MINNESOTA—Advances in the use of trees to decontaminate water moving through and possibly off landfills—an environmental approach to landfill clean-up called phytoremediation—have mostly focused on tree breeding, selection and placement. New research by scientists with the Northern Research Station and the University of Missouri focuses instead on landfill contaminants and demonstrates a new tool for prioritizing contaminants based on toxicity.

Researchers combined multiple sources of data to develop the pollutant prioritization tool. Elizabeth Rogers, a USDA Pathways intern with the Forest Service’s Northern Research Station and a doctoral student at the University of Missouri, is the lead author of a new study describing the prioritization tool, “A systematic approach for prioritizing landfill pollutants based on toxicity: Applications and opportunities,” available through the Northern Research Station.

“Thousands of contaminants can be present in landfill leachate, and contamination can vary by location and over time, so it can be difficult to determine what needs to be, or even can be targeted with environmental remediation,” Rogers said. “This tool allows site managers to prioritize the most hazardous contaminants or customize the tool to address local concerns.”

Knowing which contaminants are the most hazardous allows scientists like Ron Zalesny Jr., a supervisory research plant geneticist with the Northern Research Station and a co-author on the study, to better match trees and tree placement in landfills. “Phytoremediation research has focused on discovering which trees work best in particular soils and sites,” Zalesny said. “The ability to home in on specific contaminants will enhance phytoremediation outcomes.”

Zalesny and Rogers are currently using the tool to prioritize pollutants from two landfill sites where they are using agroforestry phytoremediation buffer systems to reduce the transport of pollutants. These phytoremediation systems are part of the regional phytotechnologies network in the Great Lakes Basin.