Grade 7 www pollution overview
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Grade 7 www pollution overview



Overview to pollution indicators for field analysis.

Overview to pollution indicators for field analysis.



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Grade 7 www pollution overview Grade 7 www pollution overview Presentation Transcript

  • Water Pollution Indicators of the Mekong Delta Grade 7 Science Saigon South International School Week Without Walls 2010
  • Key Questions:
    • Is the Mekong Delta polluted?
    • Are the waters in HCMC polluted?
    • How do we measure pollution?
  • 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.
  • What causes water pollution?
    • Industrial and municipal sewage systems
    • Pesticide and herbicide run off
    • Illegal dumping
    • Leaking storage tanks
    • www.neoscience- “Investigating Water pollutants”
  • 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
  • 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?
  • Benthic Macroinvertebrates
    • Benthic=Bottom Living
    • Macro=Small
    • Invertebrates=Having no backbone
    • Three classes, some are pollution sensitive, some are not.
  • 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.
  • 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.
  • 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.
  • 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.
  • Chemical Indicators of Water Quality
    • Dissolved Oxygen (DO)
    • Nitrates
    • Hardness
    • Phosphates
    • Carbon Dioxide (CO2)
    • Acidity
  • 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
  • Environmental Affects of Low Dissolved oxygen
    • Limits suitable habitat for oxygen filtering organisms (fish and amphibians)
  • 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
  • U.S. Fertilizer Loss Nitrogen runoff
  • 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
  • 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.
  • Hardness
    • Water Hardness Scale
    Mg/L (ppm) Classification Less than 17 Soft 17-60 Slightly Hard 60-120 Moderately Hard 120-180 Hard Over 180 Very Hard
  • 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.
  • 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
  • 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)
  • 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.
  • 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.