Plastic pollution in aquatic environments poses significant ecological risks, particularly through released leachates. While traditional or non-biodegradable plastics (non-BPs) are well-studied, biodegradable plastics (BPs) have emerged as alternatives that are designed to degrade more rapidly within the environment. However, research on the ecological risks of the leachates from aged BPs in aquatic environments is scarce. This controlled laboratory study investigated the leachate release processes and associated toxicity of traditional non-BPs, i.e., polyethylene terephthalate (PET) and polypropylene (PP) and BPs, i.e., polylactic acid (PLA) combined with polybutylene adipate terephthalate (PBAT) and starch-based plastic (SBP) under different aging time and suspended sand concentrations (0, 50, 100, 250, and 500 mg/L). The results indicated that BPs release significantly higher levels of dissolved organic carbon (DOC) than those of non-BPs, particularly at elevated suspended sand concentrations. The DOC concentrations in PLA+PBAT leachate reached 2.69 mg/L, surpassing those of PET and PP. Additionally, BPs released organic matter of larger molecular weight and protein-like substances. Toxicity tests showed that leachates from BPs inhibited the activity of Daphnia magna more than those from non-BPs. At a suspended sand concentration of 500 mg/L, PLA+PBAT leachate caused a 30 % inhibitory rate of Daphnia magna. Despite enhanced degradability, leachates from BPs may pose increased environmental risks in ecosystems with high suspended sand concentrations. Comprehensive ecological risk assessments are essential for effectively managing and mitigating these hazards of plastic pollution.

中文翻译：

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不同悬浮砂浓度下老化塑料碎片渗滤液的动态变化及其毒性


水生环境中的塑料污染会带来重大的生态风险，尤其是通过释放的渗滤液。虽然传统或不可生物降解的塑料 （non-BPs） 得到了充分的研究，但可生物降解塑料 （BPs） 已成为旨在在环境中更快降解的替代品。然而，关于水生环境中老年 BP 渗滤液的生态风险的研究很少。这项对照实验室研究调查了传统非 BPs，即聚对苯二甲酸乙二醇酯 （PET） 和聚丙烯 （PP） 和 BPs，即聚乳酸 （PLA） 与聚己二酸对苯二甲酸丁二醇酯 （PBAT） 和淀粉基塑料 （SBP） 在不同老化时间和悬浮砂浓度 （0、50、100、250 和 500 mg/L） 下的渗滤液释放过程和相关毒性。结果表明，BPs 释放的溶解有机碳 （DOC） 水平明显高于非 BPs，尤其是在悬浮砂浓度较高的情况下。PLA+PBAT 渗滤液中 DOC 浓度达到 2.69 mg/L，超过了 PET 和 PP。此外，BPs 释放出分子量较大的有机物和蛋白质样物质。毒性试验表明，BPs 中的渗滤液比非 BPs 中的渗滤液更能抑制大型溞的活性。在悬浮砂浓度为 500 mg/L 时，PLA+PBAT 渗滤液对大型溞的抑制率为 30%。尽管降解性增强，但 BP 的渗滤液可能会对悬浮沙浓度高的生态系统构成更大的环境风险。全面的生态风险评估对于有效管理和减轻塑料污染的危害至关重要。