Sometimes it seems next to impossible to find current, evidence-based information for soil cleanup utilizing plants. Since an easy-to-read textbook on the subject does not exist, below are some useful
links for preliminary investigations. These documents provide a good overview of mechanisms in the field, and summaries of contaminate studies:

Rock, Steven. 2010. EPA Phytotechnologies Fact Sheets, Office of Superfund Remediation and Technology Innovation.
http://www.epa.gov/tio/download/remed/phytotechnologies-factsheet.pdf

Interstate Technology Regulatory Council. February 2009. Phytotechnology Technical and Regulatory Guidance and Decision Trees, Revised
http://www.itrcweb.org/Documents/PHYTO-3.pdf

In addition, the EPA has a database of projects where you can search by a contaminate, plant species etc, and pull up relevant projects:

EPA Technology Innovation Program, Contaminated Site Clean-up Information
http://www.clu-in.org/