| 摘要: |
| 【目的】了解目前微塑料（microplastics，MPs）对淡水养殖生态系统的污染水平及其养殖生物的生态毒理效应和影响机制，为水产养殖业的微塑料污染管理和水产品的食品质量安全提供基础数据和决策参考。【方法】选取我国典型淡水养殖池塘的水体、底泥及2种水产品（大口黑鲈Micropterus salmoides、日本沼虾Macrobrachium nipponense），对其进行MPs的定性与定量分析，在此基础上用生态风险指数法和内梅罗污染指数评价法科学评估微塑料的污染风险。同时,以前期试验结果中微塑料（聚苯乙烯，PS）为代表，以模式生物斑马鱼（Danio rerio）为受试对象，设置不同质量浓度梯度（0，200，300，450，675，1 012.5 mg/L）微塑料溶液进行急性毒性试验，在试验基础上配制不同微塑料溶液，培养0，24，48，96 h，测定斑马鱼抗氧化酶（CAT、SOD、GST、GPx）活性、还原型谷胱甘肽（GSH）活性及脂质过氧化物丙二醛（MDA）含量，并分析免疫相关基因TNF-α和IL-1β的转录水平。【结果】微塑料在大口黑鲈和日本沼虾淡水养殖池塘的表层水、底泥沉积物及养殖生物中均有污染，形状多为纤维状和碎片状，其成分主要为聚苯乙烯（PS）、聚乙烯（PE）。微塑料在所调查的淡水养殖池塘中污染较轻且风险等级较低；微塑料PS对斑马鱼96 h的半致死质量浓度LC50为407.93 mg/L，具有中等毒性。随着微塑料PS质量浓度增加和暴露时间延长，斑马鱼抗氧化酶（CAT、SOD、GST）活性和GSH活性整体均呈下降趋势，而GPx活性和MDA含量则呈上升趋势，TNF-α和IL-1β基因表达量异常上升。【结论】微塑料在典型淡水养殖池塘中的表层水、底泥沉积物及养殖生物中均有检出，且主要通过对斑马鱼的抗氧化防御系统和免疫系统产生实质性损害，进而威胁生物生长与安全，应予以重视。 |
| 关键词: 微塑料 淡水养殖池塘 污染分布 风险评价 毒理效应 |
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| 基金项目:国家自然科学基金面上项目（31772855）；国家自然科学基金青年科学基金项目（21207036）；浙江省重点研发计划项目（2015C03018）；浙江省自然科学基金青年科学基金项目（LQ12B07001）；国家级大学生创新创业训练计划项目（202210347026） |
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| Distribution,toxicological effects and ecological risks of microplastics in typical freshwater aquaculture ponds |
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ZHANG Ai,LI Zhenzhen,ZHUANG Chengtao,et al
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| Abstract: |
| 【Objective】This study investigated the pollution levels of microplastics (MPs) in freshwater aquaculture ecosystem and the ecotoxicological effects on aquaculture organisms as well as related impact mechanisms,so as to provide basic data and decision-making reference for microplastics pollution reduction in aquaculture and food quality and safety of aquatic products.【Method】Qualitative and quantitative analysis of MPs was carried out for selected water bodies,sediments and two aquatic products (Micropterus salmoides and Macrobrachium nipponense) in typical freshwater aquaculture ponds in China.On this basis,the pollution risk of microplastics was assessed by combining the ecological risk index method and the Nemero pollution index evaluation method.Taking microplastics (polystyrene,PS) from preliminary tests as the representative and the model organism zebrafish (Danio rerio) as the test object,acute toxicity tests were conducted with microplastics solutions at different mass concentration gradients (0,200,300,450,675 and 1 012.5 mg/L).Then,different microplastics solutions were prepared for 0,24,48 and 96 hours culturing and activities of antioxidant enzymes (CAT,SOD,GST and GPx),contents of reduced glutathione (GSH) and lipid peroxide malondialdehyde (MDA) and transcription levels of immune-related genes TNF-α and IL-1β were determined.【Result】In the two typical freshwater aquaculture ponds of largemouth bass and giant river prawn,microplastics distribution was observed in surface water,sediment and culture organisms.Microplastics were mostly fibrous and fragmentary in shape and main components were polystyrene PS and polyethylene PE.Microplastics had less pollution levels and lower risk levels in the freshwater aquaculture ponds surveyed.The semi-lethal mass concentration of LC50 at 96 h of microplastic PS to zebrafish was 407.93 mg/L with moderate toxicity.With the increase of microplastic concentration and exposure time,activities of CAT,SOD and GST and GSH content showed an overall downward trend,GPx activity and MDA content increased,while expressions of TNF-α and IL-1β genes increased abnormally.【Conclusion】Microplastics were detected in surface water,bottom sediment and cultured organisms in typical freshwater aquaculture ponds,and they threatened the growth and safety of organisms mainly by causing substantial damage to the antioxidant defense system and immune system of zebrafish. |
| Key words: microplastics freshwater aquaculture ponds pollution distribution risk assessment toxicological effect |
