Interdisciplinary approach to assessing the health risk of air toxic chemicals: an overview.
To assist the regulatory branch of the Environmental Protection Agency in addressing the risk assessment of air toxics, the Health Effects Research Laboratory initiated a comprehensive inhalation toxicology program to provide key health effects data missing from the current data base. A priority ranking of chemicals based on the potential for substantial human exposure and the need for health effects data was developed to identify candidate chemicals for toxicological research. The major goal of the program is to evaluate the concentration-response from acute, intermittent and subchronic inhalation exposures to developmental, genetic, hepatic, immunologic, neurologic, pulmonary and reproductive toxicity in a manner that provides data for the regulatory health assessment of air toxic chemicals. Extrapolation and dosimetry research is also conducted to improve the basis for human risk assessment. Determination of biological endpoints to be examined will be decided on a compound-by-compound basis, depending on the physical, chemical and structural characteristics of the chemical and evaluation of the existing health data base. Although the main emphasis is on inhalation as the primary route of exposure, some of the laboratories will compare inhalation to other routes, such as oral, to better understand the influence of route of exposure and hence the potential applicability of existing health data. Acute and intermittent exposures will be done for all compounds. Upon evaluation of the acute results, a decision will be made as to whether subchronic studies are needed. Endpoints that show unusual sensitivity may be investigated in greater detail. The total length of exposure will vary from 1 to 21 days. The daily length of exposure will range from 1 to 8 hr. If adverse effects are observed at ambient levels, the time to recovery after exposure will be investigated.
Grose
E C
EC
U.S. Environmental Protection Agency, Health Effects Research Laboratory, Research Triangle Park, NC 27711.
Selgrade
M J
MJ
Busnell
P J
PJ
Simmons
J E
JE
Allen
J
J
McGee
J
J
Hauchman
F
F
Graham
J A
JA
D000280:Administration, Inhalation; D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D001273:Atmosphere Exposure Chambers; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008099:Liver / Q000187:drug effects; D008168:Lung / Q000187:drug effects / Q000502:physiology; D012307:Risk Factors; D013723:Teratogens / Q000633:toxicity
D000393:Air Pollutants; D013723:Teratogens