The response and ecological implications between various sulfur forms and environmental factors in acid mine drainage

The production of acid mine drainage (AMD) involves oxidation of FeS₂ to SO₄^2-, during which a variety of intermediate sulfur forms (S₂O₃^2-, S⁰, SnO₆^2-, SO₃^2-) are generated. This study aimed to characterize the spatiotemporal distributions of different forms and relationships to environmental factors. The sulfur form in AMD is mainly SO₄^2-, and the metastable sulfur SO₃^2-、S₂O₃^2-、S₄O₆^2- and S^2- have only a small amount of accumulation in the cyclic transformation of sulfur. The concentrations of SO₄^2- and S^2- in the dry season were higher than those in the normal season and the wet season, and SO₃^2-, S₂O₃^2-and S₄O₆^2- were the highest in the wet season. SO₄^2- decreased with increasing migration distance of AMD and showed seasonal variation closely related to precipitation and groundwater flow. The abundance and diversity of microbial community decreased with the production of AMD, mainly acidophilus and sulfur/iron-oxidizing bacteria. Ferrovum occupied an absolute dominant position in weakly acidic samples, and Acidibacter and Sphingomonas were not polluted. Neutral samples mainly include Lachnospiraceae NK4A136 group, Ralstonia and Sinomonas. S^2- is most affected by environmental factors. The lower the pH and the higher the ORP, the more easily S^2- is oxidized. Temperature promotes the generation of substable sulfur, and DO facilitates the conversion of these sulfur intermediate forms to SO₄^2-. Acidithiobacillus and Ralstonia can promote the generation of sulfur forms, especially SO₄^2-, with weak sulfur oxidizing ability. The regulation of sulfur conversion to acid is key for developing strategies for preventing and reversing AMD pollution.