title: Characteristics of mercury speciation in Minnesota rivers and streams.
abstract: Patterns of mercury (Hg) speciation were examined in four Minnesota streams ranging from the main-stem Mississippi River to small tributaries in the basin. Filtered phase concentrations of methylmercury (MeHg), inorganic Hg (IHg), and dissolved organic carbon (DOC) were higher in all streams during a major summertime runoff event, and DOC was enriched with MeHg but not with IHg. Particulate-phase MeHg and IHg concentrations generally increased with total suspended solids (TSS) concentrations but the event data did not diverge greatly from the non-event data, suggesting that sources of suspended sediments in these streams did not vary significantly between event and non-event samplings. The dissolved fractions (filtered concentration/unfiltered concentration) of both MeHg and IHg increased with increasing DOC concentrations, but varied inversely with TSS concentrations. While MeHg typically constitutes only a minor portion of the total Hg (THg) in these streams, this contribution is not constant and can vary greatly over time in response to watershed inputs.
authors.affiliation: Metropolitan Council Environmental Services, 2400 Childs Road, St. Paul, MN 55106-6724, USA. steve.balogh@metc.state.mn.us
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Balogh
authors.forename: Edward B
authors.initials: EB
authors.lastname: Swain
authors.forename: Yabing H
authors.initials: YH
authors.lastname: Nollet
mesh_terms: D002244:Carbon / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D008628:Mercury / Q000032:analysis*; D008767:Methylmercury Compounds / Q000032:analysis; D008910:Minnesota; D052638:Particulate Matter; D011891:Rain; D045483:Rivers / Q000737:chemistry*; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008767:Methylmercury Compounds; D052638:Particulate Matter; D014874:Water Pollutants, Chemical; D002244:Carbon; D008628:Mercury