Possessing sessile filter-feeding lifestyle, bivalves are more susceptible to contamination by benthic phycotoxins such as the diarrhetic shellfish toxins (DSTs). Due to the prevalence of microplastics (MPs) in aquatic environments, bivalve that experienced MP-exposure are potentially at higher risk from exposure to DSTs-producing microalgae, however, little is known about the impacts of past MP-exposure experience on the accumulation of DSTs. In this study, taking polystyrene (PS) MPs and DSTs-producing Prorocentrum lima as representatives, the impacts of MP-exposure on DSTs accumulation were evaluated in the thick-shell mussel Mytilus coruscus. Our results demonstrated that mussels with MP-exposure experience accumulated markedly higher levels of DSTs in their digestive glands, which may result from a significant impairment of detoxification. In addition, although might exert their effects through different mechanisms, both MP- and/or P. lima-exposure aggravated the level of oxidative stress and led to significant histological lesion of the digestive glands, with the highest stress and lesion observed in mussels that exposed to P. lima after a 21-day MP-exposure. Collectively, our results indicate the risk of DSTs-contamination of bivalves could be markedly aggravated by the ubiquitous presence of MPs, which may pose a severe threat to human consumers and warrants upmost attention.

中文翻译：

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微塑料暴露经历会损害排毒过程，从而加剧厚壳贻贝 Mytilus coruscus 中腹泻性贝类毒素 （DST） 的积累


双壳类动物拥有无柄滤食生活方式，较易受到底栖藻毒素（例如腹泻性贝类毒素 （DST））的污染。由于微塑料 （MP） 在水生环境中普遍存在，经历过 MP 暴露的双壳类可能因暴露于产生 DST 的微藻而面临更高的风险，但是，对于过去的 MP 暴露经历对 DST 积累的影响知之甚少。在本研究中，以聚苯乙烯 （PS） MP 和产生 DST 的 Prorocentrum lima 为代表，评估了 MP 暴露对厚壳贻贝 Mytilus coruscus 中 DST 积累的影响。我们的结果表明，有 MP 暴露经验的贻贝在其消化腺中积累的 DST 水平明显更高，这可能是由于解毒的显着损害造成的。此外，尽管可能通过不同的机制发挥其作用，但 MP 和/或 P. lima 暴露都加剧了氧化应激水平，并导致消化腺的显着组织学损伤，在 MP 暴露 21 天后暴露于 P. lima 的贻贝中观察到最高的应激和损伤。总的来说，我们的结果表明，MP 的无处不在可能会显着加剧双壳类 DST 污染的风险，这可能对人类消费者构成严重威胁，值得高度重视。