LaMotte Nitrate-Nitrogen Low Range Enzyme Kit - Manual (Page 6)

More About Ni trate Test ing
Ni trate in Na ture
Nitrogen occurs in natural waters as nitrate (NO
3
), nitrite (NO
2
), ammonia
(NH
3
) and organically bound nitrogen. Nitrate test results are expressed as
“nitrate-nitrogen” (NO
3
-N), meaning “nitrogen that is in the form of nitrate”.
Nitrate is a nutrient needed by all aquatic plants and animals to build protein.
Natural waters generally have a nitrate-nitrogen level below
1 ppm. Higher levels indicate the addition of nitrate from unnatural sources.
Nitrate-nitrogen levels above 10 ppm are considered unsafe for drinking water.
NO
3
-N Concentration
< 1 ppm natural waters
< 10 ppm safe for drinking water
> 10 ppm unsafe for drinking water
Sources of Ni trate
Nitrate has always existed in nature but not in the quantities that it does today.
When forests and wetlands surrounded waterways, nutrients and soil were held in
place by vegetation and did not run off the land into the water. Small amounts of
nitrate entered the aquatic ecosystem naturally from forest fires, fallout from
volcanoes and the decay of aquatic plants.
Now, in addition to small amounts of nutrients from natural sources, large
amounts of nitrate are created by modern land use. Farms, suburbs and cities are
built on the banks of streams, lakes and rivers. Nutrients enter the water through
point and nonpoint sources. Examples of point source pollution, which can be
traced to a specific site, are industry, and mainly, wastewater and sewage
treatment plants. Nonpoint sources of pollution cannot be contributed to a
specific location. Automobile exhaust, acid rain and fertilizer run-off and erosion
from farms contribute to excessive nutrient levels in surface and groundwater. In
suburbs, septic systems and lawn fertilizer run-off from millions of homes are an
example of nonpoint source pollution. After a rain storm in urban areas, run-off
from highways and parking lots washes nutrients into storm water systems.
Ni trate Con tam i na tion
In slow-moving, shallow bodies of water, excess nutrients encourage the growth
of algae and aquatic vegetation. In a short amount of time, vegetation may cover
the entire area and swimming and boating may become impossible. Dense mats
of algae on the surface will block sunlight needed by submerged aquatic
vegetation (SAV). As the habitat changes, the water quality becomes poor and