2.1:Monitoring Water Quality

1. GO C2 Identify processes for Measuring the Quantity of Different Substances in the Environment and for Monitoring air and water Quality. 2.1:Monitoring Water Quality

2. Guided Question Why is it important to monitor the quality of water?

3. Would you Drink this water?

4. Monitoring: keeping track of something for a specific purpose. • Water quality is determined by what water is used for. It is regulated by technicians • Their are five categories of water use: • Human drinking water • Recreation such as swimming • Livestock drinking water • Irrigation • Protection of aquatic life

5. Biological Indicators • Scientist use organisms that live in the water to help determine water quality. Microbiological Indicators • Microscopic organisms such as bacteria can cause serious health problems if they are present in high enough numbers.( E coli bacteria) Aquatic Invertebrates • Invertebrates are animals without backbones. They are used for monitoring because different invertebrates prefer different living conditions.

6. Examples of Indicators

7. Which organisms indicate a high level of dissolved O2? good water conditions Which organisms indicate a low level of dissolved O2? poor water conditions Biological Indicators

9. Chemical Factors that Affect Organisms • Water found in our environment may contain many different organic and inorganic compounds. The concentration of these compounds affects water quality. • The following are monitored as indicators of water quality: • Dissolved oxygen • Acidity • Heavy metals • Plant nutrients(such as nitrogen and phosphorus) • Pesticides • Salts(such as sodium chloride and magnesium sulfate)

10. Dissolved Oxygen The level of dissolved oxygen depends on: • Temperature (due to change in seasons) • Turbulence (due to wind or the speed of moving water) • Photosynthesis of aquatic plants or algae • # of organisms using up the oxygen Dissolved oxygen is essential for the health of aquatic life.

11. Acidity • Precipitation with a pH lower than 5.6 is considered acid rain/snow. • Acid precipitation causes major problems in the spring when the snow melts and flows into aquatic systems. Spring acid shock causes serious harm to the eggs and young offspring of fish. • As the acidity increases the diversity of organisms decreases! • Most fish disappear if the water’s pH falls to 4.5.

12. Heavy Metals • Heavy metals have a density of 5g/cm3 or higher • Include copper, zinc, lead, mercury, cadmium and nickel • They naturally occur in rocks and soil • They are mined to make: batteries, tires, paints, pipes, thermometers and fertilizers • Heavy metals must be monitored because they can be toxic to a variety of organisms

13. Plant Nutrients(Phosphorus and Nitrogen Content) • Phosphorus and nitrogen are important for all living things, but too much can cause problems. Excess P and N2 comes from: • Sewage outfalls • Runoff from fertilized fields

14. High amounts of P and N2 cause: Increased growth in algae and green plants Plants dies and becomes food for bacteria that decompose it Bacteria increase in number Increased bacteria use up dissolved oxygen Fish and aquatic insects cannot survive

15. Pesticides • Some pesticides have long lasting effects as they do not break down quickly and last in the environment for a long period of time ( DDT) • Most are now used for ONE growing season • They do however create organisms that can become RESISTANT to the pesticide • Larger numbers of pesticides are creating problems in the environment as if they are mixed together they create a TOXIC substance • TOXICITY – describes how poisonous a substance is

16. Measuring Toxicity • Toxins or poisons are substances that produce serious health problems or death when introduced into an organism. • In order to compare toxins, a measurement called LD50 is used. • LD stands for lethal dose; 50 represents 50%. • LD50 is the amount of a substance that causes 50% of animals to die if they are given a specified dose of the substance all at once. • Table salt – 3000mg/kg, Caffeine – 192 mg/kg, DDT 87mg/kg (all given to rats by mouth)

17. Measuring Chemicals in the Environment • The concentration of chemicals in the environment is usually measured in parts per million (ppm) • One part per million means that one unit of an element can be found in one million units of solution • Some times the concentrations are expressed in parts per billion (ppb) or parts per trillion (ppt)

18. 1 ppm is about the same as 1 drop of food colouring in a half filled bath tub • 1 ppb is about the same as 1 drop of food colouring in a swimming pool • 1 ppt is about the same as 1 drop of food colouring in 1000 swimming pools

19. Determining ppm ppm= Part (g or mL)ie. 1 Part per million 1 000 000 mL millilitres ppm = mg = mg = g or mL _ L 1 000mL 1 000 000mL

20. Example • If there are 20 mg of oxygen dissolved in 5 L of water, how many ppm of dissolved oxygen is there? ppm = 20 mg = 4 mg/L = 4 ppm 5 L

21. Example 2 • If there is 5mL of oxygen dissolved in 995 mL of water, how many ppm of dissolved oxygen is there? ppm = g or mL _ 1 000 000mL ppm = 5 mL = 0.005 mL/mL 1000mL ppm = 0.005 = 5000 ppm 1000

22. Water Quality – Hot Topic http://www.youtube.com/watch?v=2igTexiW3bg Do you think it will be banned? Do you think it should be? Could it be a risk to humans? Should it be used, even if not a risk to human? Homework: can you find any triclosan in your home?