Elemental contaminants monitoring at Ozark National Scenic Riverways

Williams, Michael H.

The Ozark Plateau is highly mineralized and contains economically significant lead-zinc deposits discovered by early French explorers. These and subsequently discovered deposits have been exploited at varying levels of intensity since the early 1700s. Ambient concentrations of elemental metals (cadmium, cobalt, lead, nickel, lead, zinc) in the Ozark Plateau from a??naturala?? sources have been augmented by releases from mining and ore processing activities. Karst features such as sinkholes, conduits, and springs within the area facilitate transport of mining-associated contaminants from runoff and discharges. Blue Spring, an important feature on the Current River within the park, has been contaminated by mine tailings that originate in the Black River surface watershed. The metals travel to the spring through its underground recharge system. Although lead does not accumulate to high concentrations in organisms, effects including biochemical responses to lead in fish and altered benthic fish and macro-invertebrate community composition have been associated with the release of metals from nearby lead belts. As such, park managers need to define and track concentrations of contaminant metals and possibly other potentially toxic elemental contaminants within the park, for both human health and ecological concerns. These needs may become more acute if additional economically significant lead-zinc deposits are located and exploited.