Measure of how much stuff (aka suspended solids) is mixed into the water (i.e., cloudy vs clear) Suspended solids = clay, silt, plankton, industrial wastes, sewage Should not be confused with color, since darkly colored water can still be clear This measurement should be low Problems Caused by Suspended Solids: Covers food sources, nests and eggs Blocks sunlight from plants Most common water pollutant Makes it hard for organisms to breathe
Possible Causes of Turbidity Erosion from agricultural fields construction sites driveways, roads, and lawns natural and accelerated erosion of stream bank Wastewater treatment plants Runoff from urban areas Dredging (deepening, widening) waterways Waste discharge (garbage, sewage) Excessive population of bottom-feeding fish (such as carp) that stir up bottom sediments Boat traffic
Measured with a secchi disk Unit = JTU (Jackson Turbidity Units) We use an alternate method as the stream is too shallow. We use a turbidity tube/jar and a reader card to measure turbidity with a mini secchi disk at the bottom of the tube/jar. The reader card is based on the depth of our container. The secchi disk is lowered into the water. When parts of the disk disappear, you get a JTU measurement based on depth. In the top picture, the black part has disappeared
Water color and odor can indicate water pollution.
Measures the acidic or basic (alkalinity) quality of water ph scale ranges from 0 (very acidic) to 14 (very basic); 7 is neutral 0-6 = acid 7 = neutral 8-14 = base ** see next slide for ph scale diagram ph of natural water ranges between 6.5 and 8.2 Most aquatic organisms are adapted to a specific ph and may die if the ph of the water changes even slightly. ph can be affected by Industrial waste Agricultural runoff Drainage from mining operations Acid precipitation Air pollution from cars, trucks & busses (oxides of nitrogen and sulfur, aka NOx and SOx)
ph is a logarithmic scale, meaning each number is 10x greater/less than the next. A ph of 9 is 10x more basic than a ph of 8, and 100x more basic than ph 7 A ph of 5 is 10x more acidic than a ph of 6, and 100x more acidic than a ph of 7
In nature, the ph of water is influenced by the type of rocks and soil that the water flows over, around, and through. Rapidly growing algae and vegetation remove carbon dioxide (CO 2 ) from the water during photosynthesis which causes ph levels of the water to rise. For the folks who like math: ph is the negative log of the hydrogen ion concentration ph = -log[h + ] The picture shows the ph test kits we use in Stream Study
Phosphate (PO 4 ) is a nutrient needed for plant and animal growth and other cell processes. High levels of phosphate cause algae and water weeds to grow wildly which clogs the waterway. As the plant and algae populations explode, they use up large amounts of oxygen. This can cause fish and other aquatic organisms to die. This process is called eutrophication. An algae bloom has caused this water to become scum-covered; a sign of eutrophication
Eutrophication that is a natural part of aquatic succession is not considered harmful. Eutrophication caused by people is called cultural eutrophication and is a sign of poor water quality Read the Nitrogen slides about Eutrophication too!
Sources of phosphate Fertilizer runoff from farms, lawns, golf courses, playing fields Human waste / sewage Pet, geese waste Leaves Industrial waste Detergents Forest fires
Cultural Eutrophication Anoxic = lack of oxygen
Look at the slide before this one too! Nitrate (NO 3 )is a form of nitrogen Nitrate is a nutrient used by all plants and animals to build protein. We fertilize land to help crops and lawns grow better. If the fertilizer runs off into a body of water, the nitrate helps aquatic plants to grow better as well! The increase in plant growth and decay increases bacterial growth, and they end up decreasing the amount of oxygen available in the water. This decrease in oxygen can cause fish and other aquatic organisms to die. This process of over-fertilization is called cultural eutrophication See the Phosphate slides about Eutrophication, both natural and cultural
Sources of nitrate Sewage treatment facilities Pet wastes Leaking or failing septic systems Fertilizer and agricultural runoff Farm animals, ducks, and geese that eliminate waste directly into waterways Grass clippings Sewage treatment facility
See the Phosphate slides about Eutrophication, both natural and cultural How does eutrophication actually lower oxygen levels when it is common knowledge algae produce oxygen? It is true algae produce oxygen, but only when there is enough light. Eutrophication reduces the clarity of water and underwater light. In eutrophic lakes, algae are starved for light. When algae don t have enough light they stop producing oxygen and in turn begin consuming oxygen. Moreover, when the large blooms of algae begin to die, bacterial decomposers further deplete the levels of oxygen. As a result, eutrophication can quickly remove much of the oxygen from a lake, leading to an anoxic* and lethal underwater environment. Source: http://www.lakescientist.com/lake-facts/water-quality/ * Anoxic lacking oxygen
Dissolved oxygen (DO, pronounced dee-oh ) is the oxygen in the water that aquatic organisms use to breathe DO is NOT the O of H 2 O! DO levels are decreased by: Fertilizer runoff Sewage Decaying plants Temperature increases DO levels are increased by: Water tumbling through riffles Water mixed by wind & waves Temperature decreases Aquatic plants and algae photosynthesizing Molecules of dissolved oxygen fit in between the molecules of water
Oxygen is dissolved into water when air mixes with water as it tumbles over rocks, rushes over riffles and through rapids or over waterfalls. The white in white water is air, or, dissolved oxygen! Oxygen also dissolves into water when waves, created by wind, toss the water around and up into the air.
A high DO is a sign of a healthy ecosystem. Low levels are a sign of pollution and aquatic life can die DO levels below 3 ppm are stressful to most aquatic life Levels of 5 to 7 ppm are usually needed for healthy aquatic life
Cold water can hold more DO than warm water. Fish that need a lot of oxygen will be found in colder water It is important when collecting water samples for DO tests not to add any air into the collection bottle! There should be no air bubbles in a water sample collected for DO testing! The bottle should overflow when the cap is tightened.
% Saturation When water holds all the DO it can hold at a given temperature, it is said to be 100% saturated with oxygen. If water holds half as much oxygen as it can hold at a given temperature, it is 50% saturated. High levels of bacteria from sewage pollution or large amounts of rotting plants can cause the %-saturation to decrease, which can affect the ability of aquatic organisms to thrive. From the chart, water at 6.5⁰C with 8 mgl DO = 68% sat
Temperature affects the amount of dissolved oxygen in water the rate of photosynthesis by aquatic plants how toxic wastes, parasites, and diseases affect aquatic organisms Trout prefer cooler water temps; catfish like warmer water Most aquatic animals cannot tolerate temp extremes Optimum or Preferred Temperature, C. Rainbow trout 13 Chum salmon 13.5 Sockeye salmon 15 Lake trout 15-17 Coho salmon 20 Greenthroat darter 20-23 Largemouth bass 22-25 Roach 23-24 Guppy 23-25 Carp 32 catfish Fish Temps Source: http://sciencefairwater.com/physical-water-quality-parameters/water-temperature/water-temperature-effects-on-fish-and-aquatic-life/
How Water Temperature Can Be Changed Thermal pollution is caused by human activities that add warm water to a river Industries and power plants use water to cool machinery and then return the warm water back to the river. Buildings and parking lots in built-up areas trap heat and warm up rainwater that runs off them into streams Weather rain, snow, sun, etc. Loss /removal of trees that provide shade alongside a waterway Reservoirs behind dams release cold water downstream Soil erosion will cloud water (see turbidity); cloudy water absorbs the sun s heat, increasing temperature.
Pathogenic (disease-causing) bacteria in water are a concern because of the health problems they can cause. Sources of pathogens in water are pet wastes, farm animal wastes and untreated human sewage Pathogens are hard to detect in water, and we could get sick in the process of conducting the test Instead water is tested for harmless coliform bacteria that also live in human and animal digestive tracts. A positive coliform test usually means wastes are in the water that may also contain pathogenic bacteria
Most swimmers eye, ear, nose or throat infections do not result from coliform bacteria Swimming in waste-contaminated sea water has little health risk because the salt in the ocean kills many pathogenic bacteria; also oceans are big, so the wastes are quickly diluted.
Salinity is the amount of dissolved salts in water. Sources of salt rocks and soil the fresh water flows through or over pollution from industrial waste runoff from road salt
Freshwater life is adapted to water with a very low salt content. The parts of the river closest to the ocean will have a higher salinity level than the headwaters. The area where fresh and salt water mix is an estuary An estuary is an area of transition from the river s fresh water to the ocean s salt water Estuaries have tides; the tide brings the salt water from the ocean up the estuary to mix with fresh water from the river. Because of this mixing, salt levels in the estuary are lower than the ocean, but higher than the river How the water mixes in an estuary
The Chesapeake Bay is one of the largest estuaries in the world Philadelphia is up here We live near the Delaware Bay estuary, part of the Delaware River watershed (basin) Delaware Bay Chesapeake Bay
The St. Lawrence River is the world s largest estuary. Other US estuaries: Puget Sound, WA San Francisco Bay, CA Hudson River, NYC/NY Barnegat Bay, NJ Casco Bay, ME Galveston Bay, TX Of the world s 32 largest cities, 22 are on estuaries.