Significance of submarine groundwater discharge in the coastal fluxes of mercury in Hampyeong Bay, Yellow Sea

Abstract

Submarine groundwater discharge (SGD) and various solutes released with SGD have received particular attention recently; however, understanding of the impact of SGD on trace metal fluxes in the coastal ocean is limited. To understand the contribution of SGD to the coastal Hg input, the Hg mass fluxes associated with SGD were estimated from Hampyeong Bay, a coastal embayment in the Yellow Sea. Hg concentrations in filtered groundwater and seawater ranged from 1.3 to 4.4 pM and from 0.83 to 2.0 pM, respectively, and Hg concentrations in unfiltered seawater ranged from 1.7 to 4.6 pM. The Hg flux estimation showed that SGD was the prime input source of Hg in the bay (18 12 mol yr(-1)), contributing 65% of the total input. Atmospheric deposition was the second dominant source of Hg (8.5 +/- 2.7 mol yr(-1)), contributing 31% to the total input. The results of the current study suggest that SGD can be a significant source of Hg in estuarine/coastal systems; therefore, estimating the coastal mass budgets of Hg must include SGD as a prime source of Hg. (C) 2012 Elsevier Ltd. All rights reserved.