Seasonal variations of heavy metals in water, sediments, pondweed (P. pectinatus L) and freshwa-ter fish (C. c. umbla) of lake hazar (Elaziğ-Turkey)

In this study concentrations of heavy metals, such as, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined in water, sediment, sago pondweed (Pot?mogeton pectinatus L.) and muscle, liver and gill of freshwater fish (Capoeta capoeta umbla) collected seasonally from three selected sites of Hazar Lake. The heavy metal concentrations ob- tained from water samples were low. Among the metals, the highest concentrations in water samples were found for Fe. In the sediment samples, the highest concentration was recorded for Mn and the lowest for Pb in all seasons and sites. The metal concentrations determined in sago pond- weed varied seasonally. The highest levels of Fe, Mn and Zn values in sago pondweed were in spring. Heavy metal concentrations varied significantly depending on the type of the tissue and season. The highest metal concentrations were found in liver, followed by gill and muscle. Heavy metal levels in tissues of freshwater fish C. c. umbla were increased in summer and winter, while were decreased in autumn and spring. The present study shows that precau- tions need to be taken in Hazar Lake in order to prevent heavy metal pollution that can occur in the future.