Abstract: Heavy metals in soil have the characteristics of persistent accumulation, high toxicity, and difficult to migrate. The fraction transformation is an important process influencing the toxicity and migration of heavy metals. It could be harmful to human health if heavy metals transferred into crops, water and atmosphere. Under anaerobic conditions, the existence of abundant iron and microbial Fe(III) dissimilatory reduction in soils provide favorable conditions for the formation of secondary iron minerals with different crystalline forms in the natural environment. Secondary iron minerals induced by microorganisms have unique morphology and characteristics, including nanoparticles, high surface area, and high reactivity, which play important roles in the transformation of soil heavy metals. In this review, we summarized the impacts of secondary iron mineralization driven by ironreducing bacteria on the transformation of heavy metals in soils. The secondary iron mineralization directly influences the fate of heavy metals. Thus, better understanding of the mechanisms is fundamental to its application in bioremediation.

Key words: digestive enzyme., antibiotics, combined toxicity, earthworm, heavy metal