Saturday X-tra X-Sheet: 18

EFFECTS OF POLLUTION: WATER, AIR AND SOIL Key Concepts

Exam questions, based on this section of work, will focus on the impact of the various types of pollution on the environment. Many of the questions will be in the form of data response or experiments. You must know and practise skills like: drawing of graphs from data that is provided, formulating a hypothesis, responding to data provided, applying knowledge about water, soil and air pollution and also providing strategies to prevent further damage.

Terminology & definitions

Pollutants: substances that contaminate air, water and or soil. Contaminate: to pollute or infect, or make water, soil or air unclean or impure. Bio-degradable: The ability of a substance to be broken down into simpler substances by the natural process of decay – example: crop wastes etc. Non biodegradable: Substance that cannot be broken down into simple substances by the natural process of decay, e.g., heavy metals or radioactive materials etc. X-planation

Humans populate every corner of the earth, and change the environment to suit their needs. Technological advances, industrialisation, pollution and the population explosion cause the destruction of large parts of the natural environment. We build factories, industries and houses, and plant food. In the process we produce tons of waste. This waste must be disposed of and this is not always done with consideration for the environment and future inhabitants. Pollutants are dumped in the water, air and soil, affecting the biosphere. By contaminating our environment with pollutants, the health of all living organisms suffers. Pollutants cause many health problems like asthma, respiratory tract infections, allergic reactions, headaches, nasal congestion, eye and skin irritations, coughing and sneezing, fatigue, nausea and cancer. It is the responsibility of the national and local governments to ensure that the environment is kept pollution free, with policies which stipulate rules and regulations. They also conduct impact studies to establish how community practices impact the environment and formulate ways in which to ensure a sustainable and healthy environment and development.

WATER POLLUTION

Water is an important resource because all living organisms require it to survive. Polluted water poisons plants and animals, and has a direct impact on humans. The main causes of water pollution are sewage, industrial wastes, oil spills and the use of pesticides in agriculture.

When untreated sewage is emptied into rivers, it causes diseases like typhoid, dysentery and cholera. Algae grows uncontrollably, using the oxygen in the water and causing the death of all the water organisms. Harmful bacteria flourish in untreated sewage. When drinking and swimming water becomes contaminated, the disease-causing bacteria spread rapidly, making many people ill. Sewage must be treated so that it can be recycled into the environment. Local government agencies monitor effluent levels in dams, rivers and also the sea around our country. When they find that the levels have exceeded legal allowance, investigations are conducted and the culprits are fined or operations closed down.

Many industrial processes produce toxic wastes. In some cases, toxic wastes are illegally pumped into rivers, streams and dams. Chemicals like cyanide, mercury, lead and copper, are non-biodegradable. Organisms are poisoned as the concentrations of toxins increase, and are passed through the food chain. The poisonous chemicals cause cancer and damage internal organs in people and animals. Factories and power stations sometimes pump hot water into rivers and streams causing thermal pollution. Increased temperatures kill the water plants and the fish because fish are cold-blooded and cannot tolerate extreme changes of environmental temperature. This causes matter to decay in the water, with disease-causing bacteria thriving on the rotting material. Oil tankers transport oil and sometimes they leak oil, flush their oil tanks out or sink. The oil spreads across large surfaces in the sea causing:

the death of killer whales, seals, fish and birds because they are covered in the oil

plants not to be able obtain enough CO2 for photosynthesis

plants and animals not to be able obtain enough O2 for cellular respiration

birds and penguins to ingest the oil and die Corrective actions can be put in place to prevent water pollution:

Educate the community about the importance of recycling.

Provide containers to recycle paper, glass, tin and plastic.

Enforce large fines for the illegal dumping of sewage into rivers and streams.

Ensure that informal settlements are supplied with the proper facilities for the sewage removal by municipalities

Enforce strict laws to prevent factories from dumping wastes into rivers, streams, dams and seas.

Check oil tankers thoroughly checked for seaworthiness before they leave harbours.

Enforce strict laws and very large penalties when oil tankers leak or sink and spill oil. Hold the oil companies accountable for cleaning up any oil spills.

Encourage the use of organic fertilisers instead of inorganic fertilisers.

Encourage farmers to use natural pesticides and natural enemies instead of artificial pesticides and herbicides.

Educate farmers about the use of approved pesticides and herbicides.

AIR POLLUTION

Carbon monoxide (CO) is released from the exhaust fumes of cars and trucks, and released into the atmosphere, combining easily with haemoglobin. A person inhaling CO will suffer from headaches, dizziness and feel tired. Large quantities of CO can cause death. Coal fires draw oxygen from the surrounding air and release CO, so fires made in poorly ventilated places can lead to asphyxiation and death. Factories and power stations burn gas, coal and oil to produce heat which is converted into energy. Informal settlements obtain heat from burning coal for cooking and warmth. Pollutants like sulphur dioxide, smoke, ashes and soot are released into the air. The pollutants combine with the water in the air forming a dense mass. As the air warms and dries, the particles fall to the ground. Buildings and plants in industrial areas are always coated in a black dust. The plants covered with this dust cannot photosynthesise properly, and this impacts on plant growth and health. Smog impacts on human health because it irritates the eyes, chest and lungs of humans. Asthma, bronchitis and, eventually, cancer result if large quantities of smog are inhaled on a regular basis.

Consider that fossil fuels are in limited supply. Fossil fuels were produced millions of years ago, when plants died and decomposed. The plant remains gradually became compressed to form coal, oil and gas. Fossil fuels are a limited resource because it takes so long to produce them. When fossil fuels are burned, it results in the release of carbon, which combines with oxygen in the atmosphere to form carbon dioxide and carbon monoxide in a process called combustion. If we continue to use fossils fuels at the present rate, we will run out of these resources within the next 50 years. We must look to finding alternative processes to produce energy and prevent air pollution. Corrective actions can be put in place to prevent air pollution:

The use of lead-free petrol will prevent the release of lead into the atmosphere.

Special filters will reduce smoke emissions from factories and industries. This will require government legislation and drastic intervention.

Other energy sources, like wind and water, should be found to reduce the use of fossil fuels like coal, oil and gas.

Strict policies to prevent the release of gases like CFCs and nitrogen oxide into the air, should be formulated.

Ways in which to remove Sulphur from coal to prevent acid rain should be researched.

Electrical motorcars and trucks should be developed to reduce the CO2 and CO emissions into the atmosphere.

More efficient public transport systems to reduce traffic congestion reduce fuel usage and reduce air pollution, should be introduced.

SOIL POLLUTION

Soil sustains all life on earth. Roots of plants grow in the soil and absorb nutrients and water which is used during the photosynthesis process, and also for the growth and development of the plants. Consumers, like herbivores and omnivores, eat plants. Herbivores are eaten by carnivores and omnivores in the food web, so nutrients that are absorbed from the soil will benefit all organisms. Soil provides a habitat for many organisms. When people abuse the land through careless acts, irresponsible behaviour, greed and pollution, the soil is harmed and so too all the organisms that directly and indirectly require fertile soil to survive. Forms of soil pollution are litter, dumping of toxic waste, deforestation etc.

Litter is a major problem of modern society because man-made materials, like plastic, glass and tin, are non-biodegradable. Litter results when wastes are not disposed in a regulated and proper manner. Rubbish should be placed in disposal containers for collection and dumped in landfills that are covered with soil. Exposed litter is the breeding ground for rats, mosquitoes and flies, apart from being unsightly, unhygienic and a danger to animals and plants. Toxic chemicals must be disposed of in sealed containers that are buried in special cemented landfills. If these landfills are not managed properly, containers may leak. This will result in streams and rivers becoming contaminated, causing people and animals that drink the water, to be poisoned. Crops may absorb the toxins and when eaten by people, birds and animals, cause diseases and toxic poisoning. Unscrupulous people illegally dump containers of toxic chemicals into the sea where the containers eventually corrode and leak, releasing the toxic waste. This will directly impact on the marine plant and animal life in the area.

Local government agencies work within the policies and legislation of the provincial and national government. Special areas are analysed and demarcated for dumps of toxic waste. When contravention of the Acts and laws is suspected, local government will investigate the process with the support of provincial and national departments. If people or companies are found to be guilty, they might face major fines and even imprisonment. Companies and factories might be closed down. Corrective actions can be put in place to prevent soil pollution

Educate people to reduce, re-use and recycle wastes by providing containers to recycle paper, glass, tin and plastic.

Enforce legislation to prevent dumping in unauthorised areas with strict fines.

Large fines levied when people litter, e.g., Hong Kong.

Use only indigenous trees for afforestation.

Educate farmers to ensure crop rotation.

Provide informal settlements with proper waste removal.

Ensure local government provides many dustbins in towns and cities.

Form action groups in communities to clean up polluted areas. X-ample Questions

Question 1

The table below shows the results of an investigation carried out by learners at five different places (A, B, C, D and E) along a river.

1.1. State the hypothesis that the learners set out to investigate. (2) 1.2. Describe the relationship between the number of green algae and the condition of the river water. (2) 1.3. Give a reason for the relationship indicated in Question 1.2. (2) 1.4. Write down the letters only of the places in the river where trout were found. (2) 1.5. Why were trout only found in the places named in Question 1.4? (2) (Taken from DoE November 2008 Paper 1)

Question 2

Study the bar graph below and answer the questions that follow.

2.1. By how much did the level of sulphur dioxide pollution in Sweden decrease between 2000 and 2005? (1) 2.2. Compare the general pattern of air pollution levels of France to that of the other countries. State the following:

(a) ONE similarity (1) (b) ONE difference (2)

2.3. Which country had the lowest level of sulphur dioxide pollution in 2005? (1) 2.4. Suggest TWO possible reasons for your answer to Question 1.3. (2)

(Taken from DoE November 2009 Paper 2)

Question 3

The table below shows the amount of solid waste generated in a town over a period of 6 years. Study the table and answer the questions that follow.

3.1. Draw a line graph to represent the data in the table above. (10) 3.2. What general trend is indicated by the graph you have drawn? (2) 3.3. In which year was the solid waste generated the highest? (1) 3.4. What is the difference in the amount of waste generated between 2001 and 2003? Show ALL the calculations. (3) 3.5. Name TWO main sources of the town's solid waste. (2) 3.6. What strategies could the municipality employ to manage the increase in municipal solid waste? Name TWO strategies and its impact on the environment. (4) 3.7. Distinguish between biodegradable and non-biodegradable matter AND Give an example of each. (4) (Taken from DoE Preparatory Examinations 2008 Paper 2)

X-ercise

Multiple choice questions.

Select the correct option for each of the following questions:

1. Which of the following are biodegradable waste products? A rubber, plastic, manure B metal, glass, plastic C vegetable peels, garden refuse, paper D glass, wood cuttings, batteries 2. The main cause of water pollution is:

A untreated sewage, glass bottles and plastic bags B chemical effluent, leaching of pesticides and algae C pesticides, treated sewage and litter D oil spills, untreated sewage and chemical effluent 3. Typhoid, cholera and dysentry are diseases that are spread by:

A air pollution B water pollution C land/soil pollution D the use of pesticides 4. Non-biodegradable means:

A a substance that cannot decompose naturally B a substance that is thrown away as kitchen refuse

C a substance that costs too much to recycle D a substance that will not dissolve in water

5. Deforestation is….

A is the removal of all plants and trees from a large area of land B is the complete removal of a forest to clear a large area for agriculture C is the result of a veld fire D is as a result of concentrated soil erosion 6. One solution to reduce air pollution may be…

A the use of leaded petrol B the burning of wood and coal C the use of public transport D causing veld fires 7. One of the following has a positive human influence on the environment:

A Deforestation B Overpopulation C Pollution D Conservation

8. Biological control is useful because it…

A usually attacks all plant species B can destroy an alian plant infestation or reduce its population numbers

C usually originates in the country where the alien plant destroys indigenous vegetation D usually attacks all useful micro-organisms 9. Pollutant gases have an adverse effect on the environment and on our health. The amounts of these gases have been steadily increasing over the years.

The table below shows the source and the amount of some pollutant gases produced by human activities:

Which ONE of the following statements is correct?

A The total sulphur dioxide and nitrogen dioxide produced per year is 145 million tonnes. B Carbon dioxide is produced by industries

C The Combined total pollutant gases produced by nitrogen oxide and hydrocarbons, is less than the total produced by sulphur dioxide.

D Hydrocarbons are produced by vehicle exhaust gases only. 10. The following are all sources of pollution:

i) Solid waste ii) Pesticides iii) Sewage iv) Fertilisers

Which of the following combinations contains sources of soil pollution?

A (i), (ii) and (iii) B (ii), (iii), (iv) C (i), (ii), (iii) and (iv) D (ii) and (iv)

Answers to X-ercise questions:

1. C 2. D 3. B 4. A

5. A 6. C 7. D 8. B

9. C 10. C