The Dirt on Contaminated Soil
You may not think about soil except for when you need to clean it off your clothes, sweep it off the floor, or wash it off your kids. But some soil’s trouble can be much more than just cosmetic.
Soil contaminated with heavy metals such as lead and arsenic can pose a public health risk, especially for children who might play, and inadvertently swallow it. If ingested in enough quantities, heavy metals such as lead and arsenic can lead to a variety of serious health effects.
But how do environmental managers and public health officials know when soil exposure is a health risk? Researchers at the U.S. Environmental Protection Agency are working to answer just that question.
Under current protocols, soils are tested for lead and arsenic content where contamination is suspected. That’s the easy part. While it is a relatively straight forward process to identify elevated levels of heavy metals, determining when levels pose a health risk is much more of a challenge.
EPA researchers are conducting laboratory and field research to estimate how much lead and arsenic humans are exposed to in soil and when these heavy metals are likely to be absorbed into the body after being ingested, a term scientists call “bioavailability.” Some soils can bind up contaminants, preventing them from dissolving or being absorbed, which reduces the exposure risk. Others contaminants are more readily available for absorption.
The research will help environmental managers identify those contaminated sites that pose the highest risk to public health so they can be targeted for clean up.
“This research project brings together a diverse group of environmental researchers with various scientific backgrounds and developers of environmental technologies in the federal government to address the complex issue of the bioavailability of contaminated soils to humans,” said Karen Bradham, Ph.D., research physical scientist in EPA. The project is funded by the Strategic Environmental Research and Development Program (SERDP) a collaboration with EPA’s Land Research Program, U.S. Department of Energy and U.S. Department of Defense.