1999 Progress Report: The Effect of Plants on the Bioavailability and Toxicity of Contaminants in SoilEPA Grant Number: R825413
Title: The Effect of Plants on the Bioavailability and Toxicity of Contaminants in Soil
Investigators: Banks, M. Katherine , Schwab, Arthur Paul , Smith, J. Scott
Institution: Kansas State University , Purdue University
Current Institution: Kansas State University , Purdue University
EPA Project Officer: Lasat, Mitch
Project Period: January 1, 1997 through December 31, 2000
Project Period Covered by this Report: January 1, 1999 through December 31, 2000
Project Amount: $499,941
RFA: DOE/EPA/NSF/ONR Joint Program on Bioremediation (1996) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management
The overall objective of this project is to evaluate the effect of plants on the bioavailability and toxicity of contaminants in soil. Subobjectives are listed below.
Objective 1: Evaluate the effect of plant roots and their associated rhizosphere on the availability of soil contaminants for bioremediation by soil microbes and higher plants.
Objective 2: Investigate the fate of petroleum contaminants in plant/soil systems.
Objective 3: Quantify the contribution of weathering to reduced contaminant bioavailability and toxicity.
Objective 4: Determine the impact of plants on leaching of contaminants and the toxicity of leachates.
Objective 5: Develop a chemical extractant or sequential series of extractants to rapidly assess bioavailability.
Objective 6: Assess changes in rhizosphere microbial community associated with plants established in contaminated soil.
Objective 7: Evaluate the impact of root characteristics on contaminant bioavailability, toxicity, and bioremediation/phytoremediation efficiency.
Project progress in the experimental and field studies is described below.
Fate of 14C labeled contaminants in plant chambers. The chambers were constructed and the plants established in the soil in November 1997. The chambers were dismantled in June 1998, and samples were analyzed for target contaminants and 14C. Due to excessive moisture and humidity in the chamber, the plants were not viable at the end of this experiment. No statistical differences in the samples were observed. Modifications were made in the chamber design and the study is being repeated over the period of September 1999 through June 2000.
Effect of aging on contaminant bioavailability in soil-plant systems. The contaminated soil began the aging process in April 1998. Contaminant concentration and toxicity were measured after 0, 6, 9, 12, and 18 months of aging. The greenhouse phase of this study began in October 1999. Soil contaminant concentration and toxicity will be evaluated after 5 and 10 months of exposure to plant roots.
Field evaluation of bioavailability and toxicity during phytoremediation. The Port Hueneme field study began in September 1997. The study area was constructed and plants established at the site. Soil, water, and biomass are being sampled every 3 months. The final sampling event for this study will be in mid-January 2000. Results to date indicate that the plants are reducing soil contaminants and toxicity at this site.
Development of an extraction method to predict bioavailability of soil contaminants. The extraction study is under way at Purdue University and should be completed by June 2000.
January 2000 Last sample collection at the Port Hueneme field site. Field study is complete.
June 2000 Five month take-down for the greenhouse study. Analysis of soil and biomass will occur.
July 2000 Repeated plant chamber study is complete.
September 2000 Ten month take-down for greenhouse study. Analysis of soil and biomass will occur.
October 2000 Research ends.
December 2000 Final report submitted.