A laboratory based experimental study of mercury emission from contaminated soils in the River Idrijca catchment

Abstract

Abstract.Results obtained by a laboratory flux measurement system (LFMS) focused on investigating the kinetics of the mercury emission flux (MEF) from contaminated soils of the Idrija Hg-mine region, Slovenia are presented. Representative soil samples with respect to total Hg concentrations (4-417 µg g −1 ) and land cover (forest, meadow and alluvial soil) alongside the River Idrijca were analysed to determine the variation in MEF versus distance from the source, regulating three major environmental parameters comprising soil temperature, soil moisture and solar radiation. MEFs ranged from less than 2 to 530 ng m −2 h −1 , with the highest emissions from contaminated alluvial soils and soils near the mining district in the town of Idrija. A significant decrease of MEF was then observed with increasing distance from these sites. The results revealed a strong positive effect of all three parameters investigated on momentum MEF. The light-induced flux was shown to be independent of the soil temperature, while the soil aqueous phase seems to be responsible for recharging the pool of mercury in the soil available for both the light-and thermally-induced flux. The overall flux response to simulated environmental conditions depends greatly on the form of Hg in the soil. Higher activation energies are required for the overall process to occur in soils where insoluble cinnabar prevails compared to soils where more mobile Hg forms and forms available for transformation processes are dominant.

Air–surface exchange of gaseous mercury over permafrost soil: an investigation at a high-altitude (4700 m a.s.l.) and remote site in the central Qinghai–Tibet Plateau

“…The dynamic flux chamber (DFC) technique was widely used to investigate Hg(0) flux between the air and surface because it is inexpensive, portable, easy to set up and operate (e.g., Kim and Lindberg, 1995;Carpi and Lindberg, 1998;Gustin et al, 2006;Wang et al, 2006;Dommergue et al, 2007;Fu et al, 2008a;Kocman and Horvat, 2010;Edwards and Howard, 2013). Air-surface Hg(0) flux obtained by DFC technique was calculated using Eq.…”

“…2). Many studies have confirmed that solar radiation is one of the most important drivers for soil Hg(0) emission Choi and Holsen, 2009;Kocman and Horvat, 2010); high surface temperature also facilitates Hg(0) production and subsequent emission (Park et al, 2014). Therefore, the two environmental variables jointly regulate the diurnal pattern of Hg(0) flux.…”

“…Therefore, many experiments studied the effect of water addition on the magnitude and pattern of air-soil Hg(0) flux over different timescales (Johnson et al, 2003;Gustin and Stamenkovic, 2005). However, most of studies were performed in controlled laboratory or mesocosm settings under certain well-defined but not necessarily environment relevant conditions (Johnson et al, 2003;Gustin et al, 2004;Gustin and Stamenkovic, 2005;Song and Van Heyst, 2005;Kocman and Horvat, 2010;Corbett-Hains et al, 2012;Park et al, 2014). In this study, it was also challenging to reveal the effect of rainfall on Hg 0 via field measurement since the intermittent rain events occurred irregularly during the June 2014 and September 2014 campaign (Fig.…”

“…Measurements across various types of soils and climates show that air-soil Hg(0) exchange has highly spatial and temporal variation and bidirectional exchange behavior (Agnan et al, 2016, and references therein). Field measurements and laboratory experiments highlight that various factors and processes influence air-surface Hg(0) exchange, including concentrations and species of soil Hg (Gustin et al, 1999(Gustin et al, , 2002Hintelmann et al, 2002;Bahlmann et al, 2006; Z. Ci et al: Air-surface exchange of gaseous mercury over permafrost soil Kocman and Horvat, 2010;Eckley et al, 2011;Edwards and Howard, 2013;Mazur et al, 2015), solar radiation (Gustin et al, 2002Moore and Carpi, 2005;Fu et al, 2008a;Kocman and Horvat, 2010;Park et al, 2014), precipitation (Lindberg et al, 1999;Gustin and Stamenkovic, 2005;Gabriel et al, 2011), soil temperature and moisture (Gustin et al, 1997;Gustin and Stamenkovic, 2005;Ericksen et al, 2006;Briggs and Gustin, 2013;Park et al, 2014;Mazur et al, 2015), soil organic matter and pH (Yang et al, 2007;Mauclair et al, 2008), land cover (Dommergue et al, 2003;Ericksen et al, 2005;Cobbett et al, 2007;Gabriel and Williamson, 2008;Zhu et al, 2011;Durnford et al, 2012a, b;Toyota et al, 2014a, b), atmospheric Hg(0) concentrations and other chemical compositions (Engle et al, 2004;Fu et al, 2008a), biological activity…”

Global observations and modeling of atmosphere–surface exchange of elemental mercury: a critical review

“…Soil types, soil moisture and Hg content in soil are also important factors influencing observed Hg 0 flux (Xu et al, 1999;Kocman and Horvat, 2010;Lin et al, 2010a). observed that rainfall and irrigation enhances soil Hg 0 emission by 1 order of magnitude.…”