Showing papers in "Reviews of Environmental Contamination and Toxicology in 2022"

COF-Based Composites: Extraordinary Removal Performance for Heavy Metals and Radionuclides from Aqueous Solutions

Abstract: Covalent-organic-framework-based composites (COF-based composites) are novel functional materials constructed by combining COFs and various organic/inorganic materials, which usually exhibit more advantageous physicochemical properties, stability, selectivity, and pollutant removal performance compared with pristine COFs. In this review, we highlighted the detailed categories and the recent advances of binary and ternary COF-based composites. In particular, the progress of COF-based composites for the efficient removal of heavy metals and radionuclides is comprehensively summarized. By comparing the performance with other materials, we found that the functional materials make the composites stand out. In addition, the technologies to investigate the internal mechanism of pollutants removed by COF-based composites, mainly including characterization analysis and theoretical calculations, are discussed and summarized, providing the direction for in-depth understanding of COF-based composites. According to the discussion above, the opportunities and challenges of COF-based composites in the treatment of heavy metals and radionuclides are summarized and prospected. Through this review, we desire to raise the awareness of COF-based composites and advance further studies in this field by proposing the potential research directions and applications.

An Overview of Chemical Additives on (Micro)Plastic Fibers: Occurrence, Release, and Health Risks

Abstract: Plastic fibers are ubiquitous in daily life with additives incorporated to improve their performance. Only a few restrictions exist for a paucity of common additives, while most of the additives used in textile industry have not been clearly regulated with threshold limits. The production of synthetic fibers, which can shed fibrous microplastics easily (< 5 mm) through mechanical abrasion and weathering, is increasing annually. These fibrous microplastics have become the main composition of microplastics in the environment. This review focuses on additives on synthetic fibers; we summarized the detection methods of additives, compared concentrations of different additive types (plasticizers, flame retardants, antioxidants, and surfactants) on (micro)plastic fibers, and analyzed their release and exposure pathways to environment and human beings. Our prediction shows that the amounts of predominant additives (phthalates, organophosphate esters, bisphenols, per- and polyfluoroalkyl substances, and nonylphenol ethoxylates) released from clothing microplastic fibers (MFs) are estimated to reach 35, 10, 553, 0.4, and 568 ton/year to water worldwide, respectively; and 119, 35, 1911, 1.4, and 1965 ton/year to air, respectively. Human exposure to MF additives via inhalation is estimated to be up to 4.5–6440 µg/person annually for the above five additives, and via ingestion 0.1–204 µg/person. Notably, the release of additives from face masks is nonnegligible that annual human exposure to phthalates, organophosphate esters, per- and polyfluoroalkyl substances from masks via inhalation is approximately 491–1820 µg/person. This review helps understand the environmental fate and potential risks of released additives from (micro)plastic fibers, with a view to providing a basis for future research and policy designation of textile additives.

Cellular Uptake, Transport, and Organelle Response After Exposure to Microplastics and Nanoplastics: Current Knowledge and Perspectives for Environmental and Health Risks

Abstract: Microplastics (MPs) and nanoplastics (NPs) pollution has become an increasingly serious environmental problem, drawing widespread attentions. Owing to the small size, they could be potentially accumulated and translocated in different organs, tissues, and organelles of organisms and human beings, which in turn possibly causes adverse effects on human health. Some of the organelles are very sensitive to environmental pollutants, including MPs and NPs. In this review, we summarized and discussed the cellular uptake, intracellular transport, and induced organelle response of MPs and NPs. We first discussed the cellular uptake pathways, as well as the intracellular transportation, of MPs and NPs at sizes ranging from tens of nanometers to microns. Both endocytosis and passive diffusion were required for the cellular uptake of MPs and NPs. In the cells, some organelles, such as endosome, autophagosome, and lysosome, were involved in MPs and NPs transportation. We further introduced the roles of different organelles in toxicity induction of MPs and NPs and the relevant influencing factors including plastic size, surface modification, exposure concentration, and exposure model. The organelles of mitochondria, endoplasmic reticulum, nucleus, and cytoskeleton played important roles in the toxicity induction of MPs and NPs toxicity. Moreover, we proposed further research perspectives with the concern of environmental control and health risk assessment. Owing to the long-term existence of MPs and NPs, the control of production and environmental monitoring of MPs and NPs at the cellular level should be taken into consideration in the future.Graphical Abstract

A Review on the Water Quality Criteria of Nonylphenol and the Methodological Construction for Reproduction Toxicity Endocrine Disrupting Chemicals

Abstract: Endocrine-disrupting chemicals (EDCs) can adversely impact the hormonal control, sexual differentiation, reproductive success, and community structure of aquatic organisms. Nonylphenol is one kind of typical EDCs which has attracted increasing attention in recent years. The water quality criteria (WQC) of nonylphenol have been established in several countries/institutions according to the water quality guidelines. However, the reproduction toxicity characteristic of EDCs was excluded in the previous WQC study. In this study, the current research progress on WQC for nonylphenol in different countries/institutions is summarized. In addition, the methodology for deriving the WQC based on reproduction toxicity of EDCs, such as selecting a sensitive test species with a hypothalamic–pituitary–gonadal axis or an endocrine-like system, selecting the appropriate endpoint effects for reproduction toxicity, and collecting the chronic toxicity data are discussed. Finally, the predicted no-effect concentration (PNEC) of nonylphenol derived based on the reproduction toxicity endpoint data was 0.38 μg/L. This result indicated that the PNEC based on reproductive fitness occurred at significantly lower concentrations than that of the other derived toxicity endpoints. The results of this study would provide data support for WQC research and risk assessment of endocrine disruptors.

Impact of Bisphenol A on Structure and Function of Mitochondria: A Critical Review

Abstract: Abstract Bisphenol A (BPA) is an industrial chemical used extensively to manufacture polycarbonate plastics and epoxy resins. Because of its estrogen-mimicking properties, BPA acts as an endocrine-disrupting chemical. It has gained attention due to its high chances of daily and constant human exposure, bioaccumulation, and the ability to cause cellular toxicities and diseases at extremely low doses. Several elegant studies have shown that BPA can exert cellular toxicities by interfering with the structure and function of mitochondria, leading to mitochondrial dysfunction. Exposure to BPA results in oxidative stress and alterations in mitochondrial DNA (mtDNA), mitochondrial biogenesis, bioenergetics, mitochondrial membrane potential (MMP) decline, mitophagy, and apoptosis. Accumulation of reactive oxygen species (ROS) in conjunction with oxidative damage may be responsible for causing BPA-mediated cellular toxicity. Thus, several reports have suggested using antioxidant treatment to mitigate the toxicological effects of BPA. The present literature review emphasizes the adverse effects of BPA on mitochondria, with a comprehensive note on the molecular aspects of the structural and functional alterations in mitochondria in response to BPA exposure. The review also confers the possible approaches to alleviate BPA-mediated oxidative damage and the existing knowledge gaps in this emerging area of research.

A Critical Review of Bioaccumulation and Biotransformation of Organic Chemicals in Birds

Abstract: Abstract A literature review of bioaccumulation and biotransformation of organic chemicals in birds was undertaken, aiming to support scoping and prioritization of future research. The objectives were to characterize available bioaccumulation/biotransformation data, identify knowledge gaps, determine how extant data can be used, and explore the strategy and steps forward. An intermediate approach balanced between expediency and rigor was taken given the vastness of the literature. Following a critical review of > 500 peer-reviewed studies, > 25,000 data entries and 2 million information bytes were compiled on > 700 organic compounds for ~ 320 wild species and 60 domestic breeds of birds. These data were organized into themed databases on bioaccumulation and biotransformation , field survey , microsomal enzyme activity , metabolic pathway , and bird taxonomy and diet . Significant data gaps were identified in all databases at multiple levels. Biotransformation characterization was largely fragmented over metabolite/pathway identification and characterization of enzyme activity or biotransformation kinetics. Limited biotransformation kinetic data constrained development of an avian biotransformation model. A substantial shortage of in vivo biotransformation kinetics has been observed as most reported rate constants were derived in vitro. No metric comprehensively captured all key contaminant classes or chemical groups to support broad-scope modeling of bioaccumulation or biotransformation. However, metrics such as biota-feed accumulation factor, maximum transfer factor, and total elimination rate constant were more readily usable for modeling or benchmarking than other reviewed parameters. Analysis demonstrated the lack of bioaccumulation/biotransformation characterization of shorebirds, seabirds, and raptors. In the study of bioaccumulation and biotransformation of organic chemicals in birds, this review revealed the need for greater chemical and avian species diversity, chemical measurements in environmental media, basic biometrics and exposure conditions, multiple tissues/matrices sampling, and further exploration on biotransformation. Limitations of classical bioaccumulation metrics and current research strategies used in bird studies were also discussed. Forward-looking research strategies were proposed: adopting a chemical roadmap for future investigations, integrating existing biomonitoring data, gap-filling with non-testing approaches, improving data reporting practices, expanding field sampling scopes, bridging existing models and theories, exploring biotransformation via avian genomics, and establishing an online data repository.

The Fate of Fluopyram in the Soil–Water–Plant Ecosystem: A Review

Abstract: This review aims to discuss all likely pathways of the environmental fate of fluopyram to enable a better understanding of the probable ecological risks associated with its agricultural usage. The fluopyram is a broad-spectrum molecule to control various fungal plant pathogens as well as nematodes. It belongs to a new chemical class named ‘pyridinyl ethylbenzamides’. The literature review has shown that the sorption–desorption, degradation and leaching of fluopyram differed among the soil types, and much is still to be studied concerning the fate of fluopyram in different types of the soil environment. Indeed, research suggests that the high persistent behaviour of fluopyram particularly in soil and water/sediment environment can present environmental risks. Hence, with a foreseen widespread and substantial use of fluopyram, it would be indeed crucial to assess the possible environmental risks due to injudicious usage of fluopyram.

A Systematic Review on Distribution and Ecological Risk Assessment for Chiral Pharmaceuticals in Environmental Compartments

Abstract: Chiral pharmaceuticals are an important class of environmental pollutants. Monitoring studies have shown the non-racemic presence of these contaminants in wastewater, sludge and the receiving environment. This review describes the role of chirality in the environment, especially the distribution and toxicities of enantiomers of chiral pharmaceuticals. In the first part, a systematic overview of their distribution in various environmental matrices and the main application of chiral signatures as chemical markers of water contamination are discussed. Available studies mainly focus on four drug groups including NSAIDs, β-blockers, antidepressants and illicit drugs due to their environmental pseudopersistence and ecotoxicological effects. In the second part, a summary of the enantiospecific toxicity data reported for chiral pharmaceuticals is provided. These data are of high value to improve the accuracy of environmental risk assessments in future works. Enantioselective toxicity towards aquatic organisms have been established for ten out of 36 chiral pharmaceuticals measured and detected in wastewater or surface water samples. Their enantioselective biodegradation and ecotoxicity make the risk assessment process highly recommended. The results provided in this review work support the need for new approaches to more accurately determine the toxicological risks associated to the stereochemistry of environmental contaminants.

A Global Review of Cadmium, Mercury, and Selenium in Sharks: Geographical Patterns, Baseline Levels and Human Health Implications

Abstract: Globally, there is concern about the concentrations of some metals and metalloids in sharks and the associated impacts to themselves and to human consumers. Concentrations of Hg, Cd, and Se reported in muscle, liver and fins of sharks from all the world were reviewed to define geographical patterns of elemental distribution, to model the baseline concentrations of the three elements, and to assess potential human health risk. Published information corresponded to 102 sites that belong to thirteen FAO Major Fishing Areas. The majority of the sites corresponded to the Atlantic (39 sites), followed by the Pacific Ocean (37). Statistical analysis indicated significant differences of elemental concentrations among all FAO regions and oceans. The 5% baseline levels, estimated with a cumulative frequency distribution method for each element were: for Hg, 0.129 μg g−1 in muscle, 0.147 μg g−1 in liver; for Cd, 0.517 μg g−1 in muscle, 0.290 μg g−1 in liver; for Se, 0.105 μg g−1 in muscle, 0.218 μg g−1 in liver. These baseline leves are equivalent to the 5th percentile on a normal distribution. Levels of Cd, Hg and Se in muscle of sharks were above maximum permissible limits (Cd, 0.5; Hg, 1.0; Se, 1.0 μg g−1; Nauen in FAO Fish Circ 764:1–102, 1983; CEC in Off J Eur Union 364:5–24, 2006) for human consumption in 6, 49 and 25% of the reports, respectively. Considering all the studies, hazard quotients (it indicates the risk during the lifetime of an individual different to cancer if value is above one) were Cd (0.10 ± 0.18), Se (0.11 ± 0.10) and Hg (2.05 ± 2.69); i.e. only average Hg values are of concern. The concentrations of Hg and Se in muscle of sharks from the Mediterranean were statistically different from all other oceans. In shark species with more reports, baseline levels (µg g−1 wet weight) of Hg in muscle were: for P. glauca from the Pacific Southeast (0.048), for I. oxyrinchus from the Pacific Southeast (0.034), and for S. lewini from the Pacific Eastern Central (0.55). The balance of Hg and Se molar concentrations (it is used to assess the benefit or risk to the combined occurrence of Hg and Se) in muscle of sharks was assessed through the Se health benefit value (HBVSe), positive results indicate that shark consumption is beneficial to humans. In general, HBVSe was positive (3.06 ± 13.84). According to FAO Fishing areas, negative HBVSe values corresponded to Mediterranean and Black Sea (− 48.37), Atlantic Northwest (− 5.54), Pacific Eastern Central (− 0.97), and Atlantic Southwest (− 0.21); nevertheless, HBVSe values in sharks from Mediterranean and Black Sea, and Atlantic Northwest corresponded to only one species. Overall, similar elemental concentrations were found in some FAO regions of the southern hemisphere. Baseline values of Hg were in the same magnitude order as the low atmospheric deposition flux. Under the approach of the hazard quotient, Hg is of concern because values were above one in almost half of the studies. More information related to Hg and Se in muscle of sharks is required in some FAO regions (Indian Ocean Eastern, Pacific Northeast and Pacific Southeast) to estimate HBVSe.

Novel Metal–Organic Framework Materials In-Focus Detection and Adsorption Cues for Environmental Pollutants

Abstract: Various novel nanomaterials have been successfully designed and used for the extraction and analysis of environmental contaminants. Metal–organic framework materials (MOFs) with excellent performance have been widely used for the detection and adsorption of environmental pollutants. However, considerable effort is still needed before the broad practical applications of MOFs in the field of environmental safety due to challenges in the design of smart materials resulting from the complexity of environments and emerging contaminants. In this work, the following were summarized and highlighted: (1) development of MOF-based sensors with good performance in the detection of contaminants; (2) pollutant adsorption by the developed MOFs; (3) challenges and perspective on the practical applications of novel MOFs in environmental protection. Overall, the current progress of MOFs indicates promise for the effective decrease in the risk of environmental pollution. In this work, by summarizing the current scientific progress, we expect to provide clues regarding the smart design and green synthesis of new MOFs in future applications for efficient pollutant control.

Protists, Unexpected Players in Waterborne Antibiotic Resistance?

Abstract: The emergence and spread of antibiotic resistance in aquatic environment such as rivers, lakes, and sewage have accelerated microbial threats to human health by promoting the growth of specific waterborne pathogens and transferring them from the ecosystems to humans. Identifying the unexpected drivers of and bottlenecks for human risk assessment of waterborne antibiotic resistance are crucial in understanding and managing the global ARGs transfer. We showed our current understanding of the factors, residual pollutants, bacteriophages, bacterial communities, and the unexpected players’ protists in driving emergence and transfer of waterborne antibiotic resistance. Heterotrophic protists mainly induce waterborne antibiotic resistance because they can accelerate the transfer of ARGs between bacteria and provide optimal environments for antibiotic-resistant pathogens. Current research, however, still cannot provide a comprehensive understanding of the molecular mechanisms of the impacts of protists on waterborne antibiotic resistance. We have, therefore, summarized the key information that is currently missing and discussed the assessment of resistance risk on human health and finally provided some management strategies.

Current Situation and Ecological Effects of Microplastic Pollution in Soil

Abstract: Microplastics have received more and more attention worldwide as an emerging persistent pollutant. Soil microplastic pollution can cause serious environmental problems and potentially endanger the soil ecosystems and human health. Currently, most available studies of microplastics have been performed in aquatic environments. However, soil environments have been less studied, and our understanding of microplastic pollution in soil is still lacking. Therefore, based on the existing knowledge, this review firstly focuses on the current situation of microplastic pollution in soil, basically including sources, distribution characteristics, degradation, and migration. Furthermore, analytical methods are briefly discussed, and ecological effects of microplastics in soil are summarized. Soil is a reservoir of microplastics. Microplastics have a wide distribution and high abundance in environmental media, and their distribution in soil exhibits spatial heterogeneity. Microplastics affect soil physicochemical properties, soil microorganisms, soil fauna, and plants through several mechanisms, leading to different ecological effects. Finally, future research directions of soil microplastic pollution are proposed to provide novel ideas for follow-up research.

A Critical Review of Bioaccumulation and Biotransformation of Organic Chemicals in Birds

Abstract: Abstract A literature review of bioaccumulation and biotransformation of organic chemicals in birds was undertaken, aiming to support scoping and prioritization of future research. The objectives were to characterize available bioaccumulation/biotransformation data, identify knowledge gaps, determine how extant data can be used, and explore the strategy and steps forward. An intermediate approach balanced between expediency and rigor was taken given the vastness of the literature. Following a critical review of > 500 peer-reviewed studies, > 25,000 data entries and 2 million information bytes were compiled on > 700 organic compounds for ~ 320 wild species and 60 domestic breeds of birds. These data were organized into themed databases on bioaccumulation and biotransformation , field survey , microsomal enzyme activity , metabolic pathway , and bird taxonomy and diet . Significant data gaps were identified in all databases at multiple levels. Biotransformation characterization was largely fragmented over metabolite/pathway identification and characterization of enzyme activity or biotransformation kinetics. Limited biotransformation kinetic data constrained development of an avian biotransformation model. A substantial shortage of in vivo biotransformation kinetics has been observed as most reported rate constants were derived in vitro. No metric comprehensively captured all key contaminant classes or chemical groups to support broad-scope modeling of bioaccumulation or biotransformation. However, metrics such as biota-feed accumulation factor, maximum transfer factor, and total elimination rate constant were more readily usable for modeling or benchmarking than other reviewed parameters. Analysis demonstrated the lack of bioaccumulation/biotransformation characterization of shorebirds, seabirds, and raptors. In the study of bioaccumulation and biotransformation of organic chemicals in birds, this review revealed the need for greater chemical and avian species diversity, chemical measurements in environmental media, basic biometrics and exposure conditions, multiple tissues/matrices sampling, and further exploration on biotransformation. Limitations of classical bioaccumulation metrics and current research strategies used in bird studies were also discussed. Forward-looking research strategies were proposed: adopting a chemical roadmap for future investigations, integrating existing biomonitoring data, gap-filling with non-testing approaches, improving data reporting practices, expanding field sampling scopes, bridging existing models and theories, exploring biotransformation via avian genomics, and establishing an online data repository.

Reaching the Full Potential of Machine Learning in Mitigating Environmental Impacts of Functional Materials

Abstract: In conventional ways of functional material design, the performance of synthesized materials is the focal point, whereas the toxicity of and environmental problems caused by synthesized materials are neglected to a large extent. Only with a balanced consideration of all the above-mentioned factors can we ensure the development of eco-friendly functional materials. In recent years, with big data generated by experiments and computing technology becoming increasingly accessible, data-driven solutions, especially machine learning methods have opened a new window for the discovery and rational design of eco-friendly functional materials. In this review, we first presented a brief introduction of functional materials, the most commonly used machine learning models and relevant processes. The applications of ML-based approaches and computational methods in functional prediction and material design were then summarized. More importantly, by combining machine learning methods with the toxicity prediction of functional materials, we proposed a framework for sustainable functional material design to achieve better functionality and eco-friendliness. Such a framework will ensure both the practicability and effectiveness of functional materials, balance their functionality and environmental sustainability, and eventually pave the path toward the Sustainable Development Goals set by the United Nations.

Ecosystem Mercury Recovery and Health Benefit Under the Minamata Convention in a Changing Climate

Abstract: Mercury (Hg) is a toxic metal that can be released from natural and anthropogenic processes. Gaseous elemental Hg is the main form of Hg in the atmosphere with a long residence time, allowing its long-range transport and deposition at a global scale. The deposited Hg can be transformed into methylmercuy (MeHg), which bioaccumulates and biomagnifies in aquatic ecosystems and is a known developmental neurotoxin to humans. Chronic exposure in pregnant women via fish consumption, even at the modest levels, can impact intellectual development in infants, which is considered as a global environmental health issue. To protect human health and the environment, the Minamata Convention on Mercury, a legally binding international treaty, entered into force in 2017 to reduce anthropogenic emissions and releases of Hg and Hg compounds. With the enforcement of the Convention, anthropogenic Hg emissions and releases are projected to decrease in the foreseeable future, but the recovery of the ecosystem and mitigation of health impact from Hg pollution are expected to lag behind. In this paper, we provide a critical review on the processes affecting when and to which extent Hg-affected ecosystems will recover under the Minamata Convention in the context of climate change and associated human health benefit. Our review is organized around seven major scientific questions. These seven questions covered historical Hg change in the ecosystem, major factors and processes, and future assessment. The impact of implementation of Minamata Convention and climate change on Hg emission, atmospheric transportation and deposition, biota accumulation, and human exposure should be comprehensively evaluated. The Hg stable isotope tool and process-based integrated global model should be integrated together, which also should consider future global social-economic pathways and mitigation options. We hope that the knowledge gaps and potential tools identified will assist the understanding of global biogeochemical cycling of Hg, inform policy-making on mitigation and community adaptation, and support the effectiveness evaluation and future improvement of the Minamata Convention on Mercury.Graphical Abstract

Nitrogen Pollution Originating from Wastewater and Agriculture: Advances in Treatment and Management

Abstract: Nitrogen pollution in the environment has become a global concern. Being multidimensional and complex, nitrogen pollution requires a comprehensive package of efforts for its effective management. This article reviews the existing technologies for the treatment and management of nitrogen pollution, water soluble or gaseous, originating from wastewater and agriculture. In the wastewater section, technologies for the wastewater treatment as well as the recovery of nitrogen are reviewed, including physico-chemical and biological techniques. Hybrid treatments could combine the strengths of these strategies to enhance nitrogen removal in wastewater. Moreover, the use of solid wastes to develop efficient adsorbents for nitrogen recovery from wastewater and their subsequent valorization in agricultural soils can be highly rewarding. The agriculture-associated nitrogen pollution can be addressed by the effective management of nitrogenous fertilizers, soils, and crops and the adoption of conservation agriculture practices. It is crucial to improve nitrogen use efficiency in crop production to tackle the challenges of climate change, food security, and environmental degradation. The breeding of crop genotypes possessing an improved nitrogen efficiency and engineering the legume symbiosis can be quite helpful for this. Future research directions have been recognized to foster the research into sustainable management of nitrogen. Collaborative efforts and a comprehensive understanding of existing knowledge of these techniques are required to upscale these techniques for field-scale applications. By presenting a detailed overview of strategies for nitrogen treatment and management in wastewater and agriculture, this article intends to enable a better understanding on this theme.

Use of Soil Invertebrate Avoidance Tests as an Emerging Tool in Soil Ecotoxicology

Abstract: Behavioural toxicology is an emerging field of ecotoxicology gaining prominence in both aquatic and terrestrial environments. The aim of this work is to review studies investigating the avoidance behaviour of soil invertebrates in contaminated soils. The review begins with an overview of experimental design and abiotic factors that influence soil invertebrates’ behaviour followed by trends in literature related to three contaminant classes (metals, pesticides and organics). Despite the incidence of non-avoidance or even attraction in a few cases, a common theme across all contaminants reviewed is that avoidance test appears to be the most sensitive test in a suite of tests and species-specific responses. These findings reinforce the importance of testing avoidance behaviour on a battery of test organisms. The review concludes with a synthesis of current challenges is discussed with recommendations for future directions to fill data gaps identified.

Correction: A Critical Review of Bioaccumulation and Biotransformation of Organic Chemicals in Birds

Abstract: Abstract A literature review of bioaccumulation and biotransformation of organic chemicals in birds was undertaken, aiming to support scoping and prioritization of future research. The objectives were to characterize available bioaccumulation/biotransformation data, identify knowledge gaps, determine how extant data can be used, and explore the strategy and steps forward. An intermediate approach balanced between expediency and rigor was taken given the vastness of the literature. Following a critical review of > 500 peer-reviewed studies, > 25,000 data entries and 2 million information bytes were compiled on > 700 organic compounds for ~ 320 wild species and 60 domestic breeds of birds. These data were organized into themed databases on bioaccumulation and biotransformation , field survey , microsomal enzyme activity , metabolic pathway , and bird taxonomy and diet . Significant data gaps were identified in all databases at multiple levels. Biotransformation characterization was largely fragmented over metabolite/pathway identification and characterization of enzyme activity or biotransformation kinetics. Limited biotransformation kinetic data constrained development of an avian biotransformation model. A substantial shortage of in vivo biotransformation kinetics has been observed as most reported rate constants were derived in vitro. No metric comprehensively captured all key contaminant classes or chemical groups to support broad-scope modeling of bioaccumulation or biotransformation. However, metrics such as biota-feed accumulation factor, maximum transfer factor, and total elimination rate constant were more readily usable for modeling or benchmarking than other reviewed parameters. Analysis demonstrated the lack of bioaccumulation/biotransformation characterization of shorebirds, seabirds, and raptors. In the study of bioaccumulation and biotransformation of organic chemicals in birds, this review revealed the need for greater chemical and avian species diversity, chemical measurements in environmental media, basic biometrics and exposure conditions, multiple tissues/matrices sampling, and further exploration on biotransformation. Limitations of classical bioaccumulation metrics and current research strategies used in bird studies were also discussed. Forward-looking research strategies were proposed: adopting a chemical roadmap for future investigations, integrating existing biomonitoring data, gap-filling with non-testing approaches, improving data reporting practices, expanding field sampling scopes, bridging existing models and theories, exploring biotransformation via avian genomics, and establishing an online data repository.

Occurrence of Pharmaceutical and Pesticide Transformation Products in Freshwater: Update on Environmental Levels, Toxicological Information and Future Challenges

Abstract: Pharmaceuticals and pesticides are recognized micropollutants in freshwater systems. Their ever-increasing frequency of detection, levels found and little information available about their effects on non-target organisms, make them emerging contaminants. However, parental compounds are not the only substances of concern. Their metabolites and degradation products, hereby referred to as transformation products, are increasingly detected in freshwater samples and wastewater effluents. In the past years, a wealth of publications provided concentration levels detected in freshwater and some toxicological data, which required critical systematization. This review identified concentrations for 190 transformation products (92 from pesticides and 98 from pharmaceuticals) in water bodies and wastewater effluents. A concentration heatmap was produced to easily spot the substances found at higher levels and plan future research. The very limited available toxicological data link exposure to transformation products to adverse outcomes in humans (genotoxicity and alteration in detoxification processes) and aquatic species (mostly related to apical endpoints). Overall, environmental levels of these transformation products may pose a severe threat to aquatic organisms and need to be further investigated in sound experimental designs, testing for the effects of the single substances as well as of their mixtures. Such toxicological information is highly needed to improve both water treatment technologies and monitoring programmes.

SARS-CoV-2 in the Environment: Its Transmission, Mitigation, and Prospective Strategies of Safety and Sustainability

Abstract: The emergence and spread of SARS-CoV-2 have threatened the world’s public health security. The COVID-19 pandemic has affected many countries and significantly smashed the global economy, and also affected the health of the environment. This has upraised many apprehensions about its high transmission rate. Even though the most important routes of its transmission include direct contact and respiratory droplets, the infection through non-direct contacts also plays an important role. The increasing demand for intensive healthcare, escalating death toll and disruption in supply chains and trade have directed to mass implementation of testing, quarantine, and lockdown to restrain virus transmission. The lockdown has been a boon and a bane as well when it comes to the health of the environment. It had improved the air and water quality since the industrial activities were banned and therefore there was no addition of pollutants in the environment, but the usage of plastic-based personal protective equipment (PPE) and other medical waste has simultaneously resulted in huge plastic pollution that is choking seas and marine lives. The precautionary measures given by the United Nations Environment Programme in its COVID response factsheets suggest ways to reduce medical waste and to prevent the spread of the present pandemic. The recent green innovations and environmental stringency programs have resulted in reducing the threats to the environment that would eventually help in inhibiting the spread of such pandemics. In addition, proper measures should be adopted to safeguard the complete health of humans and the environment to execute safety and sustainable development that will help in achieving a stable biome.

A Review on the Water Quality Criteria of Nonylphenol and the Methodological Construction for Reproduction Toxicity Endocrine Disrupting Chemicals

Abstract: Endocrine-disrupting chemicals (EDCs) can adversely impact the hormonal control, sexual differentiation, reproductive success, and community structure of aquatic organisms. Nonylphenol is one kind of typical EDCs which has attracted increasing attention in recent years. The water quality criteria (WQC) of nonylphenol have been established in several countries/institutions according to the water quality guidelines. However, the reproduction toxicity characteristic of EDCs was excluded in the previous WQC study. In this study, the current research progress on WQC for nonylphenol in different countries/institutions is summarized. In addition, the methodology for deriving the WQC based on reproduction toxicity of EDCs, such as selecting a sensitive test species with a hypothalamic–pituitary–gonadal axis or an endocrine-like system, selecting the appropriate endpoint effects for reproduction toxicity, and collecting the chronic toxicity data are discussed. Finally, the predicted no-effect concentration (PNEC) of nonylphenol derived based on the reproduction toxicity endpoint data was 0.38 μg/L. This result indicated that the PNEC based on reproductive fitness occurred at significantly lower concentrations than that of the other derived toxicity endpoints. The results of this study would provide data support for WQC research and risk assessment of endocrine disruptors.

Nitrogen Pollution Originating from Wastewater and Agriculture: Advances in Treatment and Management

Abstract: Nitrogen pollution in the environment has become a global concern. Being multidimensional and complex, nitrogen pollution requires a comprehensive package of efforts for its effective management. This article reviews the existing technologies for the treatment and management of nitrogen pollution, water soluble or gaseous, originating from wastewater and agriculture. In the wastewater section, technologies for the wastewater treatment as well as the recovery of nitrogen are reviewed, including physico-chemical and biological techniques. Hybrid treatments could combine the strengths of these strategies to enhance nitrogen removal in wastewater. Moreover, the use of solid wastes to develop efficient adsorbents for nitrogen recovery from wastewater and their subsequent valorization in agricultural soils can be highly rewarding. The agriculture-associated nitrogen pollution can be addressed by the effective management of nitrogenous fertilizers, soils, and crops and the adoption of conservation agriculture practices. It is crucial to improve nitrogen use efficiency in crop production to tackle the challenges of climate change, food security, and environmental degradation. The breeding of crop genotypes possessing an improved nitrogen efficiency and engineering the legume symbiosis can be quite helpful for this. Future research directions have been recognized to foster the research into sustainable management of nitrogen. Collaborative efforts and a comprehensive understanding of existing knowledge of these techniques are required to upscale these techniques for field-scale applications. By presenting a detailed overview of strategies for nitrogen treatment and management in wastewater and agriculture, this article intends to enable a better understanding on this theme.

Important But Overlooked Potential Risks of Substituted Polycyclic Aromatic Hydrocarbon: Looking Below the Tip of the Iceberg

Abstract: Substituted polycyclic aromatic hydrocarbons (PAHs) are PAH derivatives in which substituents replace hydrogen atoms on the aromatic benzene ring, or N/S/O atoms replace carbon atoms in aromatic rings. Compared to unsubstituted PAHs, some substituted PAHs have higher pollution levels and more significant toxicity than their parent PAHs (p-PAHs), and the International Agency for Research on Cancer (IARC) lists them as possible human carcinogens, which harm human health but lack sufficient examination. This paper summarizes and discusses the environmental occurrence and distribution, toxicity, and impacts of substituted PAHs on human health and compares with the 16 representative priority-controlled PAHs (PAHs16). According to occurrence of PAHs in various environmental media, it is shown that the mean concentration of individual substituted PAH in the air is higher than that of individual PAH16. The mean concentration of individual substituted PAH in the soil varies widely among different countries, with a difference of 100,000 times between the lowest level (Italy) and the highest level (USA). The mean individual alkylated PAH (APAHs) and oxygenated PAH (OPAHs) are the most abundant in surface water and sediments. In the aspect of toxicity effects, some substituted PAHs have been proved to have similar or identical toxicity as PAHs16. We summarize existing problems and propose future priority research areas through the analysis of the occurrence and toxicity of substituted PAHs in the environment, which is important for further research and regulation of substituted PAHs.

SARS-CoV-2 in the Environment: Its Transmission, Mitigation, and Prospective Strategies of Safety and Sustainability

Abstract: The emergence and spread of SARS-CoV-2 have threatened the world’s public health security. The COVID-19 pandemic has affected many countries and significantly smashed the global economy, and also affected the health of the environment. This has upraised many apprehensions about its high transmission rate. Even though the most important routes of its transmission include direct contact and respiratory droplets, the infection through non-direct contacts also plays an important role. The increasing demand for intensive healthcare, escalating death toll and disruption in supply chains and trade have directed to mass implementation of testing, quarantine, and lockdown to restrain virus transmission. The lockdown has been a boon and a bane as well when it comes to the health of the environment. It had improved the air and water quality since the industrial activities were banned and therefore there was no addition of pollutants in the environment, but the usage of plastic-based personal protective equipment (PPE) and other medical waste has simultaneously resulted in huge plastic pollution that is choking seas and marine lives. The precautionary measures given by the United Nations Environment Programme in its COVID response factsheets suggest ways to reduce medical waste and to prevent the spread of the present pandemic. The recent green innovations and environmental stringency programs have resulted in reducing the threats to the environment that would eventually help in inhibiting the spread of such pandemics. In addition, proper measures should be adopted to safeguard the complete health of humans and the environment to execute safety and sustainable development that will help in achieving a stable biome.

Use of Soil Invertebrate Avoidance Tests as an Emerging Tool in Soil Ecotoxicology

Abstract: Behavioural toxicology is an emerging field of ecotoxicology gaining prominence in both aquatic and terrestrial environments. The aim of this work is to review studies investigating the avoidance behaviour of soil invertebrates in contaminated soils. The review begins with an overview of experimental design and abiotic factors that influence soil invertebrates’ behaviour followed by trends in literature related to three contaminant classes (metals, pesticides and organics). Despite the incidence of non-avoidance or even attraction in a few cases, a common theme across all contaminants reviewed is that avoidance test appears to be the most sensitive test in a suite of tests and species-specific responses. These findings reinforce the importance of testing avoidance behaviour on a battery of test organisms. The review concludes with a synthesis of current challenges is discussed with recommendations for future directions to fill data gaps identified.

A Global Review of Cadmium, Mercury, and Selenium in Sharks: Geographical Patterns, Baseline Levels and Human Health Implications

Abstract: Globally, there is concern about the concentrations of some metals and metalloids in sharks and the associated impacts to themselves and to human consumers. Concentrations of Hg, Cd, and Se reported in muscle, liver and fins of sharks from all the world were reviewed to define geographical patterns of elemental distribution, to model the baseline concentrations of the three elements, and to assess potential human health risk. Published information corresponded to 102 sites that belong to thirteen FAO Major Fishing Areas. The majority of the sites corresponded to the Atlantic (39 sites), followed by the Pacific Ocean (37). Statistical analysis indicated significant differences of elemental concentrations among all FAO regions and oceans. The 5% baseline levels, estimated with a cumulative frequency distribution method for each element were: for Hg, 0.129 μg g−1 in muscle, 0.147 μg g−1 in liver; for Cd, 0.517 μg g−1 in muscle, 0.290 μg g−1 in liver; for Se, 0.105 μg g−1 in muscle, 0.218 μg g−1 in liver. These baseline leves are equivalent to the 5th percentile on a normal distribution. Levels of Cd, Hg and Se in muscle of sharks were above maximum permissible limits (Cd, 0.5; Hg, 1.0; Se, 1.0 μg g−1; Nauen in FAO Fish Circ 764:1–102, 1983; CEC in Off J Eur Union 364:5–24, 2006) for human consumption in 6, 49 and 25% of the reports, respectively. Considering all the studies, hazard quotients (it indicates the risk during the lifetime of an individual different to cancer if value is above one) were Cd (0.10 ± 0.18), Se (0.11 ± 0.10) and Hg (2.05 ± 2.69); i.e. only average Hg values are of concern. The concentrations of Hg and Se in muscle of sharks from the Mediterranean were statistically different from all other oceans. In shark species with more reports, baseline levels (µg g−1 wet weight) of Hg in muscle were: for P. glauca from the Pacific Southeast (0.048), for I. oxyrinchus from the Pacific Southeast (0.034), and for S. lewini from the Pacific Eastern Central (0.55). The balance of Hg and Se molar concentrations (it is used to assess the benefit or risk to the combined occurrence of Hg and Se) in muscle of sharks was assessed through the Se health benefit value (HBVSe), positive results indicate that shark consumption is beneficial to humans. In general, HBVSe was positive (3.06 ± 13.84). According to FAO Fishing areas, negative HBVSe values corresponded to Mediterranean and Black Sea (− 48.37), Atlantic Northwest (− 5.54), Pacific Eastern Central (− 0.97), and Atlantic Southwest (− 0.21); nevertheless, HBVSe values in sharks from Mediterranean and Black Sea, and Atlantic Northwest corresponded to only one species. Overall, similar elemental concentrations were found in some FAO regions of the southern hemisphere. Baseline values of Hg were in the same magnitude order as the low atmospheric deposition flux. Under the approach of the hazard quotient, Hg is of concern because values were above one in almost half of the studies. More information related to Hg and Se in muscle of sharks is required in some FAO regions (Indian Ocean Eastern, Pacific Northeast and Pacific Southeast) to estimate HBVSe.

Microfiber Pollution in the Earth System

Abstract: Microfibers, as emerging contaminants, pose a growing threat to the global environment. Microfiber pollution has been one of the hot research topics in environmental science. However, there is no consensus on microfiber definition from ecological and environmental perspectives. The underestimated sources, the distribution in the ocean and the atmosphere, the transport pathway, the potential human exposure, and mitigation strategies of microfibers from a global perspective have not been systemically discussed. So, we aim to discuss and analyze these concerns in this review. Firstly, the definition of microfiber pollutants from the ecological and environmental perspectives is proposed. Secondly, the largest source and some emerging sources of microfibers on the Earth have been explored. Thirdly, the distribution and transmission path of microfibers in the ocean and the atmosphere are discussed. Fourthly, the exposure path of microfibers to the human body is analyzed. Lastly, some applicable measures to control microfiber pollution are proposed from global environmental sustainable development perspectives.

A Systematic Review on Distribution and Ecological Risk Assessment for Chiral Pharmaceuticals in Environmental Compartments

Abstract: Chiral pharmaceuticals are an important class of environmental pollutants. Monitoring studies have shown the non-racemic presence of these contaminants in wastewater, sludge and the receiving environment. This review describes the role of chirality in the environment, especially the distribution and toxicities of enantiomers of chiral pharmaceuticals. In the first part, a systematic overview of their distribution in various environmental matrices and the main application of chiral signatures as chemical markers of water contamination are discussed. Available studies mainly focus on four drug groups including NSAIDs, β-blockers, antidepressants and illicit drugs due to their environmental pseudopersistence and ecotoxicological effects. In the second part, a summary of the enantiospecific toxicity data reported for chiral pharmaceuticals is provided. These data are of high value to improve the accuracy of environmental risk assessments in future works. Enantioselective toxicity towards aquatic organisms have been established for ten out of 36 chiral pharmaceuticals measured and detected in wastewater or surface water samples. Their enantioselective biodegradation and ecotoxicity make the risk assessment process highly recommended. The results provided in this review work support the need for new approaches to more accurately determine the toxicological risks associated to the stereochemistry of environmental contaminants.

An Updated Review on Ag NP Effects at Organismal Level: Internalization, Responses, and Influencing Factors

Abstract: Silver nanoparticles (Ag NPs) can be widely applied in daily necessities and industrial fields, leading to their mass production and discharge. Their highly active and easily bio-accumulative characteristics have resulted in environmental accumulation and toxic effects. The studies with regard to the behaviors and effects of Ag NPs have received wide attentions. Therefore, this review comprehensively summarizes the latest studies on behaviors and effects of Ag NPs based on plants, animals, and human cells models in the following aspects: physiological and biochemical alterations, variations in subcellular structure, molecular regulation (DNA, RNA, protein, and metabolites), and translocation, transformation, and internalization especially in different trophic levels or maternal transfer. Moreover, the physico- or geo-chemical properties of Ag NPs can be modified by environmental medium/conditions, leading to the variations in behaviors and effects of Ag NPs. Overall, the transfer of Ag NPs through food chain or maternal transfer and the environmental influences on behaviors and effects of Ag NPs may represent new research fronts. This review can promote in-depth understanding of Ag NP behavior and effects, simultaneously facilitating further research not only for Ag NPs, but also for other emerging contaminants.