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.

Interstate Technology Regulatory Council. February 2009. Phytotechnology Technical and Regulatory Guidance and Decision Trees, Revised

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