STOTEN：水生环境中微塑料对人类健康的影响-从海洋到食物系统 - 海洋微塑料危害生态系统研究

天笃 · 发表于海洋科普 2024-6-16 10:31:12

图文摘要 | Graphical abstract

导读 | Introduction

微塑料污染在海洋生态系统和人类食物系统中普遍存在。微塑料可能携带有毒化学物质进入到海洋生物体中，包括有毒添加剂、持久性有机污染物和从周围环境中富集的重金属。有毒化学物质可能在食物链中富集，对海洋生物和人类健康产生不利影响。塑料不仅威胁到包括大型海洋哺乳动物（如鲸鱼和海豚）以及各种鸟类、鱼类和无脊椎动物在内的800多种动物的生存，还导致化学污染、外来物种入侵和对当地旅游和渔业的破坏。2015年，海洋塑料污染以及全球气候变化、臭氧层破坏和海洋酸化被列为重要的全球环境问题。海洋塑料污染导致全球经济损失超过80亿美元，其中水产品损失为310亿美元。本文自2022年6月发表以来，已被引用139次。

Microplastic (MP) contamination is common in the marine ecosystem and human food system. MPs may carry toxic chemicals to marine organisms, including toxic additives, persistent organic pollutants, and heavy metals enriched from the surrounding environment. Toxic chemicals may be enriched along the food chain, which may cause a detrimental effect on marine life and human health. While plastic not only threatens the survival of more than 800 species of animals, including large marine mammals (such as whales and dolphins) to various birds, fish, and invertebrates, it also leads to chemical pollution, invasion of exotic species1 and damage to local tourism and fisheries. In 2015, marine plastic pollution and global climate change, ozone depletion, and ocean acidification were listed as major global environmental issues. Marine plastic pollution has caused the global economy to lose more than $ 80 × 108, including a loss of $ 31 × 108 in aquatic products.

一、报告指引及规例

Reporting guidelines and regulations

在欧洲海洋战略框架指南中首次尝试整合海洋生态系统中微塑料的采样、处理和分析。因此，提出了用于海洋和淡水生态环境的统一、标准化的微塑料监测方法学草案，以确定污染水平并使研究结果可比较。根据美国环保局（EPA）的可持续材料管理方案:在非危险材料和废物管理层次结构，减少或消除微塑料污染需要采取四个层次的方法（图1），包括源头减少和重复利用、回收利用和堆肥、能源回收、处理和处置。

The first attempt to coordinate sampling, processing and analysis of MPs in marine ecosystems has been made in the European MSFD “Guidelines for Monitoring Marine Garbage in the European Seas”. As a result, a unified, standardised protocol for MP monitoring methodologies for marine and freshwater ecology has been proposed, which presents the level of pollution and makes results comparable between studies. According to the United States Environmental Protection Agencys (EPA) Sustainable Materials Management: Non-Hazardous Materials and Waste Management Hierarchy, the reduction or elimination of MP pollution requires a four-tier approach (Fig. 1), including source reduction and reuse, recycling and composting, energy recovery, treatment and disposal.

图1 非危险材料和废物管理层次结构

Fig. 1 Non-hazardous materials and waste management hierarchy

二、微塑料的鉴定和定量

Identification and quantification

如图2所示，多种方法可用于颗粒物的鉴定和定量。在使用显微镜对颗粒进行视觉识别和预分选之后，研究人员通常使用光谱方法，如傅里叶变换红外光谱（FTIR）或拉曼光谱（RS）来鉴定聚合物。FTIR和RS是非破坏性的技术。同时，裂解气相色谱质谱法（Py-GC/MS）和热萃取热脱附-气质联用（TED-GC/MS）（TED-GC/MS）是热分析法。RS和FTIR与光学显微镜的联用通常用于提供颗粒的尺寸和数量信息，而TED-GC/MS用于推导所涉及聚合物的总质量分数。在将光谱分析用于确定颗粒的数量和大小之后，将来还将使用热分析来筛选样品和分析污染水平。随着各种技术的不断发展和改进，微塑料分析技术在未来将更加快速、灵敏且易于操作。

There are various methods for particle identification and quantification, as shown in Fig. 2. After visual recognition using microscope pre-sorting of particles, researchers generally use spectroscopic methods, Fourier Transform Interferometer (FTIR) or Raman Spectroscopy (RS), to identify polymers. FTIR and RS are non-destructive technologies. At the same time, Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC/MS) and Thermal Extraction and Desorption coupled with Gas Chromatography Mass Spectrometry (TED-GC/MS) analysis are thermal additives. RS and FTIR coupled with an optical microscope are commonly used to provide information on particle size and number, while TED-GC/ MS is used to derive the total mass fraction of polymer involved. In the future, thermal analysis will be used to screen samples and analyze contamination levels after determining the number and size of particles using spectroscopic analysis. With continuous development and improvement of various technologies, analytical techniques will be faster, more sensitive and easier to operate in the future.

图2 不同检测技术对MPs的粒径限制

Fig. 2 Size limit of different detection techniques of MPs

三、微塑料的颗粒毒性

Particle toxicity of MPs

哺乳动物细胞对微塑料的主要吸收途径是吞噬和内吞。小肠上皮细胞中的巨噬细胞通过吞噬作用吸收大于 0.5 μm 的颗粒，而蜂巢细胞则通过内吞作用将 5 μm 的颗粒内化。微塑料（粒径为 0.1 -150 μm）可以通过哺乳动物的循环系统运输到淋巴系统。最近，一项关于聚苯乙烯微塑料在小鼠组织中的分布和积累以及对特定组织造成的健康风险的研究表明，微塑料可在肝脏、肾脏（肾毒性）和肠道（胃肠道毒性）中积累。此外，还发现微塑料的粒径与组织积累动力学和分布模式密切相关。通过分析小鼠肝脏中的生化生物标志物和代谢组图谱，发现微塑料会影响氧化应激、能量和脂质代谢以及神经毒性。如图 3 所示，淋巴结能够吸收多达 0.3% 小于150 μm的塑料碎片，小于110 μm的微塑料可进入门静脉，小于20 μm甚至可进入器官。并且7%的纳米塑料可穿过上皮细胞，进入所有器官，如肝和脾脏（肝毒性）、心脏（心血管毒性）、胸腺、生殖器官（生殖毒性）和大脑（神经毒性）。此外，纳米塑料还能穿过血脑屏障和胎盘屏障进行转移。

Dominant pathways of uptake for MPs are via phagocytosis and endocytosis. Macrophages in the small intestine epithelium absorb particles larger than 0.5 μm through phagocytosis, while honeycomb cells internalize 5 μm of particles through endocytosis. MPs (particle size: between 0.1 and 150 μm) could be transported into the lymphatic system through the mammalian circulatory system. Recently, a study of mice on the distribution and accumulation of PS MPs in tissues and resulting health risks to specific tissues showed MPs accumulated in the liver, kidney (nephrotoxicity), and intestines (gastrointestinal toxicity). Also, the particle size of MPs was found to be closely related to tissue accumulation kinetics and distribution pattern. By analysing biochemical biomarkers and metabolomic profiles in mouse livers, it is noted that MPs affect oxidative stress, energy and lipid metabolism, and neurotoxicity. As shown in Fig. 3, lymph nodes are capable of absorbing up to 0.3% of plastic fragments smaller than 150 μm, while MPs smaller than 110 μm are accessible in the portal vein and into organs even when MPs are smaller than 20 μm in size. Moreover, 7% of NPs may transfer across epithelial cells and can enter all organs such as the liver and spleen (hepatotoxicity), heart (cardiovascular toxicity), thymus, reproductive organs (reproductive toxicity) and brain (neurotoxicity). In addition, NPs can cross the blood-brain barrier and the placental barrier for translocation.

图3 哺乳动物体内微塑料和纳米塑料的命运与颗粒大小的关系

Fig. 3 Relationship between the fate of microplastics and nanoplastics in mammals and particle size

四、微塑料的风险评估

MP risk assessment

微塑料的风险评估是一项艰巨的任务，因为即使形成微塑料的材料在宏观尺度上被批准可用于工业用途并受到监管，但这并不意味着微塑料具有相同的潜在风险和暴露途径。图 4 显示了微塑料风险评估的潜在框架和需要考虑的不同因素。在微观尺度上，结构决定行为。因此，在风险评估中不能将微塑料作为化学品处理。根据食品法典 2011 年发布的风险评估方法，风险评估的步骤包括危害识别、暴露评估、危害特征描述和风险特征描述。微塑料的危害识别强调风险与三个主要因素有关（图 4）：（a）暴露途径，包括海水（地表水和水体）、沉积物（沿岸或底栖）和空气；（b）微塑料的暴露水平；以及（c）微塑料的潜在危害（机械、生物和化学毒性）。

Risk assessment of MPs is a daunting task because even though the materials that form MPs are available for industrial use at the macroscopic scale, which is regulated and approved, this does not mean that the MPs have the same risk potential and same exposure pathways. Fig. 4 shows a potential framework for risk assessment of MPs and the different factors to consider. At the microscopic scale, structure determines behaviour. Therefore, MPs cannot be treated as chemicals in RA. According to the RA methodology issued by Codex Alimentarius in 2011, the steps in risk assessment include hazard identification, exposure assessment, hazard characterisation, and risk characterisation. The hazard identification of MPs highlights that risk is related to three main factors (Fig. 4): (a) Exposure pathways, including seawater (surface water and water column), sediment (coastal or benthic), and air, (b) the exposure levels of MPs, and (c) the potential hazard of MPs (mechanical, biological, and chemical toxicity).

图4 海洋环境中微塑料风险评估框架

Fig. 4 Framework for Risk Assessment of MPs in the marine environment

人类受海洋源微塑料影响的主要途径是地表水、水体和沉积物（沿岸或底栖）。这些主要污染物源自次级微塑料的直接排放，而塑料微粒的物理、化学和生物分解与人类和水生生物的潜在危害有关。暴露评估通常包括微塑料在水生环境中的归宿和不同的人类暴露途径（胃肠道摄入、呼吸道吸入和皮肤渗入：如图 5 所示）。影响人类接触微塑料的重要因素包括微塑料浓度（全球每年产生的废物量）、聚合物密度和寿命（降解性）。在对微塑料进行危害表征时，微塑料的平均粒径和基于单体毒性的聚合物潜在危害是量化微塑料对人体毒性的关键因素。不同粒径的微塑料在生物膜上的积聚能力存在明显差异，可能会造成生物毒性风险。此外，微塑料还可能根据其单体成分释放或吸附毒素（化学毒性）。风险特征描述的综合信息将生成一个完整的风险评估模型，对海洋环境中各种聚合物的微塑料对人类健康的潜在危害进行排序。

The main pathway for humans to be subjected to marine-derived MPs is through surface water, water column, and sediment (coastal or benthic). These primary pollutants originate from direct emissions of SMPs, and physical, chemical, and biological breakdown of PMPs are associated with human and aquatic organism hazard potential. The exposure assessment typically includes MPs fate in the aquatic environment and human exposure through various pathways (gastrointestinal tract ingestion, respiratory inhalation, and dermal infiltration: shown in Fig. 5). Important factors influencing the probability of human exposure to MPs are MP concentration (annual global waste generation), polymer density, and lifetime (degradability). In the hazard characterisation of MPs, the mean particle size of MPs and the potential hazard of polymers based on monomer toxicity are key factors to quantify MP toxicity to humans. MPs with different particle sizes have obvious differences in capability to accumulate on biofilms and may pose biological toxicity risk. Also, MPs may release or adsorb toxins based on their monomer composition (chemical toxicity). The combined information for risk characterisation will generate a complete risk assessment model to rank the hazard potential of MPs to human health from diverse polymers in the marine environment.

图5 释放到水生环境后的微塑料暴露、吸收、分布和降解的潜在途径

Fig. 5 otential routes of exposure, uptake, distribution, and degradation of microplastics after intentional or unintentional release into the aquatic environment

五、总结 | Conclusions

对海洋生态系统中微塑料的风险评估还有大量工作要做：（1）需要明确界定微塑料类型和大小范围；（2）需要进一步实现微塑料取样、处理、鉴定和定量标准操作程序的标准化和国际化；（3）需要有效的方法来减少或消除海洋生态系统中的微塑料，包括制定微塑料排放预防战略和加快塑料的可持续利用和处置；（4）需要可靠的方法来评估微塑料污染水平，并开发生态友好型聚合物（淀粉基塑料或聚乳酸）和 “绿色”添加剂化学品等新技术，以防止塑料排入水生环境。

There is considerable work needed to develop the area of risk assessment of MPs in marine ecosystems. First, a clear definition of MP type and size range is required. Further standardisation and internationalization of MP sampling, processing, identification, and quantification standard operating procedures are required. Effective methods to reduce or eliminate MPs from marine ecosystems are also required, including developing MP emission prevention strategies and accelerating sustainable use and disposal of plastics. Fourth, reliable methods for assessing MP pollution levels are required, and new technologies to prevent the discharge of plastics into the aquatic environment include the development of eco-friendly polymers (starch-based plastic or polylactic acid) and ‘green’ additive chemicals.

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https://www.sciencedirect.com/

science/article/pii/

S0048969722008221

本文内容来自ELSEVIER旗舰期刊Sci Total Environ第823卷发表的论文：

Yuan Z.H., Nag R., Cummins E., 2022. Human health concerns regarding microplastics in the aquatic environment- From marine to food systems. Sci. Total. Environ. 823, 153730.

DOI: https://doi.org/10.1016/j.scitotenv.2022.153730

第一作者：Zhihao Yuan

都柏林大学学院生物系统工程学院

以第一作者在Journal of Hazardous Materials、Science of the Total Environment等国际期刊发表论文3篇。

主要作者：Rajat Nag 助理教授

都柏林大学学院生物系统工程学院

Rajat是爱尔兰都柏林大学生物系统与食品工程学院生物工程讲师/助理教授、爱尔兰工程师协会的特许工程师，拥有生物系统和食品工程博士学位，是一位创新的研究者，致力于环境与人类健康风险评估（化学和微生物）、可持续性和生命周期评估以及气候变化对健康的影响。

近2年在Sci Total Environ发表的其他论文：

Nag R., Whyte P., Markey B.K., OFlaherty V., Bolton D., Fenton O., Richards K.G., Cummins E., 2020. Ranking hazards pertaining to human health concerns from land application of anaerobic digestate. Sci. Total. Environ. 710, 136297.

Nag R., Auer A., Nolan S., Russell L., Markey B.K., Whyte P., OFlaherty V., Bolton D., Fenton O., Richards K.G., Cummins E., 2021. Evaluation of pathogen concentration in anaerobic digestate using a predictive modelling approach. Sci. Total. Environ. 800, 149574.

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Elsevier旗舰期刊Science of the Total Environment (STOTEN)于1972年创刊，刊载环境及与人类相关的研究成果。2022年影响因子为9.8，位于JCR 1区。在2022谷歌学术指标期刊排名中，H5指数为225，位居全球期刊总榜第22位。

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