Effects of Humic Substances on Attenuation of Metals: Bioavailability and Mobility in Soil
Soil organic matter plays a critical role in trace element behavior. It can decrease the mobility and bioavailability (hence, increase attenuation) of elements by sorption, chelation, and sequestration. Different forms of soil organic matter can also decrease trace element attenuation by soils, enhancing transport of elements into the solution phase or, by keeping them bound in solution, preventing sorption of elements onto the solid phase. The inclusion of organic substances in assessments of the environmental risk from contaminant trace elements is essential, though rarely done. This is due to a current lack of understanding of the structure of these molecules, and how this structure inﬂuences element behavior.