ABSTRACT
This chapter 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, Human Exposure/Rodent Potency (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. Toxicological examination of synthetic chemicals such as pesticides and industrial pollutants, without similar examination of chemicals that occur naturally, has resulted in an imbalance in both data and perception about chemical carcinogens. Natural pesticides are an important subset of natural chemicals in the diet. Plants produce these toxins to defend themselves against fungi, insects, and other predators. The HERP rankings indicate that there is an enormous background of human exposure to rodent carcinogens in the diet. Some perspective is clearly needed when setting priorities for research and regulatory policy concerning chemical carcinogens and human cancer.
