We test for a number of water parameters. This mini-glossary explains what we test for. We do not perform every test at every location.
We measure water temperature in degrees Celsius. Water temperature affects respiration and metabolism in both fish and invertebrates. Water temperature has a big effect on what types of fish and bugs are present in a lake or river. Water takes a longer time to warm up or cool down compared to the air. Temperature exerts a major influence on biological activity and growth. All organisms have a preferred temperature range. If temperature gets too high or low certain species may decrease.
Temperature is also important because of its influence on water chemistry. The rate of chemical reactions generally increases at higher temperature, which in turn releases more minerals from the rock.
Water Surface Tension
Surface tension is a molecular force on the surface of water. It permits insects such as water striders to survive. Several types of substances may reduce surface tension. Surfactants such as soaps and various pollutants may reduce water surface tension. Low surface tension may indicate water pollution.
Transparency of water is affected by a number of factors. Both dissolved and suspended materials can influence water transparency. For most water bodies, the amount of solids suspended in the water is the most important factor: the more suspended materials, the lower the water transparency. In lakes, the majority of suspended solids are algae.
In streams and rivers, soil particles (predominantly silts and clays) are a more important influence on transparency as water flows downstream, carrying and depositing sediment with it.
Tracking water transparency tells us about the general health of a stream. Changes in transparency may indicate if water pollutants are present.
Aquatic invertebrates, which make up much of the diet of fish, are often more sensitive to pH changes than are fish. Insects such as mayflies, sow bugs, dragonflies, and others are especially sensitive to drops in pH. Some snail shells will begin to dissolve if pH goes below 6.0.
Adequate dissolved oxygen is necessary for good water quality. Oxygen is a necessary element to all forms of life. Natural stream purification processes require adequate oxygen levels in order to provide for aerobic life forms. As dissolved oxygen levels in water drop below 5.0 ppm, aquatic life is put under stress. The lower the concentration, the greater the stress. Oxygen levels that remain below 1-2 ppm for a few hours can result in large fish kills.
Hardness is caused by compounds of calcium and magnesium, and by a variety of other metals. General guidelines for classification of waters are: 0 to 60 ppm as calcium carbonate is classified as soft; 61 to 120 ppm as moderately hard; 121 to 180 ppm as hard; and more than 180 ppm as very hard.
Total dissolved solids (TDS)
TDS represents the total concentration of dissolved substances in water. TDS is made up of inorganic salts, as well as a small amount of organic matter. Common inorganic salts that can be found in water include calcium, magnesium, potassium and sodium, which are all cations, and carbonates, nitrates, bicarbonates, chlorides and sulfates, which are all anions. Cations are positively charged ions and anions are negatively charged ions. Some dissolved solids come from organic sources such as leaves, silt, plankton, and industrial waste and sewage. Other sources come from runoff from urban areas, road salts used on street during the winter, and fertilizers and pesticides used on lawns and farms.
Nitrates / Nitrogen
Nitrogen-containing compounds act as nutrients in streams and rivers. Nitrate reactions [NO3-] in fresh water can cause oxygen depletion. Thus, aquatic organisms depending on the supply of oxygen in the stream will die. The major routes of entry of nitrogen into bodies of water are municipal and industrial wastewater, septic tanks, feed lot discharges, animal wastes, and other sources.
Phosphorus is one of the key elements necessary for growth of plants and animals. Phosphorus in elemental form is very toxic and is subject to bioaccumulation. Phosphates PO4— are formed from this element. Phosphates exist in three forms: orthophosphate, metaphosphate (or polyphosphate) and organically bound phosphate. If there is an excess of phosphate that enters the waterway, algae and aquatic plants will grow wildly, choke up the waterway and use up large amounts of oxygen. This condition is known as eutrophication or over-fertilization of receiving waters. The rapid growth of aquatic vegetation can cause the death and decay of vegetation and aquatic life because of the decrease in dissolved oxygen levels.
Carbon dioxide is present in water in the form of a dissolved gas. Surface waters normally contain less than 10 ppm free carbon dioxide, while some ground waters may easily exceed that concentration. When the oxygen concentration in waters containing organic matter is reduced, the carbon dioxide concentration rises. The rise in carbon dioxide makes it more difficult for fish to use the limited amount of oxygen present. To take on fresh oxygen, fish must first discharge the carbon dioxide in their blood streams and this is a much slower process when there are high concentration of carbon dioxide in the water itself.
Chloride is one of the major anions to be found in water and sewage. Chlorides may enter water through industrial and human/animal wastes, and soil leaching. During the winter, road salt may increase levels up to 10,000ppm in rural areas and 25,000 ppm in urban areas. Unpolluted water would range 8-12 ppm.
Fluoride may be present in natural water supplies as well as industrial and municipal effluents. Some fluoride compounds are used as toxic agents for pest control and the residue of these compounds may appear in water.
Coliform bacteria (E.coli) is also an indicator organism of contaminated or unsafe water. They are monitored in surface waters because their presence indicates fecal contamination is present. Because it is not feasible to test for all the disease-causing organisms that can be present in surface water, E.coli is an indicator because it is commonly found in animal and human wastes. If E.coli is present above certain levels, then other disease causing organisms may be present and a potential threat to human health. The primary sources of fecal coliform bacteria to fresh water are wastewater treatment plant discharges, failing septic systems, and animal waste. Bacteria levels do not necessarily decrease as a watershed develops from rural to urban. Instead, urbanization usually generates new sources of bacteria. Farm animal manure and septic systems are replaced by domestic pets and leaking sanitary sewers. In fact, storm water runoff in urbanized areas has been found to be surprisingly high in fecal coliformbacteria concentrations.