Linear models for describing relations between sensitive bacterial taxa and ecological risk from heavy metals in soils of coal mines in semi-arid region

Abstract

Soil heavy metal pollution induced by coal production is a significant environmental issue, particularly in semi-arid region, where the ecosystem is vulnerable. The current comprehension of the impacts of heavy metals on soil microbial ecology in the vicinity of coal mines remains insufficient. As the first in-depth study that aimed to establish models for describing relations between the abundance of sensitive bacterial taxa and heavy metals in soils of coal mines in semi-arid region, soil samples were collected from six mines with different production scales (0.6–8.0 × 106 t/year), and analyzed for heavy metals and bacterial communities based on both quantitative PCR and high-throughput sequencing. The potential ecological risk from Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), Lead (Pb), and Zinc (Zn) was assessed, and their relations with the bacterial community in terms of abundance, diversity and structure were quantitatively evaluated. For bacterial abundance, statistically negative correlations with the overall ecological risk from all heavy metals and individual risk from Cr, Cd, and Zn were revealed, whereas, for bacterial diversity, a negative correlation appeared to exist with Zn. Twelve bacterial taxa sensitive to the overall risk and the individual risk from Cr, Cd, and Zn were identified, and twelve linear models were established based on their absolute abundance and the potential ecological risk from heavy metals. Water content and total phosphorus were also found vital in regulating the bacterial community in the soils of coal mines in semi-arid region. The results obtained provide more in-depth and closely relevant information for better management of the environment surrounding the coal mine areas and for realizing sustainable coal production without sacrificing the environment.