Understanding and addressing the environmental risk of microplastics

Over the past decades, the plastic production has been dramatically increased. Indeed, a category of small plastic particles mainly with the shapes of fragments, fibers, or spheres, called microplastics (particles smaller than 5 mm) and nanoplastics (particles smaller than 1 μm) have attracted particular attention. Because of its wide distribution in the environment and potential adverse effects to animal and human, microplastic pollution has been reported as a serious environment problem receiving increased attention in recent years. As one of the commonly detected emerging contaminants in the environment, recent evidence indicates that the concentration of microplastics show an increasing trend, for the reason that up to 12.7 million metric tons of plastic litter is released into aquatic environment from land-based sources each year. Furthermore, microplastic exposure levels of model organisms in laboratory studies are usually several orders of magnitude higher than those found in environment, and the microplastics exposure conditions are also different with those observed in the environment. Additionally, the detection of microplastics in feces indicates that they can be excreted out of the bodies of animal and human. Hence, great uncertainties might exist in microplastics exposure and health risk assessment based on current studies, which might be exaggerated. Policies reduce microplastic emission sources and hence minimize their environmental risks are determined. To promote the above policies, we must first overcome the technical obstacles of detecting microplastics in various samples.     

新型污染物风险防范国际实践及其对中国的启示

随着重化工业的快速发展和各类化学品的大量使用，一些新型污染物对中国居民和生态环境的危害正逐步显现并日趋严重。如何进一步完善中国新型污染物的风险防范体系，是中国生态环境治理面临的重要问题。发达国家新型污染物的风险防范工作启动较早，对中国完善新型污染物风险防范体系具有重要的借鉴意义。本文从制度建设、体制机制、评估监测、科学研究等方面比较国内外新型污染物风险防范实践的异同，立足我国国情，发现国内实践还需加强之处。在此基础上，提出国际新型污染物风险防范实践对中国的启示。     

零价铁还原和吸附去除水中污染物的研究进展

近年来,零价铁以其低毒、廉价、易操作且对环境不会产生二次污染等优点,在水污染治理中受到重视。文章介绍了零价铁处理污水的机理,对利用零价铁的还原和吸附作用去除污水中的氯代有机物、硝基芳香族化合物、偶氮染料、重金属、高氯酸盐、硝酸盐等的研究情况进行了综述,指出了零价铁废水处理技术的研究方向。     

地下水渗流补给-内源释放耦合作用下河流水质不确定模拟

针对河流-地下水环境系统的模糊性、不精确性及随机不确定性,采用梯形模糊数描述和表征河流水文、水质及水文地质参数,构建了集成地下水渗流补给与内源释放耦合影响的一维河流水质模糊模拟模型.在此基础上,就地下水渗流补给与内源释放的可能组合,设置5种情景,分别进行水质模拟,并对计算结果进行分析、对比.实例研究表明,对地下水渗流补给与内源释放耦合作用下的河流水质衰减变化规律,梯形模糊数有较好的模拟效果.     

Ecotoxicological effects of polycyclic musks and cadmium on seed germination and seedling growth of wheat (Triticum aestivum)

Single and joint toxic e ects of polycyclic musks including 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2- benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronapthalene (AHTN) and cadmium (Cd) on seed germination and seedling growth of wheat (Triticum aestivum) were investigated. The results showed that the toxicity sequence of HHCB toxic to wheat seed germination and seedling growth was similar to that of AHTN, that is, germination rate > shoot elongation > root elongation, while the toxicity of Cd was in the sequence of root elongation > shoot elongation > germination rate, according to the LC50 and EC50 values. It is suggested that polycyclic musks and Cd had di erent toxicological mechanisms. Root and shoot elongation of wheat might be good bioindicators for the contamination of polycyclic musks and Cd in soil. The mixture of polycyclic musks and Cd had synergistic e ects on T. aestivum according to the equi-toxic mixture approach when root elongation was selected as the toxicological endpoint. Thus, the joint toxicity of HHCB and Cd was significantly higher than the single toxicity of HHCB or Cd, which was also confirmed by the EC50 mix value of the mixture (EC50 mix = 0.530 TUmix). The EC50 mix value of the mixture of AHTN and Cd was 0.614 TUmix, which indicated that the mixture toxicity was strengthened when AHTN coexisted with Cd.     

Effectiveness of fluidized pellet bed for removing soluble contaminants

Fluidized pellet bed (FPB) has been successfully applied in water and wastewater treatment. However, the removal mechanism of contaminants especially the soluble ones, is still unclear. This study aimed to evaluate the e ectiveness of FPB reactor for removing soluble contaminants from synthetic wastewater. By only coagulation through jar test operation with addition of polyaluminium chloride (PACl) as primary coagulant and polyacryamide (PAM) as coagulant-aid, the removals of soluble chemical oxygen demand (COD), total phosphorus (TP), and NH4 +-N were found to be only 2.2%–7.5%, 5.7%–25.5%, and 9.9%–18.5%, respectively. However, by FPB operation under the same dosage of coagulants, these values increased to 82.7%, 37.2%, and 50%, indicating that the formation of pellets in the FPB e ectively enhanced the removal of soluble contaminants. By careful comparison of the settleablility and filterability of the pollutants after coagulation, the originally soluble contaminants could be divided into three groups, namely: (1) coagulated-andsettleable, (2) coagulated-but-nonsettleable, and (3) uncoagulable. It was found that not only the first two groups but also a large part of the third group could be e ectively removed by FPB operation. However, the mechanism for the removal of the uncoagulable pollutants by FPB operation still needs further investigation.     

环糊精在土壤有机污染物治理中的应用

综述了环糊精及其衍生物在土壤弱极性有机物治理中的应用和原理。环糊精可与土壤中弱极性有机污染物形成主客包合物,从而增加其水溶性促进其从土壤中解吸去除;能够同时去除金属离子;能够改变有机污染物理化性质促进其光解;可降低有机污染物毒性促进其微生物降解。     

抗生素抗性基因(ARGs)——一种新型环境污染物

抗生素的环境污染与生态毒性近年来引起了日益广泛的关注.水产养殖和畜牧业抗生素长期滥用的直接后果,很可能诱导动物体内抗生素抗性基因,经排泄后将对养殖区域及其周边环境造成潜在基因污染.抗性基因还极有可能在环境中传播、扩散.对公共健康和食品、饮用水安全构成威胁.为此,提出了将抗生素抗性基因作为一类新型环境污染物,对该类污染物在环境中的来源、潜在的传播途径以及国内外相关研究进展进行综述,指出了当前形势下我国开展环境中抗生素抗性基因污染研究的必要性,建议尽快从国家层面上系统进行抗生素抗性基因的环境污染机理与控制对策研究.     

Renewable inequity? Women's employment in clean energy in industrialized,emerging and developing economies

Women are globally underrepresented in the energy industry. This paper reviews existing academic and practitioner literature on women's employment in renewable energy in industrialized nations, emerging economies and developing countries. It highlights similarities and differences in occupational patterns in women's employment in renewables in different parts of the world, and makes recommendations for optimizing women's participation. Findings reveal the need for broader socially‐progressive policies and shifts in societal attitudes about gender roles, in order for women to benefit optimally from employment in renewables. In some industrialized countries, restructuring paid employment in innovative ways while unlinking social protection from employment status has been suggested as a way to balance gender equity with economic security and environmental protection. However, without more transformative social changes in gender relations, such strategies may simply reinforce rather than subvert existing gender inequities both in paid employment and in unpaid domestic labor. Grounded interventions to promote gender equality in renewable energy employment – especially within the context of increasing access to energy services for underserved communities – are more prevalent and better‐established in some non‐OECD (Organisation for Economic Co‐operation and Development) countries. OECD countries might be well‐advised to try to implement certain programs and policies that are already in place in some emerging economies.     

The rise of glyphosate and new opportunities for biosentinel early‐warning studies

Glyphosate has become the most commonly used herbicide worldwide and is reputedly environmentally benign, nontoxic, and safe for use near wildlife and humans. However, studies indicate its toxicity is underestimated and its persistence in the environment is greater than once thought. Its actions as a neurotoxin and endocrine disruptor indicate its potential to act in similar ways to persistent organic pollutants such as the organochlorines dichlorodiphenyltrichloroethane (DDT) and dioxin. Exposure to glyphosate and glyphosate‐based herbicides for both wildlife and people is likely to be chronic and at sublethal levels, with multiple and ongoing exposure events occurring in urban and agricultural landscapes. Despite this, there has been little research on the impact of glyphosate on wildlife populations, and existing studies appear in the agricultural, toxicology, and water‐chemistry literature that may have limited visibility among wildlife biologists. These studies clearly demonstrate a link between chronic exposure and neurotoxicity, endocrine disruption, cell damage, and immune suppression. There is a strong case for the recognition of glyphosate as an emerging organic contaminant and substantial potential exists for collaborative research among ecologists, toxicologists, and chemists to quantify the impact of glyphosate on wildlife and to evaluate the role of biosentinel species in a preemptive move to mitigate downstream impacts on people. There is scope to develop a decision framework to aid the choice of species to biomonitor and analysis methods based on the target contaminant, spatial and temporal extent of contamination, and perceived risk. Birds in particular offer considerable potential in this role because they span agricultural and urban environments, coastal, inland, and wetland ecosystems where glyphosate residues are known to be present.