SUB-PROBLEMS INCLUDING LEADING TO IMPAIRMENT AND BEST PRACTICES FOR POTENTIAL SOURCES OF WATER CONTAMINATION
Some of the factors leading to impairment and their associated Best Practices are discussed in this chapter.
Acid Mine Drainage
Acidic drainage from mines is caused by sulfide minerals which have been exposed to air or water and then seep into groundwater or surface water. The acidic materials are harmful to aquatic ecosystems and humans through direct contact and ingestion of water. There are an estimated 500,000 abandoned mines in the United States with 130 of them either on the National Priorities List or capable of being on it. This contamination covers more than 1 million acres of land. Surface water and groundwater is contaminated from seepage from various mine openings, waste rock, mill t ailings, waste slurries, and waste sludges which have been placed in unlined lagoons.
Best Practices for Acid Mine Drainage (See endnote 5)
- 1. Since remediation of acid mine waste sites is energy intensive, the following should be observed for testing purposes use field kits, low flow samplers, remote sensing, and existing boreholes for sampling; the use of sonic rotary drilling instead of conventional rotary drilling or hammer techniques; the use of phosphate-free detergents instead of organic solvents or acids; and the use of safe drilling fluid or water in a closed loop system. Utilize renewable sources of energy, such as wind energy, and capture and use any energy produced by the consumption of the agricultural and forestry waste products or gases from the site.
- 2. Use passive treating systems for the acid water, containing considerable metals, especially existing chemical and biological processes, such as oxidation/reaeration ponds, limestone beds, and biochemical reactors with agricultural and forestry waste products.
- 3. Capture and sell metals recovered from the biological process.
- 4. Develop extensive stormwater systems to reroute the water from rain or snow crossing the contaminated site.
- 5. Only remove the vegetation which is necessary to gain access to the site and use existing roads where possible.
- 6. When establishing a biochemical reactor, use a geomembrane liner to prevent leakage to the groundwater supply or surface water.
- 7. Install an appropriate soil cover to stabilize the soil and waste piles.
- 8. Integrate the cleanup of the land with restoration and reuse of the site.
The use of water can be limited by the presence of scum, foam, and unnatural water color and taste. Trash including plastics, litter, debris, and other solid wastes from people also cause degradation.