Impact/Purpose:

This project examines reactive HAPs that have the respiratory tract as their primary target. Data is being collected that will either validate or refute the grouping of 11 aldehydes and chlorine into a single HAPs group and allow development of a group or groups of HAPs based on mode of action rather than structure. Extrapolation from in vitro to animal to human effects is considered. Results will offer a more complete story to transmit to the program office that should greatly enhance their ability to do risk assessments for chlorine and the aldehydes on the HAPs list.

Description:

Exposure-dose-effect linkages for chemically reactive air toxic compounds. The respiratory epithelium is coated with an "airway lining fluid" that serves as a defense against chlorine and other reactive gases because it contains proteins, lipids and antioxidants that can absorb some of the oxidative damage induced by the chlorine. Exposure to chlorine and other reactive gases causes oxidation of constituents of the airway lining fluid, and is likely to be mediated through oxidative damage. Measurement of the reaction products of these gases with the lining fluid can provide useful information in several areas. First, these reactions can be monitored in vitro, thereby giving a potential quick estimate of mode of action and even potential target sites in vivo. Second, the reaction products can provide dosimetry information that can be used to validate mathematical models for the fate of these gases in the respiratory tract. Such models should be useful in generating "Exposure Dose Response" (E-D-R) models that should be useful for extrapolating between animals and humans and between exposure scenarios to ultimately improve human risk assessments. Third, the measurements of reaction products can be used to generate mathematical models that could be used to extrapolate to other reactive Air Toxic gases.

Record Details: