Nitrates are a form of nitrogen found in aquatic environments.  Forms of nitrogen in water include:

Nitrate:  NO3
Nitrite:  NO2
Ammonia:  NH3

Why We Test for Nitrates

Nitrate is necessary to aquatic plant life, but can result in excessive plant growth, especially algae, if available in disproportionate amounts.  Excess nitrates can lead to algae blooms, which increase turbidity and water temperature.  When the algae dies, it is consumed by bacteria that significantly decrease the amount of oxygen in water.  All of these affects can make habitat uninhabitable for aquatic life. 

Sources

Sources of nitrates include sewage treatment plants, septic systems, fertilizers, industrial discharges, and animal manure.

What the Numbers Mean

Wadable Stream Guidelines

• Typical values fall between 0.05 and 0.5 mg/l
• Values greater than 0.5 mg/l can cause algae problems in water with high phosphorus levels.
• Values great than 10 mg/l present a health hazard in drinking water

EPA Guidelines

• Values less than 10 mg/l are acceptable
• Values greater than 50 mg/l are toxic

How Do We Test For Nitrates:

Pdf of sampling technique used by Stream Team.