Microorganisms can change the existing state of heavy metal chromium ions in the environment, enhance the toxicity of chemicals and cause serious environmental problems, and can also enrich and accumulate heavy metals through the food chain. On the other hand, microorganisms can also remove heavy metals in the environment directly and indirectly, which is helpful to improve the environment.

The role of microorganisms:

The role of microorganisms is not limited to AMD in mines, but also reflected in ACD (Acid Rock Drainage) on the earth's surface. First of all, crustal uplift promotes continental weathering, and the existence of microorganisms will accelerate the cycle of Fe, S, C, N, etc. Secondly, microorganisms are also looking for geological records of biological origin and great oxidation events (3.4 GA); It is also an important way for heavy metals to enter the ecosystem.