Abstract

During August 2004, mercury (Hg) flux-rates from surface soil were measured at an abandoned gold mining site near Seal Harbour, Nova Scotia. The Hg amalgamation process, used to isolate gold, produced areas of Hg-laden mine tailings. Diurnal measurements of the soil surface exchange of gaseous Hg to the atmosphere and meteorological data from two tailing deposit sites are discussed. These sites have different mining histories resulting in differing levels of Hg in the surface soil (0.05 µg g−1 - Site 1, 23 µg g−1- Site 2). Site 1 showed a maximum flux-rate during mid-day at 60 ng m−2 hr−1, declining to c. 5 ng m−2 hr−1 during evening while Site 2 had a mid-day Hg flux-rate of 1292 ng m−2 hr−1 with levels of c. 300 ng m−2 hr−1 during the evening. Mercury flux from each site has continuous diurnal Hg evasion at the soil surface. Correlations of Hg flux-rate with soil temperature, air temperature and solar radiation were evident at both sites and an Arrhenius-type relation of Hg flux with soil temperature was also evident. Data from these sites were compared to flux experiments conducted at impacted and other non-impacted sites in Nova Scotia.

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