Hello everyone!
In the last series of posts, I have been focusing on groundwater pollution, its remediation, and its effects on biodiversity. Moving on from that, I would now like to talk about surface water pollution caused by Acid Mine Drainage (AMD).
What is AMD?:
AMD refers to the outflow of acidic water from abandoned mining sites or currently active ones. It is a major problem with many hard rock mines, which is the excavation of hard minerals, and including almost all mines where the metal ore is bound up with sulfur (metal sulfide mines). A large number of coal mines also suffer from acid mine drainage (Coil et al., 2014).
How does it occur?:
In most situations, this acid comes primarily from oxidation of iron sulfide (FeS2, also known as pyrite or “fool’s gold”) thus forming sulfuric acid and dissolved iron (Coil et al., 2014). Pyrite is also known as “fool’s gold” as its outer exterior resembles that of gold fooling the untrained eyes thinking that it is gold, as seen in the picture below (The Editors of Encyclopaedia Britannica, 2019). Those who were trick would end up mining for these ‘gold’ with no value. Pyrite is also found in conjunction with other valuable metals thus these potentially toxic ores are constantly exposed through mining activities.
The acid runoff further dissolves metals such as copper, lead, mercury into the ground, or surface water (Environmental Protection Agency, n.d.). Acid mine drainage is often encouraged by a biological feedback loop. Once acid mine drainage starts certain microbes that prefer the acidic environment will thrive. These microbes will increase the production of sulfuric acid from the surrounding, further poisoning the downstream environment for other organisms (Coil et al., 2014).
Some Problems Associated with AMD (Environmental Protection Agency, n.d.):
- Contamination of drinking water
- Disrupted growth and reproduction of aquatic plants and animals downstream
- Infrastructure such as bridges being corroded
- Economic cost
This is a short introductory post which I hope gave everyone a better idea of what AMD. In my next post, we will explore more about the ecological effects of AMD.
That brings me to the end of this post.
See you guys soon!
References
Coil, D., McKittrick, E., Mattox, A., Hoagland, N., Higman, B., & Zamzow, K. (2014, October 29). Acid Mine Drainage. Retrieved September 25, 2020, from http://www.groundtruthtrekking.org/Issues/MetalsMining/AcidMineDrainage.html
Environmental Protection Agency. (n.d.). What is Acid Mine Drainage [Brochure]. US: Author. Retrieved September 25, 2020, from http://www.sosbluewaters.org/epa-what-is-acid-mine-drainage%5B1%5D.pdf
The Editors of Encyclopaedia Britannica. (2019, July 29). Pyrite. Retrieved September 25, 2020, from https://www.britannica.com/science/pyrite
