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http://www.washingtonpost.com/wp-dyn/content/article/2006/09/28/AR2006092801994.html
Wildlife Waste Is Major Water
Polluter, Studies Say
By David
A. Fahrenthold
Washington Post Staff Writer
Friday, September 29, 2006;
A01
Scientists have run high-tech tests on harmful
bacteria in local rivers and streams and found that many of the germs -- and
in the Potomac and Anacostia rivers, a majority of them-- come from wildlife
dung. The strange proposition that nature is apparently polluting itself has
created a serious conundrum for government officials charged with cleaning up
the rivers.
"You need
to go back and say, 'Maybe the standards aren't exactly right' if wildlife are
causing the problem," said Thomas Henry, an Environmental Protection Agency
official who works on water pollution in the mid-Atlantic.
The story
of how wild animals -- which usually are considered the victims in
environmental dramas -- came to be cast as villains begins with the EPA's
limits on bacteria levels in streams. Bacteria such as E. coli and other fecal
coliform, which are found in both human and animal waste, can cause sickness
on their own, and they can serve as a warning that other, even nastier
pathogens might also be present.
In the
Washington area, violations of the bacteria standards have put more than two
dozen streams, including the Potomac and Anacostia rivers, on the federal
"impaired waters" list. That means they do not meet the ideal conditions for
swimming and need cleaning up.
So who --
or what -- is responsible for the contamination? The answer has become much
clearer in the past five or so years, because of high-tech tests sponsored by
states that pinpoint from which animal a particular sample of bacteria
came.
In this
area, some of what these surveys have found is not surprising. One recent
study by a Virginia Tech team found that humans are responsible for 24 percent
of the bacteria in the Anacostia and 16 percent of the Potomac's, whether the
source is a broken septic tank or the District's large sewage overflows during
heavy rains. Livestock were also a major problem around the area --
responsible for 10 percent of the Potomac's bacteria, for instance -- because
their manure washes out of pastures and the farm fields where it is spread as
fertilizer.
In the
Potomac and the Anacostia, for instance, more than half of the bacteria in the
streams came from wild creatures. EPA documents show that similar problems
were found in Maryland, where wildlife were more of a problem than humans and
livestock combined in the Magothy River, and in Northern Virginia tributaries
such as Accotink Creek, where geese were responsible for 24 percent of
bacteria, as opposed to 20 percent attributable to people.
"Wildlife
consistently came up as being . . . a major player," said Peter Gold, an
environmental scientist for the EPA.