Risk assessment

Journal Article · Fri Jan 01 04:00:00 EST 1993 · Hazmat World; (United States)

OSTI ID:5568284

Wray, T K

The chance of developing cancer from exposure to chemicals in the environment is calculated based on statistical evidence, but the task is a complex one that stirs much debate. There are as many as 2,000 substances that various groups have labeled as suspect, probable or definite human carcinogens. Only 23 substances, including aflatoxin, asbestos, vinyl chloride and benzene, have been proven through human epidemiological studies to increase cancer rates. The remainder received their carcinogenic classification based on animal studies. Animal testing usually involves feeding rats or mice extremely high doses of a substance, often the maximum amount they can tolerate without dying directly from toxicity. This approach ensures maximum sensitivity to potential carcinogenic effects and minimizes the number of lab animals required for such studies. Exposing them to levels similar to what humans experience would require millions of test animals. With few exceptions, no one denies trace exposure levels exist for most chemicals, below which no toxic effects occur in any individual. However, statistical evidence from human epidemiological studies is inadequate to detect small increases in mortality. Although animal studies are more sensitive to carcinogenic effects because of the high doses involved, they are inadequate to explain what occurs at much lower doses common in the real world. Human epidemiological studies, for example, show no evidence of increased cancer from many products containing minute quantities of substances known to cause cancer in lab animals.

• OSTI ID: 5568284
• Journal Information: Hazmat World; (United States), Journal Name: Hazmat World; (United States) Vol. 6:1; ISSN HMWOED; ISSN 0898-5685
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL MODELS
CARCINOGENS
DOSE-RESPONSE RELATIONSHIPS
ENVIRONMENTAL EXPOSURE
RISK ASSESSMENT