重质原油和轻质原油水溶性组分对紫贻贝(Mytilus edulis)毒理效应的研究

近年来,海洋石油开采与运输泄漏、石油及产品离岸排放等事故逐年增多,对近海海域生态环境产生了巨大破坏。为探究重质原油和轻质原油对紫贻贝(Mytilus edulis)毒理效应,测定了不同浓度重质原油和轻质原油暴露下紫贻贝鳃和外套膜中过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性及体内石油烃的含量变化。结果显示,石油污染暴露下,紫贻贝腮和外套膜中CAT和SOD活性变化明显,与暴露浓度和暴露时间有关。CAT活性在轻质原油组随着浓度的增大,呈现下降趋势,且随着暴露时间的延长呈现先下降后上升趋势;在重质原油暴露组,随着浓度的增大,呈现先上升后下降趋势,且随着暴露时间的延长呈现先下降后上升趋势。SOD活性在轻质原油与重质原油暴露组,随着浓度的增大,呈现下降趋势,且随着暴露时间的延长呈现上升趋势并存在一定的剂量-效应关系。重质原油和轻质原油暴露168 h后紫贻贝体内总石油烃含量呈线性递增,生物富集系数(BCF)随着暴露浓度的增加不断减小并最终趋于平稳。结果表明,以紫贻贝腮和外套膜中SOD和CAT活性作为石油烃污染的生物标志物具有一定应用前景,紫贻贝对原油溶液中石油烃的生物富集作用可用来判断污染原油的来源和性质。

The Toxicity of Water-soluble Composition of Heavy Crude and Light Crude Oil to Mytilus edulis

In recent years, with the rapid development of oil exploitation and transportation, oil spill accidents increased every year which have caused serious damage to offshore ecological environment. To explore the toxic effect of heavy crude and light crude oil on Mytilus edulis, this study measured catalase (CAT) and superoxide dismutase (SOD) activity in gills and mantle of blue mussel and the concentration of petroleum hydrocarbon in organism under different exposure concentration of heavy and light crude oil. Results showed that CAT and SOD activity changed obviously with the exposure concentration and exposure time. In the light crude oil treatment group, CAT activity declined with the increase of the concentration, and firstly decreased and then increased with the extension of exposure time. In the heavy crude oil group, CAT activity showed a downward trend after the first rise with the increase of exposure concentration, and showed upward trend after the first fall with the extension of exposure time. SOD activity, in both light and heavy crude oil groups, decreased with the increase of exposure concentration, and enhanced with the extension of exposure time in a certain dose-dependent manner. After 168 h exposure to heavy and light crude oil, a linearly increasing relationship was found between the petroleum hydrocarbon content in blue mussel and the exposure concentration of crude oil. The bioconcentration factor (BCF) decreased with the increase of exposure concentration, and then leveled off eventually. It is proposed that SOD, CAT and BCF in gills and mantle of blue mussels will serve as petroleum pollution biomarkers. The bioaccumulation of petroleum hydrocarbon in blue mussel bodies can be used to determine the source and property of crude oil.