Mercury and methyl mercury release in soil and water - their relationship with different properties in Skogaryd

Abstract

In Skogaryd research site, water samples were taken and analysed for total mercury (Hgtot) and methylmercury (MeHg) concentration along with the pH, dissolved oxygen (DO) and total organic content (TOC). This to give the condition of the site before the forest is clear-cute and a part of the land rewetted to a wetland. To complement the analysis of the water, soil samples was analyses for Hgtot, organic matter content and potential demethylation constant rate (kd). The result of the measurements shows that the Hgtot and MeHg concentrations are low in the area, indicating that Skogaryd is an area with low levels of pollution. Relationship of the Hgtot and MeHg concentrations with pH and DO were found. With higher DO and lower pH levels there will be higher concentrations of Hgtot and lower of the MeHg concentrations, indicating that demethylation of the MeHg under these conditions occurs. The soil analysis showed that there is higher organic content at a depth of 20 – 30 cm, however the highest Hgtot concentrations was found in the 0 – 10 cm depth. The samples with the highest Hgtot also had high organic content, indicating that they might have been needed to do more replicates or that there are other metals bound to the organic matter at the 20 – 30 cm depth. The result of the kd varies over the area, though due to loses of samples available for analyse makes it hard to see if there is a pattern of the variations. The kd does however range in what other studies has found in similar settings.