PDF(Pubmed)
Abstract：
Micro-sized particles of synthetic polymers (microplastics) are found in all parts of marine ecosystems. This fact requires intensive study of the degree of danger of such particles to the life activity of hydrobionts and needs additional research. It is evident that hydrobionts in the marine environment are exposed to microplastics modified by biotic and abiotic degradation. To assess the toxic potential of aging microplastic, comparative studies were conducted on the response of cytochemical and genotoxic markers in hemocytes of the mussel Mytilus trossulus (Gould, 1850) after exposure to pristine and photodegraded (UV irradiation) polystyrene microparticles (µPS). The results of cytochemical tests showed that UV-irradiated µPS strongly reduced metabolism and destabilized lysosome membranes compared to pristine µPS. Using a Comet assay, it was shown that the nuclear DNA of mussel hemocytes showed high sensitivity to exposure to both types of plastics. However, the level of DNA damage was significantly higher in mussels exposed to aging µPS. It is suggested that the mechanism of increased toxicity of photo-oxidized µPS is based on free-radical reactions induced by the UV irradiation of polymers. The risks of toxic effects will be determined by the level of physicochemical degradation of the polymer, which can significantly affect the mechanisms of toxicity.
摘要：
在海洋生态系统的所有部分都发现了合成聚合物（微塑料）的微粒。这一事实需要深入研究此类颗粒对水生生物生命活动的危险程度，并需要进一步研究。显然，海洋环境中的水生生物暴露于通过生物和非生物降解改性的微塑料中。为了评估老化的微塑料的潜在毒性，对贻贝Mytilustrossulus血细胞中细胞化学和基因毒性标志物的反应进行了比较研究（Gould，1850）暴露于原始和光降解（紫外线照射）聚苯乙烯微粒（µPS）后。细胞化学测试结果表明，与原始µPS相比，紫外线照射的µPS大大降低了代谢并使溶酶体膜不稳定。使用彗星测定法，研究表明，贻贝血细胞的核DNA对暴露于两种类型的塑料具有很高的敏感性。然而,在暴露于老化µPS的贻贝中，DNA损伤水平明显更高。建议光氧化µPS毒性增加的机理是基于聚合物紫外线照射引起的自由基反应。毒性作用的风险将由聚合物的物理化学降解水平决定，这可以显著影响毒性机制。
