2006 BES Annual Meeting Presentation and Poster Abstracts
Investigating the extent of earthworm-driven physical and chemical alteration of roadway-derived dust in urban soils
Co-Authors: W. Carroll, S. M. Lev, K. Szlavecz, E. R. Landa, R. Casey and J. Snodgrass
Abstract: A major impact of urban development is an increase in the concentration of potentially toxic trace metals in soils and surface waters. A primary source of trace metals to near-surface environments in urban ecosystems is roadway runoff and dust. Potential hazards that roadway runoff and dust pose to biota are not well understood and are the focus of extensive investigations in the multi-disciplinary field of environmental biogeochemistry. Because earthworms ingest, transport, process and digest large amounts of soil on a daily basis, earthworms can have a profound impact on soil chemistry and the bioavailability of potentially toxic trace metals. In order to evaluate this effect, a set of mesocosm experiments was carried out using environmental conditions observed in bioretention cells receiving direct storm water input from a heavily used parking lot in College Park, MD. Soils typical of the study site were amended with a surface layer of roadway dust collected from the parking area and earthworms representative of the species identified in the retention cells were allowed to process the amended soils for periods of 30, 60 and 90 days. Amended soils with earthworms exhibited evidence of extensive mixing and an alteration of the extractable fraction of roadway dust. These results suggest that earthworm processes play an important role in the fate transport and bioavailability of roadway derived trace metals in urban soils.