The toxic sensitivity in different physiological levels of chromium (Cr) contaminated soils with environmentally equivalent concentrations (EEC) was fully unknown. The earthworm Eisenia fetida was exposed to a Cr-contaminated soil at the EEC level (referred to as Cr-CS) to characterize the induced toxicity at the whole body, organ, tissue, subcellular structure and metabolic levels. The results showed that the survival rate, weight and biodiversity of the gut microorganisms (organ) had no significant difference (p > 0.05) between control and Cr-CS groups. Qualitative histopathological and subcellular evaluations from morphology showed earthworms obvious injuries. The organelle injuries combined with the metabolic changes provided additional evidence that the Cr-CS damaged the nucleus and probably disturbed the nucleic acid metabolism of earthworms. 2-hexyl-5-ethyl-3-furansulfonate, dimethylglycine, betaine and scyllo-inositol were sensitive and relatively quantitative metabolites that were recommended as potential biomarkers for Cr-CS based on their significant weights in the multivariate analysis model. In addition, the relative abundance of Burkholderiaceae, Enterobacteriaceae and Microscillaceae of the earthworm guts in the Cr-CS group significantly increased, particularly for Burkholderiaceae (increased by 13.1%), while that of Aeromonadaceae significantly decreased by 5.6% in contrast with the control group. These results provided new insights into our understanding of the toxic effects of the EEC level of Cr contaminated soil from different physiological levels of earthworms and extend our knowledge on the composition and sensitivity of the earthworm gut microbiota in Cr contaminated soil ecosystems. Furthermore, these toxic responses from gut microorganisms to metabolites of earthworms provided important data to improve the adverse outcome pathway and toxic mechanism of the Cr-CS if the earthworm genomics and proteomics would be also gained in the future.

Microsorum pteropus is a novel potential Cd (cadmium) aquatic hyperaccumulator. In the present study, hydroponic experiments were conducted to assess the accumulation and subcellular distribution of Cd in the root, stem and leaf of M. pteropus. SEM (scanning electron microscopy) – EDX (energy dispersive X-ray fluorescence spectrometer) and TEM (transmission electron microscopy) were used to observe the ultrastructure of different tissues under 500 μM Cd exposure. After exposure to 500 μM Cd for 7 days, the root, stem and leaf of M. pteropus can accumulate to be > 400 mg/kg Cd in dry mass with no significant influence on the growth. In the root and leaf of M. pteropus, the Cd was more likely to store in the cell wall fraction. However, Cd in the stem was mainly stored in both the cell wall fraction and the cytoplasm fraction. Under SEM observation and EDX detection, 1) Cd was found to be sequestrated in the epidermis or chelated in the root cells, 2) no significant deposit spots were observed in the stem, 3) Cd was found in the trichome of the leaf, and the sporangium was not damaged. TEM observations revealed 1) possible Cd precipitations in the root cell and 2) no significant ultrastructure variation in the stem, and 3) the chloroplast retained its structure and was not affected by the Cd. M. pteropus showed great capacity for Cd accumulation without influencing growth. In addition, the ultrastructure of all the tissues was not damaged by the Cd. M. pteropus showed a great potential in phytoremediation in heavy metal polluted water solutions, and may provide new directions for the study of resistance mechanisms of aquatic hyperaccumulators.

The present study utilizes 18 years of long-term (2001–2018) data collected from six active AERONET sites over the Indo-Gangetic Plain (IGP) and the North China Plain (NCP) areas in Southeast Asia. The annual mean (±SD) aerosol optical thickness at 440 nm (AOT₄₄₀) was found high at XiangHe (0.92 ± 0.69) and Taihu (0.90 ± 0.51) followed by Beijing (0.81 ± 0.69), Lahore (0.81 ± 0.43), and Kanpur (0.73 ± 0.35) and low at Karachi (0.52 ± 0.23). Seasonally, high AOT₄₄₀ with corresponding high Ångström exponent (ANG₄₄₀₋₈₇₀) noticed during JJA for all sites, except Kanpur, suggesting the dominance of fine-mode particles, generally associated with large anthropogenic emissions. Climatologically, an increasing (decreasing) trend was observed over IGP (NCP) sites, with the highest (lowest) percentage of departures in AOT₄₄₀ found over Beijing (Karachi). We further identified major aerosol types which showed the dominance of biomass burning, urban-industrial followed by the mixed type of aerosols. In addition, single scattering albedo (SSA), asymmetry parameter (ASP), volume size distribution (VSD), and complex aerosol refractive index (RI) showed significant temporal and spectral changes, illustrating the complexity of aerosol types. At last, the annual mean direct aerosol radiative forcing at the top, bottom, and within the atmosphere for all sites were found in the range from −17.36 ± 3.75 to −45.17 ± 4.87 W m⁻², -64.6 ± 4.86 to −93.7 ± 10.27 W m⁻², and 40.5 ± 6.43 to 68.25 ± 7.26 W m⁻², respectively, with an averaged atmospheric heating rate of 0.9–2.3 K day⁻¹. A large amount of anthropogenic aerosols showed a significant effect of heating (cooling) on the atmosphere (surface) results obviously, due to an increased rate of atmospheric heating. Therefore, the thermodynamic effects of anthropogenic aerosols on the atmospheric circulation and its structure should be taken into consideration for future study over the experimental sites.

Nowadays, environmental pollution by microplastics (<5 mm; MP) is a major issue. MP are contaminating marine organisms consumed by humans. This work studied MP contamination in two bivalve species of commercial interest: blue mussel (Mytilus edulis) and common cockle (Cerastoderma edule) sampled on the Channel coastlines (France). In parallel, 13 plastic additives and 27 hydrophobic organic compounds (HOC) were quantified in bivalves flesh using SBSE-TD-GS-MS/MS to explore a possible relationship between their concentrations and MP contamination levels. MP were extracted using a 10% potassium hydroxide digestion method then identified by μ-Raman spectroscopy. The proportion of contaminated bivalves by MP ranged from 34 to 58%. Blue mussels and common cockles exhibited 0.76 ± 0.40 and 2.46 ± 1.16 MP/individual and between 0.15 ± 0.06 and 0.74 ± 0.35 MP/g of tissue wet weight. Some HOC and plastic additives were detected in bivalves. However, no significant Pearson or Spearman correlation was found between MP loads and plastic additives or HOC concentrations in bivalve tissues for the two species.

Between 1920 and 1967, approximatively 8200 tons of ammunition waste were dumped into some Swiss lakes. This study is part of the extensive historical and technical investigations performed since 1995 by Swiss authorities to provide a risk assessment. It aims to assess whether explosive monitoring by passive sampling is feasible in lake-bottom waters. Polar organic chemical integrative sampler (POCIS) and Chemcatcher were first calibrated in a channel system supplied with continuously refreshed lake water spiked with two nitroamines (HMX and RDX), one nitrate ester (PETN), and six nitroaromatics (including TNT). Exposure parameters were kept as close as possible to the ones expected at the bottom of two affected lakes. Sixteen POCIS and Chemcatcher were simultaneously deployed in the channel system and removed in duplicates at 8 different intervals over 21 days. Sorbents and polyethersulfone (PES) membranes were separately extracted and analyzed by UPLC-MS/MS. When possible, a three-compartment model was used to describe the uptake of compounds from water, over the PES membrane into the sorbent. Uptake of target compounds by sorbents was shown not to approach equilibrium during 21 days. However, nitroaromatics strongly accumulated in PES, thus delaying the transfer of these compounds to sorbents (lag-phase up to 9 days). Whereas sampling rate (RS) of nitroamines were in the range of 0.06–0.14 L day⁻¹, RS of nitroaromatics were up to 10 times lower. As nitroaromatic accumulation in PES was integrative over 21 days, PES was used as receiving phase for these compounds. The samplers were then deployed at lake bottoms. To ensure that exposure conditions were similar between calibration and field experiments, low-density polyethylene strips spiked with performance reference compounds were co-deployed in both experiments and dissipation data were compared. Integrative concentrations of explosives measured in the lakes confirmed results obtained by previous studies based on grab sampling.

Various environmental studies have employed the biomonitoring of fish in their aquatic ecosystems in order to identify potential metabolic responses to the exposome. In this study, we applied in vivo solid-phase microextraction (SPME) to perform non-lethal sampling on the muscle tissue of living fish to extract toxicants and various endogenous metabolites. Sixty white suckers (Catastomus commersonii) were sampled from sites upstream, adjacent, and downstream from the oil sands development region of the Athabasca River (Alberta, Canada) in order to track their biochemical responses to potential contaminants. In vivo SPME sampling facilitated the extraction of a wide range of endogenous metabolites, mainly related to lipid metabolism. The obtained results revealed significant changes in the levels of numerous metabolites, including eicosanoids, linoleic acids, and fat-soluble vitamins, in fish sampled in different areas of the river, thus demonstrating SPME's applicability for the direct monitoring of exposure to different environmental toxicants. In addition, several classes of toxins, including petroleum-related compounds, that can cause serious physiological impairment were tentatively identified in the extracts. In vivo SPME, combined with the analysis of contaminants and endogenous metabolites, provided important information about the exposome; as such, this approach represents a potentially powerful and non-lethal tool for identifying the mechanisms that produce altered metabolic pathways in response to the mixtures of different environmental pollutants.

Human pressure exerts a significant influence on animals and the environment. One of its consequences, plastic pollution is considered one of the major threats to fauna as well as a significant conservation issue. In this research, we examined the global pattern of one example of avian behavior in response to pollution—namely, the incorporation of anthropogenic materials into nests—as well as the existing knowledge on this subject. Based on 25 articles, we studied 51 populations, involving 24 bird species, and checked 10,790 nests; as a result, we found that incorporation of debris is correlated with increasing human influence on the environment, measured as the Human Footprint Index. Moreover, the probability of debris incorporation is higher in terrestrial than in marine species. We also identified knowledge bias in favor of marine as opposed to terrestrial species: namely, marine species attract more scientific attention than terrestrial. Furthermore, research approaches to these two ecosystems differ. Undeniably, the factors which influence debris incorporation by birds, the scale of this behavior, and particular forms of use of debris in bird nests are aspects which require long-term standardized research. This is the first global review paper on debris incorporation by birds to demonstrate a close link to human pressure as a driver.

The Pearl River Estuary (PRE) is the third largest estuary in China, where estuarine organisms are under metal stress at various biological levels. Based on the metal concentrations measured in oyster Crassostrea hongkongensis, we documented a change in dominance of metal contamination from Cd, Cr, Cu, Ni and Zn to Ag, Cd, Cu and Zn. In general, metal concentrations were higher in upstream stations and displayed a clear up-downstream gradient. Compared to the historical values, we noted the reductions in Cd, Cr and Ni concentrations, and the changing inputs due to evolving industrial activities were responsible for shaping the metal contamination profile in the PRE region. Along with metal concentrations, a suite of biomarkers was analyzed. Among the metals measured in the oyster tissues, Ag, Cd, Cu, Ni and Zn showed the strongest associations with pro-oxidant and oxidative stress responses (superoxide dismutase, lipid peroxidation and lysosomal membrane destabilization) and detoxification responses (glutathione and metallothionein), suggesting that the present metal contamination still exerts significant amount of stress in biota in the PRE. Metal contamination in estuaries in China is still severe compared to other countries, therefore continuous efforts should be taken to monitor the changing metal profiles with necessary control and remediation measures.

In the present study Mytilus galloprovincialis mussels were exposed for 28 days to three salinities: 30 (control), 25 and 35. Simultaneously, organisms at each salinity were exposed to either the antimicrobial agent Triclosan (TCS) or the pharmaceutical drug Diclofenac (DIC) at 1 μg/L. Salinity alone and exposure to PPCPs changed mussel's metabolic capacity and oxidative status, but no additive or synergetic effects resulting from the combined exposures were observed. Overall, the metabolic capacity of mussels was decreased when exposed to TCS and DIC under control salinity, which was less pronounced at salinities out of the control level. TCS had a notorious effect over glutathione peroxidase activity while DIC exposure enhanced catalase response. Such defence mechanisms were able to prevent cellular damage but still a clear reduction in GSH/GSSG ratio after PPCPs exposures indicates oxidative stress which could compromise bivalve's performance to further stressing events.

Arctic permafrost soils contain large amounts of organic carbon and the pollutant mercury (Hg). Arctic warming and associated changes in hydrology, biogeochemistry and ecology risk mobilizing soil Hg to rivers and to the Arctic Ocean, yet little is known about the quantity, timing and mechanisms involved. Here we investigate seasonal particulate Hg (PHg) and organic carbon (POC) export in 32 small and medium rivers across a 1700 km latitudinal permafrost transect of the western Siberian Lowland. The PHg concentrations in suspended matter increased with decreasing watershed size. This underlines the significance of POC-rich small streams and wetlands in PHg export from watersheds. Maximum PHg concentrations and export fluxes were located in rivers at the beginning of permafrost zone (sporadic permafrost). We suggest this reflects enhanced Hg mobilization at the permafrost boundary, due to maximal depth of the thawed peat layer. Both the thickness of the active (unfrozen) peat layer and PHg run-off progressively move to the north during the summer and fall seasons, thus leading to maximal PHg export at the sporadic to discontinuous permafrost zone. The discharge-weighed PHg:POC ratio in western Siberian rivers (2.7 ± 0.5 μg Hg: g C) extrapolated to the whole Ob River basin yields a PHg flux of 1.5 ± 0.3 Mg y⁻¹, consistent with previous estimates. For current climate warming and permafrost thaw scenarios in western Siberia, we predict that a northward shift of permafrost boundaries and increase of active layer depth may enhance the PHg export by small rivers to the Arctic Ocean by a factor of two over the next 10–50 years.