Distribution and partitioning of mercury in a river catchment impacted by former mercury mining activity
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Mercury distribution and partitioning was studied in the River Idrijca system, draining the area of the former Idrija mercury mine, Slovenia. Mercury dynamics were assessed by speciation analysis of mercury in water and river bed sediment samples during a 2-year study at locations on the River Idrijca and its major tributaries. Simultaneously, the influence of some major physico-chemical parameters that influence the fate of mercury in the aquatic environment was investigated. The distribution of mercury species in the River Idrijca catchment indicated contamination from mine tailings distributed in the town of Idrija and erosion of contaminated soils. The partitioning between dissolved and particulate mercury phases in river water was found to be mostly controlled by the variable content of suspended solids resulting from changing hydrological conditions and complexation with various ligands present in river water, among which dissolved organic carbon (DOC) seems to be the most important. Overall results indicate that mercury is transported downstream from the mining area mainly as finely suspended material including colloids rather than in the dissolved phase. This riverine transport occurs mostly during short, but extreme hydro-meteorological conditions when remobilization of mercury from the river bed sediments occurs. A significant part of the mercury particulate phase in water corresponds to cinnabar particles. During its transport, important Hg transformation mechanisms that increase the risk of mercury uptake by biota take place, evidenced by the increase in the relative contribution of reactive mercury (HgR), dissolved gaseous mercury (DGM) and monomethylmercury (MeHg) downstream from the Idrija mine. However, our data revealed relatively low methylation efficiency in this contaminated river system. We attribute this to the site specific physico-chemical conditions responsible for making inorganic mercury unavailable and limiting the capacity of methylating bacteria.
KeywordsIdrija Mercury River system Sediment Speciation Water
The authors acknowledge financial support from the state budget by the Slovenian Research Agency (L1-0367) and the research group “Cycling of nutrients and contaminants in the environment, mass balances and modeling environmental processes and risk analysis” (P1-0143). The measurements of cations, anions and DOC were performed at University of Michigan, Ann Arbor, USA. For that, special thanks are given to Dr. Lyn Walter. Authors also thank Dr. A. Byrne for linguistic corrections. Dr. J. Kotnik and Dr. S. Žižek are acknowledged for their help with mercury analysis.
- Bonzongo JC, Lyons WB, Hines ME, Warwick JJ, Faganeli J, Horvat M, Lechler PJ, Miller JR (2002) Mercury in surface waters of three mine-dominated river systems: Idrija River, Slovenia; Carson River, Nevada; and Madeira River, Brazilian Amazon. Geochem Explor Environ Anal 2:111–119CrossRefGoogle Scholar
- Boszke L, Glosinska G, Siepak J (2002) Some aspects of speciation of mercury in a water environment. Pol J Environ Stud 11:285–295Google Scholar
- Boszke L, Kowalski A, Gosiska G, Szarek R, Siepak J (2003) Environmental factors affecting the speciation of mercury in the bottom sediments; an overview. Pol J Environ Stud 12:5–13Google Scholar
- Dizdarevič T (2001) The influence of mercury production in Idrija mine on the environment in the Idrija region and over a broad area. RMZ—Mater Geoenviron 48:56–64Google Scholar
- Hissler C, Probst JL, Mortatti J (2006) Annual inorganic mercury speciation in river water disturbed by chlor-alkali effluents: role and competition of ligands (Cl−, Br−, DOC). Geochim Bras 20:133–147Google Scholar
- Horvat M, Zvonarič T, Stegnar P (1987) Determination of mercury in seawater by cold vapour atomic absorption spectroscopy. Acta Adria 28:59–63Google Scholar
- Kobal AB, Horvat M, Prezelj M, Sešek-Briški A, Krsnik M, Dizdarevič T, Mazej D, Falnoga I, Stibilj V, Arnerič N, Kobal D, Osredkar J (2004) The impact of long-term past exposure to elemental mercury on antioxidative capacity and lipid peroxidation in mercury miners. J Trace Elem Med Bio 17:261–274CrossRefGoogle Scholar
- Liang L, Horvat M, Cernichiari E, Gelein B, Balogh S (1996) Simple solvent extraction technique for elimination of matrix interferences in the determination of methylmercury in environmental and biological samples by ethylation-gas chromatography-cold vapor atomic fluorescence spectrometry. Talanta 43:1883–1888CrossRefGoogle Scholar
- O’Driscoll NJ, Beauchamp S, Siciliano SD, Rencz AN, Lean DRS (2003) Continuous analysis of dissolved gaseous mercury (DGM) and mercury flux in two freshwater lakes in Kejimkujik Park, Nova Scotia: evaluating mercury flux models with quantitative data. Environ Sci Technol 37:2226–2235CrossRefGoogle Scholar
- U.S.EPA (1992) Water quality standards, establishment of numeric criteria for priority toxic pollutants, state’s compliance, final ruleGoogle Scholar