Detection of Genotoxic Agents in the River Water by Analyzing Breaks and Gaps Type Damages in Fish Chromosomes

Frequency of break and gap type changes were detected in fish Perca fluviatilis, L. (Percidae, Pisces) chromosomes. Fish specimens were caught at four different localities of Danube (by Beška, Zemun, Višnjica and Grocka) during three consecutive years (1986, 1987 and 1988) and cytogenetically analyzed. The highest frequency of changes was recorded in fish caught at the localities situated downstream from Belgrade, i.e. by Višnjica and Grocka. Some of the values found in fishes caught at these localities ranged within the values of the presumed critical zone (3.0-3.5%) or were even higher. So these localities can be taken as periodically or permanently contaminated with genotoxic agents and hazardous in aspect of genetic material of leaving organisms.