Determination of water-soluble and insoluble (dilute-HCl-extractable) fractions of Cd, Pb and Cu in Antarctic aerosol by square wave anodic stripping voltammetry: distribution and summer seasonal evolution at Terra Nova Bay (Victoria Land)

Abstract

Eight PM10 aerosol samples were collected in the vicinity of the "Mario Zucchelli" Italian Antarctic Station (formerly Terra Nova Bay Station) during the 2000-2001 austral summer using a high-volume sampler and precleaned cellulose filters. The aerosol mass was determined by differential weighing of filters carried out in a clean chemistry laboratory under controlled temperature and humidity. A two-step sequential extraction procedure was used to separate the water-soluble and the insoluble (dilute-HCl-extractable) fractions. Cd, Pb and Cu were determined in the two fractions using an ultrasensitive square wave anodic stripping voltammetric (SWASV) procedure set up for and applied to aerosol samples for the first time. Total extractable metals showed maxima at midsummer for Cd and Pb and a less clear trend for Cu. In particular, particulate metal concentrations ranged as follows: Cd 0.84-9.2 microg g(-1) (average 4.7 microg g(-1)), Pb 13.2-81 microg g(-1) (average 33 microg g(-1)), Cu 126-628 microg g(-1) (average 378 microg g(-1)). In terms of atmospheric concentration, the values were: Cd 0.55-6.3 pg m(-3) (average 3.4 pg m(-3)), Pb 8.7-48 pg m(-3) (average 24 pg m(-3)), Cu 75-365 pg m(-3) (average 266 pg m(-3)). At the beginning of the season the three metals appear widely distributed in the insoluble (HCl-extractable) fraction (higher proportions for Cd and Pb, 90-100%, and lower for Cu, 70-90%) with maxima in the second half of December. The soluble fraction then increases, and at the end of the season Cd and Pb are approximately equidistributed between the two fractions, while for Cu the soluble fraction reaches its maximum level of 36%. Practically negligible contributions are estimated for crustal and sea-spray sources. Low but significant volcanic contributions are estimated for Cd and Pb (approximately 10% and approximately 5%, respectively), while there is an evident although not quantified marine biogenic source, at least for Cd. The estimated natural contributions (possibly including the marine biogenic source) cannot account for the high fractions of the metal contents, particularly for Pb and Cu, and this suggests that pollution from long-range transport is the dominant source.

Atmospheric trace elements in aerosols observed over the Southern Ocean and coastal East Antarctica

“…60% of the atmospheric Se budget (Weller et al 2008). In general, the concentrations of Ni, Cd and Se observed during this study were low and comparable with previous observations (Rä dlein & Heumann 1992, 1995Annibaldi et al 2007;Weller et al 2008). …”

On site stripping voltammetric determination of Zn(II), Cd(II) and Pb(II) in water samples of the Cananéia-Iguape Estuarine-Lagoon complex in São Paulo state, Brazil

“…Hence, the acid-soluble fraction of the metallic ions was calculated as the ratio of the acid-soluble concentration to the total concentration, and values of 30, 29 and 50% were found for Zn(II), Cd(II), and Pb(II), respectively. These values are consistent with those obtained by Annibaldi et al, 11 who found that ions complexed with organic matter became soluble by adding hydrochloric acid.…”

“…[6][7][8] For instance, the use of stripping voltammetric methods for the determination of various toxic metallic ions in seawater has been reported. [9][10][11][12] Mercury-based electrodes have been used in stripping techniques because of their high area reproducibility, but the use of bismuth films presents an attractive alternative to the mercury films owing to their environmentally friendly nature, as well as their easy preparation, high sensitivity, well-defined and undistorted stripping signals, and excellent neighboring peak resolution. [13][14][15][16][17][18][19][20] Additional sensitivity is obtained if electroanalytical determinations are performed with microelectrodes.…”

“…A simplified, three-fraction scheme has been recently proposed 11 and includes the following: (i) the watersoluble fraction, (ii) the insoluble/dilute-acid-extractable fraction and (iii) the insoluble/residual fraction. The first fraction contains free ions and soluble salts such as chlorides, sulfates, nitrates and acetates.…”

Sensitive Determination of Trace Pb2+ in Seawater Using Columnar Glassy Carbon Electrode

“…[2][3][4] Commonly, mercury-based electrodes are used as working electrodes due to their ability to form amalgams, allowing for preconcentration of the heavy metal ions prior to their determination by voltammetric stripping methods. 2,[5][6][7][8] However, in recent years, the potential dangers associated with mercury have brought about a growing interest in the use of environmentally-friendly, mercury-free electrodes. 9,10 Glassy carbon is a kind of ideal material for working electrode as the result of its intrinsic advantages: low ohmic resistance, chemical and electrochemical inertness over a broad range of potentials, high hydrogen and oxygen overvoltage resulting in a wide potential window, low residual current, ease of reproduction of the surface, maximum versatility, low cost and no toxicity.…”