Inventory and biological impact of polycyclic carcinogens in the environment.

The rapid development of the natural sciences and the technical progress during the last century have significantly changed our society and environment. During this period the average life expectancy for people in industrialized countries has doubled. A prolongation of life expectancy to this extent, due to for example, understanding of the relationship between various diseases and their corresponding causative agents, had never before occurred in mankind's history. It resulted in specific hygiene precautions. The recognition of such causal relationship was facilitated by the fact that infection diseases generally become apparent after a short incubation time, i.e. that an environmental situation causes health damage. At present, we are searching for origins of diseases of which the causal correlations with environmental influences are far more difficult to recognize than those of infection diseases, since long-term effects have to be observed. Do we have a situation similar to that which we had for infections at the end of the last century ? For diseases such as lung and larynx cancer, there are significant indications of carcinogenic compounds in the environment. Since both types of cancer are about 10 times more common among cigarette smokers who inhale than among non-smokers, a correlation to the risk factor "smoking" is beyond doubt. Living and working in larger cities or highly populated areas are additional factors which many enhance the lung cancer incidence ("urbanisation factor"). The air quality of these areas is supposed to be the reason for this effect. However, the present "bad air quality" at most doubles the disease incidence. A large number of epidemiological studies report on local differences of the incidence rates as well as significant increases or decreases of the mortality rates for some cancer diseases during comparatively short periods. A summary recently has been published by Misfeld (1). As an example, the mortality rate due to lung cancer for males in the F.R.G. has almost doubled during 1955-1975 from 36.5 per 100,000 to 65.9 per 100,000. This holds true for cancer of the rectum which increased from 8.8 per 100,000 to 18.9 per 100,000 during the same period. In contrast, mortality due to stomach cancer decreased from 59.3 to 36.6 per 100,000 and uterine cancer in females decreased from 16.6. to 8.5 per 100,000 (2). The pronounced changes in mortality rates cannot be explained by alterations of the genetic disposition during such a short period. Improved diagnostic and therapeutic techniques might explain decreases but not increases of mortality rates.(ABSTRACT TRUNCATED AT 400 WORDS)