What exactly is arsenic?

Arsenic is a metallic element notorious for its toxicity.

It can cause skin, lung and bladder cancer in people. It also may have links to high blood pressure, diabetes and other health problems. It can accumulate in a body over time if a person is repeatedly exposed.

Although a legendary favorite of poisoners, many people are exposed by environmental factors such as pollutants or water containing naturally dissolved arsenic.

According to the U.S. Geologi-cal Survey fact sheet on arsenic in the Cook Inlet basin, certain geologic features are associated with high arsenic levels.

"Abundant mineral resources, recent glaciation and volcanic activity contribute to the widespread distribution of arsenic in the environment," the report said.

Arsenic occurs naturally in the ground and gets into water by leaching. It is more likely to appear in ground water in association with rust, coal, alkaline water and other chemical factors.

"The addition of arsenic to water in the Cook Inlet Basin by humans is minimal," it said.

Statewide, Alaskans have had arsenic problems in "hot spots" such as Ester Dome near Fairbanks and the Sand Lake area of Anchorage in addition to the Kenai Peninsula.

Nationwide, background levels tend to be low in the eastern states and concentrated in the west.