CONTAMINANTS IN ARCTIC SNOW COLLECTED OVER
NORTHWEST ALASKAN SEA ICE
JOHN R. GARBARINO
, ELAINE SNYDER-CONN
, THOMAS J. LEIKER
GERALD L. HOFFMAN
U.S. Geological Survey, National Water Quality Laboratory, Denver Federal Center, Denver, CO,
U.S. Fish and Wildlife Service, Arlington, VA, U.S.A.
(Received 12 February 2001; accepted 20 November 2001)
Abstract. Snow cores were collected over sea ice from four northwest Alaskan Arctic estuaries
that represented the annual snowfall from the 1995–1996 season. Dissolved trace metals, major
cations and anions, total mercury, and organochlorine compounds were determined and compared
to concentrations in previous arctic studies. Traces (<4 nanograms per liter, ng L
trans-chlordane, dimethyl 2,3,5,6-tetrachloroterephthalate, dieldrin, endosulfan II, and PCBs were
detected in some samples, with endosulfan I consistently present. High chlorpyrifos concentrations
(70–80 ng L
) also were estimated at three sites. The snow was highly enriched in sulfates (69–
394 mg L
), with high proportions of nonsea salt sulfates at three of ﬁve sites (9 of 15 samples),
thus indicating possible contamination through long-distance transport and deposition of sulfate-
rich atmospheric aerosols. Mercury, cadmium, chromium, molybdenum, and uranium were typically
higher in the marine snow (n = 15) in relation to snow from arctic terrestrial studies, whereas cations
associated with terrigenous sources, such as aluminum, frequently were lower over the sea ice. One
Kasegaluk Lagoon site (Chukchi Sea) had especially high concentrations of total mercury (mean =
214 ng L
, standard deviation = 5 ng L
), but no methyl mercury was detected above the method
detection limit (0.036 ng L
) at any of the sites. Elevated concentrations of sulfate, mercury, and
certain heavy metals might indicate mechanisms of contaminant loss from the arctic atmosphere over
marine water not previously reported over land areas. Scavenging by snow, fog, or riming processes
and the high content of deposited halides might facilitate the loss of such contaminants from the
atmosphere. Both the mercury and chlorpyrifos concentrations merit further investigation in view of
their toxicity to aquatic organisms at low concentrations.
Keywords: Alaska, anions, arctic, atmospheric, Beaufort, chlorpyrifos, Chukchi, contaminants, mer-
cury, metals, organochlorine, snow
Unexpectedly high concentrations of soot, volatile and semivolatile organics, non-
marine sulfates, nutrients, and heavy metals are now well documented in the arc-
tic atmosphere, including Alaska’s (Mitchell, 1957; Rahn, 1981a, b; Shaw, 1982,
1991a, b; Raatz and Shaw, 1984; Lowenthal and Rahn, 1985; Halter et al., 1985).
Most of these contaminants are in the submicron aerosols fraction, and appear in
The U.S. Government’s right to retain a non-exclusive, royalty free licence in and to any
copyright is acknowledged.
Water, Air, and Soil Pollution 139: 183–214, 2002.
© 2002 Kluwer Academic Publishers. Printed in the Netherlands.