Arsenic

What is arsenic?

Arsenic is a gray, brittle, metal-like substance that is a natural part of the earth's soil and rocks. Arsenic compounds are present in many kinds of rocks, especially in ores that contain copper or lead. Arsenic levels in soil vary from one part arsenic per million parts soil (ppm) up to about 100 ppm. It can be released into the environment by natural sources such as erosion from mineral deposits and volcanic eruptions. Arsenic is found in water, both above-ground and underground. Arsenic is released into the air as dust from the soil.

Approximately half of the arsenic released to the air comes from soil dust. The other half comes from human activity such as industrial processes. Roughly 75% of human-induced arsenic emissions result from metal processing (such as copper smelting).

Human activities can release arsenic into the soil, air, and water.

• Soil releases: Industrial processes account for nearly 95% of all arsenic released into land. Arsenic is also released into the soil as a result of pesticide application, solid waste disposal, and sewage sludge.
• Air releases: About half of the arsenic released into the air (about 8,500 tons each year) comes from natural sources like volcanic eruptions and forest fires. Airborne arsenic releases also come from various industrial processes, agricultural products (such as pesticides), and electricity production.
• Water releases: Most of the arsenic released into the water results from natural, weather-related processes. The remainder is discharged from industrial facilities, leached from landfills, and released from urban runoff.

How is arsenic used?

The main use of arsenic today is as a wood preservative. Arsenic is also used in the production of agricultural products such as insecticides, herbicides, algicides, and fertilizers. Small amounts of arsenic are used in the production of glass, metals, and electronics. Also, arsenic compounds are used to treat severe parasitic diseases.

Arsenic used in pesticides like rat and ant poison has been banned due to human health concerns in production, use, and accidental poisoning.

Do electric utilities release arsenic into the environment?

Yes. Small amounts of arsenic are naturally present in coal or oil, which are used to generate electricity. When coal and oil are burned, ash is produced which contains most of this naturally occurring arsenic. About 99% of the ash is captured for disposal or for recycling into commercial products. EPA does not consider fly ash to be hazardous.

Electric utilities in the U.S. actually release less than 1% of all manmade arsenic emissions in the world.

How could arsenic affect me?

Arsenic’s low-level presence in the environment and routine arsenic releases discussed here are too low to cause significant health effects. EPA acknowledges that low levels of arsenic will be present in soil, food, water, and air regardless of whether it is produced by human activities. Interestingly, very small amounts of arsenic in people’s diets may actually improve health.

People with occupations that involve arsenic production or use (such as copper or lead smelting, wood treatment, or pesticide application) can be exposed to above average levels of arsenic. Research has found some relationship between long-term arsenic inhalation and cancer.

What does EPA say?

The U.S. Environmental Protection Agency (EPA) acknowledges that arsenic is a naturally occurring substance that will always be present in the environment. Nonetheless, EPA monitors the amount of arsenic in drinking water and has acted to curb manmade arsenic releases by curtailing the use of arsenic in pesticides.

EPA has evaluated the relationship between cancer and breathing arsenic for people living near power plants. The evaluation determined that the cancer risk related to airborne arsenic near power plants is very low.

Where can I get more information?

• Electric Power Research Institute, 3412 Hillview Ave., P.O. Box 10412, Palo Alto, California 94303; phone (650)855-2000.
  
  
• Integrated Risk Information System, U.S. Environmental Protection Agency.
  
  
• Office of Compliance Sector Notebook Project, Profile of the Fossil Fuel Electric Power Generation Industry, U.S. Environmental Protection Agency, Office of Enforcement & Compliance Assurance, 1997.
  
  
• Statistical Abstract of the United States 1997, The National Data Book, U.S. Department of Commerce, Economics & Statistics Administration, Bureau of Census, 1997.
  
  
• Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units - Final Report to Congress, Volume 1 and 2, U.S. Environmental Protection Agency, 1998.
  
  
• Toxicological Profile for Arsenic Compounds, U.S. Department of Health & Human Services, Public Health Service, Agency for Toxic Substances & Disease Registry, 1993.