Part 3-Lesson 1

Australias Aquatic PastTopic 4-Lesson 1IntroductionWe already know that Australia is very old. We have a rock record going back 4.1 billion years. In that time Australia has undergone changes. The Continent has build up over time in a west to east direction and most of the rocks formed in aquatic environments as sediments settled at the bottom of lakes, lagoons and seas.

ActivityComplete activity 3.12 pg 102 Prelim Spotlight TextWater PollutantsPollutants are any substance that is harmful to the environment or life. Water pollutants are categorised into the following types:Oxygen-demandingPathogensSynthetic organic compoundsNutrientsInorganic chemicalsSedimentsRadioactive Thermal discharge

Oxygen-Demanding SubstancesOrganic material that is not completely decomposed. As this material enters a body of water is continues to decompose and use up oxygen from the water. This reduces the levels of dissolved oxygen for plants and animals. Examples of this is untreated sewage and dead animals.

PathogensThese are organisms that can cause disease if found in water bodies. In 1998 protozoan parasites Giardia and Cryptosporidium contaminated Sydneys water supply. These organisms can cause intestinal cramping and diarrhoea. These waterborne diseases are common in Third World countries and can kill you. Cholera and typhoid are examples that are fatal.

Synthetic Organic CompoundsThese are human manufactured chemicals made mostly of carbon and hydrogen. Petroleum is the most common type which floats on top of the water and prevents light penetration and covers shorelines. This type of pollution can blind, poison and drown fish, birds and other animals.

NutrientsThese are natural or synthetic substances that promote plant growth. These typically contain nitrogen and or phosphorus. Examples include manure, humus, detergents and fertilisers. This type of pollution can promote the growth of non native plants and algal blooms.

Inorganic ChemicalsThese can be pesticides and herbicides or substances released by industrial processes. They can interfere with normal functions of individual organisms or entire ecosystems. In humans this type of pollution can cause cancer, skin disease, organ failure and disorders of the nervous system, immune system and reproductive system. An example of this is heavy metals released by industry.

SedimentsWater in natural environments is usually quite clear. Erosion transports sediments into rivers and streams making them murky. During floods this naturally happens however due to land clearing more sediments are washed into rivers and streams. This can clog the gills of fish, block the suns rays and interfere with gases dissolved in the water.

Radioactive SubstancesThis is currently a problem in some Northern Hemisphere locations who use nuclear reactors to generate electricity. Radiation damages DNA and results in mutations and diseases. Australias uranium mines pose the most likely source of low level radioactive contamination.

Thermal Discharge Some industries use water as a coolant and release the waste water into lakes, streams and rivers. This waste water is free of pollutants but is hot or warm and can kill plants and animals. We know hot water holds less dissolved gas so it can suffocate fish and plants.

Sources of water pollutionThe main sources of water pollution includes sewage, agriculture, industrial waste and garbage. Water is arguably out most vital natural resource and its important to protect and conserve our water supplies.

How can you protect waterways?

ActivityRead How you can protect waterways section of Prelim Spotlight Text page 105.

Discuss Table 3.3 pg 106 Prelim Spotlight Text

Discuss Activity 3.15 (Students need to complete for homework)ReviewPollutants are any substance that is harmful to the environment or life. Water pollutants are categorised into the following types:Oxygen-demandingPathogensSynthetic organic compoundsNutrientsInorganic chemicalsSedimentsRadioactive Thermal discharge

HomeworkRead pages 101-105 Prelim Spotlight TextUpdate electronic vocabularyComplete Activity 3.15 pg 107 Prelim Spotlight TextComplete DOT Point 4.1-4.2

Australias Aquatic PastTopic 4-Lesson 2ReviewPollutants are any substance that is harmful to the environment or life. Water pollutants are categorised into the following types:Oxygen-demandingPathogensSynthetic organic compoundsNutrientsInorganic chemicalsSedimentsRadioactive Thermal discharge

Water RecyclingThe ideal situation for water use would be to have two water supplies. One for drinking and one for all other uses. Its very expensive to produce water safe for human consumption and according to Sydney Water, more than half the treated water is used for washing and watering gardens.

Water RecyclingWater authorities in Australia are moving towards water recycling to try and reduce water consumption. Recycled water (non-potable water) is not suitable for drinking, cooking or bathing but can be used more than once for other things.

Water RecyclingConsumers would have to add an additional set of pipes for the non-potable water which would initially be expensive but the recycled water would be cost about 1/3 the price of potable water.

Water RecyclingIn 2001 the sewage treatment plant at Rose Hill in Sydneys north west was the first to produce non-potable water for public use. They chose to do it here because it was a new development area. The cost of laying a non-potable set of pipes at the same time as the potable set was not a great deal more. Do you think this should be mandatory for all future development sites?

Benefits of Conservation and RecyclingReducing water billsLess chance of water restrictionsReducing the need for new damsRecycled water contains more nitrates and phosphates which would reduce the need for fertilisers on lawns and gardensReduces discharge of nutrient-laden water into riversSaves drinking water Reduces the impact of urban development on waterwaysGround waterGround water represents a large component of the global fresh water. Its the larges reservoir for drinking water and is therefore an important natural resource that needs to be managed carefully.

Ground WaterGround water is held within the pores of saturated rocks and sediments below the surface. It comes from rain soaking through the soil and into underlying rocks where it slowly makes its way down hill due to the force of gravity.

Ground WaterThe movement of ground water is influenced by the types of rocks is encounters. For example, porous rocks like sandstone act like reservoirs for ground water. Non-porous rocks like shales act as barriers. See Figure 3.31 Prelim Spotlight Text pg 110.

Ground WaterThe top layer of groundwater is called the water table. This varies in depth depending on the geology and precipitation of an area. If conditions are right, this water can exit the ground and form natural lakes, springs, swamps and rivers. Groundwater can sustain a river system during dry periods.

Problems with Ground WaterThe quality of ground water is naturally variable. Some aquifers release water that is very clear and has few dissolved minerals while others can be murky and saline.

Problems with Ground WaterSaltwater intrusion and pollution can negatively affect ground water. Saltwater intrusion happens when we remove water from Aquifers and salty water then fills this space.

Problems with Ground WaterPollution of ground water is a serious problem. Most pollutants move through groundwater slower than water. If safe practices are not in place for everyone, ground water can be polluted by a number of activities.Waste disposalAgricultureChemical, petroleum and transportMining Problems with Ground WaterThe treatment of polluted ground water is expensive and time consuming. One way this is done is pumping the water to the surface, treating it, and then pumping it back into the aquifer.

ReviewThe ideal situation for water use would be to have two water supplies. One for drinking and one for all other uses.Ground water represents a large component of the global fresh water. Its the larges reservoir for drinking water and is therefore an important natural resource that needs to be managed carefully. The movement of ground water is influenced by the types of rocks is encounters.Saltwater intrusion and pollution can negatively affect ground water.The treatment of polluted ground water is expensive and time consuming.

HomeworkRead pages 108-112 Prelim Spotlight TextUpdate electronic vocabularyComplete To Think About Prelim Spotlight Text pg 113Complete DOT Point 4.3-4.5QuizTopic 4-Lesson 3