Assessment of carcinogen exposure in man

The statistical evidence that much human cancer has an environmental aetiology has led to a search for causative agents. Whilst some human carcinogens have been identified, it is true to say that at the present time the major causative agents, other than cigarette smoke, are unknown. Analysis of environmental samples for potential carcinogens using physico-chemical methods, particularly mass spectrometry, has reached a stage that concentrations at the parts per trillion level can be detected. It requires a great leap of the imagination to link the sensitivity of environmental analytical detection methods with the doses of the same chemicals required to produce cancer in animals. A fundamental gap in knowledge exists between, on the one hand, measuring human exposure to carcinogens using such methods, and, on the other hand, determining whether or not such exposure is of biological significance.