The current use of chemicals puts pressure on human and ecological health. Based on the Aarhus Convention, citizens have the right to have access to information on substances in their local... Show moreThe current use of chemicals puts pressure on human and ecological health. Based on the Aarhus Convention, citizens have the right to have access to information on substances in their local environment. Providing this information is a major challenge, especially considering complex mixtures, as the current substance-by-substance risk assessment may not adequately address the risk of co-exposure to multiple substances. Here, we provide an overview of the currently available indicators in the Netherlands to explore current scientific possibilities to indicate the impacts of complex chemical mixtures in the environment on human health and ecology at the local scale. This is limited to impact estimates on freshwater species for 701 substances, impact estimates of four metals on soil organisms, and impacts on human health for particulate matter (PM10) and nitrogen dioxide (NO2) in air. The main limiting factors in developing and expanding these indicators to cover more compartments and substances are the availability of emission and concentration data of substances and dose-response relationships at the population (human health) or community (ecology) level. As ways forward, we propose; 1) developing cumulative assessment groups (CAGs) for substances on the European Pollutant Transfer and Release Register and Water Framework Directive substance lists, to enable the development of mixture indicators based on mixture risk assessment and concentration addition principles; 2) to gain insight into local mixtures by also applying these CAGs to emission data, which is available for soil and air for more substances than concentrations data; 3) the application of analytical non-target screening methods as well as effect-based methods for whole-mixture assessment. Show less
III–V/Silicon tandem solar cells offer one of the most promising avenues for high-efficiency, high-stability photovoltaics. However, a key concern is the potential environmental release of group... Show moreIII–V/Silicon tandem solar cells offer one of the most promising avenues for high-efficiency, high-stability photovoltaics. However, a key concern is the potential environmental release of group III–V elements, especially arsenic. To inform long-term policies on the energy transition and energy security, we develop and implement a framework that fully integrates future PV demand scenarios with dynamic stock, emission, and fate models in a probabilistic ecological risk assessment. We examine three geographical scales: local (including a floating utility-scale PV and waste treatment), regional (city-wide), and continental (Europe). Our probabilistic assessment considers a wide range of possible values for over one hundred uncertain technical, environmental, and regulatory parameters. We find that III–V/silicon PV integration in energy grids at all scales presents low-to-negligible risks to soil and freshwater organisms. Risks are further abated if recycling of III–V materials is considered at the panels' end-of-life. Show less
Environmental contextDecades of research tried to understand the inherent complexity of biodegradation of contaminants. We describe calculus of biodegradation driven by bioavailability, redox,... Show moreEnvironmental contextDecades of research tried to understand the inherent complexity of biodegradation of contaminants. We describe calculus of biodegradation driven by bioavailability, redox, geometry and acclimation (adaptation) of microbiota. We tested predictions for thousands of contaminants across wastewater treatment plants, explaining up to 70% of the variance in observations. This competes with more intensive methods, and enables more efficient monitoring, experimentation and data interpretation.RationaleRelease of harmful contaminants of emerging concern (CECs) in the environment prompts possible adverse toxicological effects. Increasing population, water use and process wastewater generation require more efficient removal of contaminants that allows for effluent discharge within environmental regulatory limits. Wastewater treatment plants (WWTPs) can remove hazardous contaminants, limiting unwanted release. Fine-tuning WWTP settings to fit the location, time, season, wastewater type, etc. may enhance removals to reduce CEC concentrations and toxic pressures.MethodologyFor this purpose, we need robust tools to calculate removal efficiencies. We studied influences of operational settings and CEC properties on their removal in WWTPs. For this purpose, we parameterised thermochemical properties of CECs: for their (1) speciation and acidification, (2) (re/im)mobilisation due to (de)sorption into solid/water, (3) redox-mediated biotransformation and (4) acclimation of biomass so to utilise metabolic pathways for biotransformation. By combining these parameters, we developed an energy-based framework for calculating biotransformation rates.ResultsWe evaluated our calculus using removal efficiency (%) data for 373 measurements of 60 CECs in 14 different Dutch WWTPs and an additional 667 CECs in 49 WWTPs across the world. Our prediction precision, R2 ≈ 0.65 (P < 10−5), captures influences of wastewater characteristics (multiple measurements for each WWTP). It is higher than R2-values of modelling approaches currently available. Our model explains CEC removal with appreciative certainty. We identified outliers during evaluation. These outliers were attributed mostly to back-transformation and uncertainty in long-term background concentrations of contaminants, causing consequent acclimation of microbial consortia.DiscussionBiodegradability and CEC-degrading biomass can be estimated from concentration and environmental residence time. Our framework and underlying parametrisations have a mechanistic basis, utilising simple WWTP operational information (CEC concentration, temperature, suspended solids concentration, oxygen demand, etc.). Thereby, our work has wide potential for implementation. Our approach can supplement current fate assessment for CECs for improved environmental risk assessments. We conclude by discussing the potential for removal enhancement. Show less
Micro- and nano-plastics (MNPs) pollution has become a pressing global environmental issue, with growing concerns regarding its impact on human health. However, evidence on the effects of MNPs on... Show moreMicro- and nano-plastics (MNPs) pollution has become a pressing global environmental issue, with growing concerns regarding its impact on human health. However, evidence on the effects of MNPs on human health remains limited. This paper reviews the three routes of human exposure to MNPs, which include ingestion, inhalation, and dermal contact. It further discusses the potential routes of translocation of MNPs in human lungs, intestines, and skin, analyses the potential impact of MNPs on the homeostasis of human organ systems, and provides an outlook on future research priorities for MNPs in human health. There is growing evidence that MNPs are present in human tissues or fluids. Lab studies, including in vivo animal models and in vitro human-derived cell cultures, revealed that MNPs exposure could negatively affect human health. MNPs exposure could cause oxidative stress, cytotoxicity, disruption of internal barriers like the intestinal, the air–blood and the placental barrier, tissue damage, as well as immune homeostasis imbalance, endocrine disruption, and reproductive and developmental toxicity. Limitedly available epidemiological studies suggest that disorders like lung nodules, asthma, and blood thrombus might be caused or exacerbated by MNPs exposure. However, direct evidence for the effects of MNPs on human health is still scarce, and future research in this area is needed to provide quantitative support for assessing the risk of MNPs to human health. Show less
Fully understanding the cellular uptake and intracellular localization of MoS2 nanosheets (NSMoS2) is a prerequisite for their safe applications. Here, we characterized the uptake profile of NSMoS2... Show moreFully understanding the cellular uptake and intracellular localization of MoS2 nanosheets (NSMoS2) is a prerequisite for their safe applications. Here, we characterized the uptake profile of NSMoS2 by functional coelomocytes of the earthworm Eisenia fetida. Considering that vacancy engineering is widely applied to enhance the NSMoS2 performance, we assessed the potential role of such atomic vacancies in regulating cellular uptake processes. Coelomocyte internalization and lysosomal accumulation of NSMoS2 were tracked by fluorescent labeling imaging. Cellular uptake inhibitors, proteomics, and transcriptomics helped to mechanistically distinguish vacancy-mediated endocytosis pathways. Specifically, Mo ions activated transmembrane transporter and ion-binding pathways, entering the coelomocyte through assisted diffusion. Unlike molybdate, pristine NSMoS2 (P-NSMoS2) induced protein polymerization and upregulated gene expression related to actin filament binding, which phenotypically initiated actin-mediated endocytosis. Conversely, vacancy-rich NSMoS2 (V-NSMoS2) were internalized by coelomocytes through a vesicle-mediated and energy-dependent pathway. Mechanistically, atomic vacancies inhibited mitochondrial transport gene expression and likely induced membrane stress, significantly enhancing endocytosis (20.3%, p < 0.001). Molecular dynamics modeling revealed structural and conformational damage of cytoskeletal protein caused by P-NSMoS2, as well as the rapid response of transport protein to V-NSMoS2. These findings demonstrate that earthworm functional coelomocytes can accumulate NSMoS2 and directly mediate cytotoxicity and that atomic vacancies can alter the endocytic pathway and enhance cellular uptake by reprogramming protein response and gene expression patterns. This study provides an important mechanistic understanding of the ecological risks of NSMoS2. Show less
Despite the increasing concern about the harmful effects of micro- and nanoplastics (MNPs), there are no harmonized guidelines or protocols yet available for MNP ecotoxicity testing. Current... Show moreDespite the increasing concern about the harmful effects of micro- and nanoplastics (MNPs), there are no harmonized guidelines or protocols yet available for MNP ecotoxicity testing. Current ecotoxicity studies often use commercial spherical particles as models for MNPs, but in nature, MNPs occur in variable shapes, sizes and chemical compositions. Moreover, protocols developed for chemicals that dissolve or form stable dispersions are currently used for assessing the ecotoxicity of MNPs. Plastic particles, however, do not dissolve and also show dynamic behavior in the exposure medium, depending on, for example, MNP physicochemical properties and the medium’s conditions such as pH and ionic strength. Here we describe an exposure protocol that considers the particle-specific properties of MNPs and their dynamic behavior in exposure systems. Procedure 1 describes the top-down production of more realistic MNPs as representative of MNPs in nature and particle characterization (e.g., using thermal extraction desorption-gas chromatography/mass spectrometry). Then, we describe exposure system development for short- and long-term toxicity tests for soil (Procedure 2) and aquatic (Procedure 3) organisms. Procedures 2 and 3 explain how to modify existing ecotoxicity guidelines for chemicals to target testing MNPs in selected exposure systems. We show some examples that were used to develop the protocol to test, for example, MNP toxicity in marine rotifers, freshwater mussels, daphnids and earthworms. The present protocol takes between 24 h and 2 months, depending on the test of interest and can be applied by students, academics, environmental risk assessors and industries. Show less
Novel nanomaterial-based pesticide formulations are increasingly perceived as promising aids in the transition to more efficient agricultural production systems. The current understanding of... Show moreNovel nanomaterial-based pesticide formulations are increasingly perceived as promising aids in the transition to more efficient agricultural production systems. The current understanding of potential unintended (eco)toxicological impacts of nano-formulated pesticides is scarce, in particular with regard to (non-target) aquatic organisms and ecosystems. The present study reports the results of a long-term freshwater mesocosm experiment which assessed responses of individual zooplankton taxa and communities to a novel TiO2-coated nano-formulation of the fungicidecarbendazim. Population- and community trends were assessed and compared in response to the nano-formulation and its constituents applied individually (i.e. nano-sized TiO2, carbendazim) and in combination (i.e. nano-sized TiO2 & carbendazim). Minimal differences were observed between effects induced by the nano-formulation and its active ingredient (i.e. carbendazim) when applied at equivalent nominal test concentrations (4 μg L−1). Nano-sized TiO2 was found to affect zooplankton community trends when applied separately at environmentally realistic concentrations (20 μg L−1 nominal test concentration). However, when nano-sized TiO2 was applied in combination with carbendazim, nano-sized TiO2 was found not to alter effects on community trends induced by carbendazim. The findings of the current study provide an extensive and timely addition to the current body of work available on non-target impacts of nano-formulated pesticides. Show less
In the current industrial scenario, chromium (Cr) as a metal is of great importance but poses a major threat to the ecosystem because of its toxicity, but fewer studies have been conducted on its... Show moreIn the current industrial scenario, chromium (Cr) as a metal is of great importance but poses a major threat to the ecosystem because of its toxicity, but fewer studies have been conducted on its effects and alleviation strategies by using nanoparticles (NPs) and plant growth promoting rhizobacteria (PGPR). Taking into consideration the positive effects of silver⎯nanoparticles (Ag⎯NPs) and (HAS31) rhizobacteria in reducing Cr toxicity in plants, the present study was conducted. A pot experiment was conducted to determine the effects of single and/or combined application of different levels [0 (no Ag⎯NPS), 15 and 30 mM] of Ag⎯NPs and HAS31 [0 (no HAS31), 50 g and 100 g] on Cr accumulation, morpho-physiological and antioxidative defense attributes of barley (Hordeum vulgare L.) exposed to severe Cr stress [0 (without Cr stress), 50 and 100 μM)]. Results from the present study showed that the increasing levels of Cr in the soil significantly (P < 0.05) decreased plant growth and biomass, photosynthetic pigments, gas exchange attributes, sugars, and nutritional contents from the roots and shoots of the plants. In contrast, increasing levels of Cr in the soil significantly (P < 0.05) increased oxidative stress indicators in term of malondialdehyde, hydrogen peroxide, and electrolyte leakage, and also increased organic acid exudation patter in the roots of H. vulgare. Although, the activities of enzymatic antioxidants and the response of their gene expressions in the roots and shoots of the plants and non-enzymatic such as phenolic, flavonoid, ascorbic acid, and anthocyanin contents were increased by increasing the Cr concentration in the soil. The negative impacts of Cr injury were reduced by the application of PGPR (HAS31) and Ag⎯NPs, which increased plant growth and biomass, improved photosynthetic apparatus, antioxidant enzymes, and mineral uptake, as well as diminished the exudation of organic acids and oxidative stress indicators in roots of H. vulgare by decreasing Cr toxicity. Research findings, therefore, suggest that the application of PGPR (HAS31) and Ag⎯NPs can ameliorate Cr toxicity in H. vulgare, resulting in improved plant growth and composition under metal stress, as depicted by balanced exudation of organic acids. Show less
Dissolved organic matter (DOM) plays an important role in the biogeochemical cycle in natural waters. The determination and characterization of the excited triplet state of DOM (3DOM*) have... Show moreDissolved organic matter (DOM) plays an important role in the biogeochemical cycle in natural waters. The determination and characterization of the excited triplet state of DOM (3DOM*) have attracted much attention recently. However, the underlying differences of determined 3DOM* through different pathways are not yet fully understood. In this study, the differences and underlying mechanisms of the determined 3DOM* using 2,4-hexadien-1-ol (HDO) through an energy transfer pathway and 2,4,6-trimethylphenol (TMP) through an electron transfer pathway, were investigated. The results showed that the determined quantum yields of 3DOM* (Φ3DOM*) for four commercial and four isolated local DOMs are different using HDO ((0.04 ± 0.00) × 10−2 to (2.9 ± 0.17) × 10−2)) and TMP ((0.08 ± 0.01) × 10−2 to (1.2 ± 0.17) × 10−2), respectively. For 17 DOM-analogs, significant differences were also observed with the quantum yields of their 3DOM* determined using HDO (ΦHDO) and the triplet-state quantum yield coefficients determined using TMP (fTMP). It indicates the different reactivity of TMP and HDO with the excited triplet of the chromophores with different structures within the isolated DOM. Based on the experimental and predicted values of fTMP and ΦHDO for different DOM-analogs, the impact of substituents on differences in 3DOM* values were further revealed. These results demonstrated that the levels of 3DOM* depended on the chemical functionalities present in the DOM-analogs. Show less
The European Green Deal policy ambitions set out in the Chemicals Strategy for Sustainability and the Zero Pollution Action Plan identify the transition to a Safe and Sustainable by Design (SSbD)... Show moreThe European Green Deal policy ambitions set out in the Chemicals Strategy for Sustainability and the Zero Pollution Action Plan identify the transition to a Safe and Sustainable by Design (SSbD) approach to chemicals and materials. The H2020 SUNSHINE project has developed an approach to operationalize SSbD, specifically addressing multi-component nanomaterials (MCNMs), and applied it to two case studies. This approach enables assessment of safety and sustainability aspects at each stage of product development from a lifecycle perspective. This is achieved via a tiered approach that uses qualitative (Tier 1), semi-quantitative (Tier 2) and quantitative (Tier 3) assessment methods. The present work focuses on the Tier 1 (self-assessment) methodology designed to evaluate the safety, functionality and sustainability in the early R&D stages of the lifecycle of chemicals and materials. This approach was developed to be implementable by industries in a straightforward manner as often there is lack of time and/or expertise to engage in resource-intensive safety and sustainability evaluations. The approach was tested using two real industrial case studies, namely nano-enabled PFAS (Polyfluoroalkyl substances)-free anti-sticking coating for bakery molds, and nano-drops of essential oil anchored to the surface of nano clays and encapsulated in a polymeric film. The results indicate that these innovative materials have a high probability to have better safety, functionality and sustainability performance compared to conventional benchmark materials. Show less
Micro- and nanoplastics are emerging concerns due to their environmental ubiquity and currently largely unknown ecological impacts. Leveraging on a recently developed method using europium-doped... Show moreMicro- and nanoplastics are emerging concerns due to their environmental ubiquity and currently largely unknown ecological impacts. Leveraging on a recently developed method using europium-doped polystyrene particles (PS-Eu), our present work aimed to accurately trace the uptake and transport of micro- and nanoplastics in aquatic plants and shed insights into the potential of different aquatic plants for trapping and removal of plastics from water environment. Seedlings of Vallisneria denseserrulata Makino (submerged plant), Iris tectorum Maxim (emergent plant), and Eichhornia crassipes Solms (floating plant) were exposed to 100 nm and 2 μm PS-Eu in freshwater (5 μg/mL) or sediments (5 μg/g) for 8 weeks. Fluorescence imaging clearly evidenced that PS-Eu mainly accumulated in the intercellular space and were transported from roots to leaves via the apoplastic path and vascular bundle. Mass spectrum analysis demonstrated that up to 6250 μg/g nanoplastics were trapped in aquatic plants (mainly in roots) with a bioconcentration factor of 306.5, depending on exposure routes and plant species. Owing to their excellent capture capability and high tolerance to plastic exposures, floating plants like E. crassipes are promising for immobilizing and removing fine plastics from the water environment. Show less
Little information is available on how the types, concentrations, and distribution of chemicals have evolved over the years. The objective of the present study is therefore to review the spatial and .Show moreLittle information is available on how the types, concentrations, and distribution of chemicals have evolved over the years. The objective of the present study is therefore to review the spatial and temporal distribution profile of emerging contaminants with limited toxicology data in the pearl river basin over the years to build up the emerging contaminants database in this region for risk assessment and regulatory purposes. The result revealed that seven groups of emerging contaminants were abundant in this region, and many emerging contaminants had been detected at much higher concentrations before 2011. Specifically, antibiotics, phenolic compounds, and acidic pharmaceuticals were the most abundant emerging contaminants detected in the aquatic compartment, while phenolic compounds were of the most profound concern in soil. Flame retardants and plastics were the most frequently studied chemicals in organisms. The abundance of the field concentrations and frequencies varied considerably over the years, and currently available data can hardly be used for regulation purposes. It is suggested that watershed management should establish a regular monitoring scheme and comprehensive database to monitor the distribution of emerging contaminants considering the highly condensed population in this region. The priority monitoring list should be formed in consideration of historical abundance, potential toxic effects of emerging contaminants as well as the distribution of heavily polluting industries in the region. Show less
Molybdenum disulfide (MoS2) nanosheets are increasingly applied in several fields, but effective and accurate strategies to fully characterize potential risks to soil ecosystems are lacking. We... Show moreMolybdenum disulfide (MoS2) nanosheets are increasingly applied in several fields, but effective and accurate strategies to fully characterize potential risks to soil ecosystems are lacking. We introduce a coelomocyte-based in vivo exposure strategy to identify novel adverse outcome pathways (AOPs) and molecular endpoints from nontransformed (NTMoS2) and ultraviolet-transformed (UTMoS2) MoS2 nanosheets (10 and 100 mg Mo/L) on the earthworm Eisenia fetida using nontargeted lipidomics integrated with transcriptomics. Machine learning-based digital pathology analysis coupled with phenotypic monitoring was further used to establish the correlation between lipid profiling and whole organism effects. As an ionic control, Na2MoO4 exposure significantly reduced (61.2–79.5%) the cellular contents of membrane-associated lipids (glycerophospholipids) in earthworm coelomocytes. Downregulation of the unsaturated fatty acid synthesis pathway and leakage of lactate dehydrogenase (LDH) verified the Na2MoO4-induced membrane stress. Compared to conventional molybdate, NTMoS2 inhibited genes related to transmembrane transport and caused the differential upregulation of phospholipid content. Unlike NTMoS2, UTMoS2 specifically upregulated the glyceride metabolism (10.3–179%) and lipid peroxidation degree (50.4–69.4%). Consequently, lipolytic pathways were activated to compensate for the potential energy deprivation. With pathology image quantification, we report that UTMoS2 caused more severe epithelial damage and intestinal steatosis than NTMoS2, which is attributed to the edge effect and higher Mo release upon UV irradiation. Our results reveal differential AOPs involving soil sentinel organisms exposed to different Mo forms, demonstrating the potential of liposome analysis to identify novel AOPs and furthermore accurate soil risk assessment strategies for emerging contaminants. Show less
The spread of antibiotic resistant bacteria (ARB) in the environment poses a potential threat to human health, and the reactivation of inactivated ARB accelerated the spread of ARB. However, little... Show moreThe spread of antibiotic resistant bacteria (ARB) in the environment poses a potential threat to human health, and the reactivation of inactivated ARB accelerated the spread of ARB. However, little is known about the reactivation of sunlight-inactivated ARB in natural waters. In this study, the reactivation of sunlight-inactivated ARB in dark conditions was investigated with tetracycline-resistant E. coli (Tc-AR E. coli) as a representative. Results showed that sunlight-inactivated Tc-AR E. coli underwent dark repair to regain tetracycline resistance with dark repair ratios increasing from (0.124 ± 0.012)‱ within 24 h dark treatment to (0.891 ± 0.033)‱ within 48 h. The presence of Suwannee River fulvic acid (SRFA) promoted the reactivation of sunlight-inactivated Tc-AR E. coli and tetracycline inhibited their reactivation. The reactivation of sunlight-inactivated Tc-AR E. coli is mainly attributed to the repair of the tetracycline-specific efflux pump in the cell membrane. Tc-AR E. coli in a viable but non-culturable (VBNC) state was observed and dominated the reactivation as the inactivated ARB remain present in the dark for more than 20 h. These results explained the reason for distribution difference of Tc-ARB at different depths in natural waters, which are of great significance for understanding the environmental behavior of ARB. Show less
Schlender, T.; Viljanen, M.; Rijn, J.N. van; Mohr, F.; Peijnenburg, W.J.G.M.; Hoos, H.H.; ... ; Wong, A. 2023
Toxicological information as needed for risk assessments of chemical compounds is often sparse. Unfortunately, gathering new toxicological information experimentally often involves animal testing.... Show moreToxicological information as needed for risk assessments of chemical compounds is often sparse. Unfortunately, gathering new toxicological information experimentally often involves animal testing. Simulated alternatives, e.g., quantitative structure – activity relationship (QSAR) models, are preferred to infer the toxicity of new compounds. Aquatic toxicity data collections consist of many related tasks, each predicting the toxicity of new compounds on a given species. Since many of these tasks are inherently low-resource, i.e., involve few associated compounds, this is challenging. Meta-learning is a subfield of artificial intelligence that can lead to more accurate models by enabling the utilization of information across tasks. In our work, we benchmark various state-of-the-art meta-learning techniques for building QSAR models, focusing on knowledge sharing between species. Specifically, we employ and compare transformational machine learning, model-agnostic meta-learning, fine-tuning, and multi-task models. Our experiments show that established knowledge-sharing techniques outperform single-task approaches. We recommend the use of multi task random forest models for aquatic toxicity modeling, which matched or exceeded the performance of other approaches and robustly produced good results in the low-resource settings we studied. This model functions on a species level, predicting toxicity for multiple species across various phyla, with flexible exposure duration and on a large chemical applicability domain. Show less
Dissolution of nanoparticles (NPs) determines the fate and subsequently the actual exposure of biota to the NPs. Whether and to what extent NPs dissolve or remain in their particulate form in... Show moreDissolution of nanoparticles (NPs) determines the fate and subsequently the actual exposure of biota to the NPs. Whether and to what extent NPs dissolve or remain in their particulate form in aqueous media is thus of pivotal knowledge for the safety assessments of NPs. In this research, secondary data on dissolution of NPs were systematically collected. A range of dissolution rates could be recalculated, as dependent on the characteristics of the NPs and the exposure medium. For example, two nanoparticles which are identical in terms of chemical composition of the particle core and of the coating, had a fully different dissolution behaviour, as subject to different surface modifications. A model was derived for calculating dissolution rate constants of NPs. The model is based on the initial kinetics of dissolution of NPs under different exposure scenarios and on the assumption of pseudo-first order reaction kinetics at the particle surface. Characterizing the dissolution rates and the parameters which modify dissolution allows for grouping of those NPs that dissolve either very slowly or very quickly. This information can be used for risk assessment of NPs, and once sufficient kinetic dissolution data are available, will ultimately allow for development of predictive models for the dissolution kinetics of newly developed nanomaterials. Show less
Little information is available on how the types, concentrations, and distribution of chemicals have evolved over the years. The objective of the present study is therefore to review the spatial and .Show moreLittle information is available on how the types, concentrations, and distribution of chemicals have evolved over the years. The objective of the present study is therefore to review the spatial and temporal distribution profile of emerging contaminants with limited toxicology data in the pearl river basin over the years to build up the emerging contaminants database in this region for risk assessment and regulatory purposes. The result revealed that seven groups of emerging contaminants were abundant in this region, and many emerging contaminants had been detected at much higher concentrations before 2011. Specifically, antibiotics, phenolic compounds, and acidic pharmaceuticals were the most abundant emerging contaminants detected in the aquatic compartment, while phenolic compounds were of the most profound concern in soil. Flame retardants and plastics were the most frequently studied chemicals in organisms. The abundance of the field concentrations and frequencies varied considerably over the years, and currently available data can hardly be used for regulation purposes. It is suggested that watershed management should establish a regular monitoring scheme and comprehensive database to monitor the distribution of emerging contaminants considering the highly condensed population in this region. The priority monitoring list should be formed in consideration of historical abundance, potential toxic effects of emerging contaminants as well as the distribution of heavily polluting industries in the region. Show less
Increasing knowledge of the impacts of pesticides on soil ecological communities is fundamental to a comprehensive understanding of the functional changes in the global agroecosystem industry. In... Show moreIncreasing knowledge of the impacts of pesticides on soil ecological communities is fundamental to a comprehensive understanding of the functional changes in the global agroecosystem industry. In this study, we examined microbial community shifts in the gut of the soil-dwelling organism Enchytraeus crypticus and functional shifts in the soil microbiome (bacteria and viruses) after 21 d of exposure to difenoconazole, one of the main fungicides in intensified agriculture. Our results demonstrated reduced body weight and increased oxidative stress levels of E. crypticus under difenoconazole treatment. Meanwhile, difenoconazole not only altered the composition and structure of the gut microbial community, but also interfered with the soil-soil fauna microecology stability by impairing the abundance of beneficial bacteria. Using soil metagenomics, we revealed that bacterial genes encoding detoxification and viruses encoding carbon cycle genes exhibited a dependent enrichment in the toxicity of pesticides via metabolism. Taken together, these findings advance the understanding of the ecotoxicological impact of residual difenoconazole on the soil-soil fauna micro-ecology, and the ecological importance of virus-encoded auxiliary metabolic genes under pesticide stress. Show less