Grantee Research Project Results

1998 Progress Report: Bioavailability and Biostabilization of PCBs in Soil

EPA Grant Number: R825365
Title: Bioavailability and Biostabilization of PCBs in Soil
Investigators: Luthy, Richard G. , McNamara, Sean W.
Current Investigators: Luthy, Richard G. , Dzombak, David A. , McNamara, Sean W.
Institution: Carnegie Mellon University
EPA Project Officer: Aja, Hayley
Project Period: January 1, 1997 through December 31, 1999
Project Period Covered by this Report: January 1, 1998 through December 31, 1999
Project Amount: $499,056
RFA: DOE/EPA/NSF/ONR Joint Program on Bioremediation (1996) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management

Objective:

The objective of this study is to investigate the mobility of polychlorinated biphenyls, PCBs, in soils and soil/sludge materials through the development of novel field sampling methods. By advancing scientific knowledge in this area, the new sampling techniques will yield improved estimates of the potential release of residual PCBs in soil. This knowledge will provide further insight into the concept of biostabilization, which envisions that contaminated materials can be actively, and passively, biotreated to remove a large fraction of potentially mobile and bioavailable organic contaminants, thus reducing risk.

This work entails three primary tasks:

• Task 1. Design and evaluate sampling devices to monitor the slow release of PCBs in field soils, sludges, and pilot-scale land biotreatment units.
• Task 1. Perform field and laboratory assessments of PCB leachability from field soils, including biotreated soil/sludge mixtures
• Task 2. Assess the potential for reduction in PCB mobility that may occur in land biotreatment units operated under intrinsic conditions following active biotreatment and examine how this reduction affects risk.

This work is being performed in collaboration with the Aluminum Company of America (Alcoa) in Pittsburgh, PA and Massena, NY, and builds on prior studies between Carnegie Mellon University and Alcoa. Testing will be performed in various site soils at the Massena facility, including that in the field biotreatment units. The data from the field biotreatment units will provide information on how leachability of residual PCBs occurs in subsequent years under passive conditions following active land biotreatment. The impact of the research will be to link a rational model for bioavailability for aged samples with practical measurements relevant to bioremediation engineering practice, and to use those measurements to assess the extent that biostabilization reduces risk and uncertainty in risk assessment.

Progress Summary:

Over the past calendar year, most of the research has focused on Task 1 - the development of the sampling technique/device. A thorough literature review was performed to ascertain whether any existing sampling techniques for unsaturated soils could be easily modified to suit our application. The search revealed several deficiencies in existing techniques; the most important being that none simultaneously provided for both a target organic chemical and water accessed mass-balance.

A new sampling device has been developed to address this problem. Laboratory research has been directed on evaluating the hydraulic performance of this device in various soils across the range of expected soil moisture and flux conditions. A complete computer-aided data acquisition/signal conditioning system was developed for this purpose. This measurement system allows for testing and optimization the various sampler parameters. Once optimized for the soil of interest, the sampling device should allow for sampling pore water even under very low soil moisture conditions.

Future Activities:

Research is expected to continue over the summer to optimize the hydraulic performance of the sampler. Additional laboratory tests are planned to characterize the efficiency of chemical capture and to develop a standard sampling and extraction technique for the device. Laboratory results will be compared to those predicted using an unsaturated flow and transport model -HYDRUS-2D. Field trials are expected to begin in late summer, proceed until late October, and resume in the Spring of 1999.

Journal Articles:

No journal articles submitted with this report: View all 7 publications for this project

Supplemental Keywords:

bioremediation, bioavailability, biostabilization, polychlorinated biphenyls., RFA, Scientific Discipline, Toxics, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Bioavailability, Remediation, Chemical Mixtures - Environmental Exposure & Risk, Contaminated Sediments, Environmental Chemistry, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Chemistry, HAPS, chemical mixtures, Ecological Effects - Environmental Exposure & Risk, Ecological Effects - Human Health, Bioremediation, Biology, Engineering, Ecological Indicators, risk assessment, fate and transport, fate, biostabilization, biostabilization of PCBs, contaminant transport, contaminated sediment, PCBs, biodegradation, hydraulic oils, chemical transport, kinetic studies, land biotreatment, chemical contaminants, bioremediation of soils, contaminants in soil, environmentally acceptable endpoints, models, vadose zone, physicochemical

Relevant Websites:

http://www.ce.cmu.edu/~mcnamara/RESEARCH/overview.htm Exit
http://www.ce.cmu.edu/~rl10/ Exit
http://www.ce.cmu.edu/EnvInst/ Exit

Progress and Final Reports:

Original Abstract

1997 Progress Report

Final Report