Effects of heavy metals and environmental variables on soil microbial communities in different land-use types of Yellow River Delta (YRD), China

Comprehensive assessment of heavy metals and environmental factors on soil bacterial communities in YRD are still limited. In this study, the heavy metals and bacterial community compositions of soil samples from different land use types in YRD were analyzed. The EF, I_geo and PLI assessment results indicated that severe heavy metal pollution was observed in crude oil contaminated soil samples. Moreover, the highest bacterial community richness was observed in soil samples of cotton field, while the richness was lowest for soils around a chemical factory. The bacterial community composition and structure were different among different land use types in YRD, which was consistent with beta-diversity indices. Results showed that the dominant bacterial phyla in YRD soils were Proteobacteria, Chloroflexi, Actinobacteria and Acidobacteria. Redundancy analysis (RDA) showed that the nutrients (SOM, TC, TN and TK) and heavy metals (Cd, Zn, Cu and As) had important effects on soil bacterial communities. Furthermore, the resistant bacteria strains may have great potential for remediation of contaminated soils. Therefore, the present study contributes to a deeper insight into the crucial influencing factors on bacterial community structure in soil samples of YRD, which may provide early warnings of environmental pollution and ecological destruction of ecosystems.