WATER, CONTAMINANTS, AND ROOTS: THE ARGONNE PHYTOREMEDIATION EXPERIENCE

In 1999, a phytoremediation system consisting of 800 hybrid poplar and willow trees was installed at Argonne National Laboratory in northeast Illinois. The purpose of the system was to provide hydraulic control and remediation of VOC- and tritium-contaminated groundwater . A key component of the system was hundreds of poplars specially installed in 2-foot diameter boreholes through over 25 feet of fine-grained glacial till to reach the contaminated confined, sandy aquifer. Monitoring of the site has resulted in a large amount of interrelated information on continuous groundwater levels in numerous monitoring wells, weather data, sap flow, groundwater sampling, stratigraphy, tree-health surveys, tissue and transpirate sampling, and recent examination of hydraulically excavated tree roots. Altogether, the data have refined the understanding of the movement of groundwater and contaminants and the distribution of roots.