Mine waste water can cause major health problems across the developing nations. When local water supply is polluted then the consequences can dire. However with a little help from bacteria it is possible to make mine water safe to drink. Research has shown that dissolved zinc can be turned into solid form with bacteria.
Understanding the role that bacteria play in wetlands can greatly improve their efficiency in removing the pollutants that can cause problems further downstream. The research showed that bacteria can lock up pollutants into zinc sulfide crystals – sphalerite – to such an extent that contaminated water could meet drinking water standards.
The bacteria used in the research was collected from a flooded mine tunnel in Tennyson and were found to be a member of the Desulfobacteriaceae family. This bacteria was found to grow microscopic spheres of sphalerite on which a biofilm grew. These spheres can hold zinc up to a million times more concentration of the surrounding water and could even lock up small amounts of arsenic and selenium.
While many species of bacteria that thrive in mine waste water do not like oxygen there are some species that thrive in low levels of oxygenated water and this is important for efficient sulphide precipitation. That will allow effective removal of contaminants is groundwater and wetlands.
As mineral exploitation moves in to areas that are vulnerable to pollution then the use of biological methods to control mine waste water is essential to protect local populations and wildlife as well. Mining for minerals in nature reserves or deep in the heart of unspoilt wilderness is increasing and methods need to be developed to reduce the impacts on the environment.
