Ecological effects of soil properties and metal concentrations on the composition and diversity of microbial communities associated with land use patterns in an electronic waste recycling region

- E-waste recycling activities affected soil microbial communities in fields.
- Microbial community composition was strongly influenced by land use patterns.
- Microbial assemblages were primarily influenced by available P, moisture and mercury.
- Mercury concentration was the key factor regulating microbial community diversity.
- Nitrososphaera, Solibacter, and Nitrospira dominated in e-waste recycling sites.

Soil microbes play vital roles in ecosystem functions, and soil microbial communities may be strongly structured by land use patterns associated with electronic waste (e-waste) recycling activities, which can increase the heavy metal concentration in soils. In this study, a suite of soils from five land use types (paddy field, vegetable field, dry field, forest field, and e-waste recycling site) were collected in Longtang Town, Guangdong Province, South China. Soil physicochemical properties and heavy metal concentrations were measured, and the indigenous microbial assemblages were profiled using 16S rRNA high-throughput sequencing and clone library analyses. The results showed that mercury concentration was positively correlated with both Faith's PD and Chao1 estimates, suggesting that the soil microbial alpha diversity was predominantly regulated by mercury. In addition, redundancy analysis indicated that available phosphorus, soil moisture, and mercury were the three major drivers affecting the microbial assemblages. Overall, the microbial composition was determined primarily by land use patterns, and this study provides a novel insight on the composition and diversity of microbial communities in soils associated with e-waste recycling activities.

Redundancy analyses of microbial data and a subset of eight environmental variables. Paddy field (PAF); vegetable field (VEF); dry field (DRF); forest field (FOF); e-waste recycling site (ERS); reference site (REF); copper (Cu); mercury (Hg); lead (Pb);iron (Fe); moisture content (moisture); total organic carbon (TOC); available phosphorus (AP); ammonium nitrogen (AN).218