Future research directions to characterize environmental mutagens in highly polluted area.

Population monitoring using methods of molecular epidemiology combined with reliable data on exposure is an extremely powerful approach to determine the effect of mutagens on human populations. Although human blood and urine have traditionally been used for biomonitoring, an increase in the use of placental and buccal smear samples should be expected. As biomarkers of exposure, DNA strand breaks and hemoglobin and albumin adducts seem to be most sensitive. As biomarkers of response, cytogenetic analysis determining chromosome aberrations or micronuclei has been widely used Additional information can be obtained by using the chromosome painting technique and by determining gene mutations at the hprt locus: however, epidemiological studies exhibiting a relationship between these biomarkers and environmental pollution are still lacking. The use of sperm to analyze the effect of environmental mutagens in germ cells (e.g, sperm morphology and sperm aneuploidy) should be encouraged. The determination of susceptibility by analyzing genetic polymorphism, which is responsible for individual differences in the biotransformation of mutagens and carcinogens, will gain importance for risk assessment. Future research should include validating molecular methods, studying adaptive response to chemical carcinogens, and studying the modulatory effect of antioxidants, as well as the effect of carcinogens on immunity.