Nitrogen pollution (water)
Human Health Risk
Ecological Risk
Socioeconomic Risk
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The natural nitrogen cycle is disrupted by the use of nitrogen fertilizers and by the
production of nitrogen oxides (NOx) during combustion. Excess nitrogen from fertilizers
enters aquatic ecosystems, causing algal blooms and reducing oxygen levels and
other ecological effects. Additionally, NOx are present in precipitation, adding to the
ecological impacts caused by fertilizer runoff. High nitrate levels in drinking water can
contribute to “blue-baby syndrome,” which reduces the ability of blood to carry oxygen.
Atmospheric NO x is considered separately, as are the impacts of ozone and acid
precipitation, stressors to which NO x are an important contributing factor.
What’s at risk?
STRESSOR SUMMARIES
All freshwater and coastal ecosystems are exposed to excess nitrogen, but impacts are primarily to estuarine and coastal ecosystems. In the
form of ammonia, nitrogen is toxic to fish,
particularly trout.
What are the human health impacts in New
Jersey?
No cases of “blue-baby syndrome” have been
attributed to drinking water in recent years. Most
drinking water in New Jersey meets the public
health standard, and no cases of this syndrome have
occurred at or below that level. Perhaps 10 to 20
infants a year, minus those who are breast-fed,
would be at risk for exposure to clinically significant
levels of nitrates in water from private wells in
New Jersey.
to fish, and its conversion to nitrate can result in
oxygen depletion in aquatic systems. Low
dissolved oxygen, or hypoxia, often occurs in
coastal waters during summer, with severe
ecological effects. High nitrogen levels contribute
to the growth of problematic algae, resulting in
the loss of submerged vegetation and fish and
shellfish mortality (see reports on brown tide,
red/green tide, pfiesteria). Ammonia levels
exceeding water quality standards are found in
about 10% of trout habitats.
What are the socioeconomic impacts in
New Jersey?
Socioeconomic impacts were judged to be
minor and associated with the potential for
localized employment impacts.
What’s being done?
What are the ecological impacts in New
Jersey?
The effects of excess nitrogen in aquatic systems
are most noticeable in marine and estuarine
systems. Freshwater systems are more affected
by excessive amounts of phosphorus (considered in a separate report). Ammonia can be toxic
Fertilizer use is not regulated, but efforts to
reduce the incidence of excessive use are important in watershed management efforts.
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Final Report of the New Jersey State Comparative Risk Project