Abstract
In this study, a new sampler for the determination of dissolved gaseous mercury (DGM) in seawater was developed. Using this sampler, the analytical procedures from seawater sampling to purge and trap of DGM can be handled without any decanting processes, by which the volatilization loss of DGM from samples is driven. The DGM concentration was a maximum of 27% higher using the new sampler compared to that with other sampling methods that had decanting processes. It was clear that the average loss of DGM caused by the decanting processes was – 15 ± 10% (N = 12). Thus, more accurate measurements of DGM in seawater were achieved using the new sampler with no decanting processes. The concentrations of DGM in the surface seawater in the eastern part of the Seto Inland Sea and Minamata Bay were measured using the new sampler. The results indicate that the DGM concentrations in the Seto Island Sea and Minamata Bay were 61 ± 19 pg L−1 and 182 ± 95 pg L−1, respectively. On the basis of the observed data, mercury emission fluxes were calculated using an existing gas exchange model for sea surface. Then, the influences of the loss of DGM due to the decanting processes in sampling on the estimating mercury fluxes were evaluated.
