There is growing concern about the threat that nanoplastics (NPs) pose to ecosystems. However, a comprehensive risk assessment of NPs is currently constrained by the paucity of knowledge on the chemical reactivity of NPs, which were previously thought to be chemically inert. This review identifies the chemical reactivity of NPs that have undergone abiotic and biotic weathering, including the formation of free radicals, the increase in the content of oxygen-containing functional groups, and the release of plastic leachates. Their interaction with legacy contaminants, such as heavy metals (HMs), is then examined, highlighting their critical role in the oxidation and reduction of HMs, through free radical-mediated redox processes and electron shuttling by carbonyl groups. This review offers new insights into the risk of NPs, where their interaction with legacy contaminants determines the long-term exposure scenario for ecosystems. The unexpectedly large pool of reactive NPs in nature will not only affect their risks but also impact the biogeochemistry of HMs and other contaminants that could react with free radicals and carbonyl groups.

中文翻译：

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风化纳米塑料的化学反应性及其与重金属的相互作用


人们越来越担心纳米塑料 （NPs） 对生态系统构成的威胁。然而，由于 NP 的化学反应性知识匮乏，目前对 NP 的全面风险评估受到限制，以前认为 NP 具有化学惰性。本综述确定了经历非生物和生物风化的 NPs 的化学反应性，包括自由基的形成、含氧官能团含量的增加以及塑料渗滤液的释放。然后检查它们与重金属 （HM） 等传统污染物的相互作用，强调它们通过自由基介导的氧化还原过程和羰基的电子穿梭在 HM 的氧化和还原中的关键作用。本综述为 NP 的风险提供了新的见解，其中它们与遗留污染物的相互作用决定了生态系统的长期暴露情景。自然界中出乎意料的大量反应性 NP 不仅会影响它们的风险，还会影响 HM 和其他可能与自由基和羰基反应的污染物的生物地球化学。