Analysis of Trace Metal Distribution Throughout the Soil Profile in An Acid Mine Drainage-Impacted Ecosystem.

Acid mine drainage (AMD) is well-known as a serious threat to the quality of rivers, streams, and aquatic organisms in Virginia. Many safeguards are in place for active mines, but thousands of long abandoned mines continue to adversely affect the nearby ecosystems. The Contrary Creek stream watershed in Louisa County, Virginia, contains a few abandoned pyrite mines that closed 100 years ago but continue to cause multiple problems, including a decrease in streamwater pH to 3 and a release of excess trace metals. Our recent studies have demonstrated the extent of damage to the surrounding soils as well. This study analyzes the distribution of trace metals both among various soil fractions and throughout the soil profile. Environmental samples were collected from sites along Contrary Creek and analyzed for trace metals, pH, organic matter, phosphorus, and other factors. Soil samples were acid digested to determine total metal content. An adapted sequential extraction procedure was used to differentiate the distribution of metals in soil layers of 0-10 cm, 10-20 cm, 20-30 cm, and 30-40 cm, when possible. The extent of the contamination continues to be discovered, although some factors, such as organic matter levels and pH values, show signs of improvement at certain sites. Now that a real estate company is constructing a new housing development and golf course at the mouth of this contaminated stream, studies such as these may help underscore the level of ongoing remediation required to counteract the AMD impacts in this region.