Comparison of the Presence of DDt Metabolites in Sediments and Fish from Lakes Ohrid, Prespa and Dojran

The organochlorine pesticides have been detected in the samples of sediment and muscle tissue of barbell (Barbus peloponnesius, Valenciennes, (1842); Barbus macedonicus, Karaman (1924), collected from the three natural lake ecosystems in the Republic of Macedonia, i.e. Lake Ohrid, Lake Prespa and Lake Dojran, in the period from 2004 to 2006. Special attention has been paid to the presence of the insecticide DDT degradation products, 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (p,p’-DDT), 1,1-dichloro-2,2bis(p-chlorophenyl)ethylene (p,p’-DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (p,p’-DDD), as dominant components in comparison to the other organochlorine pesticides. The results that have been obtained indicated that dominant metabolic forms in the samples of sediment from Lake Ohrid and Lake Prespa is p,p’-DDE. The mean values for the content of this forms has been estimated at 0.84 μg kg-1 dry sediment in the samples collected from Ohrid and 1.56 μg kg-1 dry sediment in the samples from Lake Prespa. In the samples of sediment that have been collected from Lake Dojran, the dominant was the p,p’-DDT form, while it’s content has been estimated at 4.06 μg kg-1 dry sediment. The highest values for the content of the sum of DDT metabolic forms in the fish muscle tissue have been evidenced in the samples of fish collected from Lake Dojran and the average value of this sum has been estimated at 16.38 μg kg-1 fresh tissue. The dominant metabolic forms for the analyzed muscle tissues of fish for all three lake ecosystems has been p,p’-DDE. The content of this form have been estimated at 5.98 μg kg-1, 7.21 μg kg-1 and 9.77 μg kg-1 for the samples collected from Lake Ohrid, Lake Prespa and Lake Dojran, respectively. Thus, the highest evidenced value for the presence of p,p’-DDE has been recorded for the samples collected from Lake Dojran, i.e. 9,77 μg kg-1 fresh tissue.