STUDY OF CONTAMINATION RESULTING FROM HISTORICAL MINING WITHIN THE OLD LEAD BELT: MINERAL FORK WATERSHED, 2021-2022

The Old Lead Belt in Missouri has been mined extensively over the past two hundred years, and significant mining operations continue today. Historical mining practices often did not follow modern procedures for environmental protection, and significant soil and water contamination have resulted in some areas. This study focuses on the Mineral Fork watershed in Washington County, Missouri, which includes portions of four separate Superfund sites. In this study, we exam the impact of historical mining on the health of alluvial systems, as evaluated by lead and barium concentrations in the suspended and streambank sediments and surface water samples in tributaries of the Mineral Fork river system. We will also evaluate the health of macroinvertebrate ecosystems in these tributaries. To relate this to historic mining, the concentrations of lead and barite, as well as the biotic index, will be compared to the density of recorded mining operations in the sub-watershed of each tributary. Six sub-watersheds will be evaluated using eight sampling locations within the Mineral Fork watershed. Previous work on suspended and streambank sediment in sub-watersheds in the Mineral Fork watershed showed slight correlation between recorded mining activity and metal concentrations, but this previous work used a smaller number of sampling locations, and sampling occurred for only four months. This work expands upon previous work by increasing the sample resolution (expanding the number of sub-watersheds sampled), extending the study for a longer time period, acquiring surface water samples, and adding macroinvertebrate assessment. Additionally, we will also relate all results (current and previous) to stream discharge rates and precipitation between periods of sample collection. This project is currently active, with ongoing sample collection and analysis.