Water pollution
by TEO SHAO KAI ROSYTH
1. Untreated sewage
1.1. Households, factories, public places without proper sewage facilities.
1.2. •When realeased into the sea, germs from untreated sewage can cause deseases. •Bacteria in water uses up oxygen when breaking down sewage which reduces the oxygen content of the water. •Encouages exessive growth of algae which blocks sunlight to the water plants. The rate of photosynthesis is then reduced so less oxygen is produced. Thus, aquatic animals soon die due to the lack of dissolved oxygen.
2. Fertilizers
2.1. Polluted from gardens, farms, agrcultural plots.
2.2. •Contaminates rivers with weed-killers, insecticides and chemicals. •Bacteria breaking down the fertilizers uses up oxygen in the water. •Encouages exessive growth of algae which blocks sunlight to the water plants. The rate of photosynthesis is then reduced so less oxygen is produced. Thus, aquatic animals soon die due to the lack of dissolved oxygen.
3. Its control
3.1. Methods carried out by the government: •Campaigns to educate people about water pollution. •Laws to ensure that industries and individuals do not pollute the water. •Upgrading of the sewage systems.
3.2. Methods carried out by individuals: •Not poring detergents or chemicals into open drains. •Disposing litter properly. •Not littering in public places such as drains, rivers, and lakes. •Cleaning up public places which include beaches and parks.
4. Pesticides
4.1. Households, farms, warehouses, factories.
4.2. •Plants containing poisonous pesticides can harm animals or people after eaten. •Can get water-borne deseases such as typhoid, cholera and dysentery if the contaminated water is consumed.
5. Toxic waste
5.1. Factories, automobiles.
5.2. •Causes poisoning like mercury and lead poisoning in animals and plants.
6. Litter
6.1. Polluted from households, factories, public places, roads.
6.2. •Contains non-biodegradable wastes. •Chokes birds and fishes which eat them. •Strangles and kills marine life. •Blocks sunlight to water plants.
7. Oil
7.1. Sea vessels, boat repair yards, oil refineries, oil tankers.
7.2. •Poisons and kills birds, animals and marine life which swallow it. •Coats and damages the feathers of birds which prevents them from flying away in search of food.
8. Soil erosion
8.1. Forests, agricultural vegetation
8.2. •Washed or blown into rivers and lakes causing water to become turbid. •Blocks sunlight to the water plants. The rate of photosynthesis is then reduced so less oxygen is produced. Thus, aquatic animals soon die due to the lack of dissolved oxygen.
