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Ecological risk assessment of soil in contaminated sites provides the scientific basis for accurately developing soil quality standards, confirming remediation targets, and making safe use of contaminated soil. It thus is a critical mean to protect soil health and safety. "Weight-of-Evidence" (WoE) has been widely used in ecological risk assessment due to its systematic, integrated and scientific properties. However, most current WoE approaches are poor in objectivity and comparability because they rely too much on expertise scoring in weighing and the difficulty to collect complete evidence bodies with quantitative and comprehensive information. Focusing on those issues above, we developed an improved framework of WoE approach for ecological risk assessment of contaminated site soil based on the "Four-Step" framework of EPA coupled with the concept of hierarchy. Assessment methods and procedures for each tier were unified. Weights were weighed quantitatively through multiple criteria decision analysis. The relative independence among bodies of evidence was assured by the pre-establishment of hierarchy. The "site specific" was stressed based on matrix trails and field investigation. Finally, a case study in an electroplating site in Jingjiang was conducted to verify the approach. Results of the case study suggested that the approach was practical and that the assessment results were objective, scientific, and accurate.

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The introduction of exotic species negatively affects the distribution and interactions within local biological communities in an ecosystem and can threaten ecosystem health. This study aimed to provide the basic data required to manage P. clarkii in the Yeongsan River basin. We identified the dispersion pattern and evaluated the ecosystem risk of this newly introduced species. The distribution survey investigated Procambarus clarkii populations at 25 sites in the Yeongsan River basin over a four-year period. The initial introduction occurred in Jiseok Stream. The larvae of P. clarkii were most abundant in areas with a dense aquatic plant cover, whereas adults preferred silt/clay areas. The alterations in the water flow by the river refurbishment project (carried out in 2012) increased their preferred habitats and contributed to P. clarkii dispersion. However, stable isotope analysis showed that the dispersion has had little effect on the freshwater ecosystem. The interrelationship between P. clarkii (i.e., larvae and adults) and other biological communities has been limited. Although the rapid dispersion by P. clarkii in the Yeongsan River basin has not impacted the freshwater ecosystem, further ecological information is required on how to manage P. clarkii beyond this early stage of invasion.

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The quality of irrigation water and drainage water is essential for local ecosystem and human health in agricultural regions. In this study, the transport analysis, source identification, and environmental risk assessment of perfluoroalkyl acids (PFAAs) were conducted in the largest irrigation area in northern China. The concentrations of the total PFAAs (ΣPFAA) ranged from 41.5 to 263 ng/L in surface water, and the short-chain perfluoroalkyl carboxylic acids (PFCAs) and perfluorooctanoic acid (PFOA), were dominant with a total contribution of 94%. Generally, the ΣPFAA levels increased from irrigation waters to drainage and receiving lake waters. PFOA showed the highest increase, with potential emission sources located in the catchment of the sub main drainage ditch D5. More PFOA (36.8 kg/y) was outflowed from Ulansuhai Lake to the Yellow River than that inflowed from the Yellow River to the irrigation district (6.15 kg/y). The results of a risk assessment indicated that avian wildlife living in Ulansuhai Lake were threatened by the PFOA and perfluorobutane sulfonate (PFBS) pollution. The estimated daily intakes (EDIs) of the sum of the PFOA, perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), and perfluorooctane sulfonic acid (PFOS) through aquatic food consumption for people with the different aquatic food preferences accounted for 6-42% (urban) and 4-27% (rural) of the strictest tolerant daily intake (TDI) value. The results of this study highlight the impact of local emissions of PFAS on massive irrigation and drainage systems, and ultimately, the ecosystem and human health.

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Ecosystem functioning and related risks could become compromised by climate change and severely affect livestock in different ways. Based on four climate indices (i.e., SPI, SPEI, PDSI and SEDI), livestock determinants and biogeochemical proxies, we analysed the temporal and geographical extent of terrestrial ecosystem shift probabilities and drought-wetness risk severity at multiple scales (i.e., land cover, climate and elevation) in the greater Mekong subregion (GMS) during the period 1981-2020 by using different cartographic techniques. The results indicated that in the GMS area, approximately 3.8% experienced the highest ecosystem shift probability, 4% was exposed to a high risk of drought and wetness, and only approximately 55% experienced a low risk of drought and/or wetness stress. Cambodia and Thailand experienced the highest ecosystem shift probability ratio and drought-wetness risk severity compared to other GMS countries. Woody savanna and urban land covers; temperate-fully humid-cold summer and tropical rainfall fully humid climate zones; and elevations -47-200 m and ≥2500 m showed common characteristics leading to a very high ecosystem shift probability and experienced high drought-wetness risk severity. This study provides useful information that may exert to a strong control and improved future terrestrial in the context of changes in climate and biogeophysical aspects at the regional and country scales.

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The widely occurring debris of plastic materials, particularly microplastics, can be an important source of flame retardants, which are one of the main groups of chemicals added in the production of plastics from polymers. This review provides an overview on the use of flame retardants in plastic manufacturing, the kinetics of their releases from microplastics, the factors affecting their releases, and the potential environmental and ecosystem risk of the released flame retardants. The releases of flame retardants from microplastics typically involve three major steps: internal diffusion, mass transfer across the plastic-medium boundary layer, and diffusion in the environmental medium, while the overall mass transfer rate is commonly controlled by diffusion within the plastic matrix. The overall release rates of additive flame retardants from microplastics, which are dependent on the particle's geometry, can often be described by the Fick's Law. The physicochemical properties of flame retardant and plastic matrix, and ambient temperature all affect the release rate, which can be predicted with empirical and semi-empirical models. Weathering of microplastics, which reduces their particle sizes and likely disrupts their polymeric structures, can greatly accelerate the releases of flame retardants. Flame retardants could also be released directly from the microplastics ingested by aquatic organisms and seabirds, with physical and chemical digestion in the bodies significantly enhancing their release rates. Limited by the extremely slow diffusion in plastic matrices, the fluxes of flame retardants released from microplastics are very low, and are unlikely to pose significant risk to the ecosystem in general. More research is needed to characterize the mechanical, chemical, and biological processes that degrade microplastics and accelerate the releases of flame retardants and to model their release kinetics from microplastics, while efforts should also be made to develop environmentally benign flame retardants to ultimately minimize their risk to the environment and ecosystem.

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The Ecological Risk Assessment (ERA) is a reliable tool for communicating risk to decision makers in a comprehensive and scientific evidence-based way. In this work, a site-specific ERA methodology based on the TRIAD approach was applied to contaminated soil surrounding a closed non-sealed landfill, as a case study to implement and validate such ERA methodology in the Basque Country (northern Spain). Initially, the procedure consisted of the application of a Parameter Selection Module aimed at selecting the most suitable parameters for the specific characteristics of the landfill contaminated soil, taking into consideration the envisioned land use, intended ecosystem services and nature of contaminants. Afterwards, the selected parameters were determined in soil samples collected from two sampling points located downstream of the abovementioned landfill. The results from these tests were normalized to make them comparable and integrable in a risk index. Then, risk assessment criteria were developed and applied to the two landfill contaminated soil samples. Although the lack of a proper control soil was evidenced, a natural land use was approved by the ERA (at Tier 2) for the two landfill contaminated soils. However, the existence of a potential future risk resulting from a hypothetical soil acidification must be considered.

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The newly developed IUCN Red List of Ecosystems is part of a growing toolbox for assessing risks to biodiversity, which addresses ecosystems and their functioning. The Red List of Ecosystems standard allows systematic assessment of all freshwater, marine, terrestrial and subterranean ecosystem types in terms of their global risk of collapse. In addition, the Red List of Ecosystems categories and criteria provide a technical base for assessments of ecosystem status at the regional, national, or subnational level. While the Red List of Ecosystems criteria were designed to be widely applicable by scientists and practitioners, guidelines are needed to ensure they are implemented in a standardized manner to reduce epistemic uncertainties and allow robust comparisons among ecosystems and over time. We review the intended application of the Red List of Ecosystems assessment process, summarize 'best-practice' methods for ecosystem assessments and outline approaches to ensure operational rigour of assessments. The Red List of Ecosystems will inform priority setting for ecosystem types worldwide, and strengthen capacity to report on progress towards the Aichi Targets of the Convention on Biological Diversity. When integrated with other IUCN knowledge products, such as the World Database of Protected Areas/Protected Planet, Key Biodiversity Areas and the IUCN Red List of Threatened Species, the Red List of Ecosystems will contribute to providing the most complete global measure of the status of biodiversity yet achieved.

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The AQUATOX model considers the direct toxic effects of chemicals and their indirect effects through foodwebs. For this study, the AQUATOX model was applied to evaluating the ecological risk of Polybrominated diphenyl ethers (PBDEs) in a highly anthropogenically disturbed lake-Baiyangdian Lake. Calibration and validation results indicated that the model can adequately describe the dynamics of 18 biological populations. Sensitivity analysis results suggested that the model is highly sensitive to temperature limitation. PBDEs risk estimate results demonstrate that estimated risk for natural ecosystems cannot be fully explained by single species toxicity data alone. The AQUATOX model could provide a good basis in ascertaining ecological protection levels of "chemicals of concern" for aquatic ecosystems. Therefore, AQUATOX can potentially be used to provide necessary information corresponding to early warning and rapid forecasting of pollutant transport and fate in the management of chemicals that put aquatic ecosystems at risk.

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This paper examines the increasingly close interaction between natural and social scientists, non-governmental organizations (NGO) and industry, in pursuit of responsible ecosystem-based management of fisheries. South Africa has committed to implementing an ecosystem approach to fisheries management. Management advice stems from multi-stakeholder representation on government-led scientific and management working groups. In the hake Merluccius capensis and Merluccius paradoxus fishery, the primary management measure is an annual total allowable catch (TAC), the level of which is calculated using a management procedure (MP) that is revised approximately every 4 years. Revision of the MP is a consultative process involving most stakeholders, and is based on simulation modelling of projected probable scenarios of resource and fishery dynamics under various management options. NGOs, such as the Worldwide Fund for Nature in South Africa (WWF-SA), have played an important role in influencing consumers, the fishing industry and government to develop responsible fishing practices that minimize damage to marine ecosystems. Cooperation between industry, government and scientists has helped to improve sustainability and facilitated the meeting of market-based incentives for more responsible fisheries. Research includes ecosystem modelling, spatial analysis and ecosystem risk assessment with increasing research focus on social and economic aspects of the fishery. A four-year cooperative experiment to quantify the effect of trawling on benthic community structure is being planned. The food requirements of top predators still need to be included in the TAC-setting formulae and more social and economic research is needed. This paper also demonstrates how NGO initiatives such as Marine Stewardship Council certification and the Southern African Sustainable Seafood Initiative, a traffic light system of classifying seafood for consumers, have contributed to responsible fishing practices, increased ecosystem research and public awareness. This fishery appears to have a good future, provided that the monitoring, control and surveillance systems continue to function, TACs remain within ecologically sustainable limits and the effective collaboration between government, industry, scientists and NGOs continues to drive positive change.

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