Pollution

1. Pollution Noadswood Science, 2011

2. Pollution • To understand how we can use organisms as indicators of pollution

3. Developing & Developed • Look at the following – a recent scene from the Glastonbury festival and a shanty town in South America • What issues are involved with this many people?

4. Developing & Developed • In a given area if the population becomes this vast there is a huge strain on resources needed: space / shelter; food; water (and mates) • There is also a great strain on removal of waste • This impacts not only human populations, but any surrounding flora and fauna

5. Human Population Projection • Human beings compete with other living things for resources and space – as the world’s population continues to increase, and standards of living improve, there is serious danger of a permanent change to the global environment • Human activities have led to the pollution of the environment, and a reduction in the amount of land available for other animals and plants, which makes it difficult for some species to survive • There is a need to achieve a level of development that also sustains the environment for future generations…

6. Human Population Projection • Like all living things, humans exploit their surroundings for resources – before the beginning of agriculture about 10,000 years ago, small groups of humans wandered across large areas, hunting and gathering just enough food to stay alive • Population numbers were kept low because of the difficulty of finding food • The development of agriculture led to a population explosion that has accelerated enormously during the past 500 years – unlike other species, humans can adapt to and survive in almost all habitats and climates

7. Human Population Projection • Using the data in the table below plot a graph showing how the human population has changed over the last 10’000 years: -

8. Human Population Projection • Human population graph over the past 10’000 years: -

9. Human Population • In the last 200 years or so the human population has grown very quickly – why? • We can grow more food • We can cure and prevent illness or disease • We have no natural predators • Standard of living has improved (electricity, fuel, heat, cars etc…)

10. Standards Of Living • People in the developed world enjoy a high standard of living, with abundant food, cars and comfortable housing • People in the developing world have a lower standard of living, but many countries are catching up quickly • Strains on the global environment include: - • Non-renewable energy resources (e.g. coal, oil and natural gas) are being used up rapidly • Raw materials are being used up rapidly • More waste is being produced • More pollution is being caused

11. Waste • Pollution is the addition of substances to the environment that may be harmful to living organisms • Population growth and increases in the standard of living cause more waste to be produced – If this waste is not handled correctly, it leads to pollution • Pollution can be categorised into the following: - • Land pollution • Water pollution • Air pollution

12. Land Pollution • Most rubbish is buried in landfill sites and not all of it comprises safe materials – even common household items can contain toxic chemicals such as poisonous metals (many smoke alarms contain radioactive americium) • Industrial waste is also discharged onto the land – many farmers apply pesticides to improve their crops, but these can damage living things (toxic chemicals can be washed from the land into rivers, lakes and seas causing eutrophication) Eutrophication in the Caspian Sea (turbidity in North)

13. Fertiliser Problems • Fertiliser problems arise when the fertiliser finds its way out of the soil and into rivers and streams • This can happen easily if too much fertiliser is applied or it rains immediately after it has been applied • The result is called eutrophication Caspian Sea (rapid algae growth can be seen in the northern part increasing the water’s turbidity (cloudiness))

14. Eutrophication • Eutrophication occurs when excess nitrates make their way into rivers and lakes causing rapid growth of some plants and algae • Some plants then start dying due increased competition for light which results in micro-organisms feeding on the dead plant (they respire using up lots of oxygen) • This increased level of decomposition results in high levels of oxygen being taken from the water, making it very difficult for larger organisms such as fish to survive - a real danger

15. Eutrophication • Excess nitrates make their way into rivers and lakes causing rapid growth of some plants and algae • Some plants and algae then start dying due increased competition for light • Micro-organisms feed on the dead plant (which respire using up lots of oxygen) • A lack of oxygen in the water can be very bad news for larger organisms such as fish

16. Water Pollution • Water pollution is caused by the discharge of harmful substances into rivers, lakes and seas • Many aquatic invertebrate animals cannot survive in polluted water, so their presence or absence indicates the extent to which a body of water is polluted

17. Air Pollution • The most common source of air pollution is the combustion of fossil fuels

18. Pollution Indicators • Lichens are plants that grow in exposed places such as rocks or tree bark – they need to be very good at absorbing water and nutrients to grow there, and rainwater contains just enough nutrients to keep them alive • Air pollutants dissolved in rainwater, especially sulphur dioxide, can damage lichens, and prevent them from growing – this makes lichens natural indicators of air pollution, e.g. • Bushy lichens need really clean air • Leafy lichens can survive a small amount of air pollution • Crusty lichens can survive in more polluted air • In places where no lichens are growing, it's often a sign that the air is heavily polluted with sulphur dioxide

19. Lichens • Lichens can be used as air pollution indicators: - Lichens (very clean air) Lichens (clean air) Lichens (dirty air)

20. Insects • Insects can be used as water pollution indicators: - Leeches and midges survive (dirty water) More species such as dragonfly and cranefly survive (average water) Many species such as mayfly and caddisfly survive (clean water)

21. Non-Living Indicators • Environmental changes can be measured using non-living indicators including: - • Oxygen levels • Carbon dioxide levels • Particulate levels (ppm) • Temperature (global average / maximum and minimum in areas) • Rainfall (global average / maximum and minimum in areas)