METALS ANALYSIS AS A TOOL FOR UNDERSTANDING HEADWATER HEALTH AND STREAM PROCESSES IN THE SOUTHERN APPALACHIAN COAL REGION: AN EXPLORATORY ANALYSIS

Major and trace metal analysis was applied to four coal-country headwater streams to better understand the fate of metals in headwater streams affected by mining over time and to determine headwater health. The study watersheds were located in southeastern Kentucky and consisted of an active mine site, a site mined prior to the passage of the Surface Mine Control and Reclamation Act of 1977 (SMCRA), a post-SMCRA reclaimed mine site, and an undisturbed forest control site. Dissolved water metals and suspended sediment metals were sampled at each source, middle, and outlet. Samples were analyzed on an ICP-OES, and spatial trends were examined. In general, metals concentrations decreased from upstream to downstream, but there were a few outliers—likely associated with localized land use and tributary inputs Total organic sediment carbon and total sediment nitrogen were positively correlated with many of the metals, suggesting a relationship with in-stream processes.

A discriminant analysis was used to determine whether the metals signatures of the watersheds were distinctly different. When both water and sediment samples were used, 77% of the samples were assigned to the correct watershed. When either the water samples alone or the sediment samples alone were used, 100% of the samples were assigned to the correct watershed. These findings suggest that, when using metals to evaluate stream health, it is important to look at water and sediment samples separately since they reveal different aspects of metals fate and transport in headwater streams.

Both dissolved metals concentrations and sediment metals concentrations were high in the post-SMCRA and actively mined watersheds. The highest water concentrations were in the post-SMRCA watershed—also the only watershed with significant residential activity. The control and pre-SMCRA watersheds both had low dissolved metals concentrations, but the sediment concentrations remained high in the pre-SMCRA site. This suggests that some metals may flush out of the water column, but that they may remain in sediments at high levels for many years after reclamation.

Future research should include more sample sites and seasonal sampling to account for temporal variation, and also deep bed sediment sampling to better characterize the fate of metals in these systems.