Grantee Research Project Results
1998 Progress Report: Bioavailability & Risk Assessment of Complex Mixtures
EPA Grant Number: R825408Title: Bioavailability & Risk Assessment of Complex Mixtures
Investigators: Donnelly, Kirby C. , Reeves, William
Current Investigators: Donnelly, Kirby C. , Safe, Stephen H. , Autenrieth, R. L. , McDonald, T. J. , Reeves, William , Huebner, Henry J.
Institution: Texas A & M University
EPA Project Officer: Hahn, Intaek
Project Period: November 15, 1996 through November 14, 1999 (Extended to April 15, 2000)
Project Period Covered by this Report: November 15, 1997 through November 14, 1998
Project Amount: $443,997
RFA: Environmental Fate and Treatment of Toxics and Hazardous Wastes (1996) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management , Safer Chemicals
Objective:
The proposed research is designed to develop and accurate methodology for estimating risk and bioaccessibility of complex mixtures at uncontrolled hazardous waste sites. The research has three major objectives: (1) to develop a protocol for preparation of a water soluble fraction (WSF) as a method for estimating residual contaminant concentrations that are protective of human health and the environment; (2) to develop a quantitative toxicokinetic model using genotoxicity and enzyme induction assays to interpret the interactions of complex mixtures of PAHs and HAHs; and, (3) to validate the WSF protocol by analysis and risk assessment of soils from four Superfund sites before and after remediation.Progress Summary:
Initial experiments for the WSF protocol are complete at this time. Once the final samples from the desorption experiments have been analyzed, a manuscript will be prepared and submitted for publication. Results indicate dramatic differences between the desorptive behavior of pyrene originating from simple vs. complex mixtures. After 360 days of aging, pyrene from wood preserving waste (WPW) soil show little if any effect of aging while pyrene from the model chemical soil became less available over the course of the 360 days.The fractionation portion of the project has been completed. The coal tar was initially separated on an alumina column as described previously. PAHs were isolated in this manner into two fractions with hexane and toluene, respectively. Fraction 1 contained alkanes and 2-3 ring PAHs. Fraction 2 contained 3-5+ ring PAHs. These hexane and toluene fractions from the alumina column were then separated with normal phase HPLC. HPLC fractions were pooled according to the retention times of standards to give five groups designated A, B, C, D and E. Group A contains 2-ring PAHs, B contains 3-ring PAHs, C contains 4-ring PAHs, D contains 5-ring PAHs and E contains PAHs with 5 or more rings.
As an additional method for determining the factors controlling the release of complex mixtures from soil, a feeding study was conducted. The experiments employed 25 Fischer 344 rats divided into 5 groups. Aged and freshly spiked coal tar (CT) soils along with a CT spiked non-soil vehicle were fed along with control feeds to each of the five groups for a period of 17 days. Urine and feces were collected along with liver lungs and kidneys for DNA adduct and chemical analysis.
Accomplishments and Research Results:
As expected, the desorption experiments define two compartments of contaminants. The first is rapidly released and is thought to be limited by dissolution into the aqueous phase and the other is slowly released and thought to be limited by desorption/diffusion. The magnitude of the rapidly released portion decreases with time in the model chemical soil. Results indicate dramatic differences between the desorptive behavior of pyrene originating from simple vs. complex mixtures. After 360 days of aging, pyrene from wood preserving waste (WPW) soil show little if any effect of aging while pyrene from the model chemical soil became less available over the course of the 360 days. It is believed that these differences are a result of matrix effects. From this initial data, it seems that rapid sorption of PAHs to soil is a phenomenon that predominates with simple PAH mixtures only.
Analysis of the PAH fractions in the Salmonella/microsome assay is complete and analysis in other bioassays is underway. Initial results indicate that toxic equivalency factors (TEFs) do not predict the mutagenicity of the fractions. TEFs were in the order E > D > C > B > A, the sum of carcinogenic PAHs was in the order C > D > E > B > A and BaP content was in the order D > E > C > A > B. At doses of 10 and 20 mg/ml, the rank of mutagenic activity was in the order C > D > E > B > A. At lower doses BaP content best predicted mutagenicity.
Future Activities:
In the coming year, the analysis of the samples from the initial bioavailability experiments will be completed and the data will be submitted for publication. Additional bioassays for the PAH fractionation are scheduled and will include the chick embryo screening test and enzyme induction assays. In addition, the samples from the feeding study will be analyzed for PAHs, metabolites and DNA adducts. Finally, the samples for the validation of the WSF protocol will be obtained and extracted according to the methods of choice.Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 8 publications | 4 publications in selected types | All 4 journal articles |
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Type | Citation | ||
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Bordelon NR, Donnelly KC, King LC, Wolf DC, Reeves WR, George SE. Bioavailability of the genotoxic components in coal tar contaminated soils in Fischer 344 rats. Toxicological Sciences 2000;56(1):37-48. |
R825408 (1998) R825408 (1999) |
not available |
Supplemental Keywords:
bioaccessibility, complex mixtures, polycyclic aromatic hydrocarbon, toxic equivalency factor., RFA, Health, Scientific Discipline, Toxics, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Bioavailability, Contaminated Sediments, Remediation, Geochemistry, Environmental Chemistry, Health Risk Assessment, pesticides, Chemistry, Risk Assessments, chemical mixtures, Fate & Transport, complex mixtures, risk assessment, fate and transport, cumulative risk, fate, coal gasification sites, Superfund sites, effects assessment, risk assessment techniques, contaminant transport, soil sediment, acceptable residue levels, contaminated sediment, complex mitures, sediment transport, transport contaminants, geotoxicity, PAH metal mixtures, adverse human health affects, chemical contaminants, soils, contaminated soil, PAH, human exposure, toxicity, characterizing chemical mixtures, environmental transport and fate, public health, furans, environmental toxicant, Toxic Equivalency Factor, hazardous materials exposure, assessment methods, refinery sites, vadose zone, hazardous waste sites, dioxins, exposure assessment, environmental chemicals, toxicokineticsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.