Mercury in the Izmir Bay: An assessment of contamination

Abstract

The levels of mercury in suspended particulate matter, sediment, plankton and fish were investigated in Izmir Bay (Eastern Aegean). The study aimed to assess the level of mercury in different environmental compartments of the Izmir Bay. Seasonal (dry and wet season) and spatial variations in suspended particulate Hg concentrations showed that pluvial transport is the major pathway to the bay. Suspended particulate matter was the main vehicle for carrying mercury from land based sources to the bay. Gediz River and inactive mining sites (Karaburun) were the most important inputs of mercury to the outer bay. Hg concentrations ranged from 0.70 to 28.7 nmol g − 1 (dry weight) in suspended particulate, from 0.60 to 3.19 nmol g − 1 (dry weight) in plankton, from 0.20 to 3.14 nmol g − 1 (dry weight) in sediment and from 0.05 to 4.54 nmol g − 1 (wet weight) in organisms. Plankton, sediment Hg concentrations and its organic matter contents increased from outer bay to middle–inner bays. Based on the correlation matrix obtained for mercury data, organic matter was the dominant factor controlling Hg distribution in the sediment. There was a correlation between fish length and Hg (muscle tissue) concentrations in Mullus barbatus and Merluccius merluccius. In the other species these were not related to fish length. The maximum permissible mercury limit accepted by WHO for edible parts of marine organisms is 3.5 nmol g − 1 (wet weight); our results indicated that Merlangius merlangus and Pagellus erythrinus exceed this limit.