王琳,马旖旎,季荣.PS和PVC微塑料对小球藻的生长抑制效应及其影响途径[J].环境科学学报,2021,41(4):1538-1544
PS和PVC微塑料对小球藻的生长抑制效应及其影响途径
- Effects of PS and PVC microplastics on the growth of Chlorella sp.
- 基金项目：国家重点研发项目（No.2016YFC1402203）；国家自然科学基金（No.21876079）
- 王琳
- 南京大学环境学院, 污染控制与资源化研究国家重点实验室, 南京 210023
- 马旖旎
- 南京大学环境学院, 污染控制与资源化研究国家重点实验室, 南京 210023
- 季荣
- 南京大学环境学院, 污染控制与资源化研究国家重点实验室, 南京 210023
- 摘要：近年来海洋微塑料污染已成为不可忽略的全球性环境问题.海洋中的微塑料可能被海洋动物摄入，对其造成物理损伤或生化毒性；同时与浮游植物形成团聚物，影响其生长和光合作用等，从而对海洋生态系统构成威胁.海洋小球藻（Chlorella sp.）作为食物链中的重要生产者，是污染物在食物链中富集的起点.为了解微塑料对小球藻的毒性作用及其作用途径，本研究测定了聚苯乙烯微塑料（PS， d=150~200 μm）以及聚氯乙烯微塑料（PVC， d=1~2 μm）对海洋小球藻生长速率的影响，并进一步探究了不同微塑料对小球藻的可能致毒机理.研究发现微塑料浓度低于2500 mg·L-1时对小球藻的生长无显著效应，研究中只有极高浓度下（5000 mg·L-1）的PVC和PS会对小球藻的生长产生抑制作用，且PVC的抑制作用大于PS.进一步实验显示二者产生抑制作用的机理存在差异：PS对小球藻生长的抑制作用主要是由于其浸出的小分子有机物质对小球藻产生毒性；而PVC微塑料对小球藻生长抑制除浸出物质毒性以外，还可能由于其小粒径和相对较大的密度，在水中呈悬浮状态产生遮光效应，同时与小球藻产生吸附团聚作用.本研究结果表明，高浓度情况下微塑料可能对海洋浮游植物存在生态风险，该结果对进一步探究微塑料对海洋食物链及海洋生态系统的影响提供了参考依据.
- Abstract：Microplastics (MPs) pollution in the marine environment has become a global concern. By causing physical damage or other biological effects to zooplanktons and influencing the growth and photosynthesis of phytoplankton MPs may pose a threat to marine ecosystems. Marine Chlorella (Chlorella sp.) as an important primary producer, is the starting point of the marine food chain. To understand the effects of MPs on the growth of Chlorella, two types of MPs-polystyrene (PS, d=150~200 μm) and polyvinyl chloride (PVC) (PVC, d=1~2 μm) were chosen to test their impact on the growth rate of Chlorella. The results showed that MPs had no significant effect on the growth of Chlorella at concentrations below 2500 mg·L-1. Only at very high concentrations (5000 mg·L-1), PVC and PS had an inhibitory effect on Chlorella growth, and the effect caused by PVC was greater than that by PS. Further experiment results showed that the mechanisms of the inhibition effects were different between two MPs. The inhibition effect of PS (150~200 μm) on Chlorella growth was mainly caused by the toxic substances leached out from MPs. While the toxicity of PVC (1~2 μm) leachates to Chlorella was lower than toxicity of MPs, indicating other mechanisms-blocking of light as well as forming heterogeneous aggregates with Chlorella. The later two effects are likely due to the smaller size and higher density of PVC used in this study compared with PS. Afterall, the results from this study proved the ecological risks of MPs to marine phytoplankton at high concentrations, which provides a hint for further evaluation of their impacts on the marine food chain and marine ecosystems.
