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塑料废弃物是高分子聚合物的混合物,其大小从几米到几纳米不等,包括塑料袋、农用塑料、食品包装、工业颗粒和化妆品微珠等物品,以及这些物品风化产生的碎片[1]。随着紫外线辐射、水力冲刷、物理磨损、生物栖息地以及冻融循环等外界因素的影响,大块的塑料废弃物被分解并降解成微小的塑料碎片或颗粒[2]。当粒径小于5 mm时,塑料碎片或颗粒被称为微塑料[3]。目前,微塑料已在世界范围内的海洋环境[3-4]、地表水系统[5-8]、陆地系统[9-11]和空气粉尘[12-13]中被广泛检出。微塑料体积小,比表面积大,老化后极易吸附环境中的有毒有害物质,如重金属[14]、抗生素[15]和细菌[16],可通过食物链[17]传播,对生物体生长发育、内分泌和繁殖产生不利影响[14-18]。微塑料的污染问题已成为当前研究热点。对于微塑料污染的研究长期以来一直集中在海洋环境,但是海洋中80%的微塑料源自于陆域[19],而河流是微塑料向海洋传输的重要途径[20]。因此,越来越多的学者和专家开始关注河流和湖泊等淡水环境中的微塑料[21-25]。河湖污染“表象在水里,根子在岸上”,大量的污染物均可通过排污口进入河湖。因此,应摸清入河排污口水体中微塑料的分布特征和主要来源,进而促进微塑料的有效管控。
沁河是黄河中下游重要的一级支流,素有“小黄河”之称。沁河下游主要位于河南省焦作市境内,其平面形态基本为平直型,河道断面较为规整,河床较宽,部分区域主槽宽度达20~30 m[26],已成为焦作市经济社会发展的重要水源地。因此,其水体微塑料污染情况对沁河流域和黄河下游的水体环境质量具有重要影响。2023年初河南省人民政府发布的《河南省新污染物治理工作方案》和《河南省加强入河排污口监督管理工作方案》均将微塑料列为重点关注的新污染物,并明确指出要建立新污染物排放源清单,开展环境健康风险评估,而沁河则是河南进行排污口排查的主要河流之一。目前,对于沁河的微塑料污染调查与评估,尤其是排污口水体的微塑料污染特征和行为的研究尚未见文献报道。因此,本研究拟通过对沁河 (焦作段) 入河排污口进行现场调查取样,重点探讨研究区域水体中微塑料的污染分布和特征,以及其可能带来的环境风险,以期对流域微塑料污染研究与防治工作提供参考。
沁河 (焦作段) 入河排污水体微塑料污染特征及风险评价
Pollution characteristic and risk assessment of microplastics from sewage outlets in the Qin River(Jiaozuo section)
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摘要: 河岸排污是引起河流水环境微塑料升高的主要途径。摸清沿河两岸排污水体中微塑料的赋存特征及其环境风险,是进行微塑料污染控制的前提。以黄河支流沁河 (焦作段) 为研究对象,采集7个入河排污口的污水样品,采用体视显微镜对微塑料丰度和形貌特征 (包括尺寸、形状及颜色等) 进行分析,发现微塑料在所有样点均有检出,尺寸为500~2 000 μm,颜色以透明和蓝色为主,纤维状是微塑料在各个样点的主要形状。进一步借助显微红外光谱仪对各样点污水中的聚合物类型进行了鉴定,结果显示排污口水体中微塑料种类以聚乙烯为主,其可能与周边区域的农业生产和居民生活排放有关。环境风险评价结果表明,研究区段整体处于低风险水平;排污口微塑料引起的环境风险不仅与其丰度有关,还依赖于微塑料的种类,有聚氯乙烯检出的样点1和6均呈现较高的环境风险。该研究结果可为黄河及其支流微塑料风险防控提供参考。Abstract: Wastewater discharge is the major source of microplastic pollution in river. Identification of the characteristics of microplastics and their environmental risks in the discharged waters along sides of river is a prerequisite for microplastic pollution control. The Qin River (Jiaozuo section), a tributary of the Yellow River, was selected as the research object and a total of 7 water samples were collected from sewage outlets. The abundance and morphological features of microplastics, including size, shape and color, were classified by using a stereomicroscope. Microplastics were found in all sample sites, and the sizes varied mainly between 500 and 2 000 μm. In addition, the colors were mainly transparent and blue, and fibrous was the main shape of microplastics at each sample point. Further, the types of polymers at all points were identified using microinfrared spectrometry. The results showed that the main type of microplastics in the sewage outlets was polyethylene, which mainly came from agricultural production and residential emissions in the surrounding areas. The results of the environmental risk assessment showed that the study area was at a low risk level overall. The environmental risk posed by microplastics at the outfalls was not only related to its abundance, but also depended on the type of microplastics. Sample sites 1 and 6 both presented higher environmental risks as polyvinyl chloride was detected. Research results could provide theoretical basis and data support for the prevention and control of microplastic risks in the Yellow River and its tributaries.
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Key words:
- microplastics /
- sewage outlets /
- pollution characteristic /
- risk assessment /
- abundance
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表 1 微塑料危害评分表
Table 1. Hazard score of microplastic polymers
聚合物种类 缩写 危害评分 聚丙烯 PP 1 聚对苯二甲酸乙二醇酯 PET 4 聚乙烯 PE 11 聚苯乙烯 PS 30 聚酰胺 PA 47 聚氯乙烯 PVC 10 551 表 2 微塑料风险评价等级划分
Table 2. Criteria for microplastic pollution risk
风险等级 I II III IV V PLI <10 10~20 20~30 >30 HI 0~1 1~10 10~100 100~1 000 >1 000 RI <150 150~300 300~600 600~1 200 >1 200 表 3 研究区段整体微塑料排污环境风险
Table 3. The overall environmental risk of microplastics in the study area
样 点 1 2 3 4 5 6 7 $ \mathrm{CF}_i $ 1.83 2.17 1.39 1.00 7.11 1.78 4.72 $ \mathrm{PLI}_i $ 1.35 1.47 1.18 1.00 2.67 1.33 2.17 $ {\mathrm{P}\mathrm{L}\mathrm{I}}_{\mathrm{z}\mathrm{o}\mathrm{n}\mathrm{e}} $ 1.51 表 4 各种类型微塑料在每个排污口中引起的风险指数
Table 4. Hazard score caused by microplastics to the risk of each outfall
样 点 1 2 3 4 5 6 7 HI-PE 2.33 4.51 3.08 3.06 3.52 4.81 4.92 HI-PP 0.24 0.13 0.28 0.22 0.16 0.03 0.13 HI-PA 11.39 8.44 1.88 5.22 6.61 4.41 5.53 HI-PET 0.48 0.82 0.48 1.33 0.53 0.63 0.33 HI-PS — — — 30.00 30.00 30.00 — HI-PVC 10 551.00 — — — — 10 551.00 — HI 10 565.45 13.90 5.72 39.83 40.83 10 590.88 10.91 风险等级 V III II III III V III 注:“—”表示所在样点无对应聚合物检出。 表 5 各排污口微塑料聚合物潜在生态风险
Table 5. Potential ecological risks of different polymer in each outfall
样点 1 2 3 4 5 6 7 Ei r-PE 2.33 4.51 3.08 3.06 3.52 4.81 4.92 Ei r-PP 0.24 0.13 0.28 0.22 0.16 0.03 0.13 Ei r-PA 11.39 8.44 1.88 5.22 6.61 4.41 5.53 Ei r-PET 0.48 0.82 0.48 1.33 0.53 0.63 0.33 Ei r-PS — — — 1.67 0.23 0.94 — Ei r-PVC 319.73 — — — — 329.72 — RI 334.18 13.90 5.72 11.50 11.06 340.53 10.91 风险等级 III I I I I III I 注:“—”表示所在样点无对应聚合物检出。 -
[1] ZHANG Y, WANG Q, YALIKUN N, et al. A comprehensive review of separation technologies for waste plastics in urban mine[J]. Resources, Conservation and Recycling, 2023, 197: 107087. doi: 10.1016/j.resconrec.2023.107087 [2] ANDRADY A L. Microplastics in the marine environment[J]. Marine Pollution Bulletin, 2011, 62(8): 1596-1605. doi: 10.1016/j.marpolbul.2011.05.030 [3] THOMPSON R C, OLSEN Y, MITCHELL R P, et al. Lost at sea: where is all the plastic?[J]. Science, 2004, 304(5672): 838-838. doi: 10.1126/science.1094559 [4] NAKANO H, ARAKAWA H. Oceanic microplastics in Japan: A brief review on research protocol and present pollution[J]. Regional Studies in Marine Science, 2022, 51: 102201. doi: 10.1016/j.rsma.2022.102201 [5] DING L, FAN M R, GUO X , et al. Microplastics in surface waters and sediments of the Wei River, in the northwest of China [J]. Science of The Total Environment, 2019, 667: 427-434. [6] WANG W, YUAN W, CHEN Y, et al. Microplastics in surface waters of Dongting Lake and Hong Lake, China[J]. Science of The Total Environment, 2018, 633: 539-545. doi: 10.1016/j.scitotenv.2018.03.211 [7] HAN M, NIU X, TANG M, et al. Distribution of microplastics in surface water of the lower Yellow River near estuary[J]. Science of The total environment, 2020, 707: 135601. doi: 10.1016/j.scitotenv.2019.135601 [8] ALAM F C, SEMBIRING E, MUNTALIF B S, et al. Microplastic distribution in surface water and sediment river around slum and industrial area (case study: Ciwalengke River, Majalaya district, Indonesia)[J]. Chemosphere, 2019, 224: 637-645. doi: 10.1016/j.chemosphere.2019.02.188 [9] YA H, JIANG B, XING Y, et al. Recent advances on ecological effects of microplastics on soil environment[J]. Science of The Total Environment, 2021, 798: 149338. doi: 10.1016/j.scitotenv.2021.149338 [10] HARLEY-NYANG D, MEMON F A, OSORIO BAQUERO A, et al. Variation in microplastic concentration, characteristics and distribution in sewage sludge & biosolids around the world[J]. Science of The Total Environment, 2023, 891: 164068. doi: 10.1016/j.scitotenv.2023.164068 [11] CORRADINI F, MEZA P, EGUILUZ R, et al. Evidence of microplastic accumulation in agricultural soils from sewage sludge disposal[J]. Science of The Total Environment, 2019, 671: 411-420. doi: 10.1016/j.scitotenv.2019.03.368 [12] CHOUDHURY A, SIMNANI F Z, SINGH D, et al. Atmospheric microplastic and nanoplastic: The toxicological paradigm on the cellular system[J]. Ecotoxicology and Environmental Safety, 2023, 259: 115018. doi: 10.1016/j.ecoenv.2023.115018 [13] JIA Q, DUAN Y, HAN X, et al. Atmospheric deposition of microplastics in the megalopolis (Shanghai) during rainy season: Characteristics, influence factors, and source[J]. Science of The Total Environment, 2022, 847: 157609. doi: 10.1016/j.scitotenv.2022.157609 [14] WEN X, YIN L, ZHOU Z, et al. Microplastics can affect soil properties and chemical speciation of metals in yellow-brown soil[J]. Ecotoxicology and Environmental Safety, 2022, 243: 113958. doi: 10.1016/j.ecoenv.2022.113958 [15] WANG L, YANG H, GUO M H, et al. Adsorption of antibiotics on different microplastics (MPs): Behavior and mechanism[J]. Science of The Total Environment, 2023, 863: 161022. doi: 10.1016/j.scitotenv.2022.161022 [16] SHEN M, ZENG Z, LI L, et al. Microplastics act as an important protective umbrella for bacteria during water/wastewater disinfection[J]. Journal of Cleaner Production, 2021, 315: 128188. doi: 10.1016/j.jclepro.2021.128188 [17] CASTRO-CASTELLON A T, HORTON A A, HUGHES J M R, et al. Ecotoxicity of microplastics to freshwater biota: Considering exposure and hazard across trophic levels[J]. Science of the Total Environment, 2022, 816: 151638. doi: 10.1016/j.scitotenv.2021.151638 [18] SONG X, DU L, SIMA L, et al. Effects of micro(nano)plastics on the reproductive system: A review[J]. Chemosphere, 2023, 336: 139138. doi: 10.1016/j.chemosphere.2023.139138 [19] ROCHMAN C M. Microplastics research—from sink to source[J]. Science, 2018, 360(6384): 28-29. doi: 10.1126/science.aar7734 [20] LEBRETON L C M, VAN DER ZWET J, DAMSTEEG J W, et al. River plastic emissions to the world's oceans[J]. Nature Communications, 2017, 8(1): 15611. doi: 10.1038/ncomms15611 [21] FAN Y, ZHENG K, ZHU Z, et al. Distribution, sedimentary record, and persistence of microplastics in the Pearl River catchment, China[J]. Environmental Pollution, 2019, 251: 862-870. doi: 10.1016/j.envpol.2019.05.056 [22] YUAN W, LIU X, WANG W, et al. Microplastic abundance, distribution and composition in water, sediments, and wild fish from Poyang Lake, China[J]. Ecotoxicology and Environmental Safety, 2019, 170: 180-187. doi: 10.1016/j.ecoenv.2018.11.126 [23] LI J, OUYANG Z, LIU P, et al. Distribution and characteristics of microplastics in the basin of Chishui River in Renhuai, China[J]. Science of The Total Environment, 2021, 773: 145591. doi: 10.1016/j.scitotenv.2021.145591 [24] DAI L, WANG Z, GUO T, et al. Pollution characteristics and source analysis of microplastics in the Qiantang River in southeastern China[J]. Chemosphere, 2022, 293: 133576. doi: 10.1016/j.chemosphere.2022.133576 [25] MIN R, MA K, ZHANG H, et al. Distribution and risk assessment of microplastics in Liujiaxia Reservoir on the upper Yellow River[J]. Chemosphere, 2023, 320: 138031. doi: 10.1016/j.chemosphere.2023.138031 [26] 纪义虎, 左其亭, 马军霞. 基于Tapio和LMDI模型的沁河流域碳排放与水资源利用脱钩关系分析[J]. 水资源保护, 2023, 39(4): 94-101. [27] 刘强军, 牛晨煜, 赵珺. 黄河中游沁河流域汛期降水特征及突变分析[J]. 水电能源科学, 2021, 39(11): 19-22. [28] TOMLINSON D L, WILSON J G, HARRIS C R, et al. Problems in the assessment of heavy-metal levels in estuaries and the formation of a pollution index[J]. Helgolä nder Meeresuntersuchungen, 1980, 33(1): 566-575. [29] LITHNER D, LARSSON Å, DAVE G. Environmental and health hazard ranking and assessment of plastic polymers based on chemical composition[J]. Science of The Total Environment, 2011, 409(18): 3309-3324. doi: 10.1016/j.scitotenv.2011.04.038 [30] HAKANSON L. An ecological risk index for aquatic pollution control. a sedimentological approach[J]. Water Research, 1980, 14(8): 975-1001. doi: 10.1016/0043-1354(80)90143-8 [31] PENG G, XU P, ZHU B, et al. Microplastics in freshwater river sediments in Shanghai, China: A case study of risk assessment in mega-cities[J]. Environmental Pollution, 2018, 234: 448-456. doi: 10.1016/j.envpol.2017.11.034 [32] EVERAERT G, VAN CAUWENBERGHE L, DE RIJCKE M, et al. Risk assessment of microplastics in the ocean: Modelling approach and first conclusions[J]. Environmental Pollution, 2018, 242: 1930-1938. doi: 10.1016/j.envpol.2018.07.069 [33] 赵长民, 和兵, 李和通, 等. 汜水河(荥阳段)入河排污口水体微塑料赋存特征及风险评估 [J/OL]. 环境科学: 1-17. DOI:10.13227/j.hjkx.202304057. [34] BROWNE M A, CRUMP P, NIVEN S J, et al. Accumulation of microplastic on shorelines woldwide: sources and sinks[J]. Environmental Science & Technology, 2011, 45(21): 9175-9179. [35] 周刚, 徐晨烨, 沈忱思, 等. 微塑料在淀山湖水环境的污染分布、组成特征和生态风险[J]. 环境科学学报, 2022, 42(4): 214-224. [36] 山泽萱, 张妍, 张成前, 等. 渭河微塑料污染现状与风险评价[J]. 环境科学, 2023, 44(1): 231-242. [37] 周泽妍, 王思琦, 张盼月, 等. 白洋淀-府河入淀口段沉积物中微塑料的丰度及分布特征[J]. 环境工程学报, 2021, 15(1): 360-367. doi: 10.12030/j.cjee.202003181 [38] 门聪, 李頔, 左剑恶, 等. 北京市通州区河流中微塑料组成的空间分布及潜在来源解析[J]. 环境科学, 2022, 43(7): 3656-3663. [39] YAN M, NIE H, XU K, et al. Microplastic abundance, distribution and composition in the Pearl River along Guangzhou city and Pearl River estuary, China[J]. Chemosphere, 2019, 217: 879-886. doi: 10.1016/j.chemosphere.2018.11.093 [40] ZHANG Z, ZULPIYA M, WANG P. Occurrence and sources of microplastics in dust of the Ebinur lake Basin, northwest China[J]. Environmental Geochemistry and Health, 2023, 45(5): 1461-1474. doi: 10.1007/s10653-022-01279-9 [41] 郝若男, 史小红, 刘禹, 等. 乌梁素海水体微塑料空间分布规律及影响因素[J]. 中国环境科学, 2022, 42(7): 3316-3324. doi: 10.3969/j.issn.1000-6923.2022.07.035 [42] 孙雪纯, 侯书贵, 黄壬晖, 等. 可可西里特拉什湖中微塑料污染特征、来源和生态风险[J]. 环境科学学报, 2023, 43(2): 231-240. [43] 范梦苑, 黄懿梅, 张海鑫, 等. 湟水河流域地表水体微塑料分布、风险及影响因素[J]. 环境科学, 2022, 43(10): 4430-4439.