THE CHEMICAL PROPERTIES OF PM AND THEIR TOXICOLOGICAL IMPLICATIONS
Impact/Purpose:
The overall objectives of Project 3 are: to characterize ambient particulate matter (PM) samples from a variety of PM sources collected in Project 1 according to their potential to induce redox chemistry and oxidative stress in biological tissues; to apply new measures of PM exposure that determine redox activity and thiol depletion; to study particle matrix and size effects on the cellular uptake, intracellular disposition, and biotransformation of particles and selected adsorbed components; and to characterize chemical interactions in PM with respect to reactivity and cellular effects. The central hypothesis of this project is that many adverse health effects associated with PM exposure derive from the induction of oxidative stress, caused by reactive oxygen species generation or the depletion of thiols. Our previous studies have focused on the chemical basis for these actions, i.e., the chemical reactivities of PM that could cause these processes. We have developed a redox assay that determines the catalytic capacity of PM to generate superoxide and have used it to characterize PM from different sources throughout the Los Angeles Basin (LAB).
Description:
This Project will characterize ambient PM samples from key sources according to their reactivity in redox and electrophilicity assays, and in association with toxicological findings, will provide a basis for identifying PM of the greatest concern for public health in terms of potential to induce oxidative stress and related health effects.
Record Details:
Record Type:PROJECT(
ABSTRACT
)
Start Date:10/01/2005
Completion Date:09/30/2010
Record ID:
144564
Keywords:
BIOAVAILABILITY, METABOLISM, CHEMICALS, OXIDATION-REDUCTION, BIOCHEMISTRY, AMBIENT AIR, PARTICULATE MATTER, OXIDATIVE STRESS,
Related Organizations:
Role
:OWNER
Organization Name
:MICHIGAN STATE UNIVERSITY
Organization Name
:SCPC
Role
:OWNER
Organization Name
:UNIVERSITY OF TSUKUBA
Organization Name
:SCPC
Role
:OWNER
Organization Name
:UNIVERSITY OF CALIFORNIA - LOS ANGELES
Organization Name
:SCPC
Project Information:
Approach
: In the next phase of this research, we plan to apply the redox assay and two other chemical assays, one of which determines the reaction with thiols, to assess differences in chemical reactivity among major source types, season and size fraction in PM samples from the LAB. These differences will be analyzed in terms of the chemical constituents found in Project 1 and used to interpret the toxicological findings from Projects 2 and 4. We shall investigate the quantitative relationship between ROS chemistry and intracellular measures of oxidative stress and cellular toxicity. In a second component of the Project, we will study the interaction between carbon black particles and various adsorbed compounds to determine the effect of the particle matrix on chemical and biological activity. These studies are based on our observations that demonstrate residual redox activity in diesel exhaust particles after extractions and those of others showing differences in cellular toxicity of organic compounds when they are adsorbed onto particles. We will thus establish an experimental system of carbon black particles of varying dimensions to which selected organic and inorganic species are adsorbed. The chemical and biological properties of the particles will be determined and the effects of the matrix on the actions of the adsorbed species will be assessed.
Cost
:$.00
Research Component
:Health Effects
Project IDs:
ID Code
:R832413C003
Project type
:Center