It is very important that the community water supply be kept clean and free of germs and chemicals.
2.1 Diseases which can come from polluted drinking waterDiseases in Indigenous communities caused by germs from polluted water
- acute diarrhoea (caused by E. coli)
- hepatitis A
- hookworm infection (there is some evidence that hookworm larvae can live in drinking water)
Fig. 6.12: Stomach upsets can be caused by contaminated drinking water.
In most parts of Australia and many other countries, proper water treatment methods have almost eliminated the germs that cause many of these diseases from water supplies. However, water treatment and hygiene standards in Indigenous communities, especially small communities or camps, are often inadequate and this is why many of these diseases still occur in Indigenous communities.
The germs may get into the water:
- a lagoon overflow effluent pipe discharging into a river or stream supplying drinking water
- the presence of dead animals in the water
- people or other animals swimming, washing or going to the toilet in a drinking water supply
- contamination from an effluent system, such as a leach drain too close to a bore or the overflow from a lagoon flowing into a water supply
- People washing themselves or going to the toilet in or near a water source
2.2 Water contamination and how it can be preventedAnything which contaminates water is called a contaminant or pollutant. Water can be contaminated or polluted by:
- Organic materials such as:
- animal carcasses
- animal and human faeces and sewage
- food waste
- plant matter (grass, leaves, wood)
- oil, petrol and grease.
- Inorganic materials such as:
- scrap metal and junk
Water can be contaminated at:
- the source, such as the river or bore
- in storage, such as in elevated tanks
- in the pipe system which delivers water to the user
Fig. 6.13: Drinking or swimming in contaminated water can be dangerous to health.
Different types of water supplies can become contaminated in a number of ways. Some of these, and their methods of prevention are described below.
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Domestic rainwater tanks
ContaminationThe rain which fails onto the roof of a house is usually clean, and should not normally contain germs. However, there may be a lot of dirt and rubbish on the roof, especially if it has not rained for a long time.
This dirt might include the faeces from birds and small animals. Also, the wind can carry germs in dust blown onto the roof. When it rains the dirt and rubbish will be washed into the storage tank, along with the germs. Some of these germs may cause disease.
Dirt, animals and bird faeces can get into a storage tank if it does not have a lid. All these things can carry disease-causing germs. Often animals are trapped in water tanks and drown. As dead bodies rot, germs will grow and contaminate the water.
The inside of the tank walls and floor may also become dirty after a period of time. This dirt can contaminate the water.
PreventionIf a house has a rainwater tank as its water supply, these are the things which should be done to keep the water clean:
- Install a first flush diverter. This prevents the first flush of water, which may have contaminants from the roof, from entering the tank.
- Keep the roof and gutters clean.
- Keep a lid on the water tank.
- Check for and repair any leaks.
- Regularly look into the tank. If the water or walls or floor are dirty the tank will need to be cleaned.
Rivers and billabongs
ContaminationThere are several ways in which rivers and billabongs can become contaminated with germs or chemicals:
- Rubbish may fall into or be washed into the river or billabong, for example, from a nearby dump
- Sewage may seep into the river or billabong from nearby septic tanks and leach drains
- Faeces may be deposited directly into the river by people or other animals
- Faeces deposited near the river may be washed into it by rain
- Chemicals or poisons sprayed onto land near the river or billabong may be washed into the water
- People or animals may wash themselves in the river or billabong
- near where a contaminant enters the water such as an effluent discharge point
- where contamination is occurring, such as a swimming area
Fig. 6.14: Faeces contaminate drinking water.
Fig. 6.15: People washing or swimming in a water source can pollute it.
Fig. 6.16: Water supply contaminated by effluent discharge.
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PreventionIt is important to try and stop the river or billabong from being contaminated, particularly in the area from which the community takes its water supply. Discharging effluent into rivers and streams should always be avoided.
Sometimes it is not possible to stop the contamination of a river or billabong. This is because the contamination source is not known, or cannot be controlled, like if the contamination is occurring upstream or is because of not being able to keep cattle out of a billabong.
The following prevention methods can be adopted:
- If the community water supply comes from a river make sure:
- it is obtained upstream from any possible contamination sources, for example, swimming holes or effluent runoff points
- it is taken from the deepest possible point in the body of water
- Make sure that there is little or no building development near the water supply source. There are laws which control where people can put septic tanks/leach drains, effluent ponds, and rubbish tips in relation to water supplies.
- Make sure people do not use the area around the water supply source for recreational purposes, such as playing sport and having picnics.
- In the case of a billabong, it may be possible to fence the water source to prevent contamination by people and other animals.
Fig. 6.17: Take drinking water upstream from effluent discharge.
ContaminationBores can become contaminated:
- underground. (This can happen if a contaminant is able to get to the water body, for example, if a leach drain is built too close to the water source, or a faulty effluent disposal system allows disease-causing germs to soak down into the groundwater)
- While bringing it to the surface
Fig. 6.18: Leach drain too close to water supply.
This could occur in the bore itself or at the place where the bore pipe comes out of the ground. This is called the bore head.
If the bore head is unprotected then animals can spread disease causing germs and parasites to the water via the equipment. For example, if the equipment leaks and allows water to pool, animals will be attracted (especially stock and birds) and their faeces may enter the water at the bore head.
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PreventionIt is important that:
- covers be placed over bore heads
- there are fences around bore heads to keep animals away
- the bore head area is protected from flooding as this can carry disease-causing germs into the bore. The bore head is usually protected by raising it above ground level
- septic tanks/leach drains and effluent disposal sites are well away from the bore.
Fig. 6.19: Protective cover for bore.
Laws control the distances these facilities must be away from a bore or water source.
Community water tanks
ContaminationIf a large community tank does not have a proper fitting lid, then people, especially children, birds or other animals may find their way into it and contaminate the water with disease-causing germs.
Occasionally, the inside of the community water tank will get dirty and can contaminate the water.
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PreventionTo make sure that the water in the community tank is always clean:
- The tank should have a proper fitting lid
- There should be a high fence, with a locked gate, around the tank
- The tank should be regularly inspected to make sure that it is not leaking and that the water is clean and free of animals, such as frogs
- If the inside of the tank is dirty it must be cleaned. The proper way to clean a tank is described in Section 6.2
Community water pipes and household plumbing
ContaminationA water supply can become contaminated between the source and the community water tank or the user. The pipes that carry the water can be below or on the surface of the ground. They can be above the ground also, such as in the case of pipes carrying water from an elevated tank to the ground. An elevated tank is one that is raised above the user's water outlets either on a stand or on a hill.
Fig. 6.20: Community elevated water tank.
If a pipe is leaking around a joint or has been broken, disease-causing germs and parasites can get into the water and contaminate it. These germs and parasites can come from:
- the surrounding soil
- the wind
- animals, including people, attracted to leak or the pools of water.
PreventionContamination of water in pipes can be avoided by ensuring that:
- all joints are maintained free of leaks
- pipes are placed below ground whenever possible to protect them from damage
- any above ground pipes are held secure and are protected from damage, especially from vehicles
- any leaks or broken pipes are repaired as soon as possible
- connections to tanks, pumps and bores are well maintained and kept free of leaks