USGS Data Series 603  - Discrete and Continuous Water-Quality Data and Hydrologic Parameters from Seven Agricultural Watersheds in the United States, 2002

Table 3. Nutrients measured during the U.S. Geological Survey National Water-Quality Assessment Program’s Agricultural Chemicals Team studies. 

[–, information not available; mg/L, milligrams per liter] 

Analyte	Chemical registry No.	Matrix	PCODE	Method reporting limit  (mg/L)
Nitrogen, ammonia	2105357	water, filtered	00608	0.04
Nitrogen, ammonia + organic, N	17778-88-0	water, whole	00625	.03
Nitrogen, ammonia + organic, N	17778-88-0	water, filtered	00623	.03
Nitrogen, ammonia, field	2105357	water, filtered	99120	–
Nitrogen, nitrate, field	84145-82-4	water, whole	99121	–
Nitrogen, nitrite	14797-65-0	water, filtered	00613	.008
Nitrogen, nitrite + nitrate	–	water, filtered	00631	.06
Nitrogen, nitrate	84145-82-4	water, filtered	71851	–
Nitrogen, nitrite	14797-65-0	water, filtered	71856	–
Nitrogen, total	–	water, whole	62854	.1
Nitrogen, total	–	water, whole	62855	.1
Phosphorus, phosphate, ortho	14265-44-2	water, filtered	00671	.006
Phosphorus, phosphate, ortho, field	14265-44-2	water, filtered	99122
Phosphorus, total	7723-14-0	water, whole	00665	.004