Nanoscale zero-valent iron changes microbial co-occurrence pattern in pentachlorophenol-contaminated soil

Abstract

Nanoscale zero-valent iron (nZVI) is a prominent nanomaterial for the remediation of organochlorine-contaminated soil and groundwater. However, a knowledge gap regarding the effects of the coexistence of nZVI and pollutants on soil microorganisms remains. 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 soils. The addition of nZVI (1000 mg/kg) had no obvious recovery effect on the microbial community structure of PCP-contaminated soil, but enhanced the connection and lowered the modularity of the microbial network. These changes were mainly present in the bacterial network rather than in the fungal or archaeal network. Moreover, the addition of nZVI increased the number of keystone taxa in the PCP-contaminated soil from 29 to 76. These keystone taxa are related to the degradation of organochlorine pollutants, carbon metabolism, and nitrogen metabolism and may thus be helpful in recovering soil ecological functions. These findings provide new insights into the interaction among nanomaterials, microorganisms, and pollutants.