Mercury pollution in doha (Qatar) coastal environment

Abstract

Surface water and sediment samples were collected from the Doha coastal area and analyzed for content of physico-chemical forms of mercury. Dissolved reactive Hg (2.9 ng L?1) represented 81.0% of the total dissolved Hg (3.5 ng L?1). Organic Hg (0.6 ng L?1) contributed only 5.0% of total Hg. Mercury showed a strong tendency to be associated with suspended matter in Doha coastal waters, as it represented about 73.0% of the total. Total Hg in bulk Doha surface sediments fluctuated between 0.14 and 1.75 ?g g?1 dry weight, with an average of 0.54 � 0.46 ?g g?1 dry weight. The sediment fraction past 63 ?m contained 0.73 ?0.60?g g?1 dry weight total Hg. Leachable and methyl Hg averaged 0.10 � 0.11 and 0.02 �0.03 ?g g?1 dry weight, respectively, in the <63-?m sediment fraction. There is a general trend for all Hg species determined in water and sediments to decrease seaward. The significantly elevated Hg levels at certain locations indicated that the main Hg sources to Doha coastal environment are leachate from the solid waste disposal site, the two harbors, and surface-water discharge.