Environmental Characterization of Lake Ecosystems Located in Serbo Macedonian Massif (FYRM)

Abstract

This chapter represents the mineralogical, geochemical and isotopic characteristics of recent lacustrine sediments, shells of the Anodonta cygnea and fish species (Rutilus rutilus dojranensis) from the Lake Dojran (FY Republic of Macedonia, southern part of the Serbo-Macedonian Massif (SMM)) which provide indirect evidence regarding biomineralization and calcification processes as well as various geological problems. Environmental pollution can seriously contribute to different biological processes concerning the condition of physiological secretion of carbonate material into the shells. For comparison, sediments and fish species V. melanops from the Lake Kalimanci, located in northern part of the SMM, were also implicated into the study. X-ray powder diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS) and C and O stable isotope analyses were performed, and thereupon enrichment factor (EF) values were calculated. The XRD results revealed close association of sediment mineralogy with the prevailing metamorphic, volcanic and igneous rocks of the region surrounding both lakes (Dojran and Kalimanci). According to the EF value results, surficial Lake Dojran sediments are little enriched with Co, Cr, Cu, Pb, and Zn, moderately enriched with Au, Ni and Sb, moderately severely enriched with Au, severely enriched with Sb and very severely enriched with As. This elemental enrichment originates from various geogenic (geological background and polymetallic mineralization) and anthropogenic (tourism, traffic, coatings, untreated wastewater discharge and agrochemicals) sources. Calculated EF revealed that surficial sediments from Lake Kalimanci are extremely severe enriched with Pb, Zn, and Cd, meanwhile As and Cu shows very severe enrichment. Comparing to Lake Dojran, calculated EF is much higher in Lake Kalimanci than in Dojran. Stable isotope signature results showed that Lake Dojran sediments were strongly influenced by evaporation effect. Their δ18O values range from -5.60 to +1.49 ‰ and the δ13CVPDB composition range from -6.45 to -1.65 ‰. Shells Anodonta cygnea are mainly composed from mineral aragonite and their δ18O values varies between 0.43 ‰ and +1.94 ‰, and δ13CVPDB between -2.48 to -1.72 ‰. δ18O signature in shells might be explained by precipitation of the carbonate from isotopically heavier oxygen lake water. The unussualy heavy skeletal oxygen suggested calcification at the elevated temperature and evaporation. Analyses also identified particularly high levels for Cr, Hg, Ni and Pb in fish (V. Melanops) and frog (R. Temporaria) samples from Lake Kalimanci with mean values [µgkg-1]: 1090 – 6.5, 339 – 117, 567 – 5100 and 1127 – 435, respectively. Meanwhile, the contents of Cr, Hg, Ni and Pb in fish samples (R. rutilus dojranensis) from Lake Dojran are a bit lower [µgkg-1]: 2320, 1690, 700 and 50.