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Article

Melting Glaciers: A Probable Source of DDT to the Antarctic Marine Ecosystem

Supporting Info

Heidi N. Geisz*, Rebecca M. Dickhut, Michele A. Cochran, William R. Fraser^† and Hugh W. Ducklow^‡

Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, Virginia 23062, Polar Oceans Research Group, Sheridan, Montana 59749, and Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543

Environ. Sci. Technol., 2008, 42 (11), pp 3958–3962

DOI: 10.1021/es702919n

Publication Date (Web): April 30, 2008

* Corresponding author phone: (804) 684-7474 ; fax: (804) 684-7786; e-mail: heidig@vims.edu.

†

Polar Oceans Research Group, Sheridan, MT 59749.

‡

Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543.

Abstract

Persistent organic pollutants reach polar regions by long-range atmospheric transport and biomagnify through the food web accumulating in higher trophic level predators. We analyzed Adlie penguin (Pygoscelis adeliae) samples collected from 2004 to 2006 to evaluate current levels of ∑DDT (p,p′-DDT + p,p′-DDE) in these birds, which are confined to Antarctica. Ratios of p,p′-DDT to p,p′-DDE in Adlie penguins have declined significantly since 1964 indicating current exposure to old rather than new sources of ΣDDT. However, ∑DDT has not declined in Adlie penguins from the Western Antarctic Peninsula for more than 30 years and the presence of p,p′-DDT in these birds indicates that there is a current source of DDT to the Antarctic marine food web. DDT has been banned or severely restricted since peak use in the 1970s, implicating glacier meltwater as a likely source for DDT contamination in coastal Antarctic seas. Our estimates indicate that 1−4 kg·y⁻¹ ΣDDT are currently being released into coastal waters along the Western Antarctic Ice Sheet due to glacier ablation.