Levels of Arsenic in Water

by Angela Schnaubelt

Overview

Arsenic is toxic.

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Arsenic is toxic to the human body in high amounts. Water can contain varying amounts of arsenic, which is tasteless, odorless and colorless.
Levels

The arsenic rule has been hotly debated for decades by lawmakers and scientists. The current allowable level by the U.S. Environmental Protection Agency was reduced from 50 ppb (parts per billion) to 10 ppb in 2002.

Sources

Inorganic arsenic found in water mainly comes from the natural breakdown of minerals from weathered rocks and soils. Organic arsenic can also pollute the groundwater from pesticides and wood treatments leaching into the ground.
Health Risks

High levels of arsenic cause death. Ingesting it over a long period of time has been linked to several kinds of cancer, and arsenic is classified as a known carcinogen. Even low levels of the inorganic substance have been linked to Type 2 diabetes. Low to moderate levels of arsenic ingestion have been attributed to a "large number of non-carcinogenic effects," according to the U.S. EPA.
Removal

Simple carbon filters do not remove arsenic from water, nor does ultraviolet light. The reverse osmosis technologies that use a thin film composite for the membrane are capable of removing even trace amounts of arsenic.
Geography

Arsenic is found in private wells in the highest amounts in the western United States, in western Minnesota and the eastern Dakotas, and in southern Texas.
Testing

Most counties in the U.S. offer testing for free or for less than $20. Call the Department of Health in your county to find out how you can get your private well tested. Municipal water is treated at a water treatment plant, and it is tested frequently for arsenic. These levels are then required to be reported to the public in an annual consumer confidence report, also known as a water quality report.