Dust sample testing in California is showing arsenic levels as high as 460,000 times over what the federal government says is safe, according to the Associated Press (AP). Not new news, as last year, the Geological Society of America (GSA) said that soil and groundwater contamination by arsenic at some former Mother Lode Gold Belt mines in northeast-central California had become an issue of concern over residential areas developing onto old mined areas.
An Environmental Protection Agency grant project was recently awarded to California Department of Toxic Substances Control to conduct “Research to Advance the Science of Characterizing Arsenic at Mine-Scarred Land Sites.” The project overview discuses the major threat to health and the environment posed by mine-scarred lands in California. According to the project. the California Department of Conservation has identified 47,000 abandoned mines in that state that present a threat to human health and the environment from arsenic, mercury, and other heavy metals, as well as from acid mine drainage and physical hazards. The AP notes that experts are concerned over arsenic particles being spread by winds and note the many gold and silver mines in the 150 miles northeast of Los Angeles as well as the estimated 500,000 abandoned mines nationwide.
The GSA says arsenic has been linked with Mother Lode-type gold ore deposits because the mines, in an attempt to recover gold, used chlorination or cyanide leaching which allowed large arsenic amounts—called tailings—to be leaked into streams and rivers. Farmers lobbied early in the last century for legislative relief, but mine owner agreements to impound the tailings left many owners simply leaving the tailings at the mines, which mostly closed by the late 1950s.
Arsenic in tailings, soil, and groundwater surrounding these mines has caused considerable legal issues and lawsuits by State and Federal agencies, and remediation and litigation of arsenic-impacted areas from tailings has been expensive, said the GSA. The AP noted that in a federal audit released this summer, it concluded that the “problem was not being effectively dealt with by the Bureau of Land Management” and last year, auditors located contaminated mine waste in residents’ backyards as well as arsenic-contaminated trails used by what it described as thousands of off-road bikers.
The Centers for Disease Control and Prevention (CDC) notes that arsenic cannot be destroyed in the environment and the chemical accumulates in fish and shellfish. Exposure in humans occurs by ingesting arsenic and breathing in arsenic-tainted dust. High doses can result in death, but at lower levels, arsenic can cause nausea and vomiting, decreased production of red and white blood cells, abnormal heart rhythm, damage to blood vessels, and a sensation of “pins and needles” in hands and feet.
Over long periods, inorganic arsenic can darken the skin and cause small “corns” or “warts” on the palms, soles, and torso; skin contact may cause redness and swelling. Several reputable studies have linked arsenic with skin cancer and cancer in the liver, bladder, and lungs and inhalation can cause increased risk of lung cancer; lower IQ scores in children; increased mortality in young adults when exposed in utero; problems in pregnancy and in the fetus, such as low birth weight, fetal malformations, and fetal death.
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