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Grade 7 www pollution overview

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.