Download Soil and Water Science Department University of Florida Field

Field applications of phosphate rock for remediation of metal contaminated soils
Ma, L. Q., W. Harris, and R.H. Stamps
4/2002-3/2006
Lead and arsenic contamination is of great environmental concern due to their adverse
health effects on humans and animals, and the extent and severeness of the
contamination. Successful remediation of metal-contaminated soils would provide
significant environmental and monetary benefits. The proposed research examines two
cost-effective and environmentally-friendly remediation technologies, i.e. in situ lead
immobilization using P amendments and arsenic phytoremediation using plant. It
integrates three separate projects, which all utilize phosphate rock (PR), into an
integrated synergetic one.
The primary objectives are to: 1) assess long-term effectiveness of P amendments
in immobilizing lead in contaminated soils; 2) explore the feasibility of using PR to
remediate lead contaminated soils from shooting ranges; 3) evaluate the beneficial effects
of PR in enhancing phytoremediation of arsenic contaminated soils using a newly
discovered hyperaccumulating plant. For the 1st objective, efforts will be focused on
biologically and chemically evaluating metal bioavailability on a long term basis, which
is critical for the technology acceptance. Plant uptake study, in vitro bioavailability
assay, microbial toxicity assay, TCLP test and sequential extraction will be used. For the
2nd objective, efforts will be concentrated on the effectiveness of PR in reducing lead
availability in soils from shooting ranges due to increased soil pH and reduced lead
solubility. Efforts will also be spent on determining the optimum PR application rates
and characterization of a shooting range for field application. For the 3rd objective,
efforts will be centered on the effectiveness and optimum application rates of PR in
enhancing arsenic uptake due to increased soil arsenic via increasing phosphate and soil
pH, and characterization of an arsenic contaminated soil. PR will be applied to a selected
shooting range and an arsenic contaminated soils, and soil, groundwater, and plant
samples will be collected and analyzed to assess the effectiveness of PR in remediating
metal contaminated soils.
The demonstrated effectiveness of using P amendments to reduce metal
bioavailability for lead immobilization and increase arsenic bioavailability for
phytoremediation in the field will greatly increase the visibility and acceptability of these
relatively new technologies to treat metal-contaminated soils. Demand for these
technologies will substantially drive the market values for P amendments, especially
phosphate rock.
Soil and Water Science Department
University of Florida