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When a
plow passes, spreading salt and sand in its wake, most are
relieved to know the road behind it is left safer. As an
avid fly fisherman, Bob Meyen is more aware than most about
the problem posed by salt in streams, where high concentrations
can be toxic to fish, or the critters fish eat.
''I
used to work in Canada quite a bit and they don't salt the
roads there. They plow them and you learn to run on packed
snow. You learn to slow down. That's something that doesn't
happen around here,'' the Salt Point resident said. ''It's
difficult to control the environment and to live the lifestyle
that we're used to.''
Scientists
are beginning to grapple with the unintended consequences
of safe winter travel.
Salt has been steadily increasing in streams throughout
the Northeast, including those in the Hudson Valley. The
Hudson River Environmental Society hosted a gathering of
scientists in Kingston last month to share research and
discuss how the salt is affecting stream life.
Salt
is representative of the type of pollution harming Hudson
Valley streams. A generation after the Clean Water Act outlawed
dumping of chemicals and sewage, the main sources of pollution
now are diffuse and difficult to control.
Like gasoline, oil and other automotive chemicals, it runs
off roads and parking lots into storm drains and eventually
streams. Like bacteria, viruses and a host of personal care
products and pharmaceuticals, it also reaches streams through
septic and sewer systems.
Changes needed
The
Clean Water Act was successful because it targeted large
single pollution sources -- industrial and sewage outfalls.
Curbing salt pollution, like other forms of so-called ''non-point''
pollution, would require broader changes to everyday activities
-- finding alternatives, establishing best-management practices
and controlling roadside runoff, for instance.
''It is a problem, but it's also a solution, too, to significant
issues we have in terms of road safety,'' said William Dey,
president of the Hudson River Environmental Society.
An icy and snowy day like Thursday is a reminder how important
salt is for keeping roads safe and the economy running.
The
state Department of Transportation spends $96.7 million
keeping roads clear each year, about a quarter of which
is spent on road salt. County and municipal highway crews
are responsible for local roads.
The DOT estimates every dollar spent clearing roads saves
$6.50 for the economy, which would otherwise suffer from
travel and shipment delays, lost wages and damaged property.
Accidents that cause injury are eight to nine times higher
on roads that have not been treated.
Beyond
that, after a couple generations of aggressive road clearing,
people often expect to be able to reach work, or the supermarket,
no matter what the weather.
''Once
upon a time when it snowed heavily, people just stayed home,''
said Jeanne Hewitt, head of the DOT's Environmental Analysis
Bureau. No more. With increased demand for clear roads,
and more roads to support a burgeoning population, residual
salt levels are on the rise. The concentration of chloride,
a component of salt, detected in the Hudson River at Troy
is seven times greater than it was at the start of the 20th
century, according to Leo Hetling, a former Department of
Health scientist. Road salt was first used in the 1940s
and accounts for an estimated 68 percent of the salt in
the upper Hudson Watershed north of Troy, he said.
In Dutchess County, the East Branch of the Wappinger Creek,
as well as Stony Creek and Saw Kill in Red Hook, have been
studied, and also show evidence of increasing chloride concentrations
-- though road salt may not be the primary reason for those
increases, scientists said.
Pollution
sources
Other contributors include water softeners and discharges
through septic and sewage systems, said Serena Cirparis,
a research associate for the Hudson River National Estuarine
Research Reserve.
''Sources
other than road salt may be important, especially in less-developed
areas,'' Cirparis said.
The
concentration of chlorides in the Saw Kill has doubled since
1991. The source appears to be the residential community,
not salt from roads in winter. The rising concentrations
in the Stony Creek were linked to sewage treatment plant
discharges. The concentrations measured in Hudson Valley
streams is still far below the concentration the Environmental
Protection Agency has set as a concern for drinking water.
''We're
well below any water supply or ecological considerations,''
Hetling said. ''But any time things begin to rise, you worry.''
Humans
are not the only source of chlorides in the environment.
Rainwater picks up chloride from the oceans, as well as
from coal-fired power plants and factories. Bedrock has
chloride, and volcanoes can release it.
Construction of new roads and homes in previously undeveloped
areas appears to be the root of the rising concentrations
of chlorides in streams, scientists agreed.
Based
on new housing construction, the U.S. Census estimated the
population of Dutchess and Ulster increased by 14,000 from
2000 to 2003, a jump of 3 percent, following a decade of
8 percent growth in the 1990s.
New
homes often mean new roads. Both cover the landscape with
impervious surfaces that prevent rain from naturally percolating
into the ground, and increase the sources of salt and petroleum
in runoff.
River's health is key
The
streams that feed the Hudson River snake over 13,500 square
miles, a vast area that includes the Mohawk River in central
New York and the southern portion of the Adirondack Mountains.
Protecting the Hudson's tributaries is important for protecting
the health of the river itself, which is an estuary that
mixes with seawater south of Troy.
''Healthy streams are critical to the estuary ecosystem,''
said Scott Cuppett, Hudson River watershed coordinator for
the Department of Environmental Conservation's Hudson River
Estuary Program.
Fish
use tributaries to spawn, forage or take shelter, he said.
The dynamics of freshwater entering the river from tributaries
and salt water entering from the Atlantic Ocean creates
the estuarine environment that is particularly fruitful
for life.
''Suburban runoff is currently the No. 1 source of pollution,''
Cuppett said. ''Chlorides and road salt are definitely part
of that source of pollution.''
A DEC study of water quality has showed that the state's
streams are slowly becoming degraded, said Margaret Novak,
chief of the statewide waters monitoring for the DEC.
Between 1972, when the Clean Water Act was passed, and 1992,
the water quality in 39 percent of streams improved, with
all others staying the same. In the 10 years that followed,
16 percent improved -- but 18 percent declined.
Effect
of development
The
streams that showed a decline in water quality were those
that had previously been pristine. Development in previously
open land and forest is likely a culprit, she said.
Aside from glaring examples -- such as when a salt pile
at Woodbury Commons in Orange County leaked into a nearby
pond at the head of the Woodbury Creek -- salt has not directly
killed the water bugs and worms that DEC used to assess
stream quality, Novak said.
The DEC identified the problem at Woodbury Commons during
its stream assessments in 2003 and the parking lot operator
covered the salt pile. Identifying and covering salt piles
to prevent them dissolving into streams is the easy part
of the solution, Novak said.
''The
larger issue is these changes in land use, the increase
in impervious surfaces and the runoff,'' Novak said. ''That's
going to be the next set of issues,'' she added, ''the next
battlefront for us to remedy.''
A Geological Survey study of the Croton Watershed, which
includes part of Southern Dutchess County and supplies New
York City and Westchester County with drinking water, found
salt used on roads is held in roadside soil, providing a
year-round source to the groundwater.
In
some cases, nearby homes with wells can have elevated salt
in their drinking water, and some nearby streams had chloride
at levels that were toxic to fish.
''Right now,'' said Paul Hesig, a hydrologist for the Geological
Survey, ''there's far too much salt being applied to the
watershed. ''
Dan Shapley can be reached at dshapley@poughkeepsiejournal.com
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