium bioaccessibility was high in all grains (9.08–23.6%) except the low accumulator (LA) rice cultivar (7.93%). The mean estimated daily intake of Cd via the cultivars (except LA) exceeded the FAO/WHO permissible limit based not only on the total grain Cd concentration but also on bioaccessible Cd concentration. A dose-proportional correlation between the in vitro bioaccessible and total grain Cd concentrations was observed, suggesting that Cd bioaccessibility accurately reflects the transfer of Cd from rice grain to humans. Toxicity assay results demonstrated that Cd from rice grains could commence oxidative stress and injury in HL-7702 cells, except the LA rice, which did not exhibit significant alteration in HL-7702 cells owing to its low Cd concentration. These results provide primary evidence to suggest that the cultivation of the LA rice cultivar is an effective agronomic approach to avert Cd entry into the food chain and alleviate Cd toxicity in humans.

Wild organisms are increasingly exposed to multiple anthropogenic and natural stressors that can interact in complex ways and lead to unexpected effects. In aquatic ecosystems, contamination by trace metals has deleterious effects on fish health and commonly co-occurs with pathogens, which affect similar physiological and behavioral traits. However, the combined effects of metal contamination and parasitism are still poorly known. In addition, the sensitivity to multiple stressors could be highly variable among different fish populations depending on their evolutionary history, but this intraspecific variability is rarely taken into account in existing ecotoxicological studies. Here, we investigated i) the interactive effects of metal contamination (i.e., realistic mixture of Cd, Cu and Zn) and immune challenge mimicking a parasite attack on fish health across biological levels. In addition, we compared ii) the physiological and behavioral responses among five populations of gudgeon fish (Gobio occitaniae) having evolved along a gradient of metal contamination. Results show that single stressors exposure resulted in an increase of immune defenses and oxidative stress at the expense of body mass (contamination) or fish swimming activity (immune challenge). Multiple stressors had fewer interactive effects than expected, especially on physiological traits, but mainly resulted in antagonistic effects on fish swimming activity. Indeed, the immune challenge modified or inhibited the effects of contamination on fish behavior in most populations, suggesting that multiple stressors could reduce behavioral plasticity. Interestingly, the effects of stressors were highly variable among populations, with lower deleterious effects of metal contamination in populations from highly contaminated environments, although the underlying evolutionary mechanisms remain to be investigated. This study highlights the importance of considering multiple stressors effects and intraspecific variability of sensitivity to refine our ability to predict the effects of environmental contaminants on aquatic wildlife.

Acoustic pollution in aquatic environments has increased with adverse effects on many aquatic organisms. However, little work has been done considering the effects of the vibratory component of acoustic stimuli, which can be transmitted in the substrate and propagated into the aquatic medium. Benthic marine organisms, including many invertebrates, are capable of sensing seabed vibration, yet the responses they trigger on organism have received little attention. This study investigates the impact of underwater vibration on the physiology and behaviour of a ubiquitous inhabitant of coastal areas of the northern hemisphere, the shore crab Carcinus maenas. We developed a novel vibratory apparatus with geophones supported on a softly sprung frame to induce a seabed vibration of 20 Hz frequency, as observed during dredging, piling and other anthropogenic activities. The geophone internal mass caused the frame to vibrate in a controlled manner. Our results show that transition from ambient to anthropogenic vibrations induced an increase in activity and antennae beats in shore crabs, indicating perception of the vibratory stimulus and a higher stress level. There was also a trend on sex-specific responses to anthropogenic vibration, with males showing a higher activity level than females. However, no effect of anthropogenic vibrations was found upon oxygen consumption. These results show that anthropogenic underwater vibration induces behavioural responses in Carcinus maenas. This highlights the importance of evaluating man-made vibratory activities on coastal invertebrates and the necessity of evaluating anthropogenic effects on both sexes.

Natural wetland has great retention effect on Cr(VI) migration due to its abiotic and biotic reduction abilities, however, the zoning characteristics of dominating reduction mechanism along Cr(VI) pollution plume in wetland is still unclear. In this study, a Cr(VI) contaminated natural wetland was explored to investigate the distributions of Cr and Fe in groundwater and sediment, and their relationship with microorganisms according to metagenomics, aiming to reveal the natural attenuation mechanism of Cr(VI) from the perspective of zoning characteristics of abiotic and biotic effects. The wetland was divided into contaminated zone, transition zone and uncontaminated zone according to the contamination states of groundwater and sediment. At the upstream of contaminated zone, Cr(VI) concentration in groundwater was as high as 26.7 mg L⁻¹, which has significant inhibition effect on microbial growth, and thus chemical reduction of Cr(VI) by natural organic matters (NOMs) dominated in this area, leading to the increasing of H/C and O/C ratios of NOMs because of the oxidation of aromatic moieties. At the downstream of contaminated zone, Cr(VI) concentration in groundwater decreased to less than 4.46 mg L⁻¹ resulting from dilution and attenuation, but the microbial community was altered substantially, chromate resistant bacteria with ChrA, ChrR, NemA and AzoR genes were enriched, such as Sphingomonas, Mesorhizobium and Comamonadaceae, and thus the direct microbial reduction of Cr(VI) dominated in this area. While at the transition zone, which is located at the front edge of the pollution plume, Cr(VI) could only reached in this area intermittently, and the microbial community remained similar to that of the uncontaminated zone, dominated by Chloroflexi and Acidobateria phylum with dissimilatory ferric iron reduction capacity, and thus Cr(VI) was indirectly reduced by Fe²⁺ intermediately in this area.

The black soldier fly (BSF) Hermetia illucens has a strong tolerance to cadmium stress. This helps to use BSF in entomoremediation of heavy metal pollution. Rich metallothionein (MT) proteins were thought to be important for some insects to endure the toxicity of heavy metal. We identified and characterized three MTs genes in BSF (BSFMTs), including BSFMT1, BSFMT2A, and BSFMT2B. Molecular modeling was used to predict metal binding sites. Phylogenetic analysis was used to identify gene families. Overexpression of the recombinant black soldier fly metallothioneins was found to confer Cd tolerance in Escherichia coli. Finally, functions of BSFMTs in BSF were explored through RNA interference (RNAi). RNAi results of BSFMT2B showed that the larval fresh weight decreased significantly, and the larvae mortality increased significantly. This study suggests that BSFMTs have important properties in Cd detoxification and tolerance in BSF. Further characterization analyses of physiological function about metallothioneins are necessary in BSF and other insects.