YO SYSTEMS STUDENTS! QUIZ (FRIDAY MAY 23rd) – HYDROSPHERE Syllabus Details A-J

Monitoring Water Pollution Topic 8 A.S: G – J

Review of Pollution Monitoring What does monitoring pollution mean? Can be: direct measuring = TESTING FOR POLLUTANT LEVEL Ex: Testing for nitrates and phosphates, amount of organic matter or bacteria, and heavy metal concentrations (ie: mercury or lead) or indirect measuring = testing other aspects that can give you an indication of water quality Abioitic ex: dissolved oxygen (ie Biochemical Oxygen Demand) Biotic ex: presence or absence of an indicator species = Why should we measure aquatic pollution in a polluted and unpolluted area (like upstream and downstream)?

Why should we measure aquatic pollution in a polluted and unpolluted area (like upstream and downstream)?

Dissolved Oxygen Dissolved oxygen (DO) analysis measures the amount of gaseous oxygen (O2) dissolved in a body of water. What factors would effect the amount of DO in a body of water? Light, plant life, any life….like bacteria Moving water, amount of submerged aquatic vegetation (SAV), temperature, amount of light getting through the water to the SAV.

Biochemical Oxygen Demand Biochemical Oxygen Demand or Biological Oxygen Demand (BOD) is a how fast bacteria use up oxygen in a body of water Measures the amount of dissolved oxygen needed by aerobic decomposers to break down the organic materials in a given volume of water What pollutants would cause BOD to go up? So is a high BOD good or bad for an aquatic ecosystem? Why?

BOD Test BOD measures mass (in milligrams) of dissolved oxygen consumed per liter of water. Sample bottle is filled completely submerged underwater. Why? DO is tested. Sample is incubated at a temperature of 20°C for five days in the dark. Why in the dark? DO is tested again…how do you then calculate BOD?

BOD Values? Most pristine rivers will have a 5-day BOD below 5 mg/L Moderately polluted rivers may have a BOD value in the range of 5 to 10 mg/L Municipal sewage that is efficiently treated would have a value of about 20-60 mg/L. Untreated sewage varies, but averages around 350 mg/L Cattle slurry is around 10,000 mg/L Paper pulp mill is around 25,000 mg/L

Indirect Method using Biotic Index A biotic index is a scale (1-10) that gives a measure of the quality of an ecosystem by the presence and abundance of certain species living in it. Indicator species = plants or animals that show something about the environment by their presence, absence, abundance or scarcity. They are early warning signs because they are the most sensitive to change or they are very tolerant of chemicals or low levels of oxygen. Why are these indirect methods?

Using the method How could you use this method to determine if an area of a river is polluted? Kick nets for Biotic Index Water Sample for BOD BOD and Biotic Indices are usually used together: What does the Biotic Index show that BOD and direct pollution monitoring does not?

Collecting Organisms

Turbidity Turbidity is the cloudiness or haziness of a fluid caused by individual particles, that are generally invisible to the naked eye The measurement of turbidity is a key test of water quality How can Turbidity affect the health of an aquatic ecosystem?

For use in shallow or moving water Monitoring Turbidity Turbidity Tube Turbidity Tube For use in shallow or moving water Using a Secchi Disk to measure the depth of water where photosynthesis can still occur Turbidity Columns 1 is the control with distilled water and the other has the sample water

Flow Velocity The speed of water movement Normally studied in streams or rivers Time how long it takes for objects to pass between two poles 5 meters apart at different depths and take an average. How might flow velocity affect the health of an aquatic ecosystem?