What nutrients did NAWQA study?
Five measures of nitrogen- and phosphorus-containing nutrients are discussed in this study, including nitrate, ammonia, total nitrogen, orthophosphate, and total phosphorus. All five nutrients are discussed for surface water; whereas, only the dissolved forms (nitrate, ammonia, and orthophosphate) are discussed for groundwater. Groundwater transport is different from transport in streams because only dissolved forms move substantial distances with groundwater. Nitrate readily dissolves and moves with water, and, is therefore often the dominant form of nutrient. Particle bound compounds, like phosphorus, largely are retained by the soil and aquifer materials.
