1. Topic 4.4 - Water Pollution

2. Types of Water Pollution
Anthropogenic or natural
Anthropogenic (human) pollution
Red Tide Caused by algae bloom
There are a variety of freshwater and marine pollution sources

3. Types of Water Pollution
Point Source and Non-Point Source
There are a variety of freshwater and marine pollution sources

4. Types of Water Pollution
Organic or Inorganic
Gulf of Mexico
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Human and animal waste
There are a variety of freshwater and marine pollution sources

5. Types of Water Pollution
Direct or Indirect
Dumping toxins into waterways
blogs.ntu.edu.sg
Excess nitrates entering waterways
There are a variety of freshwater and marine pollution sources

6. Possible Sources of Water Pollution
Oil spills
Heat (thermal pollution from electrical stations)
Radioactive waste
Solid domestic waste (trash debris)
Suspended particles (from erosion)
Invasive species`
Sewage (human & animal)
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Pesticides
Industry
Pathogens
Nitrates (fertilizers)
Phosphates (detergents)
Heavy metals (industry)
Types of aquatic pollutants include organic material, inorganic plant nutrients (nitrates and phosphates), toxic metals, synthetic compounds, suspended solids, hot water, oil, radioactive pollution, pathogens, light, noise, and biological (invasive species)

7. Possible Effects of Water Pollution
Eutrophication
Loss of biodiversity (species & habitat)
Increase in disease from pathogens
Bioaccumulation and biomagnification
Disruption of breeding grounds, nesting sites
Damage to coral reefs
Damage to organisms (ingesting plastics)
Types of aquatic pollutants include organic material, inorganic plant nutrients (nitrates and phosphates), toxic metals, synthetic compounds, suspended solids, hot water, oil, radioactive pollution, pathogens, light, noise, and biological (invasive species)

8. Measuring Water Pollution Direct Methods
Performed by monitoring the level of the pollutant itself pH
Nitrates or ammonia
Dissolved oxygen (DO)
Conductivity (may indicate dissolved pollutants or heavy metals)
Turbidity
Fecal coliform test
A wide range of parameters can be used to directly test the quality of aquatic ecosystems, including pH, temperature, suspended solids (turbidity), metals, nitrates and phosphates

9. Measuring Water Pollution Indirect Method - BOD
Biochemical Oxygen Demand (BOD)
= a measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity by microorganisms
If enough oxygen is present, aerobic decomposers will continue until all waste is consumed
Biochemical oxygen demand (BOD) is a measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity. BOD is sued to indirectly measure the amount of organic matter within a sample

10. Measuring Water Pollution Indirect Method - BOD
Biodegradation of organic material utilizes oxygen.
There is a finite source of oxygen, and once it is used the water becomes anoxic.
This leads to anaerobic decomposition which leads to the formation of methane, hydrogen sulphide and ammonia (toxic).

11. Measuring Water Pollution Indirect Method - BOD
Biochemical Oxygen Demand (BOD)
DO should be measured for the initial amount of oxygen in the sample
Sample should be sealed and placed in the dark (…why?)
After 5 days a second DO reading should be recorded
Calculate the change in oxygen level
Unpolluted, natural water has a BOD less that 5mg/L

12. Measuring Water Pollution Indirect Method - Indicator Species
Organisms that show something about their environment by their abundance or scarcity
These species are sensitive to changes in an environmental factor
Some species can be indicative of polluted waters and be used as indicator species

13. Measuring Water Pollution Indicator Species
In Freshwater Ecosystems the following are often indicators of the water quality
Frogs and Toads have permeable skin so are affected by water pollutants and are only present in clean water
Mayfly larva indicate clean water
Water louse indicate polluted water
Sludgeworms indicate very polluted water
Some species can be indicative of polluted waters and be used as indicator species

14. Indicator species and biotic index
Indicator species indicate whether there is pollution present or not.
A Biotic index works by assigning different levels of tolerance to pollution to the different types of organisms

15. This Biotic index (Trent Scale) is a scale of 1-10 that gives a measure of the quality of an ecosystem by presence/abundance of species in it
The Trent Biotic index is based on the fact that certain species disappear and the species diversity decreases as the organic pollution increases
The scale corresponds to 4 basic water quality (Excellent, good, fair, poor)
A biotic index indirectly measures pollution by assaying the impact on species within the community according to their tolerance, diversity and relative abundance

16. Measuring Water Pollution - Biotic Indices
Indirect measure of pollution
Often used in conjunction with BOD as invertebrates are sensitive to decreases in oxygen demand
Often used to compare 2 ecosystems or point source pollutants using Simpson’s diversity index
Measures the effect of pollutants on biodiversity

17. Eutrophication Occurs when excess nutrients enter an aquatic ecosystem
Drastic increase in algae growth
May happen in freshwater or oceans (red tide)
Natural or anthropogenic
Human influence by using fertilizers or detergents. The resulting increase of nitrate and phosphorous encourages algal growth.
This prevents sunlight from penetrating so the water plants die
Bacteria break down the dead plants and use up all the oxygen leaving the water lifeless`
Biodegradation of organic material utilizes oxygen which can lead to anoxic conditions and subsequent anaerobic decomposition which leads to formation of methane, hydrogen sulphide and ammonia (toxic gases)
Eutrophication can occur when lakes, estuaries and coastal waters receive inputs of nutrients (nitrates and phosphates) which result in an excess growth of plants and phytoplankton

18. Eutrophication
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Explain the process and impacts of eutrophication
Eutrophication can occur when lakes, estuaries and coastal waters receive inputs of nutrients (nitrates and phosphates) which result in an excess growth of plants and phytoplankton

19. Dead Zones
In costal marine environments, dead zones are regions where oxygen concentrations are very low (hypoxia)
Dead zones in both oceans and freshwater can occur when there is not enough oxygen to support marine life

20. Red tides Algal bloom of red species of phytoplankton
Produce toxins that kill fish and accumulate in shell fish – can make humans seriously ill

21. Dealing With Pollution

22. Dealing with pollution
Research methods aimed at mitigating the effects of eutrophication and place them in one of the above categories.
Then evaluate 3 of your methods.
E.g.
Ban or limit detergents with phosphate (phosphate are only needed in hard water areas).
This could be difficult as you would have to get companies to agree to making two products, and would people accept their washing powder being not as effective .