1. Water Pollution Indicators of the Mekong Delta Grade 7 Science Saigon South International School Week Without Walls 2010

2. Key Questions: Is the Mekong Delta polluted? Are the waters in HCMC polluted? How do we measure pollution?

3. What you will learn: Causes and health affects of pollution Why it’s important to measure pollution What are the two different areas of measuring/assessing water pollution.

4. What causes water pollution? Industrial and municipal sewage systems Pesticide and herbicide run off Illegal dumping Leaking storage tanks www.neoscience-www.neoscience- “Investigating Water pollutants”

5. Why assess water quality? Safe for growing crops and livestock? Bioaccumulation may lead to health affects over long term Can cause ecosystems to change Recreational use

6. 2 Indicators of Water Pollution Biological What are the living things that can live here? Are there things that used to live here, but are not anymore? (Benthic Macroinvertebrates) Chemical Are there chemicals which are dangerous to people in the water? How do we measure these chemicals? Are there acceptable amounts?

7. Benthic Macroinvertebrates Benthic=Bottom Living Macro=Small Invertebrates=Having no backbone Three classes, some are pollution sensitive, some are not.

8. Class 1 Organisms are pollution sensitive. They are associated with good water quality. They do not tolerate pollution well, and large numbers are observed only when good water quality is present.

9. Class 2 Organisms somewhat pollution tolerant. They tolerate water pollution better than Class 1 organisms. We can expect to see significant numbers of these animals when the water quality ranges from good to moderate.

10. Class 3 Organisms are pollution tolerant. They are tolerant to even higher levels of pollution than are Class 2. When these animals dominate, poor water quality is generally the reason.

11. Macroinvertebrates as pollution indicators: Review Class Class 1-Sensitive to water pollution and do not tolerate it. Class 2-More sensitive to water pollution Class 3-Very tolerant to water pollution. (Can survive in more polluted water) What does it tell you about pollution levels? If you find members of all three classes? If you find members of only class 2, and class 3. If you find members of only class 3. You find no members of any class.

12. Chemical Indicators of Water Quality Dissolved Oxygen (DO) Nitrates Hardness Phosphates Carbon Dioxide (CO2) Acidity

13. Dissolved Oxygen Between 5-6 ppm is optimal to support aquatic ecosystems Less than 4 ppm = bad 10 < Excellent A key indicator caused naturally by photosynthesis, oxygen exchanges with the atmosphere Aerobic bacteria from sewage or high amounts of decomposing plants decrease dissolved oxygen High amounts can cause pipes to corrode

14. Environmental Affects of Low Dissolved oxygen Limits suitable habitat for oxygen filtering organisms (fish and amphibians)

15. Nitrates NO3 Most common contaminant as nitrates in soil leach down into water table Industrial fertilizers, herbicides and organic wastes also cause EPA allows 10 ppm. Some biological factories can have discharges of 30 < ppm

16. U.S. Fertilizer Loss Nitrogen runoff

17. Environmental Consequences of Nitrates Eutrophocation- “A process whereby water bodies, such as lakes, estuaries, or slow- moving streams receive excess nutrients that stimulate excessive plant growth (algae, periphyton attached algae, and nuisance plants weeds)” www.usgs

18. Cause and Impact of Eutrophocation Causation Environmental Impact Agricultural fertilizer run off, factory discharge into rivers Reduces dissolved oxygen in the process when increased amounts of algae die and decompose.

19. Hardness Water Hardness Scale Mg/L (ppm)Classification Less than 17Soft 17-60Slightly Hard 60-120Moderately Hard 120-180Hard Over 180Very Hard

20. Health Affects of Hardness Too much can lead to kidney stones, although the data is inconclusive Damage machinery Defeats the ability of soap as a cleaning solution Can cause clothes to feel “stiff” when washed in hard water.

21. Phosphates Important in fertilizers because it is a plant nutrient. Phosphate treated plants may accumulate in water ways and lead to algae blooms. Cleaners like soap a domestic contributor Expressed in mg/l (PPM) 4 ppm or higher have high levels of bacteria

22. Carbon Dioxide Present in low levels due to plant and animal respiration Used in Photosynthesis High levels can make water corrosive or toxic to aquatic life (above 10 mg/L) (above 10 ppm)

23. Outline for Pollution Management Altering human activity Regulating and reducing quantities of pollutant released at the point of emission Cleaning up the pollutant and restoring ecosystems after pollution has occurred.

24. Acidity 100-120 ppm are acceptable If sample is below 100 pm, an error occurred and the water should be retested. Over 120 ppm is too acidic.