Alkalinity and pH go hand in hand. Alkalinity, also known as a buffer capacity, measures the ability of a body of water to neutralize acidity caused by acid rain or other pollutants, or in other words, resist changes in pH. Without this ability of a water source to neutralize acidity, the addition of any acidic source, such as acid rain or industrial wastewater, would cause an immediate change in the pH of the water.

Chloride ions are a result of the splitting of salt ions in water. Salt, or sodium chloride, is made from positive sodium ions bonded to negative Chloride ions, which separate when the ionic compound dissolves in water. Some sources of Chloride Ions include runoff from salted roads, irrigation water returned to streams, and water softeners and chlorinated drinking water in wastewater. Additionally, Chloride can occur naturally in streams when the streambed is made up of salt-containing minerals.

Chloride is harmful to aquatic life. If levels remain high in a stream, they may begin to build up in the aquatic organisms, reaching toxic levels; this is known as bioaccumulation.

Also, Chloride may cause the release of metals from sediments at the bottom of a stream, which leads to metal toxicity in aquatic organisms, causing the animals to suffocate to death. In relation to drinking water, Chloride is not generally harmful at high levels, although it will start to have an unpleasant taste at levels exceeding 250 mg/l. At low levels, Chloride does not harm the human body, though it may cause unwanted taste and odor issues at higher levels.

Dissolved Oxygen enters a stream by two main sources: the atmosphere and aquatic vegetation. Oxygen from the atmosphere uses the movement of the stream to mix into the water, therefore becoming dissolved Oxygen. Faster flowing water tends to have more DO, where stagnant waters such as lakes and ponds will have less. The second source, aquatic vegetation, releases Oxygen into the stream by the process of photosynthesis.

DO levels are generally higher during mid-day, when the sun is at its peak and photosynthesis is occurring, then levels will drop at night when Oxygen is being used for respiration by plants and animals. Both temperature and atmospheric pressure will determine just how much Oxygen can dissolve into the water; lower temperatures result in higher DO, and higher altitudes result in lower DO. Some pollutants that can affect DO in water are acid mine drainage, agricultural runoff, and industrial waste. The last two pollutants mentioned possess organic matter, which must be broken down by microorganisms by a process known as decomposition, which requires the use of Dissolved Oxygen. This process causes a decrease in DO availability for all other aquatic life in the stream. Additionally, the development of land and destruction of vegetation along the stream will cause for less shade cover, resulting in a higher water temperature and therefore less DO.

Ammonia is a form of Nitrogen. Nitrogen is essential in an aquatic environment in order for plants and animals to form amino acids; however, it cannot be used in its molecular form. For this reason, it must be converted to another form, such as ammonia. In water, ammonia is present in two forms. The first form, NH3, is known as unionized ammonia; the second, NH4+, is known as ionized ammonia, or ammonium. Which form is present is dependent upon the temperature and pH of the water. The un-ionized form of ammonia, NH3, is prevalent at higher temperatures and at a pH greater than 8.0. The unionized form is also the more toxic one in relation to aquatic life. Both of these forms make up the Total Ammonia in the water.

Elevated levels of ammonia can lead to increased vegetation and algal growth. It can also lead to nitrification, a process by which ammonia is converted into nitrate by bacteria in the water. This process uses a lot of dissolved oxygen that is necessary for the survival of fish and other aquatic life. .

Total Dissolved Solids is a measure of all dissolved solids in a water source. Total dissolved solids are made up of inorganic salts, such as calcium, magnesium, potassium, sodium, bicarbonates, chlorides and sulfates, as well as some organic matter. Pure water is odorless and tasteless, whereas water contaminated with high levels of TDS may be bitter, salty, corrosive, and cause precipitates to form. Though these effects are more aesthetic concerns than anything else, high TDS levels should not be ignored, as they may also indicate the presence of toxic ions, such as lead, arsenic, cadmium and nitrate. EPA secondary drinking water standards lists the MCL (Maximum Contaminant Level) for TDS at 500 mg/L, due to a noticeable and unpleasant change in taste, odor and scale deposits. Any water exceeding 1000 mg/L is deemed unfit for consumption.