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Pollution Of Lakes
Lake Pollution: Types,
Sources, and Solutions
In an extensive sampling
effort, the Environmental Protection Agency, with the help of state and tribal
agencies, coordinated water quality assessments for the country’s lakes.
They evaluated 43% of the
lake surface area, or about 17.3 million acres of water. The study concluded
that:
· Fifty-five percent of the
study’s water acreage was judged to be of good quality. The other 45% had
waters impaired for at least one type of use (for example as drinking water
supply, for recreational fishing, swimming, or aquatic life support). When
considering man-made lakes alone, the proportion that was impaired jumped to
59%.
· Water quality is sufficiently
high to allow swimming in 77% of the waters assessed.
· Aquatic life was not supported
adequately by 29% of lake waters.
· For 35% of the lake waters
surveyed, fish consumption was not recommended.
For
the impaired lakes, the top types of pollution were:
· Nutrients (problematic in
50% of impaired waters). Nutrient pollution occurs when excess nitrogen and
phosphorus make their way into a lake.
These elements are then picked
up by algae, allowing them to grow rapidly to the detriment of the aquatic
ecosystem.
Overabundant cyanobacterial
algae blooms can lead to toxin build-up, oxygen level drops, fish kills, and
poor conditions for recreation.
Nutrient pollution and the
subsequent algae blooms are to blame for Toledo’s drinking water shortage in
the summer of 2014.
Nitrogen and phosphorus
pollution comes from inefficient sewage treatment systems and from some
agricultural practices.
· Metals (42% of impaired
waters). The two main culprits here are mercury and lead.
Mercury accumulates in lakes
mostly from atmospheric deposition of pollution coming from coal-fired power
plants.
Lead pollution is often the
result of accumulated fishing tackle like sinkers and jig heads, and from lead I
in shotgun shells.
· Sediment (21% of impaired
waters). Fine-grained particles like silt and clay may occur naturally in the environment
but when they enter lakes in large quantity, they become a serious pollution
problem.
Sediments come from the many
ways soil can be eroded on land and carried into streams then lakes: erosion
can originate from road construction, deforestation, or agricultural
activities.
· Total Dissolved Solids (TDS;
19% of impaired waters). TDS measurements can be interpreted as how salty the
water is, generally due to high concentrations of dissolved calcium,
phosphates, sodium, chloride, or potassium. These elements most often enter the
roadways as road salt, or in synthetic fertilizers.
Where do these pollutants come from? When
assessing the source of pollution for the impaired lakes, the following
findings were reported:
· Agriculture (affecting 41% of
impaired waters). Many agricultural practices contribute to lake water
pollution, including soil erosion, manure and synthetic fertilizer management,
and the use of pesticides,
· Hydrologic modifications (18%
of impaired waters). These include the presence of dams and other flow
regulation structures, and dredging activities. Dams have extensive
effects on a lake’s physical and chemical characteristics, and on aquatic
ecosystems.
· Urban runoff and storm sewers
(18% of impaired waters). Streets, parking lots, and rooftops are all
impervious surfaces that do not allow water to percolate through. As a
result, water runoff speeds up to storm drains and picks up sediments, heavy
metals, oils, and other pollutants, and carries it into lakes.
What Can You Do?
· Use soil erosion best practices
whenever you disturb soil near a lake.
· Project lake shorelines on your
property by preserving the natural vegetation. Replant shrubs and trees if
needed. Avoid fertilizing your lawn close to a lake’s edge.
· Encourage the use of sustainable
farming methods like cover crops and no-till farming. Talk to farmers at your
local farmers market to find out more about their practices.
· Keep septic systems in good working
order, and have regular inspections conducted.
· Encourage local authorities to
use alternatives to road salt in winter.
· Consider your nutrient inputs
from soaps and detergents, and reduce their use whenever possible.
· In your yard, slow down water
runoff and allow it to be filtered by plants and soil. To accomplish this,
establish rain gardens, and keep drainage ditches well vegetated. Use rain
barrels to harvest roof runoff.
· Consider using pervious
pavement in your driveway. These surfaces are designed to let water percolate
into the soil below, preventing runoff.
· Choose alternatives to lead
when selecting fishing tackle.
Frederic Beaudry is an associate
professor of environmental science and a wildlife biologist with interests in a
broad range of environmental issues.
Experience
Dr. Beaudry teaches courses in environmental
sciences at Alfred University, New
York. Prior to teaching, he worked as a wildlife biologist focusing on the
ecology and conservation of birds and turtles. He has authored several
scientific papers on land use and conservation. His current research examines
land use changes and their effects on bird and amphibian communities.
Education
Dr. Beaudry has a BS in Biology from the
Université du Québec à Rimouski, a master's degree in Natural Resources from
Humboldt State University, and a PhD in Wildlife Ecology from the University of
Maine. He conducted postdoctoral research at the University of
Wisconsin-Madison.
Frederic Beaudry
"Strong science has greatly developed our
understanding of environmental issues in the last decade. I am hoping to
connect readers with sound information about new developments affecting our
air, water, soil, and biodiversity. We are in charge of our health, that of our
land, and of the plants and animals that depend on it."
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