School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Ecotoxicology and Environmental Remediation Laboratory Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, P.R. China 31 Fukang Road, Nankai District, Tianjin 300191, China.
J Hazard Mater. 2021 Sep 5;417:126016. doi: 10.1016/j.jhazmat.2021.126016. Epub 2021 May 8.
Lead sulfide nanoparticle (nano-PbS) released into environment can cause hazards to human or ecosystem. Nano-PbS potentially undergoes oxidation in the environment, but oxidation mechanism is not understood yet. Herein, oxidation kinetics and products of nano-PbS by ozone (O), hydrogen peroxide (HO) and hydroxyl radical (HO·) in the atmosphere or natural water were investigated. Results show that oxidation process of nano-PbS can be divided into three stages, producing sulfate, ions and oxides of lead in sequence. O or HO·leads to faster release of ionic lead from nano-PbS in the initial stage than HO, but causes significant decrease of ionic lead by transforming divalent lead to tetravalent lead oxides in the second or third stage. Toxicity determined taking Chlorella Vulgaris as an example follows an order of PbO < PbO < nano-PbS < PbO < PbSO. Toxicity of lead particles is mainly determined by sizes influencing cellular uptake and solubility product constant (K) related with dissolution of lead in cells. The results indicate that the toxicity of nano-PbS increases in an initial oxidation stage and decreases in further oxidation stages. This study provides new insights into environmental behavior of nano-PbS and mechanism understandings for assessing ecological risks of nano-PbS.
硫化铅纳米颗粒（nano-PbS）释放到环境中会对人类或生态系统造成危害。nano-PbS 很可能在环境中发生氧化，但氧化机制尚不清楚。本文研究了臭氧 (O)、过氧化氢 (HO) 和羟基自由基 (HO·) 在大气或天然水中对 nano-PbS 的氧化动力学和产物。结果表明，nano-PbS 的氧化过程可分为三个阶段，依次生成硫酸盐、离子和铅氧化物。O 或 HO·在初始阶段导致比 HO 更快地从 nano-PbS 中释放出离子铅，但在第二或第三阶段通过将二价铅转化为四价铅氧化物导致离子铅的显著减少。以普通小球藻为例的毒性测定顺序为 PbO < PbO < nano-PbS < PbO < PbSO。铅颗粒的毒性主要取决于影响细胞摄取的粒径和与细胞内铅溶解有关的溶度积常数 (K)。结果表明，nano-PbS 的毒性在初始氧化阶段增加，在进一步氧化阶段降低。本研究为 nano-PbS 的环境行为提供了新的见解，并为评估 nano-PbS 的生态风险提供了机制理解。
