Nitrate+Nitrite-N: Oxidized, inorganic forms of nitrogen in water which result from the biochemical process of nitrification. Nitrite is an intermediate product which is typically present only in minute quantities in surface waters. Sources include fertilizer, sewage and animal wastes. Measured in mg/L or ppm. The MCL (Maximum Contaminant Level) for drinking water is 10 mg/L for NO3-N.
Ammonia-N: The concentration of ionized and un-ionized ammonia in water. Ionized (NH4+) and un-ionized (NH3) forms are products of the decomposition of organic matter. Reported as NH4-N or ammonia as nitrogen (mg/L). Measured in mg/L or ppm.
Total Kjeldahl Nitrogen: Nitrogen in the form of organic proteins or their decomposition product ammonia, as measured by the Kjeldahl Method. The Total Kjeldahl Nitrogen (TKN) method involves digestion and distillation to determine both organically bound nitrogen and ammonia (NH3); an indicator of the nutrient enrichment of surface waters. Measured in mg/L or ppm.
Total Phosphate as P: The total amount of phosphate, including dissolved and particulate forms, reported as phosphorus (P). Meausred in mg/L or ppm.