Current state of the heavy metal pollution, microbial diversity, and bioremediation experiments around the Qixia Mountain lead-zinc mine in Nanjing, China

Abstract

The extraction and processing of ores from lead-zinc mines, coupled with the disposal of tailings, often result in severe environmental contamination that poses significant ecological and public health risks, demanding urgent attention and action. In this study, field investigations and analyses were performed to evaluate the state of heavy metal pollution and microbial diversity in the soil around Qixia Mountain lead-zinc mine in Nanjing, China. The effect of plant-/microorganism-induced mineralization on the remediation of the contaminated soil was studied via pot experiments. Results indicated serious soil pollution around the mine, and dominant bacterial species (e.g. Sphingomonas) in different soil environments exhibited high resistance to heavy metals. Pot experiments showed that amaranth-/Bacillus velezensis-induced mineralization can significantly reduce the heavy metal pollution levels (Nemerow pollution index decreased from 4.5 to about 1.0) in soil. This study reveals the profound impacts of mining activities on soil ecology and human health, providing a theoretical basis for the prevention and control of soil pollution in farmlands surrounding lead-zinc mines.