Research Links Arsenic to Tumor Growth

A study from the University of Oklahoma Health Sciences Center indicates that environmental arsenic found in drinking water can stimulate the growth of cancerous tumors and cause them to spread faster.

What the study did not indicate is whether arsenic in drinking water actually causes cancer. The study showed that arsenic increases the growth rate of tumors that are already present.

The researchers used mice which were fed water with elevated levels of arsenic. The mice were then implanted with cancerous tumors. The mice continued to receive arsenic water, and tumor growth was monitored. The researchers found that arsenic increased the growth rate of the tumors and also caused the tumors to spread to the lungs.

The study showed that arsenic levels as low as 4 parts per billion (ppb) stimulated blood vessel growth, which may help tumors grow. Levels as low as 10 ppb caused tumors to increase in size.

The current federal arsenic standard is 50 ppb, and this standard is being lowered to 10 ppb on January 23, 2006. The Environmental Protection Agency will present this study to a congressional subcommittee this coming November.

Although this study did not link arsenic to the development of cancer, arsenic previously has been linked to skin cancer, bladder cancer, lung cancer, liver cancer, kidney cancer, and prostate cancer. The World Health Organization, the Department of Health and Human Services, and the Environmental Protection Agency have determined that inorganic arsenic is a human carcinogen (a cause of cancer). Further studies are being performed by the same group of researchers to determine if elevated arsenic levels increase the risk of developing tumors.

Arsenic is a naturally occurring element widely found in the earth's crust. Inorganic arsenic compounds are mainly used to preserve wood. Organic arsenic compounds are used as pesticides, primarily on cotton plants.

Arsenic exposure can come from many sources. Arsenic exposure may come from eating food, drinking water, or breathing air containing arsenic. Breathing sawdust or burning smoke from wood treated with arsenic can also result in arsenic exposure. Another concerning source of arsenic exposure is living near uncontrolled waste sites containing arsenic or living in areas with unusually high levels of arsenic in the rock. For more information on arsenic, visit The Agency for Toxic Substances and Disease Registry.