Water Quality Parameters
Below is a brief excerpt of each parameter and its significance from the Vermont Volunteer Surface Water Monitoring Guide. See the full manual for more information.
Temperature (oC):
Aquatic organisms, from microbes to fish, are dependent on certain temperature ranges for their optimum health. If temperatures are outside this optimal range for a prolonged period of time, organisms are stressed and can die.
pH
pH is a measure of the hydrogen ion concentration,or acidity of water. The pH is not an indicator of a particular pollutant; however, it affects many chemical and biological processes in water. For example, low pH can allow toxic elements and compounds to become mobile and “available” for uptake by aquatic plants and animals causing the death of many organisms. This can disrupt the food chain and affect higher level organisms.
Conductivity
Conductivity estimates the amount of dissolved ions in the water. Conductivity is influenced by the size of the watershed and the geology. There are a number of pollution sources that may be signaled by increased conductivity. Wastewater from sewage treatment plants and septic systems, urban runoff from roads and agricultural runoff can all contribute to increased conductivity within a waterbody.
Dissolved oxygen (%sat, and mg/l)
Water contains oxygen in the form of a dissolved gas, which most aquatic organisms use to breathe. Dissolved oxygen (DO) is the measure of the concentration of the gas dissolved in water. All aquatic organisms have an optimal range of DO for functioning. Some require very high levels in order to flourish, and at low DO concentrations, sensitive animals may move away, weaken, or die.
Alkalinity
Alkalinity is a measure of the buffering (or acid neutralizing) capacity of the water. Alkalinity is not a pollutant itself, but a measure of sensitivity to acid rain.
Total Suspended Sediment (TSS)
TSS is an important parameter to consider if you suspect sediment and water clarity issues. The total suspended solids (TSS) parameter is measured in milligrams per liter (mg/L), the mass of solids per unit volume of water.
Turbidity
Turbidity is a measure of light scattering properties of suspended materials. In theory, the more suspended material that exists, the more light scattering (turbid), and hence the less transparent. Turbidity data can reveal problems with water clarity and/ or suspended sediment in streams and rivers. Turbidity is reported in Nephelometric Turbidity Units (NTU).
Total phosphorus (TP)
Phosphorus is also an essential plant and animal nutrient and is the nutrient of greatest concern in eutrophication (nutrient enrichment). It is in most cases the “limiting nutrient,” meaning it is the one most likely to restrict plant growth because of its naturally low levels in the environment. Thus, even small increases in phosphorus loads to a waterbody can cause large algal blooms and excessive plant growth. This rapid increase in biological activity may disrupt the ecological balance of surface waters.
Total nitrogen (TN)
Nitrogen is an essential plant and animal nutrient that naturally occurs in numerous forms in surface water. High concentrations of any form of nitrogen in a waterbody may indicate that pollutants from animal manure, sewage, or fertilizers applied to land are making their way into the water via runoff.
Chloride
Chloride is an ion that is released into surface waters through the breakdown of salt compounds. Although salt is a naturally occurring mineral, elevated levels in surface waters may be attributed to winter road maintenance practices and to human activities that accelerate erosion. In addition to negatively impacting water quality, chloride in large concentrations can be corrosive; cause damage to vegetation; and enter the drinking water supply, causing discoloration, foul taste and odor.
Bacteria (E. coli)
Fecal bacteria are a particular group of bacteria primarily found in human and animal intestines and wastes. Escherichia coli (E. coli) is one of the fecal coliform bacteria widely used as indicator organisms to show the presence of such wastes in water and the possible presence of pathogenic (disease-producing) organisms. When E. coli is found in waters, its presence is not the problem of concern itself but is used rather as an indicator of fecal contamination (most strains of E. coli are not pathogenic) from humans or animals is present. E. coli monitoring is commonly conducted to ensure that the water is safe for swimmers; to establish a relationship between rainfall, bird migration migration or other wildlife activity and E. coli levels; and to identify pollution sources (e.g., septic system failure, failing manure pit) in a watershed. The bacteria is measured in organisms or colony-forming units per 100 milliliters of water (cfu/100 mL). Vermont’s Class B water quality standard sets the maximum tolerable E. coli level at 77 colonies per 100 ml of sampled water.