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Exponential modeling, washout curve reconstruction, and estimation of half-life of toluene and its metabolites.

Authors
Pierce-C; Chen-Y; Hurtle-W; Morgan-M
Source
J Toxicol Environ Health, A 2004 Jul 23; 67(14):1131-1158
NIOSHTIC No.
20029368
Abstract
Health risks from ostensible occupational and environmental toxicant exposure are difficult to quantify. Maximal use of limited biological measurements of xenobiotic or metabolite concentration in the body is therefore essential. Elimination rates of exhaled [2H8]toluene and urinary metabolites were analyzed from 33 exposures of males to 50 ppm [2H8]toluene for 2 h at rest. It was hypothesized that the shapes from our decay curves would be applicable to any occupational or environmental toluene exposure. Except for a rapid decline in toluene blood and breath levels in the 0-0.1 h period, this "curve reconstruction" method successfully fit data from published studies. Urinary hippuric acid concentrations were not well fit due to substantial background levels, whereas o-cresol levels were accurately described. Our approach was able to reconstruct data from studies where exposure duration ranged from 10 min to 7 h, and where activity level ranged from rest to 150 W (strenuous exercise). Using this approach, limited biological data following toluene exposure could be back-extrapolated to immediate postexposure concentrations, which in turn could be compared to biological indicators of exposure to determine risk.
Keywords
Metabolic-study; Metabolic-rate; Metabolism; Metabolites; Blood-analysis; Urinalysis; Biological-monitoring; Biologic-half-life; Biomarkers; Exposure-assessment; Exposure-levels; Toxic-materials; Chemical-indicators; Chemical-properties; Chemical-synthesis
Contact
Crispin H Pierce, PhD, University of Washington, Seattle, WA
CODEN
JTEHD6
CAS No.
1634-04-4; 75-65-0; 8006-61-9; 637-92-3
Publication Date
20040701
Document Type
Journal Article
Funding Amount
157522
Funding Type
Grant
Fiscal Year
2004
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-K01-OH-000164
Issue of Publication
14
ISSN
1528-7394
Source Name
Journal of Toxicology and Environmental Health, Part A: Current Issues
State
WA
Performing Organization
University of Washington, Seattle WA
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