A Resouce Guide:
The Phytoremediation of Lead in Urban, Residential Soils

This website serves as a source of information for those concerned with lead contamination in soil.  Phytoremediation can reduce the level of lead in the soil as well as provide a protective barrier.  The use of the decision tree model developed by Northwestern can help in the selection of the appropriate plants.

Information that can be found in this website:
 

      Summary
      Section 1:  Background information on lead
       Section 2:  Health Effects and Exposure Pathways
       Section 3:  General Phytoremediation
      Section 4:  Phytoremediation of Lead
       Section 5:  Decision Tree Background
      Section 6:  Monitoring and Upkeep
       Section 7:  Economics
       Section 8: Example Site
      Bibliography
      Annotated References (Soil testing Co., Phytoremediation Co.)

Project Summary
 
 

Since the 1970's federal lead-based paint intervention programs, lead levels in the general population of children have been significantly reduced; however, children residing in urban areas still face significant risks. Urban areas are of particular concern for elevated lead levels in children since there is a greater concentration and a longer history of emission sources, a higher traffic density, and a large quantity of older houses. The creation of lead free housing is not nearly sufficient, as lead in soil has been shown to be a major contributor to the high lead levels present in children. There is a need for a plan which will eliminated the soil lead exposure pathway because there are major health effects associated with lead exposure, especially in children.

The goal of this report was to create a plan where lead exposure can be prevented by eliminating the soil exposure pathway. A decision tree for landscape design and monitoring was developed that focuses on the stabilization and/or removal of lead contamination from the soil through the use of phytoremediation. Phytoremediation is the use of green plants to stabilize or remove contaminants from soils, sediments, or water. This technology is advantageous in comparison to other remediation technologies, because it is less expensive and is minimally invasive. While the phytoremediation of lead is difficult because the metal ions molecularly bind to the soil matrix, methods such as "foliar P" application, pH adjustment, and the addition of chelating agents can enhance the plant's ability of lead removal. Phytoremediation of lead has been successfully applied in both industrial and residential settings.

The decision tree is a step-by-step model geared to block the soil-lead exposure pathway in residential, urban environments. A full list of plants, which are appropriate for lead phytoremediation, serves as the foundation of the decision tree. The various steps of the decision-tree determine the selection of the appropriate plants. In the first step of the model, the general residential area is categorized by various background factors (climate, precipitation, etc.). These areas are further classified into one or more land uses (front yard, garden, etc.) that may have different factors that must be defined (durability, aesthetics). Finally plants and barriers are chosen based on the defined conditions, and the soil modification techniques (such as lowering pH, adding fertilizer) are chosen. Two Chicago residential communities are used to illustrate the application of the decision tree. Plant and lead monitoring requirements, plant upkeep information, and economic costs are included within the decision tree. While this model has been formulated for the Chicago area, the techniques can be implemented in any urban, residential community