Other types of pollutants

There are many different types of pollution which can affect waterways. The EPA (Environmental Protection Agency, a government organization) monitors some of these, and has imposed guidelines which are supposed to be followed.

One part of the river that is measured is that of biomass. What's biomass? It is simply a measurement of the amount of vegetation in the water. Sometimes, especially when Nitrogen levels increase, algae and other plants will begin to grow at an abnormally fast rate. Due to their small size and rapid reproduction and maturation rates, algae will soon dominate this growth cycle. When this happens, it is called an "Algae Bloom" and the algae will sometimes even form a thick green "mat" on the surface of the water.
The way that biomass is measured is by the amount of chlorophyll-A that is found in a water sample. Chlorophyll-A is one of the chemicals that a plants use to conduct photosynthesis, and it consists of 1.5 percent of the total algal organic matter. The concentration of the chlorophyll-A describes the discoloration of the water. Here is a sample chart that describes the relationship of the concentration to the water quality:

Another type of pollutant is known as ammonia. Ammonia (chemical formula NH₃) is probably best known to people as a cleaning agent. Ammonia comes from a variety of sources, both Point and Non-point (NPS). Non-point sources include a variety of factors. Ammonia can come in from natural sources, since bacteria produce some ammonia during the decomposition of various organic substances, and ammonia is also found in human and animal waste. It also enters the environment through the agricultural realm, usually during the accidental release of ammonia containing fertilizer during transport, over application of the same fertilizer, or through the improper disposal of livestock waste. People can also release ammonia in urban and residential area through the use of household cleaning products. However, evidence suggests that ammonia is primarily deposited through rainwater and other precipitation. Where does this ammonia come from? Mostly through waste products produced when burning occurs, like in auto engines, burning waste, and heating homes and businesses.

Nitrogen is another pollutant, on that can be troubling because it is difficult to remove even from treated waste water. It is primarily an NPS pollutant, with its sources mainly being agricultural (livestock excrement, fertilizers, decomposoing plant debris), residential (fertilizers, leaky septic/wastewater systems, sewage treatment outfalls, domestic pet waste), and other areas like the burning (combustion) of fossil fuels, industrial and agricultural gaseous discharges, and aerosols.

Phosphorus is still another possible pollutant. A lack of phosphorus is usually what keeps a plant from growing in freshwater settings, no matter what the nitrogen level is.