Determination of mercury content in a shallow firn core from Greenland by isotope dilution inductively coupled plasma mass spectrometry

• Published in: Water, air, and soil pollution air, and soil pollution, 2005-05, Vol.163 (1-4), p.19-32
• Main Authors: Mann, J.L, Long, S.E, Shuman, C.A, Kelly, W.R
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Applied sciences; Atmospheric pollution; chemical concentration; Chemistry; Environmental monitoring; Exact sciences and technology; Firn; glacier snow; isotope dilution technique; Mass spectrometry; Mass spectroscopy; Mercury; Natural water pollution; pollutants; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution; Rainwaters, run off water and others; Scientific imaging; Snow; Spectrometric and optical methods; Trace levels; Vapors; Water treatment and pollution
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-005-7607-y

The total mercury content was determined in 6 cm sections of a shallow 7 m firn core and in surrounding surface snow from Summit, Greenland (elevation: 3238 m, 72.58^sup ^N, 38.53^sup ^W) collected in May 2001 by isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICP-MS). The focus of this research was to evaluate the capability of the ID-CV-ICP-MS technique for measuring trace levels of Hg typical of polar snow and firn. Highly enriched ^sup 201^Hg isotopic spike is added to approximately 10 mL melted core and thoroughly mixed. The Hg^sup 2+^ in the sample is reduced on line with tin(II) chloride (SnCl^sub 2^) and the elemental Hg (Hg^sup ^) vapor pre-concentrated onto gold gauze using a commercial amalgam system. The Hg is then thermally desorbed and introduced into a quadrupole ICP-MS. The blank-corrected Hg concentrations determined for all samples ranged from 0.25 to 1.74 ng/L (ppt) (average 0.59 ± 0.28 ng/L (1σ)) and fall within the range of those previously determined by Boutron et al. [Geophys. Res. Lett. 25, 1998, 3315-3318] (≤ 0.05-2.0 ng/L) for the Summit site. The average blank value was 0.19 ± 0.045 ng/L (n = 6, 1σ) and the method detection limit was 0.14 ng/L. The Hg values specifically for the firn core range from 0.25 to 0.87 ng/L (average 0.51 ± 0.13 ng/L (1σ)) and show both values declining with time and larger variability in concentration in the top 1.8 m.[PUBLICATION ABSTRACT]