Gold, L.S., Slone, T.H., Stern, B.R., Manley, N.B., and Ames, B.N. Possible carcinogenic hazards from natural and synthetic chemicals: Setting priorities. Comparative Environmental Risk Assessment (R. Cothern, ed.), Lewis Publishers Inc., Boca Raton, Florida, pp. 209-235 (1993).
In order to set priorities for laboratory research, epidemiological research, and regulatory policy, a broad perspective on the chemicals to which humans are exposed is necessary. However, the enormous background of natural chemicals in the diet, such as plant pesticides and the products of cooking, has not been a focus of carcinogenicity testing. One reasonable strategy for gaining a broadened perspective is to use a rough index to compare and rank possible carcinogenic hazards from a wide variety of chemical exposures at levels that humans typically receive, and then to focus on those that rank highest. This paper presents a ranking of possible carcinogenic hazards from 80 typical daily exposures to rodent carcinogens from a variety of sources. The ranking uses an index, HERP, that relates human exposure to a chemical to its carcinogenic potency in rodents; a similar rank ordering would be expected using standard risk assessment methodology for the same exposure values.
The data indicate that when viewed against the large background of naturally-occurring chemicals in typical portions of common foods, the residues of synthetic pesticides or environmental pollutants rank low in possible carcinogenic hazard. In a separate ranking of 32 average daily exposures to natural pesticides and synthetic pesticide residues in the diet, the synthetic pesticides are all at the bottom. Although one cannot say whether the ranked exposures are likely to be of major or minor importance in human cancer, it is not prudent to focus attention on the possible hazards at the bottom of a ranking if, using the same methodology, there are numerous common human exposures with much greater possible hazards.
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Last updated: November 10, 1995