title: Antarctic snow: metals bound to high molecular weight dissolved organic matter.
abstract: In this paper we studied some heavy metals (Cu, Zn, Cd, Pb, As, U) probably associated to high molecular weight organic compounds present in the Antarctic snow. Snow-pit samples were collected and analysed for high molecular weight fraction and heavy metals bound to them by means of ultrafiltration treatment. High molecular weight dissolved organic matter (HMW-DOM) recovered by ultrafiltration showed a dissolved organic carbon concentration (HMW-DOC) of about 18-83% of the total dissolved organic carbon measured in Antarctic snow. The characterisation of HMW-DOM fraction evidenced an ageing of organic compounds going from surface layers to the deepest ones with a shift from aliphatic compounds and proteins/amino sugars to more high unsaturated character and less nitrogen content. The heavy metals associated to HMW-DOM fraction follows the order: Zn > Cu > Pb >> Cd ∼ As ∼ U. The percentage fraction of metals bound to HMW-DOM respect to total metal content follows the order: Cu >> Pb > Zn, Cd in agreement with humic substance binding ability (Irwing-William series). Going down to depth of trench, all metals except arsenic, showed a high concentration peak corresponding to 2.0-2.5 m layer. This result was attributed to particular structural characteristic of organic matter able to form different type of complexes (1:1, 1:2, 1:n) with metals.
authors.affiliation: The Italian National Institute for Environmental Protection and Research (ISPRA), Via Vitaliano Brancati, 48, 00144, Rome, Italy. Electronic address: nicoletta.calace@isprambiente.it.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Calace
authors.affiliation: ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. Casaccia, Via Anguillarese 301, 00123, Rome, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Nardi
authors.affiliation: The Italian National Institute for Environmental Protection and Research (ISPRA), Via Vitaliano Brancati, 48, 00144, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Pietroletti
authors.affiliation: The Italian National Institute for Environmental Protection and Research (ISPRA), Via Vitaliano Brancati, 48, 00144, Rome, Italy.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Bartolucci
authors.affiliation: ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. Casaccia, Via Anguillarese 301, 00123, Rome, Italy.
authors.forename: Massimiliana
authors.initials: M
authors.lastname: Pietrantonio
authors.affiliation: ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. Casaccia, Via Anguillarese 301, 00123, Rome, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Cremisini
mesh_terms: D000864:Antarctic Regions; D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D002244:Carbon / Q000032:analysis; D004784:Environmental Monitoring; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry; D008970:Molecular Weight; D009930:Organic Chemicals / Q000032:analysis* / Q000737:chemistry; D012914:Snow / Q000737:chemistry*; D014462:Ultrafiltration
chemical_list: D019216:Metals, Heavy; D009930:Organic Chemicals; D002244:Carbon; D001151:Arsenic
keywords: Antarctic snow; Heavy metals; High molecular weight organic substances; Ultrafiltration