İzmir Körfezi?ndeki organizmalarda civa birikimi ve türlerinin değerlendirilmesi

Izmir Bay is impacted by organic matter, oil and heavy metals. In this study, total mercury (THg) and methylmercury (MeHg) concentrations and the MeHg to THg ratio (%MeHg) were investigated in 297 individuals of three different species from the Izmir Bay. Biota samples were collected by trawling at 4 sampling stations during R/V K. Piri Reis cruise in the Izmir Bay between February and September 2005. The concentrations of total mercury (by cold vapour atomic absorption spectrophotometer) and methylmercury (by gas chromatography-electron capture detector) were detected in fish samples from the Izmir Bay. The levels of total mercury and methylmercury in fish tissue, ranging from 4.4 to 221.4 ug THg/kg wet wt. and 3.8-194.8 ug MeHg/kg wet wt., varied according to sampling point and season. Total and MeHg concentrations in fish differed between species and the mean levels of total mercury were 90.7 and 63.1 ug/kg wet wt. for annular sea bream (Diplodus annularis) and red mullet (Mullus barbatus), respectively. The percentages of methylated form to total mercury ranged from a minimum of 84 % in red mullet to a maximum of 98 % in annular sea bream. The positive relationship between specimen size and total mercury and methylmercury concentrations were found in red mullet. ANOVA were utilized to investigate effect of season, species and sampling area on variations in mercury concentrations. The significant differences between seasons for THg and MeHg were found in fish samples. The highest mercury concentrations were found in September, while the lowest were detected in February. None of the fish analysed was 0.500 ug/g THg, and exceed the WHO limit.