土壤中微塑料污染现状与检测技术研究进展

微塑料一般是指粒径小于5 mm的塑料碎片,作为一种新污染物已经成为全球环境领域的研究热点.土壤作为环境中微塑料的最大储库,土壤中微塑料的污染逐渐引起重视并取得了一定的研究进展.本文系统了梳理了国内外土壤中微塑料的污染现状和污染特征,介绍了土壤中微塑料检测技术研究进展,重点探讨各类样品采集、前处理和和定性定量方法的优缺点以及对土壤中微塑料检测的适用性,分析了土壤中微塑料检测技术研究面临的主要挑战,提出未来土壤中微塑料污染调查与检测技术的研究方向,以期为科学开展土壤中微塑料污染风险治理与管控提供技术支撑.     

淡水环境中微塑料的赋存、来源和生态毒理效应研究进展

塑料制品在当今社会中被大量生产和使用,导致其不断进入水环境。环境中的塑料垃圾会进一步分解为很多粒径小于5 mm的塑料残片,即微塑料。微塑料作为一类新型污染物,已受到国内外学者和公众的广泛关注。然而,现阶段有关微塑料污染的研究主要集中在海洋环境,而内陆淡水环境与人类接触频繁,其微塑料污染应受到更多重视。为全面了解淡水环境中微塑料污染现状,加强对微塑料污染的风险监控,文章总结了近些年的相关研究,综述了淡水环境中微塑料的赋存、来源和生态毒理效应。有关研究表明,微塑料污染可能在全世界淡水环境中普遍存在,其在淡水水体、沉积物和淡水生物中均有赋存;而中国内陆淡水环境中微塑料的污染可能尤为严重。淡水环境中微塑料的来源尚不明确,主要直接来源可能包括污水处理厂的尾水排放、水环境中塑料垃圾的风化降解以及水土流失或地表径流形成的陆源输入;而初始源头可能包括了个人护理品、合成纺织品、工业原料以及城镇、农业、旅游、工业区塑料垃圾的不当处置。另外,微塑料会对淡水生物造成物理性损伤和生化水平胁迫,并有可能与其他污染物形成复合污染,对淡水生物产生交互效应。因此,对淡水环境中微塑料污染的深入研究已刻不容缓。今后可在环境因素对微塑料污染特征的影响、微塑料污染的源解析、微塑料与污染物的生态交互效应这三方面加强研究。文章可为淡水环境中微塑料的污染和生态风险研究提供理论参考。     

微塑料污染的水生生态毒性与载体作用

近年来,微塑料的水生生态环境污染与生态毒害问题引起了科学界的广泛关注。在总结国内外相关研究的基础上,本文对水生态环境中微塑料的来源、形成与分布展开分析;对微塑料污染的生态毒性研究进展给予评述;并深入探讨了微塑料在生态系统中扮演的多重载体角色。鉴于微塑料污染的严峻现实,我国应尽快开展有关微塑料环境污染和生态毒理方面的系统研究,并辅以政策引导和经济支持。     

微塑料污染的水生生态毒性与载体作用

近年来微塑料的水生生态环境污染与生态毒害问题引起了科学界的广泛关注。在总结国内外相关研究的基础上,本文对水生态环境中微塑料的来源、形成与分布展开分析;对微塑料污染的生态毒性研究进展给予评述;并深入探讨了微塑料在生态系统中扮演的多重载体角色。鉴于微塑料污染的严峻现实,我国应尽快开展有关微塑料环境污染和生态毒理方面的系统研究,并辅以政策引导和经济支持。     

土壤微塑料污染管控对策研究

塑料污染是当前全球重大环境问题,也是社会关注的热点。大块塑料在环境中不断降解破碎产生的微塑料造成了更加广泛的环境污染,特别是土壤环境微塑料污染。在分析土壤微塑料污染防治所面临问题的基础上,提出我国土壤微塑料污染防控对策建议,包括制定土壤微塑料监测方法标准、将微塑料纳入土壤环境质量标准体系、提高废弃农膜和农药包装回收率、加强活性污泥资源化利用监管和提升科技支撑能力,尤其是推动源头治理,预防土壤微塑料污染。这些可为我国土壤微塑料污染防治提供思路。     

微塑料对农田土壤理化性质、土壤微生物群落结构与功能的影响

微塑料作为一种新污染物普遍存在于各类环境介质中,土壤环境中的微塑料污染已受到全球的广泛关注。该研究围绕农田土壤中微塑料污染这一主题,在总结分析国内外最新研究进展的基础上,综述了微塑料对农田土壤理化性质、土壤微生物生物量以及微生物群落结构与功能的影响。通过农业活动等途径进入农田土壤的微塑料会在非生物和生物作用下发生风化和降解,并对土壤理化性质、养分循环和污染物相互作用产生影响,进而影响微生物生物量、微生物群落结构与多样性、土壤酶活性,以及碳、氮循环和污染物降解等土壤生物地球化学过程,且微塑料对上述指标的影响与微塑料自身性质、土壤类型和暴露条件等多种因素有关。最后,对未来土壤微塑料的研究方向做了展望,以期为后续研究提供参考和思路。     

土壤中微/纳塑料的生物健康效应和食物链传递风险

微/纳塑料污染已成为亟待解决的全球性环境问题。微/纳塑料进入土壤后会长期累积在土壤中,并对土壤生态系统健康产生不良影响。该文从土壤生物健康效应和食物链传递风险角度综述了近年来国内外土壤微/纳塑料调查研究进展,分类介绍了土壤中微/纳塑料对植物、动物和微生物的影响及在陆地生物和食物链中的传递,并展望了土壤中微/纳塑料的未来研究方向。该文指出,微/纳塑料广泛存在于不同功能的土壤中,可以被植物吸收和动物摄食,通过食物链传递进入人体。未来需要加强土壤中微/纳塑料污染过程与生物健康效应研究,加强对微/纳塑料在土壤生态系统和食物链中传递的风险评估,为土壤中微/纳塑料的监测、管控和治理提供科学指导和技术方法参考。     

气候因子作用下土壤中微/纳塑料的污染特征及生态效应研究进展

塑料制品的广泛使用导致陆地生态系统积累大量塑料垃圾,其风化破碎后形成微/纳塑料残存于环境中,对土壤生态系统造成威胁。目前全球气候变化导致高温、干旱、强降雨等特殊天气发生愈加频繁,直接影响土壤生态环境。温度、降水等气候环境因子对土壤中微/纳塑料的赋存状态、迁移转化和生态毒性等能够产生不同程度的影响。该文综述了不同气候因子对土壤中微/纳塑料污染与迁移的影响以及各气候因子与微/纳塑料两者的联合效应,发现升温、干旱、冻融与洪涝现象均能在一定程度上提高土壤微/纳塑料丰度,加速微/纳塑料的老化;两者联合效应体现于土壤性质、养分循环和植物生长等方面;其中升温与干旱联合微/纳塑料对土壤碳氮循环存在显著影响。未来研究重点应从不同气候因子对土壤微/纳塑料的老化特征与环境行为的影响,以及对土壤中关键生物地球化学循环过程的影响机制等方面深入开展。     

土壤中微塑料对重金属吸附作用的研究进展

微塑料可以改变土壤的物理性质,影响土壤功能,吸附重金属形成复合污染物。通过研究归纳土壤中微塑料吸附重金属的吸附机制,并分析了微塑料对重金属吸附能力的影响因素。微塑料对重金属的吸附机制主要是微塑料的表面性质、络合作用、官能团和分子作用力等多种机制并存。影响微塑料吸附重金属能力的因素主要有土壤中重金属性质、微塑料本身性质、土壤环境的pH和盐度、温度及滞留时间等。同时,分析土壤环境中微塑料吸附重金属的吸附机制及其相关影响因素,并展望土壤中微塑料—重金属复合污染物的联合效应,及实际环境条件的复杂特性等,从而为探索土壤中微塑料—重金属的复合污染机理提供参考,以及为农田土壤中风险防控和治理提供依据。     

微塑料对陆生植物生长发育和根际环境影响研究进展

由于农业活动、大气沉降和地表径流等原因,土壤已成为微塑料重要聚集地。微塑料在土壤中积累会影响陆生植物生长发育,并威胁陆地生态系统及食物链安全。因此,研究微塑料对陆生植物生长发育影响具有重要意义。该文在综述微塑料对陆生植物生长发育和根际环境影响等方面研究进展的基础上,提出加强相关研究的展望和建议。微塑料能吸附在植物表面,并通过根尖进入植物体内,影响种子萌发和根系发育,诱导氧化应激反应,改变光合作用强度,产生细胞毒性和遗传毒性,影响植物新陈代谢和营养吸收等。微塑料的植物毒性受到微塑料特征(浓度、大小、形状、电荷和成分等)以及不同植物及其生长阶段的影响。同时,微塑料还能改变植物根际土壤特性和微生物群落,间接影响植物生长。最后,总结了微塑料对陆生植物生长发育和根际环境影响,并对未来土壤-植物系统中微塑料相关研究进行展望,为土壤及陆地生态系统微塑料污染风险防控和治理提供科学依据和技术支撑。     

A critical review of the emerging research on the detection and assessment of microplastics pollution in the coastal,marine, and urban Bangladesh

● Coastal and marine regions are the most studied for microplastic pollution. ● Tourism is a major cause of microplastic pollution in coastal regions. ● Sediments contain larger microplastics while fish ingest smaller microplastics. ● Inland lakes, rivers, and freshwater fish are impacted by microplastic pollution. ● Microplastics are found in edible salts, however, presence is less in refined salt. The research on the extent and effects of microplastics pollution in the Global South is only getting started. Bangladesh is a South Asian country with one of the fastest growing economies in the world, however, such exponential economic growth has also increased the pollution threats to its natural and urban environment. In this paper, we reviewed the recent primary research on the assessment of the extent of microplastics pollution in Bangladesh. From the online databases, we developed a compilation of emerging research articles that detected and quantified microplastics in different coastal, marine, and urban environments in Bangladesh. Most of the studies focused on the coastal environment (e.g., beach sediment) and marine fish, while limited data were available for the urban environment. We also discussed the relationship of the type of anthropogenic activities with the observed microplastic pollution. The Cox’s Bazar sea beach in south-east Bangladesh experienced microplastics pollution due to tourism activities, while fishing and other anthropogenic activities led to microplastics pollution in the Bay of Bengal. While microplastics larger than 1 mm were prevalent in the beach sediments, smaller microplastics with size below 0.5 mm were prevalent in marine fish samples. Moreover, the differences in microplastic abundance, size, shape, color, and polymer type found were depended on the sampling sites and relevant anthropogenic activities. It is imperative to identify major sources of microplastics pollution in both natural and urban environment, determine potential environmental and human health effects, and develop mitigating and prevention strategies for reducing microplastics pollution.     

Mechanism and characterization of microplastic aging process: A review

● Methods for estimating the aging of environmental micro-plastics were highlighted. ● Aging pathways & characterization methods of microplastics were related and reviewed. ● Possible approaches to reduce the contamination of microplastics were proposed. ● The prospect and deficiency of degradable plastics were analyzed. With the increasing production of petroleum-based plastics, the problem of environmental pollution caused by plastics has aroused widespread concern. Microplastics, which are formed by the fragmentation of macro plastics, are bio-accumulate easily due to their small size and slow degradation under natural conditions. The aging of plastics is an inevitable process for their degradation and enhancement of adsorption performance toward pollutants due to a series of changes in their physiochemical properties, which significantly increase the toxicity and harm of plastics. Therefore, studies should focus on the aging process of microplastics through reasonable characterization methods to promote the aging process and prevent white pollution. This review summarizes the latest progress in natural aging process and characterization methods to determine the natural aging mechanism of microplastics. In addition, recent advances in the artificial aging of microplastic pollutants are reviewed. The degradation status and by-products of biodegradable plastics in the natural environment and whether they can truly solve the plastic pollution problem have been discussed. Findings from the literature pointed out that the aging process of microplastics lacks professional and exclusive characterization methods, which include qualitative and quantitative analyses. To lessen the toxicity of microplastics in the environment, future research directions have been suggested based on existing problems in the current research. This review could provide a systematic reference for in-depth exploration of the aging mechanism and behavior of microplastics in natural and artificial systems.     

Microplastics pollution in Bangladesh: current scenario and future research perspective

ABSTRACT

Microplastics are emerging environmental pollutants that have gained tremendous scientific interest in recent years. These micropollutants are omnipresent both in the terrestrial and aquatic environments posing a deleterious threat to the ecosystem and biodiversity. So, it is important to develop a deep understanding of the environmental fate and potential adverse impacts of microplastics on the aquatic and terrestrial environments. By critically reviewing the previously published scientific literature, the present synthesis briefly outlines the characteristics, occurrence and potential toxic effects of microplastics on terrestrial and aquatic biota. The article also focuses on some innovative approaches for sustainable remediation of macroplastics as well as microplastics. Since the concept of microplastics pollution has yet in its infancy in Bangladesh, this synthesis provides an overview of the current scenario of microplastics pollution and some future research recommendations in the context of Bangladesh which might be helpful to the novice researchers of this field.     

微塑料对环境中有机污染物吸附解吸的研究进展

微塑料已成为新的全球性环境污染问题。作为强吸附剂,微塑料可以吸附共存的有机污染物,进而改变其环境行为和毒性;也可以通过解吸作用促进污染物在不同介质中的迁移。因而,微塑料与有机污染物的相互作用强度和机理是全面评估两者的环境风险和深度研究微塑料毒性机制的必要信息。目前微塑料研究处于快速发展的起始阶段,加之微塑料本身成分、粒径、表面风化情况的复杂性及共存有机污染物的多样性使两者的相互作用十分复杂,亟需理清微塑料吸附解吸作用的影响因素和相关机制。因而,本文详细综述了微塑料对有机污染物吸附解吸作用的研究进展,并着重从微塑料性质(成分、粒径和表面风化)、有机污染物性质和水环境介质性质方面探讨了吸附的影响因素和相互作用机制,希望为微塑料吸附有机污染物及吸附的后续影响研究提供借鉴与参考。     

微塑料对疏水性有机污染物的生物富集影响研究进展

近年来,海洋和淡水环境中微塑料污染已成为全球关注的热点问题。微塑料不仅会对生物体造成物理损伤,而且微塑料会吸附环境中的疏水性有机污染物(HOCs),也能释放其本身含有的添加型疏水性有机化合物至表面,从而形成复合污染物进入生物体。然而,有关微塑料在污染物生物富集过程中发挥的作用及其机制还不清楚。本文从实验室暴露、野外富集和模型模拟研究3个方面对微塑料作用下HOCs的生物富集规律进行了综述,总结了微塑料作用下的生物富集机制。最后,针对微塑料对HOCs生物富集作用的研究方向提出了几点建议。     

水环境中的微塑料及其生态效应

塑料在日常生活中无处不在,随意丢弃的塑料会在各种作用下最终进入江河、湖泊、近海、深海、以及大洋甚至极地地区。在外界条件(如高温、风化、紫外线)影响下,大型塑料结构的完整性易遭到破坏而被逐渐分解成微小的塑料碎片,当其粒径小于5 mm时即可被称为微塑料。塑料中的某些添加剂,如壬基苯酚、多溴联苯醚、邻苯二甲酸盐、双酚A等会在塑料降解为微塑料的过程中释放到水环境中,从而威胁到水生生态系统的安全。微塑料粒径小,易被浮游动物误食或沿着食物链传递,在生物体内累积转移,对机体产生不可逆转的毒害作用。此外,微塑料还能作为某些污染物富集的载体,产生较强的复合毒性。因此水环境正面临着微塑料污染的威胁,如何治理已成为全球性的环境问题。本文对水环境中微塑料的来源与分布、微塑料的迁移和转化以及微塑料对水环境的影响进行了综述,并对水环境中的微塑料污染问题提出了一些解决方案,期望能为微塑料及其在水环境中的生态效应研究提供理论基础和数据支持。     

Quantitative analysis of microplastics in coastal tidal-flat reclamation in Dongtai,China

• Reclamation projects are important disturbances on microplastic risk in coasts. • Tidal-flat reclamation area is a large storage medium for sedimentary microplastics. • Aging and distribution features of soil microplastics show spatial heterogeneity. • Coastal weathered engineering geotextiles are a significant threat to marine health. Coastal tidal flats have received considerable attention in recent years, as they provide a direct channel for the discharge of terrestrial microplastics into the ocean. Land reclamation is occurring increasingly frequently in coastal tidal-flats; however, the environmental impacts of these activities remain unclear. Therefore, this pioneering study assessed the microplastic emission characteristics of reclamation geotextiles and performed a risk assessment accordingly. Morphological characterization of geotextile samples collected from five sites in Dongtai, China, provided evidence of sedimentary weathering. Based on several assumptions, the average abundance of microplastics in soil covered by geotextiles was estimated to reach 349±137 particles/kg dry weight, with the total microplastic load in the reclaimed area estimated to be 20.67±8.06 t. Compared with previous studies, this research demonstrates that coastal reclamation areas store a high concentration of microplastics, aggravating marine microplastic pollution. Moreover, conditional fragmentation model results revealed that the weathering and distribution characteristics of soil microplastics in coastal tidal-flat areas exhibit spatial heterogeneity, being more easily affected by natural factors (such as tides) than those in inland areas. As a result of tides, the annual discharge of geotextile-originating microplastics from the studied areas into the ocean was approximately 2465.52±960.77 t. These findings prove that the risks posed by engineering-microplastics are significant, indicating that further investigations are required on the precise laws of transfer and migration, as well as the toxicity mechanisms, in order to improve analytical techniques and policies in this field.     

Metagenomic analysis on resistance genes in water and microplastics from a mariculture system

• Total 174 subtypes of ARGs were detected by metagenomic analysis. • Chloramphenicol resistance genes were the dominant ARGs in water and microplastics. • The abundances of MRGs were much higher than those of ARGs. • Proteobacteria, Bacteroidetes, and Actinobacteria were the dominant phylum. • Microplastics in mariculture system could enrich most of MRGs and some ARGs. Microplastics existing widely in different matrices have been regarded as a reservoir for emerging contaminants. Mariculture systems have been observed to host microplastics and antibiotic resistance genes (ARGs). However, more information on proliferation of ARGs and metal resistance genes (MRGs) in mariculture system at the presence of microplastics is needed. This study used metagenomic analysis to investigate the distribution of ARGs and MRGs in water and microplastics of a typical mariculture pond. Total 18 types including 174 subtypes of ARGs were detected with the total relative abundances of 1.22/1.25 copies per 16S rRNA copy for microplastics/water. Chloramphenicol resistance genes were the dominant ARGs with the abundance of 0.35/0.42 copies per 16S rRNA copy for microplastics/water. Intergron intI1 was dominant gene among 6 detected mobile genetic elements (MGEs) with the abundance of 75.46/68.70 copies per 16S rRNA copy for water/microplastics. Total 9 types including 46 subtypes of MRGs were detected with total abundance of 5.02 × 10²/6.39 × 10² copies per 16S rRNA copy for water/ microplastics while genes resistant to copper and iron served as the dominant MRGs. Proteobacteria, Bacteroidetes, and Actinobacteria accounted for 84.2%/89.5% of total microbial community. ARGs with relatively high abundance were significantly positively related to major genera, MGEs, and MRGs. Microplastics in mariculture system could enrich most of MRGs and some ARGs to serve as potential reservoir for these pollutants. The findings of this study will provide important information on resistance gene pollution at presence of microplastics in the mariculture system for further proposing suitable strategy of environmental management.