Effects of antimony contamination on bioaccumulation and gut bacterial community of earthworm Eisenia fetida

Highlights: • The mortality of earthworms showed an obvious dose-response relationship. • Sb(III) and Sb_exe were the main Sb species in the earthworm gut. • The diversity of bacteria in soil was significantly higher than that in earthworm gut. • Sb(III) had the greatest effect on the bacterial communities of earthworm gut. • The soil bacterial communities were indirectly affected by toxicity of Sb to earthworms. Antimony (Sb) contamination has brought great environmental problems to the surrounding soils. However, few studies focused on the response of bacterial communities in earthworm gut to Sb. Eisenia fetida was cultured in four soils with Sb contents (5,25,50,100 mg• kg⁻¹) to investigate the distribution of Sb species in earthworm gut and the response mechanism of bacterial communities to Sb contamination. The results showed that Sb accumulated in the gut and tissues of earthworms, and the mortality of earthworms showed a dose-response relationship with the increase of Sb content. Sb(III) and Sb_exe were the major species in gut, whereas Sb(V) and Sb_srp were predominant in surrounding soil. There were significant differences in bacterial diversity between earthworm gut and soil, but there was no significant between the two with different Sb content. The network constructed by gut bacterial community of earthworm was less stable and more sensitive to Sb species than that in soil. Sb(III) had the greatest influence on the gut bacterial community of earthworm, which not only directly affected the community through Xanthomonadaceae, Rhodomicrobiaceae and Anaerolineaceae, but also indirectly influenced through Chthoniobacteraceae. This study fills a research gap on the effect of Sb contamination on the gut bacterial community of earthworm.