State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China.
Environ Sci Technol. 2010 Oct 15;44(20):7846-51. doi: 10.1021/es1024433.
Soil contamination by combinations of heavy metals and organic contaminants has become an increasingly important environmental issue. Effects of heavy metal cations (Cu(2+), Ni(2+), and Pb(2+)) on phenanthrene sorption were systematically investigated using two soils with contrasting physicochemical properties. Spectral and microscopic analyses provide direct evidence for the modification of composition and conformation of dissolved organic carbon (DOC) and hydrophobicity of the interfaces in the presence of metal cations. Parts of rubbery organic carbon (including flexible DOC and humic acids) became condensed on solid surfaces in the presence of heavy metals as evidenced by an increase in the glass transition temperature of the soils. These modifications led to a significant increase in the capacity and nonlinearity of phenanthrene sorption in the soils. As the added metal cations aged for 70 days, the soil solution gradually recovered its original physicochemical properties, and the facilitating effects of the heavy metals on phenanthrene sorption were significantly attenuated. This work highlights the important implications of DOC properties and aging processes of metals in the sorption of hydrophobic organic compounds (HOCs) such as phenanthrene in soils and provides compelling evidence for the facilitating effects of heavy metals on HOC sorption in soils.
土壤中重金属和有机污染物的复合污染已成为一个日益重要的环境问题。本研究采用两种具有不同理化性质的土壤，系统研究了重金属阳离子（Cu(2+)、Ni(2+)和 Pb(2+)）对菲吸附的影响。光谱和微观分析为金属阳离子存在时溶解有机碳（DOC）组成和构象的变化以及界面疏水性提供了直接证据。部分橡胶态有机碳（包括柔性 DOC 和腐殖酸）在重金属存在下凝聚在固体表面上，这可以从土壤玻璃化转变温度的升高得到证明。这些变化导致土壤中菲吸附容量和非线性显著增加。随着添加的金属阳离子老化 70 天，土壤溶液逐渐恢复其原始理化性质，重金属对菲吸附的促进作用显著减弱。这项工作强调了 DOC 性质和金属老化过程在土壤中疏水性有机化合物（如菲）吸附中的重要意义，并为重金属对土壤中 HOC 吸附的促进作用提供了有力证据。
