HUMAN AND ECOLOGICAL HEALTH IMPACTS FROM CENTURY-LONG METAL MINING IN CENTRAL UNITED STATES

The presentation addresses the impacts on human and ecological health caused by century-old mining and smelting activities that had occurred in the Tri-State Mining District (TSMD) in the U.S. Midwest. This region had been a prolific producer of lead and zinc for over a century, producing an estimated 23 million tons of zinc concentrates and 4 million tons of lead concentrates. Like many other mining and smelting operations of this time period, careless management and disposal of hazardous mine and smelter wastes has yielded a legacy of contaminated sites in the region that have adversely impacted human, animal, and plant health in addition to serious degradation of water quality, and excessive heavy metal contamination of land including residential yards.

Preliminary sampling of soil and water revealed high concentrations of lead and other toxic metals in TSMD. Compared to the estimated pre-mining cadmium, lead and zinc concentrations of 0.6, 20, and 100 ppm respectively, the post-mining levels of up to 460, 7,400, and 45,000 ppm were found in streambed sediment and residential soils exhibited a maximum lead concentration of 10,000 ppm in Galena, Kansas at the Cherokee County Superfund Site. Further testing revealed high levels of lead in the residents particularly the children with venous blood lead levels of up to 25.5 micrograms per deciliter (µg/dl) in Galena, Kansas.

Remediation measures included provision of bottled water to users of lead-contaminated wells, installation of permanent water supply systems, and the remediation of mining wastes and metals-impacted residential yard soils.

Besides humans, toxic metals were found in animals and plants. Canada geese were found to suffer from adverse health effects due to lead and zinc poisoning, with organ lead and zinc concentrations much higher than at uncontaminated control sites. Horses, particularly foals, near mines and smelters, where zinc concentration ranged from 1,300 ppm to 20,000 ppm, were more susceptible to zinc poisoning that resulted in lameness, enlarged joints, twisted legs, body sores, rough ,coat, etc. Impacts to macroinvertebrates, fish, mussels, wild birds, and other plant and animal species have also been demonstrated at the Tri-State Mining District.