Study of organochlorine pesticide residues in water, sediment and fish tissue in lake Ohrid (Macedonia/Albania)

Abstract

A systematic study has been performed for determination of a range of organochlorine pesticides in the water, sediments and fish samples in the Macedonian part of the Lake Ohrid and its larger tributaries. The obtained results give an overview of the contamination levels of these problematic compounds (i) at their potential sources in the river mouths, (ii) in the potentially affected, species-rich littoral section of the lake, and (iii) in the muscle tissue of one selected fish species Barbus peloponnesius, Valenciennes, collected near the rivers' deltas. The organochlorine pesticides measured in all three matrixes were: γ-HCH, ΣHCH (sum of α-isomer, β-isomer and δ-isomer), endosulfan (total of α and β endosulfan), DDT metabolites (p,p'-DDE, p,p'-DDD and p,p'-DDT). The range of the observed concentrations for p,p'-DDT was between 0.006 μg l-1 in the water samples from Daljan and St. Naum and 0.036 μg l-1 in the water from the Koselska River. The values for p,p'-DDT measured in dry sediment ranged from 0.121 μg kg-1 in the sample from St. Naum to 1.8 μg kg-1 in the dry sediment from the Velgoška River and between 0.553 μg kg-1 for total endosulfan and 5.982 μg kg-1 for p,p'-DDE of wet fish biomass. The most abundant of the detected organochlorine pesticides was the sum of DDT metabolic forms, i.e. p,p'-DDT, p,p'-DDE and p,p'-DDD. The detected concentrations are clearly below toxic thresholds and consequently severe effects on the endemic species of Lake Ohrid are not very likely.