a consumer guide to accompany the australian drinking water guidelines

Water made clearA consumer guide to accompany the Australian Drinking Water Guidelines 2004 Endorsed by NHMRC 10–11 April 2003 Natural Resource Management Ministerial Council... To ensu

I N V E S T I N G I N A U S T R A L I A ’ S H E A L T H

Water Made Clear

A consumer guide to accompany the Australian Drinking Water Guidelines 2004

Natural Resource Management Ministerial Council

Water made clear

A consumer guide to accompany the

Australian Drinking Water Guidelines 2004

Endorsed by NHMRC 10–11 April 2003

Natural Resource Management Ministerial Council

© Australian Government 2004

Material included in this document may be freely reproduced provided that it is accompanied by an acknowledgment stating the full title of the document, the National Health and Medical Research Council and National Resource Management Ministerial Council and the date of release.ISBN (print): 1 86496 177 5

knowledge-NHMRC documents are prepared by panels of experts drawn from

appropriate Australian academic, professional, community and government organisations NHMRC is grateful to these people for the excellent work they

do on its behalf The work is usually performed on an honorary basis and in addition to their usual work commitments

This document is also available through the NHMRC homepage at

www.nhmrc.gov.au

Membership of the NHMRC Drinking Water Consumer Guide

Working Group:

Mr Alec Percival (Chair) Consumers’ Health Forum

Dr Anne Neller University of the Sunshine Coast

Mr Brian McRae Australian Water Association

Secretariat

Mr Phil Callan National Health and Medical Research Council

Technical Writers

Dr Hilary Cadman Biotext Pty Ltd

Ms Janelle Kennard Biotext Pty Ltd

Graphic Designer

Mr Sam Highley Clarus Design Pty Limited

All photos by Clarus Design unless acknowledged otherwise

Foreword 6

Water made clear 7

The essential drop 7

Where does our drinking water come from? 7

A limited supply of freshwater 8

How do we use our water? 9

What’s in the water? 10

Disease and contaminants 11

Disease-causing organisms 11

Toxic substances 11

Where do contaminants come from? 13

The journey to the tap 14

Keeping our water safe 14

Protecting catchments 15

Resting in reservoirs 15

Treating the water 16

Coagulation, flocculation and sedimentation 16

Filtration 16

Membrane filtration 17

Disinfection 17

Checking that water is safe 19

A proactive approach 20

Do I need a water filter? 20

Small water supplies 21

Rainwater supplies 21

Who is responsible for safe drinking water? 22

Australian drinking water guidelines 22

Keeping the guidelines up to date 23

What can I do to help? 24

Help to keep drinking water safe 24

Treat catchments with respect 24

Don’t tip it down the drain! 24

Keep runoff and stormwater clean 24

Keep your plumbing in good repair 25

Watch out for backflow! 25

Conserving water 26

Conclusion 27

Further information 28

Glossary 29

10–11 April 2003

Australia is the driest inhabited continent, and our supply of water is not inexhaustible With Australia in the grip of the worst drought in a century, it

is apparent that our freshwater supplies are indeed a precious resource

To ensure that the health of all Australians is not threatened by poor quality drinking water, the National Health and Medical Research Council (NHMRC) has, for over 30 years, developed guidance on water quality for

the Australian water industry The Australian Drinking Water Guidelines

continue to provide vital information to all those agencies around Australia responsible for bringing you safe, good quality water

It is now clear that the community also has an important role to play in the management of our water quality

In developing this publication, the NHMRC seeks to make information more widely available and hopes to encourage people to gain a better understanding of those processes required for the provision of safe drinking water for the whole community

This publication has been developed to highlight the many steps that water must go through before it is delivered safely to your tap, and the things that we can all do to ensure that we continue to receive the highest quality drinking water

Safe water is essential to sustain life — we all have a responsibility to make every effort to ensure the quality of our drinking water The NHMRC hopes that this document encourages you, as a consumer, to become more active

in the management of drinking water

Water is important; let’s work together to maintain this precious resource

Professor Nicholas Saunders

Chair, NHMRC (2000–2003)

Water made clear

It is easy for us to take the quality of our drinking water for granted — when

we turn on the tap, we expect safe, pleasant-tasting water to flow out

Long before water reaches our tap, carefully managed systems are in place

protecting our water and making it safe to drink, from the water falling as

rain to the point when it reaches our tap

The Australian Drinking Water Guidelines (2004) give Australia’s water

managers and suppliers guidance on providing good quality drinking water

This booklet looks at why drinking water quality is so important, the journey

our water makes to our taps, systems to ensure good water quality and how

everyone can help safeguard this most precious of resources

The essential drop

Water is essential for life Our health depends on having an adequate supply

of safe water for drinking, cooking, laundry and bathing — every day

The link between our water supply and disease has been recognised for

thousands of years — at least since Egyptian times If our water becomes

contaminated with microorganisms or chemicals, illness can result

Disease-causing microorganisms carried by water are the biggest threat to health,

causing gastrointestinal upset, diarrhoea or even death

In some cases, people can become ill after drinking contaminated water

just once

As we all depend on clean water every day, any problem with the water

supply can very quickly have major consequences for an entire community

Water is all too easily wasted or contaminated We need to use it wisely and

protect it

Where does our drinking water come from?

Our drinking water comes mainly from two sources: surface water (rainfall

and its runoff into streams and rivers) and groundwater (water that has

collected in underground stores or aquifers) Surface water can come from

a river, lake or artificial dam Groundwater is accessed through a bore

Across Australia, water suppliers access this water, treat it and distribute it

to consumers A substantial number of Australian households also collect

rainwater as their main source of drinking water

Drinking water is

… water intended primarily for human consumption, either directly, as supplied from the tap, or indirectly, in beverages or foods prepared with water.

It should contain no harmful concentrations

of chemicals or pathogenic microorganisms, and ideally it should be aesthetically pleasing in regard to appearance, taste and odour.

Source: Australian Drinking Water Guidelines, National Health and Medical Research Council (2003)

“Water is fundamental to life and health”

United Nations Committee on Economic, Cultural and Social Rights (2002)

A limited supply of freshwater

The amount of water on our planet that is suitable and available for drinking

is very small Only 2.5% of the total water on earth is freshwater Most of

this is not available for drinking, because it is frozen in glaciers or the polar

icecaps, or is unavailable in the soil Accessible freshwater is found in the

atmosphere, lakes, rivers, streams, wetlands and under the surface in aquifers

(groundwater)

Across the globe, population growth, urban development and

environmental degradation are putting freshwater supplies under

ever-increasing stress Today, 4 out of every 10 people live in areas that are

experiencing water scarcity, and nearly 50% of the world’s population is likely

to face severe water shortages by 2025

Australia is particularly dry — despite occupying 5% of the world’s land

area, it has only 1% of the water carried by the world’s rivers This is because

Australia is flat and hot, so most of the rain that falls evaporates again before

it can replenish streams, rivers and underground stores Rainfall in Australia is

also very variable — our land of ‘droughts and flooding rains’ — making the

supply of freshwater even more variable

In the face of this unpredictable supply, Australians rely on stored water

and underground supplies Large volumes of drinking water are stored in

both natural and human-made reservoirs, including planned recharge of

underground storages (aquifers) Australia stores more water per person

than any other country — the equivalent of three Olympic swimming pools

for every Australian

Groundwater provides about one-fifth of Australia’s drinking water supplies

Some regions use little or no groundwater, while others rely heavily on this

source The Great Artesian Basin, Australia’s largest source of groundwater,

provides the only reliable and continuous water supply for much of the arid

outback, particularly in Queensland, New South Wales and South Australia

Being difficult to access, groundwater is extremely difficult to clean up if it

becomes polluted Therefore, it is vital to protect groundwater at source

Saline water (97.5%)

World's total water Breakdown of 2.5% freshwater soil and surface water Breakdown of 0.5%

Ice caps and

lakes (54%) Groundwater

(38%)

Atmosphere (8%) Soil

(23.5%)

Accessible water (0.5%) Freshwater (2.5%)

How do we use our water?

By far the biggest consumer of water in Australia is agriculture, which

accounts for more than 70% of water use, mainly for irrigation Some

industries are also heavy water users, such as manufacturing (approximately

3% of total water used in Australia) and the production of electricity and

gas (around 8%) Approximately 8% of the water used in Australia is used in

homes

The water that is used in most Australian homes and gardens is of drinking

water quality This means that it has been carefully managed and treated

to make it safe to drink Yet only around 1% of drinking water is actually

used for drinking, considerably more being used for activities like cooking,

washing clothes, showering and flushing the toilet The garden takes the

most drinking water, typically accounting for around 35% of consumption,

although in hot, dry summers, this figure can be as high as 90% in some

parts of Australia

The water cycle

The water we drink has been around for hundreds of millions of years It travels in a continuous cycle between the oceans, the air, the earth’s surface

and underground storages (aquifers), undergoing natural cleansing as it makes this journey, but also potentially becoming contaminated Water vapour condenses to form clouds, which release water as rain, hail or snow when conditions are suitable As the water falls to earth it either moves into the soil

or runs into rivers and the ocean Surface water in lakes, streams and oceans evaporates, returning moisture to the atmosphere Plants also return water

to the atmosphere by taking water from the ground through their roots and releasing it from their leaves in a process known as transpiration.

Typical use of drinking water in the home

Transpiration

Surface runoff

Ocean Groundwater to lakes and streams

Moisture transport

Evaporation Precipitation

Percolation

Soil moisture Water table

Solar radiation

Drinking Kitchen Washing clothes

Flushing toilet Showering Garden

What’s in the water?

In its purest form, water is simply H2O; that is, two atoms of hydrogen

attached to each atom of oxygen Because water is such a good solvent, in

the environment it will always contain dissolved or suspended impurities

The types of impurities found in water can be divided into four groups:

microbial (microorganisms), physical, chemical, and radiological

Having impurities in drinking water is not necessarily a bad thing — many

constituents of normal drinking water are harmless or even desirable For

example, the minerals calcium and magnesium, which can enter water from

soil and rocks, are good for human health and give the water a pleasant taste

Other impurities can affect the aesthetic qualities of water such as

appearance, taste, smell and ‘feel’ Such impurities are not necessarily

hazardous to human health In fact, the taste, smell and appearance of water

is not a good guide to its safety Water that is cloudy, has a distinctive odour

or has a strong taste is not necessarily harmful to health, while clear, pleasant

tasting water may still contain harmful microorganisms

While not all impurities are a problem, some have serious health consequences

Types of impurities found in water

Types of impurities Examples

Microbial

Physical

Taste and odour Geosmin, methyl isoborneol

Appearance Silt, suspended particles, plankton

Chemical

Naturally occurring Manganese, nitrate

Agricultural Atrazine, chlordane

Water treatment Chlorine, fluoride

Industrial Poly Aromatic Hydrocarbons, mercury

Disease and contaminants

A number of organisms or substances that cause human disease can

contaminate water supplies The most serious of these are microorganisms

They can have immediate and devastating effects on our health Some

chemical contaminants also cause human disease Usually, the effects of

such contaminants are only seen after long periods of exposure These two

broad categories of disease-causing contaminants are examined below

Disease-causing organisms

Pathogenic (disease-causing) microorganisms in drinking water pose the

greatest potential threat to human health Over three million people a year,

many of them children under five years of age, die from waterborne and

sanitation-related diseases Most of these deaths occur in the developing

world, where many communities have no access to clean or treated water, or

adequate sanitation

Since the 1930s and 1940s water supplies in Australia have been subjected to

widespread disinfection Before this time, death from water-borne diseases

was much more common than it is today While the potential threat

remains, in most parts of Australia, waterborne disease is controlled by

good water management In some parts of Australia, water quality remains a

problem, especially in some rural and indigenous communities

Microorganisms include bacteria, viruses and protozoa, only a few of which

cause disease However, microorganisms in human and animal faeces are

responsible for most waterborne diseases In some parts of the world,

waterborne diseases such as dysentery, hepatitis, cholera and typhoid cause

severe, and at times fatal, diarrhoea

Cryptosporidium and Giardia were recently brought to attention in Australia

by the 1998 Sydney ‘water crisis’ They are protozoans — parasites that

consist of a single cell Cryptosporidium and Giardia are a problem for the

water supply industry because they are widespread in surface water, can

survive for long periods and are difficult to treat

Toxic substances

Blue-green algae

Cyanobacteria, better known as blue-green algae, are a health hazard

because of the toxins they release Some toxins result only in a skin rash,

but others are more serious, causing liver and nerve damage The toxins are

released into the water and can remain even when the bacteria themselves

have been removed If contamination occurs, it may not be sufficient to

boil the water Boiling destroys the cells, but not all of the toxins Therefore,

special treatment is required to remove the toxins from water contaminated

by blue-green algae

Did you know that …

Australia experienced the world’s worst ever algal bloom in 1991, covering more than

1000 km of the Barwon and Darling rivers in New South Wales Drinking water had to be brought into the area for residents of regional and rural towns supplied by the rivers A number of animals (but no humans) died from drinking the contaminated water.

Algal blooms are actually caused by bacteria (cyanobacteria), which are very widespread in the environment These organisms become

a problem when nutrient levels rise This can happen when agricultural activity results in large amounts of fertilisers entering warm, slow-moving waterways.

Contaminated water claims lives

An outbreak of waterborne illness in Canada in

2000 highlighted the importance of protecting water supplies and the danger of waterborne microorganisms to human health Over 2000 people became ill, 65 were hospitalised and 7 died as a result of a contamination of the water supply in Walkerton, Ontario.

Two major bacterial contaminants were

discovered: a disease-causing strain of E coli

which caused a sometimes fatal condition called ‘haemolytic uraemic syndrome’ (the same condition that occurred in the Garabaldi food poisoning incident in Adelaide); and

Campylobacter, a bacteria from human and

animal waste that causes gastroenteritis The two strains matched those found in cattle on farms near local water bores.

An inquiry found that many faults in the local water management had contributed to the outbreak, including inadequate protection

of the catchment surrounding the bores, insufficient chlorination, an assumption that bores were secure water sources and inadequate training of staff operating the treatment plant.

Fertilisers and pesticides from agriculture and forestry

Hazardous wastes from industryLivestock waste from farming

Human waste from urban

development

Runoff from mining and quarrying

Leaks from landfill sites

Substances that can pollute drinking water sources

Pathogenic microorganisms have fairly immediate effects but health effects

from potentially harmful chemical and radioactive contaminants in drinking

water become evident only after long exposure (typically many years) For

example, low levels of arsenic in drinking water might increase the incidence of

skin, lung or bladder cancer, in a population that had been drinking the water

for many years

Chemicals of concern for drinking water include some naturally occurring

chemicals, such as nitrate, selenium and uranium; agricultural chemicals

such as pesticides and fertilisers; and the chemical byproducts formed

when water is treated with a disinfectant (these disinfection byproducts

are discussed in detail below in the section on water treatment) However,

the amount of these chemicals in our drinking water is generally very

small — much lower than the levels that would be considered harmful to

health Indeed, we are exposed to higher levels of these chemicals in our

environment and our food (though they are well below what is considered a

safe level)

Radioactive contaminants

The health effect most strongly associated with radioactive contaminants is

cancer Extremely low levels of radiation are a naturally occurring characteristic

of water in our environment Drinking water is likely to contribute only a very

small proportion of a person’s overall natural exposure to radiation

Where do contaminants come from?

Microbiological, physical, chemical and radiological materials can all be found

naturally in water in the environment, and can also result from a range of human

activities For example, inadequately treated sewage or animal wastes from

agriculture can contaminate surface and groundwater with microorganisms

Agriculture, industry, household activities and runoff from roads can

contam-inate water with chemicals such as nitrates, pesticides, fertilisers, heavy metals,

solvents and volatile organic compounds, such as petroleum products

Certain chemicals are added to water as part of the treatment process For

example, aluminium sulfate is used to help remove particles from water,

chlorine is added as a disinfectant and fluoride is often added to improve

dental health The Australian Drinking Water Guidelines specify the safe,

tolerable level of these additives Water suppliers ensure that chemicals that

are added during treatment and may remain in the water when it reaches

the consumer do not exceed these levels

A further source of chemicals can be household plumbing that contains

copper or lead These chemicals can leach into drinking water on its way to

the tap Consumers who are concerned about their household plumbing

should discuss this matter with their local health or water authority

Australia’s drinking water supplies are carefully managed to ensure that

dangerous contaminants either do not get into the untreated water, or are

reduced to safe levels long before the water reaches our taps

The journey to the tap

The following sections track the journey that our water takes from rainfall to

the tap They outline how the safety of our water is ensured along the way

In Australia, the way our water is treated and managed depends on where

we live Our population is generally clustered in large cities along the coast,

vast areas of Australia are only very sparsely populated As a consequence,

there is a huge variation in scale in water-delivery systems Some water

authorities supply populations of more than a million (Sydney Water

services four million people in the Sydney region, for example) while many

others service as few as several thousand (such as AQWEST, in Bunbury,

Western Australia, servicing around 34,000 people) In addition, some local

governments run small systems that supply drinking water to as few as 20

people, while about one in six Australian homes use rainwater collected on

roof catchments

Because large metropolitan systems supply the majority of Australians with

their water, such systems are used in the following section to illustrate the

practices that keep our water safe Many of these practices also apply to the

smaller distribution systems Particular issues for smaller systems are outlined

in a separate section

Keeping our water safe

We keep our drinking water safe through a combination of protection and

treatment, aimed at ensuring that water is safe for human consumption,

pleasant to drink and reasonably priced

No single intervention is sufficient to deliver safe, high quality drinking

water to consumers Ideally, the primary focus of the water authority is on

preventing the water from becoming contaminated; that is, protecting the

water The idea is that the combined effects of multiple barriers prevent

and/or reduce hazards to tolerable levels In the event that one barrier fails,

other barriers should be sufficient (at least in the short term) to compensate

Traditional barriers include:

• protecting the catchments and source water

• holding water in protected reservoirs or storage

• treatment

• disinfection

• protecting the distribution system

Protecting catchments

The condition of the catchment — the area over which rainwater is caught

and drains into a water supply — is probably the most important factor

influencing the quality of water It also determines how much treatment is

needed before the water is safe to drink Water drawn from a pristine natural

catchment will be of higher quality and need less treatment than water

that has flowed through a heavily used urban or agricultural area Where

practical, catchments can be protected by excluding industry, agriculture

and urban development and by limiting human access to the area Even

where land uses are permitted within the catchment, the condition of the

riparian (river or stream) corridors can have a great influence on the quality

of the water supplies

Rainfall patterns over the catchment also affect the quantity and quality

of water flowing into supplies Experience has shown that unusually heavy

rainfall can wash large amounts of contaminants from the catchment into

storage reservoirs It can also mix water and sediment within reservoirs,

stirring up microbes and other matter that had previously settled

The Australian Drinking Water Guidelines provide information for water

authorities on how to set out careful catchment management plans The

plans identify possible risks and hazards, such as grazing livestock or sudden

heavy rainfall, which could cause contamination Appropriate responses

are incorporated into management plans, to ensure that the water supply

remains safe, despite these possible hazards For example, following heavy

rainfall, authorities could select water from an alternative source, or adjust

the water treatment to cope with the influx of contaminants

Resting in reservoirs

Water running off the catchment area is stored in protected reservoirs

before being drawn off for treatment and distribution Water may remain in

a reservoir for a month or two—or up to several years—before it is drawn

off for treatment and use This allows many contaminants to settle out of

the water and many microorganisms to be destroyed by natural ultraviolet

(UV) radiation from the sun Storage also allows water to be drawn off

from different levels, so that the highest quality water can be selected for

treatment

Treating the water

Water treatment mainly involves the removal of sediments and

contaminants, followed by disinfection to kill potentially harmful

microorganisms Treatment can also include measures to improve aesthetic

qualities such as the colour, taste and smell of drinking water The choice

of treatment depends on where the water comes from, what type of

contaminants might be present and the cost of the treatment compared to

the savings made through the prevention of diseases in the community

The water treatment applied most widely in Australia is a combination of

coagulation, flocculation, sedimentation and filtration It is based on the

fairly simple technologies that were developed in the 19th century and

have been refined to require less time, space and cost and to operate more

efficiently and effectively However, water treatment technology is beginning

to change in response to technical advances, better understanding of the

contaminants present in drinking water and their health risks, rising public

expectations and the need to balance cost against effectiveness

Coagulation, flocculation and sedimentation

Fine particles like clay, silt and algae do not settle out on standing; instead

they are removed using a chemical called a coagulant or flocculant The

coagulant binds the particles into large clumps (flocs) that either settle

out or can be removed by filtration Commonly used coagulants include

aluminium sulfate (alum), polymers and iron salts Together, coagulation,

flocculation and sedimentation remove more than 99% of bacteria and

viruses, organic matter from soil and vegetation, and some chemicals

These processes do not completely remove dissolved material, which can

include toxins and compounds that affect taste and smell, and organic

matter that encourages growth of microorganisms and formation of

disinfection byproducts An additional mechanical or chemical purification

step, such as treating water with activated carbon, can be used to remove

this type of contaminant

Filtration

The passage of water through a bed of fine particles (eg sand and gravel)

removes fine suspended solids and larger microorganisms Filtration can

be used alone (particularly if the source water does not contain a lot of

suspended material) or in combination with coagulation and flocculation

Carbon added to filter beds can remove objectionable tastes or odours The

carbon works through adsorption, drawing contaminants out like a sponge

or magnet, rather than physically filtering them out

A novel approach to water treatment

Cost effective management of dissolved organic carbon (DOC) in water is one of the key challenges facing today’s water treatment industry At best, traditional treatment processes generally remove only about half of the organic matter in water The material that remains can have a major impact on coagulation, maintenance of disinfection residual and the formation of chemical byproducts It can also produce undesirable taste, odour and appearance of the water.

After many years of research, the Australian Water Quality Centre and the South Australian Water Corporation, in collaboration with CSIRO and Orica, has developed a new resin, which could be the answer to this problem MIEX®

DOC resin is a simple to use, cost-effective and environmentally friendly way to improve management of water quality The resin removes organic material by absorption and is then regenerated using salt No chemicals are added to water during the process, and because the resin can be recycled, it is cost effective.

The first commercially operating water treatment plant in the world that incorporates MIEX® DOC resin technology is located at Mount Pleasant in South Australia, and provides water to Mount Pleasant, Eden Valley.