Exposures to organic solvents in the workplace constitute an important hazard with potential transient and persistent effects on neurobehavioral function. However, the dose-effect relationships for workplace exposures and these health parameters have not been well characterized because of methodological limitations in evaluating both exposures and effects. In this study, we propose using industrial hygiene sampling and exhaled breath and urine analysis coupled with biomathematical dose models to estimate central nervous system (CNS) concentrations of various solvents used by industrial spray painters. We will assess transient changes in CNS function using a computer-administered neurobehavioral test battery. The methods and hypotheses which are described in this proposal derive from nine separate investigations of approximately 600 solvent-exposed workers and other, smaller investigations of unexposed populations which we have conducted over the past three years. Subjects drawn from spray painter (exposed) and drywall taper (unexposed) populations will be tested before, during, and after the work day, and individual changes in performance will be compared to estimates of CNS solvent dose. To reduce the complexity of exposure estimation, a population selection procedure has been developed to identify individuals spray painting with systems using only aromatic solvents, primarily toluene and xylene. Prior human exposure chamber studies have shown impaired memory, reaction time, and hand-eye coordination in individuals exposed to toluene and xylene alone; the tests contained within our test battery will evaluate these functions. Since exposure to solvent mixtures is more common and potentially more toxic than unitary exposures, we propose studying spray painters during periods of heavy exposure to mixtures of aromatic solvents. This study is analogous in design to prior exposure chamber studies in that exposure will be monitored continuously and health status evaluated periodically over a work day. We anticipate that this study will provide information directly relevant to the setting of workplace exposure standards and will improve our ability to monitor exposure and effect in solvent-exposed workers.
