【摘要】 纳米铅颗粒是大气细颗粒物的重要组分之一,目前对其植物毒性机制所知甚少。本研究以纳米硫酸铅（nano-PbSO₄）为例,以普通小球藻作为受试生物,通过比较nano-PbSO₄和铅离子(Pb²⁺)对小球藻形貌及生长率的影响,阐明二者毒性效应差异;通过测定nano-PbSO₄在培养基中的Pb²⁺溶出率,探讨其毒性效应机制。结果表明:nano-PbSO₄附着于小球藻表面,使其表面明显凹陷; nano-PbSO₄对普通小球藻生长的抑制率随浓度增大而升高,符合两参数非线性函数Logit模型。相同浓度nano-PbSO₄对小球藻生长的抑制明显低于Pb²⁺,半数效应浓度为后者的4.2倍。Nano-PbSO₄(0.01～1 mmol·L^-1)在培养基中的Pb²⁺溶出率仅为0.31%～0.81%,说明nano-PbSO₄对小球藻毒性效应主要由纳米颗粒的毒性效应导致,溶出的Pb²⁺对毒性的贡献较小。本研究可为纳米Pb污染物的生态风险评价提供参考。更多还原

【Abstract】 Lead nanoparticles are major pollutants adsorbed to atmospheric fine particles. The phytotoxicity of lead nanoparticles is largely unknown. Here,the toxicity of lead nanoparticles to Chlorella vulgaris was investigated by taking lead sulfate nanoparticles（ nano-PbSO₄） as a model. The morphology and growth inhibition of C. vulgaris exposed to nano-PbSO₄ or lead ion( Pb²⁺) were examined to elucidate the toxic effects. The concentration of Pb²⁺in the culture medium containing nano-PbSO₄ was analyzed to probe the toxicity mechanism. The results showed that C. vulgaris cells were sunken and shrunken after being exposed to nano-PbSO₄,with visible nanoparticle aggregation on the surface. The inhibition on the growth of C. vulgaris increased with the increases of nano-PbSO₄ concentration and followed the nonlinear Logit model. The inhibition of nano-PbSO₄ to the growth of C. vulgaris was significantly lower than that of corresponding concentration of Pb²⁺,with the median effective concentration being 4.2 times of that of Pb²⁺. Only0.31%-0.81% of the nano-PbSO₄( 0.01-1 mmol·L^-1) was dissolved into Pb²⁺in the culture medium,indicating that the toxicity of nano-PbSO₄ was mainly attributed to the nano-effects with minor contribution of dissolved Pb²⁺. Our results provide reference for ecological risk assessment of lead nanoparticles.更多还原