2 Land and water pollution

p.266

Objectives

• Students should learn:• that more waste is being produced which may

pollute water with sewage, fertilisers or toxic chemicals

• that land can be polluted with toxic chemicals that can be washed into water

Outcomes

• Most students should be able to:• describe how pesticides and herbicides can pollute

the land• understand the need for the proper treatment of

sewage• describe what happens when water is polluted by

fertilisers.• Some students should also be able to:• assess the impact of land and water pollution on the

environment.

Specification

• Waste may pollute:• – water, with sewage, fertiliser or toxic chemicals …• – land, with toxic chemicals such as pesticides and

herbicides, which may be washed from the land into waterways. [B3.4.1 b)]

• Controlled Assessment: B4.3 Collect primary and secondary data. [B4.3.2 a) b) c) e) f)]; B4.4 Select and process primary and secondary data. [B4.4.1 a) b)], [B4.4.2 a) b) c)]; B4.5 Analyse and interpret primary and secondary data. [B4.5.4 a) b) c)]

Biology B3 4.2 Land and water pollution

Answers to in-text questions

a Sewage. b Nitrates.

Summary answers

1 population, waste, pollute, land/air, air/land, chemicals, water 2 Pollution of the land – pesticides and herbicides sprayed to reduce pest damage and overcrowding of crops soak into the soil and pollute it – can become part of food webs and damage predators.

Pollution of the water – pesticides and herbicides sprayed as above, and fertilisers added to the soil to improve crop yields, can be washed out of the soil into waterways by rain. Toxic chemicals can kill water organisms through food webs. Nitrates from fertilisers cause eutrophication – excess plant growth, needing many microorganisms to decompose the plants, using up oxygen in water so fish and other animals die from lack of oxygen. This adds to the problem – more death, more decay etc.

Compulsory slides you must complete and use;

Pollution of land

• Give detail/example on toxic chemicals e.g. pesticides and herbicides (see text p266)

• Include bioaccumulation in a food chain e.g. DDT

• Could use Simpson clips in folder

Pollution of watersewage

• Give detail• Include eutrophication steps• Make a eutrophication poem…

Pollution of waterpesticide

Pollution of watertoxic chemical

Pollution indicators of water

• Freshwater invertebrates• Look back to y9 reserve work

‘fun’ activity

• Make a matching word/definition to play with the class (see nest slide)

Make a matching game for the class

• http://hotpot.uvic.ca/ • Use jmatch for the words eutrophication,

bioaccumulation, pesticide, herbicide, fertilizer, toxic chemical

• You will need to make up a correct definition to put into the program

Useful slides you may use;

Water pollution

Fertilizers and sewage can easily be washed into rivers, streams and lakes. The nutrients, phosphates and nitrates in these substances cause eutrophication.

Sewage, industrial waste, oil, pesticides and fertilizers all pollute water.

Eutrophication is the accumulation of nutrients in water, which causes excessive algal growth. This leads to a reduction in oxygen levels and the death of aquatic life.

Eutrophication

Eutrophication

Land pollutionLand and soil can be polluted by two main types of substance:

solid waste – such as plastic, metal, paper and other man-made substances

chemicals – such as herbicides and pesticides, crude oil and waste from industrial processes.

Land pollution often leads to water pollution, as chemicals are washed into rivers and lakes.

How much waste?Every year, billions of tonnes of paper, plastics, synthetic materials, metal and wood are thrown away.

On average, each UK household produces over 1 tonne of rubbish each year.

How could you estimate the amount of rubbish you throw away each year?