Continuing Acid Mine Drainage Impacts On the Environmental Health of the Soils, Streams, and Macroinvertebrates In a Virginia Ecosystem.

Acid mine drainage (AMD) continues to affect the 8-km long Contrary Creek, a minor tributary of the York River in the Chesapeake Bay watershed, located in Louisa County, Virginia, although the pyrite mines closed in the 1920s. The land is now in private hands and sits unused and unmonitored. A few follow-up studies, as well as our research, showed that remediation from the 1970s has had mixed success. The pH values and dissolved metal concentrations of Contrary Creek waters have not greatly improved. This is the first study, however, to look at the impacts of the AMD on the surrounding ecosystem as a whole.

Soil samples along transects from the Creek and its tributaries were collected. Streamwater and sediment samples in the main creek and several tributaries were also collected and analyzed. All environmental samples were analyzed for pH, organic content, and metal concentrations. Summary surveys of macroinvertebrate and plant populations of Contrary Creek, its tributaries, and the nearby land were completed as indicators of ecosystem health. Macroinvertebrates were also analyzed for metal content and possible bioaccumulation.

Results show that the AMD effects extend further than expected. There is still significant contamination of the soils with little sign of recovery. Even soils near the “cleaner” tributary and soils 40 meters from the creek show substantial AMD effects, with low pH (< 5) and high trace metal concentrations at all sites. Bioaccumulation of some metals was detected in the macroinvertebrates that do survive here. In conclusion, the Contrary Creek ecosystem remains adversely impacted by AMD, although some parts of this ecosystem, mainly tributary streamwaters, show improvement.