Non-Point Source Pollution: Pollutants that enter the river from diffuse or undefined sources, and usually carried by runoff. These sources include cleared or agricultural land, coal mines, construction sites, roads and urban areas. Air-borne non-point source pollutants can be deposited directly into a water body. Because non-point sources are diffuse, they are often difficult to identify or locate precisely, and thus pollutants from them cannot be controlled easily.

Point-Source Pollution: Pollutants entering the river from one, easily recognizable location such as a pipe associated with an industrial or municipal wastewater treatment facility.

Pollution: Contribution of substances from human activities that may adversely affect a desired use of water.

Runoff: Water that moves across (or through) soils on the land during snowmelt or rainstorms.

Watershed: A term often used interchangeably with the word "drainage basin", but in the strictest sense it refers to the outer boundary of the drainage basin itself, as defined by topographic features.

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Specific Conductance: or conductivity, indicates water's ability to conduct an electrical current. It provides an indication of the amount of dissolved substances in the water - when conductivity is high, the concentration of dissolved material is also high.

Suspended Solids: particles suspended in the water, primarily soil particles eroded from the land. Suspended solids concentrations normally increase with increases in river flow, as a result of scouring of the river bed and banks. High suspended solids loads can cause siltation of the river bed and smother plants and animals, decrease light penetration, cause stress to aquatic organisms and reduce photosynthesis. In addition, suspended solids may adsorb organic compounds, heavy metals and nutrients.

Turbidity: or cloudiness, of the water is determined by the presence of suspended particles such as clay, silt, organic matter and living organisms. High turbidity may reduce light transmission, and therefore reduce photosynthesis of aquatic plants.

Water Temperature: the temperature of the water plays an important role in influencing physical, chemical and biological processes, and is regulated mainly by the season, weather conditions, time of day and in moving water, the flow rate.

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General Chemistry

Alkalinity: the acid-neutralizing capacity of water.

Biochemical Oxygen Demand: (BOD) is a measure of the amount of oxygen needed for microorganisms to convert organic matter to inorganic matter. It is typically measured as the amount of oxygen consumed in laboratory tests over a five-day period at 20 degrees C.

Cyanide: is a general term for a diverse group of organic and inorganic compounds containing carbon and nitrogen, some of which are toxic. They are generally found in low concentrations in surface waters as a result of natural decomposition of certain plants and metabolism of microorganisms. They are also released into the aquatic environment in discharges from mining industries, steel mills, oil refineries and electroplating industries.

Dissolved Oxygen: is required by aquatic organisms for aerobic respiration. Oxygen is added to the water by photosynthetic activity of plants and reaeration from the atmosphere. It is removed from the water by respiration of bacteria, plants and animals and various chemical processes. In winter, ice cover restricts the amount of oxygen that can enter the water, and replenishment by photosynthesis is greatly reduced. In summer, dissolved oxygen levels may fluctuate dramatically from day to night.

Fluoride: is present in trace amounts in soil and rocks and is released naturally to the aquatic environment by geochemical weathering. Fluoride is also released into surface waters from municipal wastewater as a result of fluoridation of drinking water.

Hardness: a measure of the amount of certain dissolved substances in the water, primarily calcium and magnesium. Concerns with hardness relate mainly to encrustation and excessive soap consumption in water supplies, although it can also influence the form and toxicity of numerous heavy metals.

Major Ions: occur naturally in water as a result of geochemical weathering of rocks, surface runoff and atmospheric deposition. The eight major ions - calcium, magnesium, sodium, potassium, bicarbonate, carbonate, sulphate, and chloride - account for most of the total dissolved solids in surface waters.

pH: a measure of the intensity of the acid or base chemistry of the water. A pH of 7 is neutral, below 7 is acidic and above 7 is basic. Technically, pH is defined as the negative logarithm of hydrogen ion activity. pH in surface water is regulated by the geology and geochemistry of the area, and affected by biological activity. The distribution of aquatic organisms and the toxicity of some common pollutants are strongly affected by pH.

Total Dissolved Solids (TDS): a measure of the concentration of dissolved matter in water. It is measured by evaporating water that has passed through a very fine textured filter to remove suspended solids. The residue is then weighed. TDS is often used as an estimate of water's salinity, which may affect the distribution of aquatic organisms.

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Metals and Trace Elements

Aluminum: is abundant in rocks and clays, and it can be mobilized from soils by natural weathering. Sources also include effluents from industries that use aluminum in their processing or use alum as a flocculent. Low concentrations are not a concern, but toxicity of aluminum increases if the pH of the water is less than 6.

Arsenic: is released naturally into the aquatic environment as a result of weathering of arsenic-containing rocks, from industrial and municipal discharges, and from combustion of fossil fuels.

Barium: is a common element in the earth's crust, although only trace levels are normally found in natural surface waters.

Boron: is released naturally into the aquatic environment from weathering of rocks and soil, and is present in municipal sewage.

Cadmium: is present in trace concentrations in fresh water as a result of natural weathering processes. Concentrations above about 0.01 mg/L can usually be attributed to human activities such as mining, agriculture and the burning of fossil fuels. Concentrations above this level may be toxic to aquatic life.

Chromium: is released into rivers by weathering of rocks and soil, and in industrial discharges such as from metal plating plants. Chromium is toxic to certain aquatic invertebrates at low concentrations, but fish are less sensitive.

Cobalt: is released into the environment from weathering of cobalt-rich ores and from anthropogenic sources such as emission from coal burning industries.

Copper: sources to aquatic environments include the weathering of copper minerals and native copper, and numerous sources from human activities. Background concentrations in surface waters are usually below 0.02 mg/L. Higher levels are generally related to human acitivities.

Iron: is released naturally into the aquatic environment by weathering of sulphide ores and rocks and leaching from sandstones. Human sources include the burning of coal, acid mine drainage, mineral processing, sewage and landfill leachates.

Lead: is toxic to fish and other organisms, particularly in soft water. Although there are natural sources of lead, human sources often supply a greater quantity to surface waters. Sources include weathering of sulphide ores, urban runoff, atmospheric deposition and industrial and municipal discharges.

Manganese: is an essential trace element for living things. Soils, sediments and rocks are significant natural sources of manganese, whereas industrial discharges are the primary source from human activities.

Mercury: deposits occur in all types of rocks, and human sources of mercury to the aquatic environment include industrial and municipal discharges, atmospheric deposition or industrial emissions and leaching from landfill sites. Mercury is of particular concern because of its toxicity to aquatic organisms and its adverse effects on human health.

Nickel: enters the aquatic environment through the weathering of rocks and as a result of human activities, primarily the burning of fossil fuels and from smelting and electroplating industries.

Selenium: enters surface waters as a result of weathering and erosion of soils and discharge from copper and lead refineries and municipal wastewater.

Vanadium: is released to the aquatic environment primarily by surface erosion. The major human-related sources are from atmospheric deposition as a result of emissions associated with oil, gas and steel production.

Zinc: enters the aquatic environment primarily as a result of geochemical weathering and industrial and municipal discharges. Zinc is an essential element for living organisms.

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Nutrients

Nitrogen: is an essential nutrient for the growth of plants. Only inorganic forms may be used by plants, specifically nitrate-nitrogen and ammonia-nitrogen, NH3-N (which includes the ammonium ion and free ammonia). Free ammonia, NH3, is toxic in aquatic ecosystems, but it is generally scarce except at high pH and temperature.

Phosphorus: is an essential nutrient for the growth of plants. In aquatic systems, low phosphorus levels may limit plant productivity, whereas high levels may result in nuisance growth of aquatic plants. Phosphorus occurs in inorganic and organic compounds and in dissolved and particulate forms.

Silica: refers to the oxides of silicon in water. It is present in most surface waters and originates primarily from weathering of aluminosilicate minerals. Silica is an essential nutrient for diatom algae.

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Organic Constituents

Organic Carbon: is the most abundant element found in all organisms. In aquatic environments, organic carbon is produced by plant photosynthesis and bacterial growth. Leaching of humic substances and decomposition of plants and animals are also natural sources of organic carbon to surface waters. Human-related sources include agricultural runoff and municipal and industrial effluents.

Pesticides: chemical compounds used to control unwanted species that attack crops, animals and man. This diverse group of chemicals (organic and inorganic) includes herbicides, fungicides, and insecticides.

PAHs: Polycyclic Aromatic Hydrocarbons are formed by the incomplete combustion of organic materials such as wood, coal, and refuse. They are found in petroleum products and creosote and include compounds such as naphthalene, anthracene and benzo-a-pyrene.

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Biological Characteristics

Bacteria: are a diverse group of microorganisms that occur naturally in aquatic environments. Bacteria that occur naturally in surface water generally are not harmful to humans. But pathogenic bacteria can be introduced into surface waters from wastewater, particularly from municipal sewage effluents. Bacterial analyses include tests for fecal coliforms, total coliforms and fecal streptococci. These tests do not detect pathogenic bacteria directly, but are used as an indicator of possible contamination. The fecal coliform test is used to differentiate between coliforms of fecal origin (from warm-blooded animals) and coliforms from other sources.

Benthic Invertebrates: animals that live on river and lake bottoms. Benthos refers to the bottom, and these animals are also called zoobenthos. Many of these inhabitants are immature stages of insects such as mayflies, stoneflies, caddisflies and midges. Other types of animals include aquatic earthworms or bristleworms, roundworms, snails and leeches. The variety and abundance of benthic invertebrates in a river reflects the type of habitats the river provides.

Chlorophyll a: is a photosynthetic pigment found in most algae, and concentrations of chlorophyll a in a water sample provide a good estimate of the amount of algae suspended in the water. Chlorophyll a may also be extracted from algae attached to rocks in the river.

Trophic Status: This term refers to the overall level of biological productivity (or fertility) of a lake and is usually defined by the concentrations of key nutrients (phosphorus and nitrogen) and algae that are present. Alberta is a province with very diverse ecoregions and as a result our lakes vary widely in trophic state. Some lakes, such as those in the foothills and mountains, tend to have low nutrient concentrations. Others, like those in the central plains area tend to have very high nutrient and algal concentrations.

Lakes in Alberta are categorized into four trophic levels:

• Oligotrophic (low productivity)
• Mesotrophic (moderate productivity)
• Eutrophic (high productivity)
• Hypereutrophic (very high productivity)