This PPT talks about the indications of a few types of pollutions and the impact of various farming activities on the environment. It also talks about the poison in food chain.

1. Environment
Abhishek Mukherjee, Diya Devdas, Mahima Shah,
Naisha Wadhwa and Siya Vaid

2. Indicators of Pollution (Air Pollution)
Things that show us if pollution is present are not.
Some living things are sensitive and can be used as biological indicators.
Bushy lichens can grow in unpolluted air.
Lichens that are sensitive to pollution cannot grow in polluted air.
Leafy lichens can grow in semi-polluted air.
Crusty lichens can grow in polluted air.
Protoctistas might grow in polluted air.

3. Indicators of Pollution (Water Pollution)
Invertebrate animals are good indicators of water pollution.
Some animals can live in extremely polluted water, some can only live in clean
water.
Fishes:
Need oxygen to live in water.
If water is polluted the oxygen levels fall and the fishes begin
to die.

4. Intensive Farming
Farmer cultivates a small plot of land.
Uses simple tools and more labour.
More than one crop annually because of more number of days with sunshine.
(Farmer tries to produce more from a small piece of land)

5. Intensive Farming (Fertilizers)
Impact on the soil:
Using excessive amount of fertilizer can increase the acid levels in the
soil.
Tend to kill beneficial micro-organism that are necessary for a plant
production and overall soil health.

6. Intensive Farming (Fertilizers)
Impact on the water bodies:
Using excessive amount of fertilizer can lead to eutrophication.
Fertilizers contain nitrates and phosphorus that are flooded into water bodies
through rain and sewage and causes excessive growth of algae.
Therefore causing lack of oxygen levels for aquatic life and indirectly affects
the food chain.

7. Intensive Farming (Fertilizers)
Impact on Global Warming:
Fertilizers contain substances and chemicals including methane, carbon
dioxide, ammonia and nitrogen, resulting in the increase of greenhouse
gasses.

8. Intensive Farming (Fertilizers)
Impact on Human Health:
The chemicals aforementioned can also affect the groundwater and
contaminate the water source for domestic usage.
Other health problems linked with the contact or consumption of fertilizer-
infected air, water etc can cause several form of cancer and respiratory
problems.

9. Herbicides and Weeds
A herbicide is a chemical that is used to kill unwanted plants
(weeds)
Weeds are killed because:
Tall weeds block view of drivers at times
Spoiling the experience of a golf course
Sharp-edged grasses annoy grass
They compete with wanted plants for water, sunlight and
minerals
They can also carry microorganisms which negatively affect
wanted plants

10. Herbicides and Weeds
Selective Herbicides:
Selective herbicides will only kill
the weeds.
Herbicides can be spread by the
air into surrounding areas.
This can negatively impact crops
around the area.
Non-Selective Herbicides:
Non-selective herbicides will kill
any plant.
This will be used to clear all
areas of plant life once the crop
is already grown.

11. Poison in the Food Chain
Swiss chemist Paul Müller (1899-1965)
Set up a research programme to find a substance that would kill insects but
not harm any other animals.
Insects were his target since:
Some were plant pests
Destroyed farm crops
Some carried microorganisms that caused disease

12. Poison in the Food Chain
In 1993, Paul made a chemical called: Dichlorodiphenyltrichloroethane (DDT)
This chemical met all the requirements and soon was used worldwide.
Eventually, the top carnivores, (in the habitats where DDT was spread) were
found dead.
The concentration of DDT was too weak to kill the top carnivore directly, so
investigations on the food chain had to me made.

13. Poison in the Food Chain
In Clear Lake, California, DDT had been sprayed onto the water to kill gnat larvae.
The concentration of DDT was 0.015 parts per million.
The concentration of DDT found in dead bodies of fish-eating birds called western
grebes was 1600 parts per million.
When planktonic organisms in the water were examined, the bodies contained 5
parts per million of DDT.
Small fish that fed on the plankton contained 10 parts per million of DDT.

14. Sources
https://www.britannica.com/science/herbicide
https://www.britannica.com/plant/weed
https://www.britannica.com/topic/intensive-agriculture
https://helpsavenature.com/how-do-fertilizers-affect-environment