Arsenic compounds occur naturally in small amounts on land or in water. Humans can be exposed to arsenic through tap water or food. Fish and seafood, for example, can be loaded with arsenic because they absorb it into the water in which they live. Until now, it was believed that this exposure to minimal doses of arsenic had no impact on health. However, a study by the American National Institutes of Health suggests that, even at low doses, arsenic can be carcinogenic. At least in mice.
A large number of lung cancers
For this study, the researchers exposed male mice to doses of arsenic present in drinking water, comparable to that which we drink. However, to their surprise, the mice developed more benign and malignant tumors than the mice that were not exposed. And a large number have developed lung cancer. In female mice, an increase in the number of benign tumors was observed only.
“This study is the first to show the development of tumors in animals exposed to very low levels of arsenic, levels similar to which humans may be exposed,” said Michael Waalkes, lead author of the article and director of the National Toxicology Program laboratory. “These results are unexpected and are a real cause for concern.”
The arsenic present in drinking water comes largely from pesticides and fungicides which were used until the beginning of the 2000s on agricultural lands and which infiltrated the soil and groundwater. According to the criteria of the International Agency for Research on Cancer (IARC), arsenic, inhaled or absorbed by water, has been a proven carcinogen since 1980. It is the source of lung cancer, skin and bladder.
