Impact/Purpose:

The main objective is to apply the method of continuous breath sampling developed by Battelle under EPA sponsorship to perceived environmental problems. Problems selected include the question of dermal exposure to chloroform during baths and showers, inhalation exposure to certain toxic and carcinogenic VOCs in environmental tobacco smoke, and total (dermal + inhalation) exposure to MTBE in baths and showers.

Description:

This is a continuation of an Internal Grant research project with the focus on completing the research due to initial funding delays and then analyzing and reporting the research results. This project will employ a new continuous breath sampling methodology to investigate dose and body burden due to exposures to compounds of interest to EPA. The new methodology has been recently fully evaluated for a number of VOCs. It makes possible for the first time the collection of abundant data with which to trace the uptake, distribution in the body, and decay of a number of compounds of intense interest to EPA. These include constituents of environmental tobacco smoke (ETS) and oxygenated fuel additives (e.g., MTBE). The new methods are particularly well suited to study exposure through non-inhalation routes, such as ingestion and dermal absorption. The two VOCs that are most closely associated with multiple routes of exposure are chloroform and d-limonene; the relation between all three major routes of exposure and the nature of uptake and distribution in the body will be studied for these chemicals.

One task will be to apply the new methodology to investigate possible marker VOCs for smoking and for exposure to ETS. A number of polar nitrogen-containing and nonpolar compounds will be investigated, including 3-ethenyl pyridine (3-EP) and 2,5-dimethylfuran.

A second task will be to investigate the role of dermal absorption as routes of exposure to certain VOCs. For example, dermal uptake of chloroform during baths will be investigated.

A third task will be to investigate the exposure, uptake, distribution, and decay of oxygenated fuel additives, especially methyl-tert-butyl ether (MTBE).

Concurrently with all tasks, two existing physiological models, a compartmental model and a PBPK model, will be compared and applied to selected compounds studied in the project. With the abundance of breath data, particularly in the uptake phase, made possible by the new continuous sampling method, it will be possible to make more rigorous tests of these models (as applied to human exposure at near-environmental levels) than has previously been possible.

Record Details:

Record Type:PROJECT

Start Date:10/01/1996

Completion Date:09/01/2001

Record ID: 56130

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Project Information:

Progress :Field work on the chloroform and ETS exposures has been completed. A paper was published showing a strong effect of water temperature on dermal absorption of chloroform (Gordon et al, EHP, 1998). An EPA report was completed providing a modified PBPK model to account for this effect (Corley, 1998), and a journal article has been accepted for publication. A paper is being prepared announcing the first measurements of 1,3-butadiene in smokers' and passive smokers' breath. A contract task order has been awarded for the MTBE study.

02-MAY-00 Gordon, S.M., Kenny, D., Callahan, P.J., Brinkman, M.C., Wallace, L.A., and Ashley, D.L. Controlled, short-term dermal and inhalation exposure to chloroform. Abstract presented at: ISEA 2000 Exposure Analysis in

the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Pennisula, CA, October 24-27, 2000.



Relevance :Several existing models, including an EPA model, of dermal absorption disagree on the time taken for VOCs to penetrate the skin. Use of the continuous breath sampling equipment was able to settle this question in the case of chloroform, the most common of the regulated trihalomethanes, and also to show that the amount of dermal absorption varies by a factor of 30 with a 10 C change in water temperature. This will be useful in future exposure assessments of dermal absorption of VOCs.

The ETS studies resulted in the first measurement of 1,3-butadiene in smokers' and also in passive smokers' breath. This is a carcinogenic chemical of considerable potency, and may be useful as a biomarker of smoking (together with benzene, an earlier biomarker explored by our program.)

Clients :Other ORD labs, Office of Water, EPA Regional Offices

Project IDs:

ID Code :1752

Project type :OMIS