by Andreas Saldivar & Vicki Soto
Arsenic is an element found in nature in rocks, soils, water and air—in fact, it is one of the most common elements on earth. While arsenic has been used historically in industry in fertilizers and preservatives, it is probably best known as a poison, toxic to humans who ingest it. Large doses are fatal relatively quickly, while smaller doses over time can cause diseases such as several types of cancer and skin disorders. Arsenic can become an environmental hazard when it is "weathered" from local geologic units and enters the groundwater supply. In the world today, many populations are at risk for arsenic poisoning due to exposure from contaminated drinking water.