PHYTOREMEDIATION OF URBAN SOILS

Mary Ellen Helgren Johnson Park in Racine, Wisconsin is the former site of a tennis club adjacent to Root River. The parcel was purchased by the Kenosha/Racine Land Trust (KRLT) and donated to City of Racine. This site had also been a location for disposal and dumping of foundry sands in the 1960's and 1970's. These industrial wastes have introduced uniformly measurable quantities of Cr, and created “hot spots” (hundreds of ppm) of Pb contamination. Now, a cooperative project among KRLT, Univ. Wisconsin-Parkside, the Milwaukee Community Service Corps, and students from St. Rita's School in Racine is underway to restore this site via phytoremediation. In Fall, 2007, ten 3m x 3m plots were prepared for planting. Each plot was the site of one of the higher Pb levels, and each had a companion control area, which was not planted. As the wooded nature of the site creates light obstacles, it has been necessary to use shade-tolerant plants, in this case, Canada rye grass. Seeding of the test plots was augmented with Glomus intraradices inoculant, in order to enhance the uptake of Pb and Cr. Effectiveness of the rye grass/Glomus mixture will be assessed by comparing levels of Pb and Cr in the grass tissue to background levels of Pb and Cr in tissues of forbs that grow abundantly at the site. Pre- and post-treatment values of soil Pb and Cr will be presented, with comparisons to control plot soil values.