1. Acid Mine Drainage (AMD)

2. Acid Mine Drainage
Outflow of acidic water, usually from abandoned coal mines
Old mine fills up with water
Heavy metals get into the water (pyrite – iron sulfide)
Forms sulfuric acid and dissolved iron
When water comes in contact with air it oxidizes the iron and turns orange

4. AMD in Pa
Pa has relatively high amounts of AMD b/c of the high number of coal mines
Mostly in Western PA
Also in West Virgina, Ohio, etc

5. Effects Lowers pH of the stream – usually ph of 5 or below
Effects growth / reproduction of aquatic plants and aquatic organism (like macroinvertebrates)
Effects fish populations
In drinking water can cause birth defects
Effects recreation and tourism

6. Treatments Active Treatment Passive Treatment
Add basic substances to the water to try to neutralize the acidity
Passive Treatment
Construct wetlands – add neutralized water and allow heavy metals to precipitate out

7. Causes…
AMD occurs when the pyrite iron sulfide from the coal becomes exposed and reacts with both the water from the stream and oxygen, causing dissolved iron and sulfuric acid to form.
The rate and extent to which it forms varies depending on certain bacteria.

8. Effects?
The yellow/orange discoloration in the streams harms ecosystems because it smothers the animal and plant life and increases the pH levels.
Because of the highly toxic levels of acidity, left over metals, and sediments all animal life in the streams die.

9. AMD In Pennsylvania…
Because of all the abandoned coal mines, more than 3,000 miles of streams are contaminated in PA.
It is the most extensive water pollution problem in the four major rivers in PA.
PA loses 67 million a year in treatment of the contaminations.

10. Active Treatment Pros & Cons:
Is a great to raise pH levels and reduce the presence of metals.
Cons:
Lime, soda ash, and ammonia are very expensive to maintain
Disposal of metal loaded waste can be a problem.

11. Passive Treatment
Passive treatment has been used since early 1990’s. It uses a variety of treatment to raise pH levels.

12. Passive Treatment Pros & Cons:
It needs only periodic maintenance
Lower costs than Active Treatment
Cons:
not enough land