Recent Metal Pollution in Agassiz Ice Cap

Abstract

Metal data for Pb, Zn, Al, Cd, and Tl show seasonal variations of high levels during the winter−early spring period and low levels during the summer−fall period. In terms of Pb magnitudes and seasonal variations, our data of the late 1980s and early 1990s (unleaded gasoline era) appear compatible with those of Murozumi et al. (Murozumi, M.; Chow, T. J.; Patterson, C. C. Geochim. Cosmochim. Acta 1969, 33, 1247−1294.) of the 1950s and 1965 (leaded gasoline era). This is probably due to the close proximity and similar elevation of the two areas (Agassiz Ice Cap, Canadian Arctic and Camp Century, northwest Greenland), which are likely subjected to the same polluted air masses. Despite the implementation of unleaded gasoline since the early 1970s, our data show that the Agassiz Ice Cap still received a significant amount of lead during the late 1980s and early 1990s; this is in contrast to Summit, Greenland, which saw a very drastic decrease of the element during similar periods. This is because of the different locations and altitudes, as well as different sources, mainly Eurasian for Agassiz versus mainly U.S. for Summit. Lead was determined by laser-induced fluorescence spectrometry via the direct injection of microliter sample sizes. Its fallout flux was estimated to be 1.2 ng cm-2 year-1. The lead concentration in the surface snow appears to follow the order of Agassiz and northwest Greenland > central Greenland > Antarctica.

Bryophytes as Heavy Metal Biomonitors in the Canadian High Arctic

“…Lake sediment profiles from a single high arctic (NW Greenland) locality and several low arctic localities (Baffin Island) have revealed nonsignificant reduction in atmospheric deposition of heavy metals over the last ,140 years (Michelutti et al, 2009). As well, other proxy data from high arctic ice cores (Cheam et al, 1998;Zheng et al, 2007) and atmospheric aerosols (Gong and Barrie, 2005) indicate a general reduction of heavy metals, although nonsignificant. European contamination studies utilizing mosses have also noted a general reduction in heavy metal concentrations over the past few decades (Steinnes et al, 2003;Poikolainen et al, 2004;TABLE 3 Average and median enrichment factors (EFs) values for heavy metals (As, Cr, Cu, Ni, Pb, and Zn) Average and standard deviation (1s) Pb-isotope ratios of bryophytes from each study area and years collected are presented along with values of arctic aerosols presented in Mercier et al (2001).…”

“…Seasonal fluctuations in heavy metal concentrations in the High Arctic have been observed in Alert atmospheric aerosols (Sturges and Barrie, 1989;Mercier et al, 2001;Gong and Barrie, 2005) and ice cores of the Agassiz Ice Cap from Ellesmere Island (Cheam et al, 1998). These fluctuations indicate different source regions for heavy metals deposited in the High Arctic (Sturges and Barrie, 1989;Mercier et al, 2001;Gong and Barrie, 2005).…”

“…Temporal changes of heavy metal deposition to the Canadian Arctic have been investigated in several different environmental archives such as lake sediment profiles (Michelutti et al, 2009), glacial ice cores (Cheam et al, 1998;Zheng et al, 2007), and atmospheric aerosols (Gong and Barrie, 2005). Lake sediment profiles from a single high arctic (NW Greenland) locality and several low arctic localities (Baffin Island) have revealed nonsignificant reduction in atmospheric deposition of heavy metals over the last ,140 years (Michelutti et al, 2009).…”

“…Recent studies of heavy metal accumulation in Canadian arctic biota has focused on polar bears (Rush et al, 2008), arctic hare (Pedersen and Lierhagen, 2006), birds (Braune and Scheuhammer, 2008;Wayland et al, 2008), or fish (Campbell et al, 2005;Evans et al, 2005;Gantner et al, 2009). Studies of abiotic systems have focused on glacier ice cores (Cheam et al, 1998;Zheng et al, 2007), marine systems (Crane et al, 2001;Kirk et al, 2008), atmospheric aerosols (Mercier et al, 2001;Gong and Barrie, 2005), and lake sediments (Outridge et al, 2002(Outridge et al, , 2005Michelutti et al, 2009). Accumulation of heavy metals that indicate anthropogenic influence have been found in both biotic and abiotic components of arctic ecosystems.…”

Introduction

“…The initial source might be hundreds of kilometers away (diffuse source) from the impacted areas (Asami, 1984;Dudka and Adriano, 1997). For example, the documented contamination of ice in polar regions (e.g., Pb, Hg, Zn) illustrates the role of long-distance transport of contaminants virtually causing global contamination (Cheam et al, 1998;Murozumi et al, 1969;Rosman et al, 1993). In later chapters on specific elements in this book, ecological effects on forest ecosystems are discussed in sections on Nature for most of the elements.…”