About the author: Ganga Hettiarachchi is soil and environmental sciences professor for Kansas State University. Hettiarachchi can be reached at [email protected].
In late August 2016, a New York Times report highlighted a case of soil lead contamination in Calumet, Ill., with levels 300 times greater than U.S. Environmental Protection Agency (EPA) standards. Calumet is not the only community faced with such contamination. Ganga Hettiarachchi, soil and environmental chemistry professor for Kansas State University, spoke with SWS Associate Editor Bob Crossen about soil contamination's prevalence in the U.S.
Bob Crossen: How does location dictate which contaminants are found in soil?
Ganga Hettiarachchi: Whether it is natural or anthropogenic, location dictates which contaminants are found. Due to geogenic reasons, in some regions of the U.S. or elsewhere in the world, concentrations of certain naturally occurring compounds may be higher than those in other areas. For example, typical levels of arsenic in the soils of some areas of Kansas can exceed recommended values, but it is due to natural reasons. On the other hand, the former use of a property dictates what potential anthropogenic soil contaminants [are] associated with a specific location.
Crossen: Why is lead commonly found in urban soil?
Hettiarachchi: A significant amount of anthropogenic lead in the environment is due to leaded gasoline and lead-based paint usage in the past. Lead-based paint was banned in the U.S. for household use in 1978. In 1986, leaded gasoline was banned in the U.S. Its use is phased out in many developing countries as well now. Out of those two most common sources, leaded gasoline has caused widespread increases in background levels of lead in urban areas. Lead has been identified as the second [most common] major hazardous substance at Superfund sites currently on the U.S. EPA’s National Priorities List.
Crossen: How prevalent is soil contamination in the U.S.?
Hettiarachchi: Quite prevalent. As of Oct. 3, 2016, there are 1,337 sites on the National Priorities List. Additionally, we have about 450,000 brownfields in the U.S. Brownfields are everywhere—every community, large or small, rural or urban, has them.
Crossen: What steps can be taken to mitigate or prevent contamination?
Hettiarachchi: First, we do need to understand what the sources causing contamination are and then try our best to manage and reduce that contamination. For example, if ... indoor dust is [continuously] found to be carrying contaminants, care should be taken to minimize that. This may involve repainting the home, establishing grass cover around the home, frequent vacuuming and cleaning toys, not tracking dust/contaminated soils home, etc.
Crossen: What recourse do communities have when contamination is revealed?
Hettiarachchi: They can contact their county extension agent, who usually is an excellent person to contact with questions. Their state agency and/or their regional EPA office may even perform soil sampling via the Targeted Brownfield Assessments program. They may also ask their local health department.
