Caring for the Country

1 Australia’s land surfaces exhibit the effects of long periods of weathering and erosion

describe the low fertility of most Australian soils in terms of:– long period of depletion of

nutrient ions– stability of the Australian

continent – the low relief of the Australian

continent

Present information comparing the fertility of a basalt-derived soil from recent volcanic activity in eastern Australia with a deeply weathered lateritic soil from Western Australia.

Describe the low fertility of most Australian soils in terms of: Depletion of nutrient ions Stability of the Australian continent Low Relief of the Australian continent

Depletion of nutrient ions:- Soil is formed from weathering and biological activities. Volcanoes play a crucial role in the

replacement of nutrients- Nutrient replacement is typically slow as Australia is relatively geologically stable meaning

there are no active volcanoes. Nutrients are produced from the weathering of rocks, however, this is slow

- As such the same soil has been in constant use by organisms over billions of years with little nutrient flows creating poor fertility in soils

- Soil in Eastern Australia is relatively newer as the land formed from tectonic activity meaning that the soil is more fertile and allowing for sustained growth

- Soil in western and central Australia has generally poor fertility as well as many shrubs and grasses

Stability of the Australian continent:- Australia is relatively geologically stable and not located on a plate boundary meaning

tectonic processes such as volcanism cannot produce fertile soils- There is a slow replenishment of nutrients

Low Relief of the Australian continent:- The flat areas in Australia may cause leaching - when soluble minerals in soil are moved

vertically down soil layers by the percolation of water- Less erosion occurs on flat areas as opposed to mountainous areas therefore, there is less

soil/rock and nutrient movement and an overall slow nutrient flow

2 Soil as a resource that requires careful management

outline a cause of soil erosion in NSW due to:– an agricultural process– urbanisation and identify a management strategy that prevents or reduces both of these causes of soil erosion

plan and perform a series of investigations to determine the effect of compaction or tracking on a soil

gather information from first-hand or secondary sources to evaluate a program or strategy used in NSW to treat soil erosion

Outline a cause of soil erosion in NSW due to: Agricultural processes Urbanisation

Erosion – the removal and transportation of material in soilWeathering – the breaking down of rocks into smaller pieces

- The two main physical forms that cause erosion areo Windo Water

- Although these are natural factors, human activity can enhance the effects- Erosion can occur in both rural and urban areas

Agricultural processes which cause an increase in erosion:- Overgrazing by stock and landclearing

o Removal of vegetation which anchors soil allowing it to be easily moved by either the wind or by water

- Soil compaction by hoofed animals- Leaving unplanted fields for a period of time- Little or no vegetation on the banks of waterways

Urban processes that cause and increase in erosion- Land clearing

o Allows for soil which has no anchorage to be moved easily- Natural water pathways may be blocked and re routed causing erosion along the new path- Soil compaction- Reduction in soil infiltration

o There are many impenetrable materials used in urban places such as concreteo These materials reduce the amount of water which can enter the soil

Identify a management strategy that prevents or reduces both of these causes of soil erosion:

Policy management strategies Practical management strategies

- Management strategies can either be a practical application of an idea, or a policy aimed at reducing impact

- Management strategies are the responsibility of differing levels of government such as federal, state and local.

Policy management strategy- NSW department of land and water conservation passed a policy in 1987 aimed at the

proper management of soil in order to minimise environmental impact while hopefully improving productivity

- The key pointso Soil use should not lead to degradationo The Government and interested parties have joint responsibilityo A state soil conservation is given powers to prevent further degradation, protect and

improve soilso Total catchment management required to conserve and rehabilitate soilso Agricultural soils should be maintained and improvedo Soil use should be minimised

Practical management strategy- Crop rotation: using seasonal plants over the course of the year- Planting trees around water ways- Not farming on steep slopes- Ensuring there are some areas of permanent dense vegetation which acts as a wind break

and holds soil- Grassed strips in waterways: many waterways are dry and by laying grass in them, water will

not wash away the soil when the rain comes- Alternating crops- Building contours or terracing: crops are placed in organised lines perpendicular to rhe slope

reducing the energy of water running down a slope

Case Study – Ian Cooling’s Farm

- Ian Coolings farm is located in the Central West of NSW and was affected by salinity, however, land management strategies have been implemented with the assistance of the Department of Primary industry and the Woodsflat Creek Landcare Group

- The Farm like many other farms in NSW was affected by Salinity due to a rising water table from over irrigation from a variety of farms in the area. Furthermore, a fault located under the farm was pushing groundwater vertically creating a discharge area of saline water

- The farm produces sheep, wheat and canola

- These land management issues have been managed in the following wayso Salinisation reduced from planting of tree corridors to reduce the affects of

groundwater. The farm composes of 20% trees and has proved to still be profitableo Crops rotated and fallow time reduced o Monitoring of the water tableo No till farming

- The farm demonstrates the following wello Effective land management and reducing the water table through the planting of

vegetationo Demonstrates a precautionary approach. As his second farm which was not affected

by salinity has the same management strategies implemented

3 Salinity of soils and water

identify regions of Australia with naturally saline soils

identify data sources and gather, process and present information as a case study of a successful rehabilitation program of a salt-affected area, including:– the origins of the problem– the impact of the salinity

problem on the biotic and abiotic environment

– the rehabilitation strategy used and the scientific basis for this strategy

examine the possible consequences for soil salinity of land clearing and irrigation and outline precautions that could minimise the problem in each case

Identify regions of Australia with naturally saline soils

- Australia has about 30 million hectares of naturally saline soil- Central Australian areas such as South Australia and the Northern Territory have saline soils

for example the lake Eyre basin- The Murry – Darling basin in South Australia, NSW, Victoria- South West Western Australia

Identify the possible consequences for soil salinity due to:

Land clearing Irrigation

- Primary salinityo Granite rocks have high quantities of minerals which weather producing saline soils

- Atmospherico Wind may blow salt from the sea hundreds of kilometres inlando Cloud may transport salt before it rains

- Secondary salinisationo Human induced salinityo Caused by the clearing of native vegetation, over watering which raises the

watertable causing the saline watertable to create saline soil

- Dryland salinityo Caused by either the removal of native plants by overgrazing or the removal of

native plants for other cropso When areas are cleared water can penetrate through soil and rock permeating

dissolved salt into the water tableo The clearing of vegetation can cause the water table to rise carrying the dissolved

salts closer the surface of the soilo This can cause salty soil which is useless for agricultural purposes and harmful to

native plantso This can cause saline river systems affecting marine organisms and

ecosystems/organisms adjacent to the river system- Irrigation salinity

o Over irrigation can cause the water table to rise and carry dissolved salts to the surface again increasing the concentration of salt in the soil

o This is particularly bad in the Murry – Darling Basin where farmers have diverted rivers to lower ground creating saline rivers, useless for agriculture

Outline precautions which could reduce the impact of salinity

- It is necessary to combat salinity as it contributes to massive losses in agricultural productivity

- Prevention strategieso Prevention strategies focus on reducing the amount of water reaching the water

table through changes to land use and managemento Ensures there is enough vegetation throughout the entire river catchment, if there is

not enough then revegetation should be appliedo Monitoring of the water table depth can be achieved through a piezometer which is

useful to determine the necessary strategies in a areao Traditional management practices by farmers were a major cause of salinity through

over irrigation this can be prevented by using drip irrigation Drip irrigation allows for a controlled amount of water to reach crops

o Farmers are encouraged to use deep rooted crops to maximise water uptakeo Farmers are encouraged to reduce their fallow time

Fallow time refers to the time between harvesting crops and sowing the next – reducing the time soil is left bare

- Government strategieso Drainage systems can divert water before it reaches a high water tableo Surface – drainage is done by collecting and controlling water entering and leaving

an area to minimise infiltrationo The water table can be moved lower away from top of the soil through bores

4 The effect of excessive use and long-term consequences of using some

discuss the effect of continually introducing new pesticides into the environment, including – effect on non-target species– accumulation in individuals

gather information from secondary sources to identify a pesticide whose use is now banned and summarise its use, the reasons for stopping

pesticides (bio-accumulation) and magnification in animals higher up the food chain (biomagnification)

– human health impacts

assess alternative management practices that do not require the use of pesticides

its use and available evidence to assess the impact of its residual chemicals in the environment

gather and analyse information from secondary sources about alternatives to pesticides as a management practice

Discuss the effect of continually introducing new pesticides into the environment, including:

Effect on non target species Accumulation in individuals (bio accumulation & bio magnification) in animals

higher up the food chain Human health impacts

- Pesticide: a chemical substances that kills groups of organisms, used to try to reduce pest problems. (pests – both plants, animals, fungi and bacteria)

- Types of pesticideso Insecticides: Kills pests in the form of insectso Herbicides: Kills unwanted pests in the forms of vegetationo Fungicides: Kills pests in the form of funguso Rodenticides: kills pests in the forms of rodentso Disinfectants: Kills and destroys bacteria

- Propertieso When pesticides are released into the environment they can either break down or

degrade from sunlight, water or other chemicals. Or they resist degradation and remain unchanged in the environment

o Persistence (half life): determines how long it takes for a pesticide to break down. It may become more or less toxic after it has broken down

o Volatility: Refers to the pesticides ability to evaporate. With higher volatility the pesticide can go into the atmosphere easier

o Solubility: Refers to the pesticides ability to dissolve. If it has high solubility it can dissolve into water easier

Effect on non target species

- Pesticides are made to be toxic, as such they can affect more than just their intended target- Pesticides may directly kill an organism which was not the target of the pesticide

o For example insects such as bees which feed off plants- Pesticides may result in the disruption of food chains or the habitat of other organisms

o For example herbicides used to kill particular plants may disrupt the breeding areas of birds and leave them prone to attack by predators and the environment

o Pesticides can move through the food chain as a result of both bio accumulation and bio magnification

o Organisms can move through the environment through wind, water and organisms affecting a large area

Bio accumulation and bio magnification

- Bio accumulation: the build up of pesticides or chemicals in an organism. Some toxins organisms cannot remove for example mercury as such it may build up for many years

- Bio magnification:o the increase in concentration of a substance such as mercury or the pesticide DDT

that occurs in a food chain. o When a potentially toxic/persistent substance is released into the environment, its

concentration may be so low it causes no obvious damage. Organisms higher up the food chain begin to eat large quantities of organisms containing the toxin thus magnifying the concentration. This only occurs in regard to substances that do not degrade easily

Human health impacts

- Studies on animals have shown that pesticides can give rise too Cancerso Mutations

o Birth defectso Respiratory problemso Skin conditionso Reproductive problems

- As humans are at the top of the food chain they are at risk of consuming organisms with persistent pesticides in them

Example of a banned pesticide

- DDTo DDT was introduced to control diseases such as malaria and yellow fever by killing

mosquitoes which spread the diseaseso Very persistent pesticide which managed through bio accumulation and bio

magnification to affect all organisms and was potentially fatal to non target organisms

o DDT causes organisms to convulse, die or become paralysed o Insoluble in water and as such difficult to wash awayo Soluble in fat so as organisms consumed it, it mixed with their fato Humans are not of risk to DDT as it is difficult to absorb through the skin o DDT had a profound effect on large predatory birds as it thinned the egg shells

posing a risk to the eggs from predatorso The effects of DDT were not known until much later when much of the damage had

been done

Alternative management practices that do not require the use of pesticides

Alternative Description ExampleNative plants Native plants are more

resistant to Australian pests and climate. However, many native plants do not produce food

Native orangeIllawarra plumQuandong

Crop Rotation By rotating crops around paddocks, pests do not become accustomed a particular environment

Physical barriers Netting can enclose crops and protect them from insects and birds. Metal strips can defend against slugs

Nets, Metal strips

Traps Used for flying insects consisting of a lure inside a container that allows for an insect to enter but not leave

Fruit fly traps

Biological control Introducing a predator which ensures a pest population is kept to a minimum

Cane ToadArgentinean moth

Genetic engineering Works by genetically Some cotton in NSW is

incorporating genes from one plant that makes proteins that pests find toxic into a another plant

genetically modified

5 Maintenance of environmental flows and natural processes in water

assess management strategies and technologies used to assist in the maintenance of natural processes in surface water by:– licensing irrigation/bore water

users– treating stormwater – providing environmental flows

from dams

present information as a flow chart to summarise the steps in forms of sewage treatment

Types of irrigation including: Flood irrigation Spray/overhead irrigation Drip irrigation Positives and negatives of each

Irrigation:

- Irrigation is the artificial supply of water to plants and soils for the subsequent use of plants- Irrigation is necessary due to large scale farming practices now in use- Irrigation is commonly used in Australia as much of the continent has naturally dry or arid

area

- Flood irrigation (furrow irrigation)o Simplest method involves flooding an entire field with watero Widely used in the developing world as it is a cheap practiceo Roughly half of the water used does not reach crops and is wastedo Farmers can implement the following to make better use of irrigation

Levelling of fields allows water to flow evenly across field. Surge flooding: releasing water at prearranged intervals, reducing unwanted

runoff Capturing and reusing runoff – water which is at the edge of a field is usually

wasted, water can be pumped back up to the fieldo The main advantage is it’s the cheap price and easy implementation

- Spray irrigation (overhead irrigation)o Very common form or irrigation especially in Australia o Involves the spraying of crops and soil. It can do this either in a line or in a circleo Advantages of spray irrigation

Wide area may be covered in a short time period Farmer has control over the depth of water seeping into the ground by

altering the time of the water flowo Disadvantages of spray irrigation

Spray irrigation can result in tailwater. Tailwater refers to water which has passed through soil and become contaminated with nutrients or pollutants (eg pesticides)

This tailwater may affect areas away from the crops potentially affecting surrounding ecosystems

Run – off can lead to soil erosion Excess water may enter the water table increasing the risk of salinisation Water may be lost through evaporation by wind action

o A more efficient spray irrigation method has been created which involves hanging pipes dispersing water close to crops increasing the efficiency from 60% to 90%

- Drip irrigationo Very efficient method of irrigationo Water is sent through a network of hoses which are in contact with or just below the

soilo The hoses have small pores which water is able to drip out ofo Advantages of drip irrigation

Good control of irrigation method No tailwater occurs No water lost via evaporation Delivery of water straight to the roots of plants Very efficient method of irrigation

o Disadvantages of drip irrigation More expensive to install although typically saves money in the long run Is not easily moved to other crops like spray irrigation, meaning it is difficult

for farmers to use it in other areas/paddocks- In Australia flood irrigation should not be used, spray is acceptable but drip is the best

option

Environmental flows from dams

Environmental flows Because Australia is so dry, most of the major rivers have been dammed to trap water

and make it available for use throughout the year. Planning the location, type and size of the dam is very important as it will alter the

downstream water course forever and usually for worse. If river levels drop, natural flooding processes become halted and aquatic organisms

loses their habitat. To address this problem, environmental flows have been introduced to the river. Environmental flow - an artificial surge of water into a river system with the purpose of

restoring some of the natural flow pattern than has been lost and ultimately sustain river life.

Effects of dams Loss of natural flows can cause

o Farmers to receive less water for crops and irrigation

o Aquatic ecosystems receive less water to support breeding and organisms – loss of environment, sediment build up

o Some areas may receive more water than previously for example dammed areas. This can cause flooding

Flooding as a result of environmental flowso Replenishment of sediments, nutrients and other materialso Fine sediment carried and deposited during flooding covers organic matter and

decomposes ito Floods can also stimulate eggs to hatch and cause plant seeds to germinate.o Encourage birds to area

Damming a river may result in the flooding of the area causing the rise of the watertable

Treatment of:

Stormwater Sewage

Stormwater Stormwater is pure rainwater and anything that the rain carries with it Stormwater may contain

o Garden chemicalso Plastic bagso Papero Littero Bottles

Some treatment options:o Pollution traps – they act as filters and catch the pollution before it has a chance

to enter the water way.o Artificial wetlands – areas created so that natural processes can take place i.e.

water is slowed down so large sediment particles cannot be transported, excess nutrients are absorbed and water at the surface is exposed to UV light which breaks down chemicals. Example – Moore Reserve: Oatley, Sydney, NSW

o Oil and litter booms – booms, sometimes with vertical netting, that allow floating or suspended material to be collected.

o Gross pollutant traps –sieve type traps that trap pollutants

Stormwater is usually not treated enough, mostly pollution traps are used to remove large sediments, however, most pollutants still enter waterways

Impacts of stormwater pollutiono Excess soil and sediment can lessen the amount of light entering the water, thus

reducing photosynthesiso Sediment may clog the gills of fish and cause them to due of suffocationo Oxygen is removed when leaves and grass clippings decay which can lead to the

suffocation of organismso Toxins may harm plants and animalso Bacteria that pollution often carries can affect human health causing the closure

of beaches and waterwayso Excess nutrient such as nitrates, phosphates may cause eutrophication

Sewage treatment Human wastes, paper and vegetable matter needs to be treated because it harbours

dangerous bacteria that can affect the health of humans and organisms Industrial processes produce waster water that contains heavy metals and toxic

compounds The process of sewage treatment is divided into primary secondary and tertiary stages Primary

o Removal of solids from sewage watero Waste water initially passes through a series of screens whose mesh removes

around 65% of solidso After the screens the water enters large settling tanks

Substances which are less than water such as oil float to the top and are skimmed off

o Water then undergoes either secondary treatment or is returned to the environment

Secondaryo Removal of pathogenic micro – organismso Beneficial bacteria are used to kill and remove pathogenic bacteria

The most common way involves micro organisms growing on stones which sewage trickles down

Micro organisms feed on the bacteria in the sewageo Water then undergoes tertiary treatment or is returned to the environmento Froth flotation and aeration are used. Aeration tanks allow the solution to

oxidise which allows for the growth of organismso Sometimes the water will be chlorinated

Tertiary treatmento Not commonly used in Australiao Removes high levels of nutrients (eg nitrates, phosphates) and heavy metals (eg

mercury and lead) from treated watero First step of tertiary treatment involves adding alum to the water which causes

colloidal particles to clump togethero Water is then passed through activated charcoal removing dissolved organic

compoundso Lime is then added to water causing phosphates in water to precipitate outo Ion exchange then occurs which removes calciumo Final step of tertiary treatment uses reverse osmosis to remove calcium and

magnesium This step is not always carried out

o Water is then returned to the environmento By the end of the process all organic material, 99% of unwanted ions and most

microbes have been removedo Water is chlorinated killing micro organismso Water is treated by UV light to kills micro organisms

Originally most sewage was discharged off the coast in shallow watero This lead to high levels of pollution affecting water quality

Water is now discharged up to 3km offshore in deeper areas reducing pollution

Management strategy

Water management act

The water management act was introduced in November 2001, passed by NSW parliament

Provided a framework for managing the water resource within the state and regulating the amount of water the various categories of users may be allowed to have

A harvestable right is the amount of water as a percentage of the total rainfall falling on an area, which a farmer may use. Any excess of this requires a water license

A water use approval allows land holders to use a certain amount of water The act includes restrictions on how much water can be taken from a river and when it

can be taken

Sewage Treatment – Primary, secondary and tertiary

PrimaryWater run through

screens

65% of solids removed

Water enters settling tanks

Dense sludge forms and is used in fertiliser

Water is

sometimes chlorinated

Water may be returned to the environment

SecondaryMicro organisms are introduced to remove pathogenic bacteria

Water is chlorinated killing

any micro organisms

Water may be returned to the environment

Tertiary Alum (settles out colloidal particles), lime (causes

phosphates to settle out) and activated charcoal (removes

dissolved organic compounds) added to water

Ion exchange (removes calcium)

Reverse osmosis (removes calcium and

magnesium)

Water returned to the environment

gather and analyse information from secondary sources on the composition of emissions from vehicle exhausts

analyse, process and present information to identify the origins of greenhouse gases and acid rain from both natural and made environments, and use available evidence to propose possible local and global strategies to achieve decreased emission of carbon dioxide, methane and sulphur dioxide

Gather and analyse information from secondary sources to evaluate

– one international strategy aimed at reducing ozone depletion

– one international strategy aimed at reducing human causes of global warming

gather information from secondary sources to summarise the uses of CFCs and other halides and describe the ways in which their use is being phased out and alternative products being used

6 The results of the Industrial Revolution on the atmosphere and hydrosphere

summarise types of chemical reactions involved in the formation of greenhouse gases and acid rain from the burning of fossil fuels (word equations only)

analyse different scientific views on the causes of global warming to assess predictions on the likelihood of global warming

outline the way in which chlorofluorocarbons and other halides can reduce the percentage of ozone in the stratosphere

summarise the evidence for ozone depletion and the role of Australian scientists in this ongoing research

Chemical reactions forming: Greenhouse Gases Acid Rain

Greenhouse gases Carbon dioxide and water vapour

o Formed from natural processes such as respiration, volcanic activity and fireo CO2 is used in the photosynthesis cycleo Water is recycled through the hydrological cycleo CO2 is also formed through the burning of fossil fuels with oxygeno Water and energy are produced through this process

o This equation assumes that the fossil fuel is a pure hydrocarbono Hydrocarbons are chemicals which contain the elements hydrogen and carbon

Methaneo Produced naturally from animals and humans, when plants break decay and

organic matter breaks downo Also forms from the mining of fossil fuels, garbage in landfill and rice cultivationo These sources have greatly added to methane emissions since the industrial

revolution

Fluorocarbonso Synthetic chemicals that contain fluorine and carbono Chloroflurocarbons (CFC’s) were one used as aerosols, refrigerants and or

conditioning coolantso They have since been banned in many countries due to their impact on the

ozone layero Hydroflurocarbons (HFC’s) are used as replacements to CFC’s and are

greenhouse gases

Nitrous oxideo Emitted by nitrogenous fertiliser use, disposal of human waster in sewage

treatment, power plants and car exhaustso Nitrous oxide is both a greenhouse gas and a cause of acid rain

Fossil fuel + oxygen -> carbon dioxide + water + energy

Chloroflurocarbons chlorine + fluorocarbon

Chlorine + ozone oxygen + chlorine monoxide

Chlorine monoxide chlorine + oxygen atom

CH4 + 2O2 CO2 +2 H2OMethane + Oxygen gas carbon dioxide + water vapour

o Pure water has a pH of 7 which is neutral any less is acidic. Carbon dioxide in the atmosphere can cause rainwater to be slightly acidic. Acid rain is any rain which has a pH of 5.6 or less

o This can be caused by nitrous oxide and nitrogen dioxide being dissolved in water vapour in clouds

o When nitrous dioxide is released into the atmosphere it is oxidised to form nitrogen dioxide. This gas then reacts with water in the atmosphere producing nitric acid

Sulfur dioxideo Not a greenhouse gas but it the main cause of acid raino Occurs naturally from sea spray, volcanic emissions and rotting vegetationo Sulfur dioxide occurs from the burning of fossil fuelso When sulfur dioxide is released into the atmosphere it is oxidised to form sulfur

trioxide gaso Sulfur trioxide reacts with water in the atmosphere to create sulfuric acido Sulfuric acid can dissolve into water vapour and eventually fall as acid raino Sulfur dioxide is also an aerosol which aids in blocking the sun, hence cooling the

earth which can affects cattle loss in agriculture. This sometimes happens after a volcano.

Nitrous oxide + oxygen nitrogen dioxide

Nitrogen dioxide + water nitric acid + nitrous acid

Sulfur dioxide + oxygen sulfur trioxide

Sulfur trioxide + water sulfuric acid

Global warming Scientific views Likely hood of global warming International strategy

Scientific views:- There is no denying that the world has experienced and is experiencing climate change, this

is evident from rising temperatures and erratic weather patterns as can be seen in the rapid changing of el nino and la nina in Australia

- There are conflicting perspectives however, between scientists who believe that climate change is anthropogenic (human induced) and others who believe it is occurring from natural patterns in the earth’s temperature

- Anthropogenic:o This is the most widely accepted cause for climate change and studies greenhouse

emissions in conjunction with global warmingo Greenhouse gases act as a blanket in the atmosphere keeping heat from the sun in

the atmosphere, this is necessary to maintain life, however, with an increase in greenhouse gases more heat is trapped

o There has been a steady increase in global temperatures since the industrial revolution which brought in a higher concentration of greenhouse gases

o This increase in temperature has altered global climate resulting in erratic weather in the forms of flooding and drought

o If humans continue to release greenhouse emissions into the atmosphere, climate change will continue and as such polar ice caps may melt resulting in rising sea levels

o Rising sea levels pose a threat to island nations as well as many cities and urban settlements which are located in coastal areas

o The general belief in anthropogenic climate change is that the only way to reduce this impact is to cut greenhouse emissions

- Non anthropogenico Not fully accepted theory, some pro anthropogenic climate change scientists agree

with some aspects of this theory. Suggests that global climate change and warming is the result of natural fluctuations in temperature

o Typically this theory is viewed negatively and criticised heavily o By studying ice cores scientists are able to determine past temperatures and climatic

conditionso Over the last hundreds of thousands of years there has been a large variation in

temperature and ice ages have occurredo This theory suggests that climate change is simply a fluctuation caused through

natural processes. Scientists also claim that in the last 16,000 years the worlds temperature is actually decreases over time

o Some reason that the world is heading for an ice age

Likelihood:

- There is no denying that global warming and climate change is occurring, there has been a steady increase in global temperatures and a growth of erratic climatic conditions over the last hundred years since the industrial revolution

International strategy:- Kyoto protocol (countering global warming through reduction in greenhouse gases)

o In 1997 many nations met in Kyoto Japan to discuss ways by which greenhouse gas emissions could be reduced

o It was agreed that rich industrialised nations would cut their 1990 levels of greenhouse emissions by 5.2% by between 2008 an 2012

o China and India did not have to adopt this strategy since they are both counted as developing countries

o Australia and America at the time were not for the protocol o The prime minister of the time refused to sign any treaty putting Australian industry

or jobs at risk, as such Australia was allowed an 8% increase on the basis that the Australian economy would fail

o Australia has since accepted the protocol since the change to a labour governmento Australia has began implementing measures such as the carbon tax to reduce

greenhouse emissions

Ozone depletion Chlorofluorocarbons International strategy Role of Australian scientists

- Ozoneo Ozone (O3) is produced by ultraviolet rays causing the splitting of O2 and creating O3

(see environments through time notes)o Ozone acts as a protective layer that keeps approximately 99 – 95% of the suns UV

radiation from reaching eartho Some chemical pollutants easily breakdown ozone such as CFC’s

- Halocarbons o Halons are CFC’s which also contain bromine

- CFC’so CFC’s were widely used in refrigerants, aerosols, coolants prior to being banned by

many countrieso CFC’s are quite stable and can remain in the atmosphere for up to 75 yearso When they do finally breakdown they form radicals (very reactive atoms eg O)o For example the CFC CCl3F breaks up and forms a chlorine radical when hit by UV

radiationo These chlorine radicals are then able to react with ozone and convert it back into

oxygen

CFC + UV light CFC + Chlorine radical

Chlorine radical + Ozone Chlorine monoxide radical + Oxygen gas

Chlorine monoxide radical + Oxygen radical Chlorine radical + Oxygen gas

o The reaction between chlorine and oxygen is faster than the formation of ozoneo CFC’s originate from all areas of the world, however, are transported to the poles

due to earths rotation and wind pattern- Evidence for ozone depletion

o Evidence from satellites, weather balloons, together with surface monitoring of the amount of ultraviolet radiation has proven ozone is depleting

- International strategy aimed at reducing ozone depletion – Montreal protocolo Signed in 1987 with the aim of saving the ozone layer o Revisions of the treaty have stated that

CFC’s would not be produced after 1995 and other halocarbons would be in controlled production until 2030

Hope that this will lead to a recovery of the ozone layer by 2050o An alternative to CFC’s are HFC’s, which are a greenhouse gas as such the Montreal

protocol impacts on the Kyoto protocol as it encourages the usage of greenhouse gases

o The Montreal protocol has proved to be successful with CFC emissions being cut worldwide

o As CFC’s act as a catalyst it is likely that the impact of CFC’s will last for sometime, however, the ozone may start to be restored after 2050

- Role of Australian scientistso The bureau of meteorology has six monitoring stations each station takes daily

measurements of ozone daily The data collected is sent to research centres such as the CSIRO where it is

used to create simulations of atmospheric behaviour Predictions of loss or gain or ozone may be established which may lead to

warning systems being implemented ultimately saving liveso Dr Jonathon Banks (Australian scientist) was the chairman of the methyl bromide

technical options committee which delivered a major report recommending ways to reduce methyl bromide which was adopted by countries which signed to Montreal protocol

CFC + UV light CFC + Chlorine radical

Chlorine radical + Ozone Chlorine monoxide radical + Oxygen gas

Chlorine monoxide radical + Oxygen radical Chlorine radical + Oxygen gas

7 Rehabilitation and safe use of previously contaminated sites

define the qualities of geological features that need to be considered in selecting areas for waste dumps

perform investigations to construct and test simulations of waste treatment processes, such as filtration, sedimentation and precipitation

evaluate the methods currently used for the disposal, treatment and recycling of both solid and liquid waste gather information from first-

hand investigations or secondary information to analyse the effectiveness of landfills in disposing of solid and liquid wastes

assess the methods and effectiveness of rehabilitation at a contaminated mine site

Waste management Geological features of a landfill Methods of disposal, treatment and recycling of solids and liquids Rehabilitation of a mine site

- Most common storage of wastes are landfillso Landfills must not be build over faults or anywhere, where groundwater can riseo Clay soil is a good place for a landfill as water is unlikely yo be contaminated,

limestone is not a good place- The greatest concern of landfills is there affect of the waste on local water systems

o Leachate (bin juice) is a liquid from wastes, this liquid contains toxins, contaminates and heavy metals which can enter water systems

Insert diagram pg 161

- When a landfill is full it is covered with several layers of plastics and clays. A layer of topsoil and vegetation is placed over

- If the landfill cover has been maintained and the area deemed chemically and physically stable, the area can be used for normal activities

- Problems associated with landfillo The failure of the plastic seal by various household chemicals may enable leachate to

permeate in surrounding rocks and later be transported into groundwatero Vegetation over the top of an old landfill can send deep root systems which cause

water infiltration into the landfill possibleo Subsidence is caused by damage to the cover of an old landfill by decay, settling or

compaction of landfills content. This poses risks to a buildings foundations- Methods of disposal

o Roughly 95% of waste goes to landfills, whilst the other 5% has special treatment needs

o Material which goes into a landfill is deemed either inert or putrescible Inert wastes consists of soil and rock which is not contaminated Putrescible wastes include food scraps, paper, animal waste, rags and

disposable nappieso Wastes which are hazardous are specially treated as they pose a serious risk to

human or environmental health These include biomedical and chemical liquid wastes

o Biomedical wastes are usually either incinerated or sterilised by microwave radiationo If chemical wastes are deemed natural they are put into the drainage system, if not

they are treated by wastes specialistso Chemicals such as acids, solvents, bases are treated to make them non reactive

- Recycling o Strategy to reduce wasteo Greenwaste includes food scraps, grass, garden clippings, wood and can be

reprocessed into compost for mulching of soil conditionero This material has negative effects on landfills including leachate and subsidenceo Paper and cardboard are recycled to produce packaging and toiler paper reducing

trees being cut down- Rehabilitation of mine site

o Mining activity affects the environment by Disrupting natural flows Polluting environment through chemically changing water, air and soil

o Therefore it is necessary to rehabilitate a mine site o In the early years of mining no rehabilitation took place, leading to soil erosion, loss

of habitat for native animals/plants and admission of acid into water wayso Some old mines have since been rehabilitated

The Glen Ayr mine began to release acidic and saline water from its entrance The department of mineral resources implemented a plan to reduce the

acidity of the water The plan involved neutralising the acidic minewater through a limestone

drain and wetlando Now rehabilitation is necessary in Australia as Government legislation requires

rehabilitation methods to be determined prior to the commencement of miningo Environmental surveys map out the areas topography taking note of the height of

the land as well as flora and fauna, natural movement of the water above and below the surface

o A bond must be created with the government ensuring the mining company rehabilitates the area

o Stages of mining First stage involves clearing of land of native vegetation and collecting the

seeds & seedlings to plant after the mining process Soil and plants are stockpiled for later use Second stage involves the extraction of ore and processing it either on or off

site. The chemicals used in processing and tailings created are disposed of appropriately

Groundwater is constantly monitored during the mining process to ensure there is no contamination

The final stage of mining involves the filling of the pit with either water (creating a dam) or wastes (becoming a landfill)

Stockpiled soil is spread over the area and vegetation is introduced Animals are reintroduced

o The rehabilitation process in accessed in terms of biological, chemical and physical components. If the rehabilitation if successful the company gets its bond back