The distribution and inventory of total and methyl mercury in Kuwait Bay

Sediment (surface and core) sampling was conducted during the period from August 96–December 98 from intertidal and offshore areas in Kuwait Bay. The highest (and most variable) concentrations of total mercury (T-Hg; 36 500 ± 34 930 ng g−1) are encountered around the previous industrial outfall where sediments are disturbed by shipping activities. The concentrations of T-Hg are lower in the Shuwaikh Port area (650 ± 210 ng g−1) and continue to decrease towards the northern coastline of Kuwait Bay (average concentrations in the wider Bay region are 50 ± 30 ng g−1). These values are still above background concentrations of 15–20 ng g−1. Calculation of the total inventory of mercury in all the surface sediments of the studied area indicates that 22.5 ton is present which is similar to the estimated industrial discharges of 20 ton suggesting that the contamination is largely confined to the Bay and that releases to the wider Gulf region are small. The distributions of MeHg are similar to those of T-Hg and represent ranges between 0.23% and 0.5% of the T-Hg indicating that surface sediments within Kuwait Bay contain 80 kg of this chemical.