Phytoremediation of Arsenic, Lead, Oil and Grease in Natural Drainage Systems

by Elizabeth Teresa Martin

Chairperson of the Supervisory Committee:
Professor Kristina Hill, Department of Landscape Architecture

2004

The question this professional project thesis seeks to answer is whether phytoremediation is a viable cleanup method for contaminated soil in natural drainage systems in the Seattle area. The focus is on arsenic, lead, oil and grease because these contaminants are commonly found in urban soils and stormwater. The methods used are primarily literature review and contextual analysis. The project identifies the sources of common pollutants found in urban soils and stormwater. The process of phytoremediation is defined, and tables are presented that summarize plants and processes that assist in the clean up of arsenic, lead, oil and grease. The City of Seattle’s stormwater maintenance approach and goals are described in natural drainage systems. A discussion of natural drainage systems follows in the context of the public right of way and green infrastructure. Green infrastructure is discussed in the context of design theory and precedents. Recommendations for plant selection are made based on phytoremediation capabilities, aesthetics, and suitability to the climate of the Pacific Northwest. A review of design theory is the basis of an exploration of possible design implications of using phytoremediation in natural drainage systems.

The conclusion of this project is that phytoremediation could be a valuable cleanup method for contaminated soil in natural drainage systems sites in the Seattle area. If designed well, phytoremediation in natural drainage systems has the potential to contribute to neighborhood aesthetics as well as clean up other types of contamination in the landscape.