The bioaccumulation and biomagnification of 22 major perfluoroalkyl substances (PFAS) were investigated in tissues of polar bears (Ursus maritimus) and their major prey species, the ringed seal (Pusa hispida), from the Scoresby Sound region of East Greenland. In polar bear liver the mean Σ4PFSA (perfluoroalkyl sulfonic acid) concentration (C4, C6, C8 and C10) was 2611 ± 202 ng/g wet weight (ww; 99% perfluorooctane sulfonate (PFOS)) and two orders of magnitude higher than the 20 ± 3 ng/g ww (89% PFOS) concentration in fat. The mean Σ4PFSAs in seal liver was 111 ± 5 ng/g ww (98% PFOS) and three orders of magnitude higher relative to the 0.05 ± 0.01 ng/g ww concentration in blubber (100% perfluorohexane sulfonate). Perfluoro-1-octane sulfonamide (FOSA) was quantifiable in bear (mean 10 ± 1.4 ng/g ww) and seal (mean 0.6 ± 0.1 ng/g ww) liver but not in fat or blubber. The mean Σ13PFCAs (C4–C18; perfluoroalkyl carboxylic acids) in bear liver (924 ± 71 ng/g ww) was much greater than in seal liver (74 ± 6 ng/g ww). In bear fat and seal blubber, the mean Σ13PFCAs were 15 ± 1.9 and 0.9 ± 0.1 ng/g ww, respectively. Longer chain C11 to C14 PFCAs dominated in bear fat and seal blubber (60–80% of Σ13PFCA), whereas shorter-chain C9 to C11 PFCAs dominated in the liver (85–90% of Σ13PFCA). Biomagnification factors (BMFs) were orders of magnitude greater for PFHxS and C9 to C13 PFCAs when based on bear liver to seal blubber rather than bear liver to seal liver, and PFCA (C9 to C13) BMFs decreased with increasing chain length. Seal blubber to bear liver BMFs better reflects the dietary exposure relationship of PFAS between bears and seals.

Antibiotics in water and soil are persistent, bioaccumulative and toxic to aquatic organisms and human health. To address it, as one of the new technologies, green synthesized magnetic Fe₃O₄ nanoparticles by Excoecaria cochinchinensis extract used to remove rifampicin (RIF) was investigated in this study. Results showed the adsorption efficiency of RIF reached 98.4% and the maximum adsorption capacity is 84.8 mg/g when 20 mL of RIF at a concentration of 20 M was adsorbed by 10 mg Fe₃O₄ at a temperature of 303 K. The morphology of the green Fe₃O₄ characterized by SEM demonstrated the dimensions ranging from 20 to 30 nm. The N₂ adsorption/desorption isotherms revealed that the surface area of Fe₃O₄ was 111.8 m²/g. In addition, adsorption studies indicated that the kinetics fitted the pseudo second-order and isothermal adsorption conformed to the Langmuir isotherm. Furthermore, due to their magnetic properties, the Fe₃O₄ nanoparticles were easily separated and reused and the mechanism for removing RIF occurred through adsorption rather than chemical redox reaction. Finally, the reusability of Fe₃O₄ for adsorption of RIF showed that the removal efficiency decreased to 61.5% after five cycles.

Inspired by methods used for life cycle impact assessment (LCIA), we constructed a series of indicators to appreciate the noxiousness of radioactive materials and wastes for human and ecosystem health. According to known potential human health and ecological effects of such materials, six main impact categories were considered to initiate the development of the method: human cancer and non-cancer effects vs. ecotoxicity, considering both chemotoxicity and radiotoxicity. For ecosystems, the noxiousness indicator is based on the concept of Potentially Affected Fraction (PAF), used as a damage indicator at the ecosystem level. The PAF express the toxic pressure on the environment due to one substance. It has been enlarged to mixtures of substances as multi-substances PAF (ms-PAF), and applied to a mix of stable and radioactive substances. Combining ecotoxicity data and a simplified model of exposure of fauna and flora, we proposed a chemotoxicity indicator and a radiotoxicity indicator, ultimately aggregated into a single indicator simply by addition.According to acknowledged practices in LCIA and corresponding available data, we suggested implementing to human health an approach similar to that applied to ecosystems. We produced eigth basic indicators combining effects categories (cancer and non cancer), exposure pathways (ingestion and inhlation) and substances (chemicals and radionuclides). The principle of additivity supporting the whole proposed approach allows their complete aggregation into a single indicator also for human health. Different source terms may be then easily directly compared in terms of human and ecological noxiousness.Applied to the time evolution of a High Level radioactive Waste (HLW), the method confirmed over 1 million years the dominance of the radiotoxicity in the noxiousness of the material for both humans and environment. However there is a change with time in the ranking of the most noxious substances, with stable metals contribution going progressively up. Finally, the HLW global noxiousness, integrating human health and ecological aspects, was assessed through time at three stages and showed a temporal decrease as expected from the dominance of the radiotoxicity.

The response of sediment bacterial communities in subtropical freshwater benthic microcosms to sediment-associated triclosan (TCS; 28 d exposure) was analysed using Illumina high-throughput sequencing. This study highlights the interactive effects of TCS and the presence of benthic macroinvertebrates (Limnodrilus hoffmeisteri and Viviparidae bellamya) on sediment bacterial communities. Our results show that TCS alone significantly altered the taxonomic composition and decreased alpha diversity of sediment bacterial communities at concentrations ≥80 μg TCS/g dry weight (dw) sediment (sed). Regarding dominant phyla, TCS significantly reduced the relative abundance of Bacteroidetes and Firmicutes at these concentrations, whereas the relative abundance of Chloroflexi and Cyanobacteria increased. In the presence of benthic macroinvertebrates, the sediment bacterial community was affected by 8 μg TCS/g dw sed as well. However, the presence of benthic macroinvertebrates did not cause measurable changes to bacterial community in unspiked (i.e., control) sediment. These results indicate that TCS alone would not alter the sediment bacterial community at environmentally relevant concentrations (up till 8 μg/g dw sed), but may have an effect in combination with the presence of benthic macroinvertebrates. Therefore, we recommend to include benthic macroinvertebrates when assessing the response of sediment bacterial communities during exposure to environmental stress such as organic contaminants.

As a country with the highest CO2 emissions and at the turning point of socio-economic transition, China's effort to reduce CO2 emissions will be crucial for climate change mitigation. Yet, due to geospatial variations of CO2 emissions in different cities, it is important to develop city-specific policies and tools to help control and reduce CO2 emissions. The key question is how to identify and quantify these variations so as to provide reference for the formulation of the corresponding mitigation policies. This paper attempts to answer this question through a case study of 26 cities in the Yangtze River Delta. The CO2 emissions pattern of each city is measured by two statistics: Gini coefficient to describe its quantitative pattern and Global Moran's I index to capture its spatial pattern. It is found that Gini coefficients in all these cities are all greater than 0.94, implying a highly polarized pattern in terms of quantity; and the maximum value for Global Moran's I index is 0.071 with a standard deviation of 0.021, indicating a weak spatial clustering trend but strong difference among these cities. So, it would be more efficient for these cities at current stage to reduce CO2 emissions by focusing on the large emission sources at certain small localities, particularly the very built-up areas rather than covering all the emission sources on every plot of the urban prefectures. And by a combination of these two metrics, the 26 cities are regrouped into nine types with most of them are subject to type HL and ML. These reclassification results then can serve as reference for customizing mitigation policies accordingly and positioning these policies in a more accurate way in each city.

There is increasing concern that climate change may make organisms more sensitive to chemical pollution. Many pesticides are indeed more toxic at higher mean temperatures. Yet, we know next to nothing about the effect of another key component of climate change, the increase of daily temperature fluctuations (DTFs), on pesticide toxicity. Therefore, we tested the effect of the pesticide chlorpyrifos under different levels of DTF (constant = 0 °C, low = 5 °C (current maximum level) and high = 10 °C (predicted maximum level under global warming)) around the same mean temperature on key life history and physiological traits of Ischnura elegans damselfly larvae in a common-garden experiment. At all levels of DTF, chlorpyrifos exposure was stressful: it reduced energy storage (fat content) and the activity of its target enzyme acetylcholinesterase, while it increased the activity of the detoxification enzyme cytochrome P450 monooxygenase. Notably, chlorpyrifos did not cause mortality or reduced growth rate at the constant temperature (0 °C DTF), yet increased mortality 6x and reduced growth rate with ca. 115% in the presence of DTF. This indicates that daily short-term exposures to higher temperatures can increase pesticide toxicity. Our data suggest that when 5 °C DTF will become more common in the studied high-latitude populations, this will increase the toxicity of CPF, and that a further increase from 5° DTF to 10 °C DTF may not result in a further increase of pesticide toxicity. Our results highlight the biological importance of including daily temperature fluctuations in ecological risk assessment of pesticides and as an extra dimension in the climate-induced toxicant sensitivity concept.

Acid mine drainage (AMD) is a global environmental issue. Conventionally, a number of active and passive remediation approaches are applied to treat and manage AMD. Case studies on remediation approaches applied in actual mining sites such as lime neutralization, bioremediation, wetlands and permeable reactive barriers provide an outlook on actual long-term implications of AMD remediation. Hence, in spite of available remediation approaches, AMD treatment remains a challenge. The need for sustainable AMD treatment approaches has led to much focus on water reuse and resource recovery. This review underscores (i) characteristics and implication of AMD, (ii) remediation approaches in mining sites, (iii) alternative treatment technologies for water reuse, and (iv) resource recovery. Specifically, the role of membrane processes and alternative treatment technologies to produce water for reuse from AMD is highlighted. Although membrane processes are favorable for water reuse, they cannot achieve resource recovery, specifically selective valuable metal recovery. The approach of integrated membrane and conventional treatment processes are especially promising for attaining both water reuse and recovery of resources such as sulfuric acid, metals and rare earth elements. Overall, this review provides insights in establishing reuse and resource recovery as the holistic approach towards sustainable AMD treatment. Finally, integrated technologies that deserve in depth future exploration is highlighted.

N-nitrosamines (NAs) are an emerging group of disinfection by-products that occur as a mixture in drinking water. Although the potency of the individual NA components in drinking water is negligible, their combined effect is rarely reported. We tested whether multicomponent NAs mixtures at environmentally relevant levels would produce significant effects when each component was combined at extremely low concentrations i.e. a million times lower than its No Observed Effect Concentration (NOEC). Mixture L (the maximum values detected in drinking water) or mixture M (one order of magnitude higher than detected) were fed to male and female Sprague-Dawley (SD) rats since PND 28 for seven days. We found that the body weight gains and the triglyceride (TG) levels increased significantly in mixture M treated male rats. Correspondingly, an obesogenic microbiota profile was obtained in the mixture M treated young male rat: Firmicutes/Bacteroidetes and the obesity-related taxa including Alistipes, Ruminococcus were enriched. Collectively, this is the first in vivo demonstration of NAs mixtures at environmentally relevant levels. Despite the complicated relationship between gut microbiota and obesity, our study has demonstrated that changes in gut microbiota may contribute to the development of obesity after the exposure. Our results highlight that changes in gut microbiota could be a risk factor for obesity, which emphasizes the need to include gut microbiota in the traditional mammalian risk assessment.

Microcystin (MC) elimination is a global challenge that is necessary for the health of humans and ecosystems. Biodegradation of MC, one of the most environmental-friendly methods, had previously been focused on the aerobic condition. In this study, two enrichment cultures from Taihu sediments possessed high capacity for MC-leucine arginine (MC-LR) anaerobic biodegradation. Meanwhile, it was firstly found that MC-LR underwent similar degradation process under anaerobic conditions to that in aerobic condition. Furthermore, a novel degradation pathway, hydrolyzing of Ala-Mdha to form a new linear MC-LR intermediate, was proposed under anaerobic conditions. Combining MC-LR degradation with microbial community analysis, this study deduced that Candidatus Cloacamonas acidaminovorans str. Evry may play an important role in the degradation of MC-LR. These findings suggest an additional pathway involved in the environmental cycle of MC-LR, which implies that the biotransformation of MC-LR might play an important role in eliminating MC-LR in eutrophic lake sediments under anaerobic conditions.

The accumulation of plastic debris and herbicide residues has become a huge challenge and poses many potential risks to environmental health and soil quality. In the present study, we investigated the transport of glyphosate and its main metabolite, aminomethylphosphonic acid (AMPA) via earthworms in the presence of different concentrations of light density polyethylene microplastics in the litter layer during a 14-day mesocosm experiment. The results showed earthworm gallery weight was negatively affected by the combination of glyphosate and microplastics. Glyphosate and AMPA concentrated in the first centimetre of the top soil layer and the downward transport of glyphosate and AMPA was only detected in the earthworm burrows, ranging from 0.04 to 4.25 μg g−1 for glyphosate and from 0.01 (less than limit of detection) to 0.76 μg g−1 for AMPA. The transport rate of glyphosate (including AMPA) from the litter layer into earthworm burrows ranged from 6.6 ± 4.6% to 18.3 ± 2.4%, depending on synergetic effects of microplastics and glyphosate application. The findings imply that earthworm activities strongly influence pollutant movement into the soil, which potentially affects soil ecosystems. Further studies focused on the fate of pollutants in the microenvironment of earthworm burrows are needed.