[Pharmwaste] Unexpected human impact on Antarctica

[DeBiasi,Deborah]

http://pubs.acs.org/subscribe/journals/esthag-w/2008/jan/science/kb_anta
rcticpbde.html

Science News -January 23, 2008

Unexpected human impact on Antarctica

Treaties intended to preserve the fragile Antarctic environment don't
protect the continent from hydrophobic contaminants that adhere to
particles.

It is high summer in Antarctica, and the continent is awash in sunlight
around the clock and at its peak of activity. Up to 4000 scientists are
lodged at the southern end of the earth to perform research such as
cataloging the condition of the polar ice and surveying the population
of newly hatched penguin chicks. Despite carefully crafted treaties
intended to protect the fragile continent, new research published in
ES&T (DOI: 10.1021/es702547a) documents that these scientists are
contaminating Antarctica by their very presence.

 
A team led by Rob Hale of the Virginia Institute of Marine Sciences and
Stacy Kim of Moss Landing Marine Laboratories shed light on the
unanticipated environmental impact of human habitation on Antarctica by
looking for PBDE flame retardants. PBDEs bear "a striking structural
similarity to thyroxine," an important thyroid hormone, and recent
laboratory studies show that they may interfere with early
neurodevelopment, the researchers point out. Some PBDE compounds, or
congeners, are candidates for inclusion in the Stockholm Convention on
Persistent Organic Pollutants (POPs).

Hale's analytical team relied on samples that Kim collected at and
around Antarctica's largest human settlement, the U.S.-operated McMurdo
research base. During the summers of 2005 and 2006, Kim gathered samples
of indoor dust from vacuum cleaners, as well as sewage sludge, aquatic
sediments, and various marine animals from sites at varying distances
from where McMurdo's wastewater is discharged.

The PBDE levels measured in the McMurdo dust samples were "right on par
with median PBDE levels measured in U.S. house dust samples," says
Heather Stapleton of Duke University, who has analyzed dust from U.S.
homes. "I was quite startled by the levels," she adds. Hale, too, says
that he was "shocked to learn that the PBDE levels were [so] high."

The PBDEs in the dust likely arose from U.S. products treated with flame
retardants containing PBDEs, such as couches, televisions, and other
electronics and upholstered furniture, Hale believes. He and his
colleagues surmise that the dust is the source of some of the PBDEs that
were ultimately discharged via wastewater into the Antarctic
environment. The new research suggests that the use of maceration to
treat wastewater, which is stipulated by the 1991 Protocol on
Environmental Protection to the Antarctic Treaty, is ineffective at
removing persistent hydrophobic contaminants like PBDEs, which tend to
bind to particles.

Concentrations of PBDEs in McMurdo's wastewater sludge were "among the
highest ever reported," according to the paper. The proportion of the
lighter-weight and more bioaccumulative compounds associated with the
Penta PBDE mixture-which are currently POPs treaty candidates-in the
sludge samples was particularly high, the researchers found. Wildlife
found near McMurdo's wastewater discharge site also contained elevated
PBDE concentrations. Most notably, rock cod had body burdens of the
contaminant on a par with concentrations found in fish living near large
North American cities.

In 2003, a new fixed-film aerated wastewater treatment plant was
commissioned at McMurdo. Hale's team estimates that it now removes more
than 90% of the PBDEs from the wastewater. However, such sophisticated
treatment is expensive to install and maintain, and even large research
bases are not required to use it. Bases housing fewer than 30 people
require no treatment at all. In 2006, more than 30 bases operated by 20
different countries fell into this category, according to the Council of
Managers of National Antarctic Programs.

When Antarctic bases use only maceration-or nothing at all-to treat
their wastewater, they "could conceivably release as much hydrophobic
contaminants [like PBDEs] as larger bases employing modern treatment,"
Hale and his colleagues write. They recommend that all bases begin
removing particles from their wastewater "at a minimum."

The new research makes clear that human habitation is by far the most
significant source of PBDEs in the Antarctic, stresses Cynthia de Wit of
Stockholm University, who has published influential articles on the
prevalence of PBDEs in the worldwide environment and in the Arctic. "I
didn't expect stations in such a remote area to be such strong point
sources," she says.

The new work portends that other hydrophobic contaminants associated
with modern human lifestyles also may be found in relatively high
concentrations near Antarctic research bases. In particular,
pharmaceuticals, personal-care products, and perfluorinated compounds
are likely to be of concern, Hale says. -KELLYN BETTS




Deborah L. DeBiasi
Email:   dldebiasi at deq.virginia.gov
WEB site address:  www.deq.virginia.gov
Virginia Department of Environmental Quality
Office of Water Permit Programs
Industrial Pretreatment/Toxics Management Program
PPCPs, EDCs, and Microconstituents
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