Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; Institute of Environmental Processes and Pollution Control, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China.
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Sci Total Environ. 2022 Dec 1;850:157972. doi: 10.1016/j.scitotenv.2022.157972. Epub 2022 Aug 11.
Diverse lead (Pb) particles possess different ecological risks not only due to their own toxicity differences but also because of different abilities to release toxic dissolved Pb. Dissolved organic matter (DOM) was a key factor influencing dissolution processes of metal particles. However, impacts of DOM on dissolution of different Pb nano- or submicron particles were not known yet. Herein, impacts of DOM on dissolution kinetics of lead sulfide (PbS), lead sulfate (PbSO), lead monoxide (PbO), lead tetroxide (PbO) and lead dioxide (PbO) nano- or submicron particles were firstly investigated taking Pahokee Peat humic acid (PPHA) as an example. Results indicated PPHA improved the suspending stability of Pb particles through electrostatic repulsion, and enhanced releases of dissolved Pb. Final concentration of dissolved Pb was raised by 1.22-8.82 times with PPHA. This was attributed to ligand exchange interactions between PPHA and Pb particles. Theoretical computations indicated that not only sorption or ligand exchange energy, but also numbers of ligands on the surface of particles were key factors governing impacts of PPHA on dissolved Pb. This study provided a new mechanism insight into dissolution behavior of various Pb particles and will be beneficial to their ecological risk assessment.
不同形态的铅（Pb）颗粒由于其自身毒性的差异以及释放有毒溶解态 Pb 的能力不同，具有不同的生态风险。溶解态有机质（DOM）是影响金属颗粒溶解过程的关键因素。然而，DOM 对不同 Pb 纳米或亚微米颗粒溶解的影响尚不清楚。本文以帕霍基泥炭腐殖酸（PPHA）为例，首次研究了 DOM 对硫化铅（PbS）、硫酸铅（PbSO）、氧化铅（PbO）、四氧化三铅（PbO）和二氧化铅（PbO）纳米或亚微米颗粒溶解动力学的影响。结果表明，PPHA 通过静电排斥作用提高了 Pb 颗粒的悬浮稳定性，并促进了溶解态 Pb 的释放。与没有添加 PPHA 相比，添加 PPHA 后溶解态 Pb 的最终浓度提高了 1.22-8.82 倍。这归因于 PPHA 与 Pb 颗粒之间的配体交换相互作用。理论计算表明，不仅是吸附或配体交换能，而且是颗粒表面配体的数量也是控制 PPHA 对溶解态 Pb 影响的关键因素。本研究为各种 Pb 颗粒的溶解行为提供了新的机制见解，将有助于对其生态风险进行评估。
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