Mercury isotope analysis of sediments from Gunneklevfjorden – Method evaluation and a preliminary investigation of sources

Gunneklevfjorden in south Norway is an aquatic system where the pollution history includes decades of local industry releases and emissions. An accurate estimate of the importance of ongoing and historic sources is critical in evaluating the potential success of sediment remediation strategies. Here, we utilize a high-resolution analytical method to investigate the isotopic composition of mercury (Hg) from a selection of potential Hg sources compared to the composition found in the fjord sediments. The distinct differences in the isotopes signature (δ202Hg and Δ199Hg) from the potential sources suggests that Hg in Gunneklevfjorden sediment and suspended particles in the water column largely has originated from a source with a signature similar to the chlorine factory waste at Herøya. The results also support the previous assumption that resuspended sediment contributes to the outflow of Hg from the fjord.