title: Fractionation and size-distribution of metal and metalloid contaminants in a polluted groundwater rich in dissolved organic matter.
abstract: We investigated the concentration levels, fractionation and molecular weight distribution (MWD) of dissolved organic matter (DOM) and metals (V, Cr, Co, Ni, Cu, Zn, As, Cd, Sn, Ba, Hg and Pb) in a polluted groundwater from an industrial area in Northern Sweden. DOM was mainly recovered in the hydrophobic acidic and hydrophobic neutral sub-fractions (45 and 35%, respectively) while most metals were found in the acidic sub-fractions (46-93%) except for V, Fe and As, which were predominant in the basic sub-fractions (74-93%) and Cd in the neutral ones (50%). DOM exhibited a broad MWD in groundwaters, usually from 5 to 200kDa and was dominated by high molecular weight hydrophobic acids, low molecular weight hydrophilic acids and hydrophilic neutral compounds. Most of the studied metals (Fe, Cr, Co, Sn, Ba, Hg) were associated with the high molecular weight DOM fraction (ca. 40-100kDa). Cu, Pb, Zn, Cd and Ni interacted with a broad range of DOM size fractions but were still most abundant in the high molecular weight fraction. Few metal/metalloids (As, V and Cr in some cases) presented a very weak affinity for DOM and presumably existed predominantly as "free" inorganic ions in solution.
authors.affiliation: Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden. Electronic address: koziatnik@gmail.com.
authors.forename: Ivan
authors.initials: I
authors.lastname: Kozyatnyk
authors.affiliation: Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Bouchet
authors.affiliation: Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Björn
authors.affiliation: Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Haglund
keywords: Dissolved organic matter; ICP-MS; Metal binding; Molecular weight distribution; Size exclusion chromatography