The risk of cancer and other adverse health effects may be evaluated. The pharmacy may give you a whole bottle, but the dose is the amount you actually consume. The does is not the amount of the contaminant released to the environment. The toxicity assessment calculates how much of a substance is necessary to cause a negative health effect. Scientists calculate the dose that can cause cancer separately from the dose that can cause other health effects.
Many scientists believe any exposure to a cancer-causing substance increases the risk of cancer.
Because of this, scientists may assume that there is no completely safe level of exposure to substances known to cause cancer in humans. But scientists can calculate an acceptable dose because some risks are very small when compared to others, or the risks of some exposures are far outweighed by the benefits. Scientists determine the acceptable dose for humans by finding the acceptable level of exposure for an animal in laboratory experiments. Acceptable dose levels are calculated to be very conservative and protective of human health. It is estimated that one in three Ohioans born today will develop some type of cancer in his or her lifetime.