Toxicity

The Clear Creek and Idaho Springs superfund site, which covers about 400 square-miles, and includes the Argo Mill and tunnel, had large amounts of minerals and elements that were dangerous to to expose to humans, especially in large amounts. In addition, due to the history of mining in the superfund site, these minerals were introduced to Clear Creek, which was a water source for many members of the surrounding communities. In particular, the minerals officials were the most concerned about included zinc, arsenic and lead. Other elements such as cadmium were found in Clear Creek. Overall, the presence of these harmful elements decreased the overall pH level of Clear Creek, thus making it more acidic and unsafe for drinking (Environmental Protection Agency 2007).

More specifically, the detailed adverse effects of zinc, arsenic and lead are detailed below.

Zinc

Although Zinc is naturally found in both ground and surface waters, the initial levels of Zinc found in the Clear Creek superfund site, however, was almost 250% over the natural and safe levels of Zinc found in groundwater. Specifically, there are naturally about 40 micrograms of zinc per liter of water (World Health Organization 1996), but the Environmental Protection Agency found that the Clear Creek site contained 9770 micrograms of zinc per liter of water in 1985. Moreover, after thirty years there were still 7610 micrograms of Zinc per liter of water in 2005, which is still 190% more zinc than the safe amount (Environmental Protection Agency 2005).

As a result these increased levels of zinc can lead to many negative health repercussions such as (World Health Organization 1996):

• The development of different forms of sarcoma, a general term for a cancer that can occur anywhere in the body
  • Development of Prostate Cancer
• Respiratory disorders
• Vomiting
• Diarrhea
• Copper deficiency

Arsenic

Arsenic is a more commonly known element and is often associated with murders and death. Arsenic was initially introduced into Clear Creek through the mine systems. In particular, the ore that was excavated contained arsenic, while the tunnels associated with the Argo mine allowed for the flow of the arsenic containing material to enter Clear Creek. Moreover, the natural levels of arsenic in bodies of water are about 1 to 2 micrograms per liter or water (World Health Organization 2011). The superfund site, however, contained about 10 micrograms of arsenic per liter of water. As a result, the high levels of Arsenic in Clear Creek can lead to illnesses and adverse health effects such as (World Health Organization 2011):

• Cancer
  • Lung cancer
  • Skin cancer
  • Bladder Cancer
• Skin Lesions
• Change in skin pigmentation
• Black-foot disease
• Increased risk for diabetes

Finally, at very high levels, arsenic can also cause death in humans. The levels of arsenic found in the Clear Creek superfund site, however, did not have high enough arsenic levels to cause death.

Lead

Lead is also a more commonly known substance, and is associated with toxicity, especially after its abundant use in the mid-1900s. The recommended level of lead in water is zero due to the severe toxic nature of lead, even at low levels. In addition, lead can accumulate in the body over time and prolonged exposure, thus the effects can also become more severe. The levels of lead in the Clear Creek superfund site, however reached up to 91 micrograms per liter of water in 1985 (Environmental Protection Agency 2005). In addition, as recent as 2005, there were still 16 micrograms per liter of water found in Clear Creek. As a result, these high levels of lead contamination can lead to health effects such as (Environmental Protection Agency 2021):

• Decreased kidney functions
• Cardiovascular illnesses
• Reproductive difficulties

In addition, in children and pregnant mothers, lead can lead to:

• Anemia
• Premature birth
• Lower IQ

Figures and diagrams derived from:

Zinc: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872358/

Arsenic: https://www.researchgate.net/figure/Health-effects-associated-with-chronic-exposure-to-inorganic-arsenic-from-contaminated_fig1_313448493

Lead: https://www.businessinsider.com/lead-health-child-flint-michigan-body-pollution-water-2016-3