Thallium and cadmium in recent snow and firn layers in the Canadian Arctic by atomic fluorescence and absorption spectrometries

Abstract

Compared to the Antarctic and Greenland, the Canadian Arctic has seen extremely few trace metal studies on snow and ice. Surface, subsurface and depth samples of snow and firns were collected from the Agassiz Ice Cap, Ellesmere Island, Canada using clean room practices. Results for Tl (directly determined by LEAFS) and Cd (determined by GFAAS) are reported. To our knowledge, the thallium depth profile presented here is the first one so far reported for both polar systems, Greenland or other places. Tl concentrations peak in the winter-spring periods, when the Arctic atmosphere is loaded with foreign pollutants and suspended particulates which sometime severely reduce the visibility, creating a phenomenon commonly known as the Arctic haze. These results are in general accordance with the historical Arctic air pollution and acidity/conductivity data on ice cores. Surface concentrations of Tl range from 0.3 to 0.9 pg/g, which is a few times higher than those found in Antarctica. Cadmium shows seasonal characteristics similar to Tl although there is not a definite correlation between the two. However, there could be two predominant origins of metals which were deposited in the snow: Eurasian origin in January-April corresponding to high level metals (main deposition), and a less definite origin in May-December corresponding to low level metals.

Coal burning leaves toxic heavy metal legacy in the Arctic

“…Few studies of Tl in the Arctic have been reported (8), although historical records of Tl deposition in central Europe have been developed from peat bogs (9). Tl is highly toxic and listed by the U.S. Environmental Protection Agency as a priority pollutant (5).…”

“…Heavy metal measurements in polar ice cores are relatively few, and our continuous ACT2 measurements of Pb and Cd are in general agreement with these other measurements. To our knowledge, no measurements of Tl in Arctic ice cores have been published previously, although snow pit samples from the Agassiz Ice Cap in northeastern Canada have been reported (8).…”

Speciation and determination of thallium by on-line microcolumn separation/preconcentration by flow injection–flame atomic absorption spectrometry using immobilized oxine as sorbent

“…However as the total concentration of thallium in aquatic environment is very low an analytical technique featuring high sensitivity and low detection limit is required. Inductively coupled plasma mass spectrometry (ICP-MS) [2][3][4] laser-exited atomic florescence spectrometry (LEAFS) [5] and electhrothermal atomic absorption spectrometry [6][7][8][9][10] (ETAAS) had been used for determination of thallium, but ICP-MS is an expen- * Corresponding author. Tel.…”

Determination of thallium traces by ETAAS after on-line matrix separation and preconcentration in a flow injection system

“…Thallium had been determined by inductively coupled plasma mass spectrometry (ICP-MS) [6][7][8] and laser-excited atomic fluorescence spectrometry (LEAFS). 9 However, ICP-MS is an expensive analytical method and incurs high running cost, and LEAFS is less frequently used. 9 Electrothermal atomic absorption spectrometry (ETAAS) appears to be the method of choice for determination of metal at very low concentration.…”

“…9 However, ICP-MS is an expensive analytical method and incurs high running cost, and LEAFS is less frequently used. 9 Electrothermal atomic absorption spectrometry (ETAAS) appears to be the method of choice for determination of metal at very low concentration. 10 This very sensitive and relatively simple method has been used by several workers for determination of thallium.…”