Nanoscale Zero-Valent Iron Changes Microbial Co-Occurrence Pattern in Pentachlorophenol-Contaminated Soil

Abstract

Nanoscale zero-valent iron (nZVI) is a prominent nanomaterial for remediation of organochlorines-contaminated soil, while the ecological effects of the coexistence of nZVI and pollutants on soil microorganisms remain to be a knowledge gap. Here, we studied the effects of nZVI on the microbial community structure, co-occurrence network, and keystone taxa in pentachlorophenol (PCP, a typical organochlorine pesticide) contaminated soil. The treatment with nZVI (1000 mg/kg) enhanced the connection and lowered the modularity of microbial network in the PCP-contaminated soil. These changes were mainly present in the bacterial and archaeal networks rather than fungal network. Moreover, the addition of nZVI increased the number of keystone taxa in the PCP-contaminated soil from 29 to 76. These keystone taxa were related to the degradation of organochlorine pollutants, carbon metabolism, and nitrogen metabolism, and may thus be helpful for the recovery of soil ecological functions. These findings provide new insight into the interaction among nanomaterials, microorganisms, and pollutants, as well as help to explore novel bioremediation technology synergistically with nanomaterials.

Keywords: Nanomaterials, organochlorine pollutant, Microbial community, Co-occurrence network, keystone taxa