Effect thresholds for the earthworm Eisenia fetida: Toxicity comparison between conventional and biodegradable microplastics
Effect thresholds for the earthworm Eisenia fetida: Toxicity comparison between conventional and biodegradable microplastics
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DOI：
10.1016/j.scitotenv.2021.146884
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发表时间：
2021-04-19
影响因子：
9.8
通讯作者：
Yan, Changrong
中科院分区：
文献类型：
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作者：
Ding, Weili;Li, Zhen;Yan, Changrong
生物降解塑料的开发旨在消除传统化石燃料衍生塑料造成的逐步积累和日益增长的威胁。然而，这些生物塑料的影响，特别是在农业方面（例如生物聚合物地膜），仍然知之甚少。在这项研究中，我们比较了生物降解（聚乳酸，PLA;聚碳酸亚丙酯，PPC）和不可降解（聚乙烯，PE）微塑料的生物毒性，使用一系列标准化的生物测定使用蚯蚓。研究的反应包括：回避行为，死亡率，生物量和繁殖反应。在实验室条件下，我们在含有不同浓度微塑料（0，0.125，1.25，12.5，125，250和500 g kg（-1））的人工土壤中孵育蚯蚓。这一宽范围允许线性回归建模和微塑料效应阈值的估计。我们的研究结果表明，微塑料的浓度，而不是塑料类型是更重要的调节植物对土壤污染的反应。微塑料污染的临界阈值为40 g kg（-1），超过此阈值后，蚯蚓表现出微塑料回避行为。在浓度为53克/千克和97克/千克时，茧和幼蚯蚓的数量分别显著减少（EC 10）;而在浓度为500克/千克时，对蚯蚓的存活没有显著影响。总体而言，两种可生物降解材料（PLA和PPC）似乎并不比PE更生物友好。根据土壤中高达67 g kg（-1）的塑料污染水平，我们得出结论，微塑料现在开始对非洲人口构成威胁。为了更好地评估可生物降解和不可降解塑料带来的风险，需要进一步研究微塑料如何影响土壤行为及其对土壤功能的潜在长期影响。(C)2021爱思唯尔有限公司版权所有。
Biodegradable plastics have been developed to eliminate the progressive accumulation and ever-growing threat posed by conventional fossil fuel-derived plastics. The impact of these bioplastics, particularly in an agricultural context (e.g. biopolymer mulch films), however, remains poorly understood. In this study, we compared the biotoxicity of biodegradable (polylactic acid, PLA; polypropylene carbonate, PPC) and non-degradable (polyethylene, PE) microplastics using a series of standardized bioassays using the earthworm Eisenia fetida. The responses studied included: avoidance behavior, mortality, biomass, and reproduction responses. We incubated earthworms in artificial soils amended with different concentrations of microplastic (0, 0.125, 1.25, 12.5, 125, 250, and 500 g kg(-1)) under laboratory conditions. This wide range allowed linear regression modeling and estimation of microplastic effect thresholds. Our results showed that microplastic concentration rather than plastic type was more important in regulating earthworm responses to soil contamination. The critical threshold for microplastic contamination was 40 g kg(-1), after which earthworms exhibit microplastic avoidance behavior. A significant reduction (EC10) in number of cocoons and juvenile earthworms occurred at a concentration of 53 g kg(-1) and 97 g kg(-1), respectively; while no significant effect was found for survival of earthworm until levels of 500 g kg(-1). Overall, the two biodegradable materials (PLA and PPC), appeared to be no more biofriendly than PE. Based on reported levels of plastic contamination in soil of up to 67 g kg(-1), we conclude that microplastics are nowstarting to pose a threat to earthworm population. To better evaluate the risk posed by biodegradable and nondegradable plastics, further mechanistic studies on how microplastics affect earthworm behavior and the potential long-term impacts of this on soil functioning are required. (C) 2021 Elsevier B.V. All rights reserved.