Mercury uptake and transport in the marine environment

It has been widely reported that methylation of mercury (Hg) into its toxic methylmercury (MeHg) form occurs by biotic and abiotic processes, and that the transformation processes are influenced by several factors such as pH, temperature, sulphate deposition, and availability of biodegradable organic carbon. Although the marine environment acts as a sink for Hg and its compounds, it is probably one of the least understood in terms of Hg transformation processes and its bioavailability and bioaccumulation in biota. This paper reviewed the pathways of Hg in terms of its speciation, uptake and transport in the marine environment and associated biota. The review indicates a paucity of data on Hg in the marine environment. As can be expected piscivorous predators in the marine environment have relatively higher MeHg concentrations in blood than non-piscivorous animals in the terrestrial environment. A comparison of Hg exposure and impacts in New Zealand, Seychelles and the Faroe Island is also made, and recommendations for further research in the marine environment are presented