Clyde River and Jervis Bay
Water Quality Objectives
explained
| Contents | Background
| Consultation | Objectives | WQOs | RFOs | Glossary | Bibliography | Map |
At a Glance |
This section explains each of the eleven Water Quality Objectives (WQOs) developed for NSW rivers and estuaries, and provides guideline levels to assist water quality planning and management. Guideline levels are not provided for industrial water supplies as requirements are industry specific.
See the WQOs that apply to each
part of the Clyde River and Jervis Bay catchments.
Achieving each WQO will mean improving poor water quality or maintaining existing good
water quality.
Objectives consist of three parts: environmental values, their indicators
and their guideline levels. For example, if the objective is to protect secondary
contact recreation (environmental value), we need to keep the faecal coliform
levels in the water (the indicator) below a specified number or
guideline level.
The objectives comprise community-based environmental values and their associated national
criteria drawn from the ANZECC 2000 Guidelines. They provide the statewide context for taking this work forward into
catchment action plans, regional strategies and local environmental plans.
Tailoring Water Quality Objectives to local conditions
Local water quality varies naturally because of various factors, including the type of
land the waters are draining (e.g. soils, slope), or rainfall and runoff patterns (e.g.
ephemeral or permanent streams). Different land use and land management practices also
affect water quality. Local WQOs must take account of these variations, particularly for
the environmental value of aquatic ecosystems.
The ANZECC 2000 Guidelines move away from setting fixed single number water quality criteria, and emphasise water quality criteria that can be determined on a case by case basis, according to local environmental conditions. This is done through the use of local reference data and risk based decision frameworks — see section 2.2.1.4 Tailoring guidelines for local conditions (ANZECC 2000
Guidelines). The ANZECC 2000 Guidelines establish default trigger values that are set conservatively and can be used as a benchmark for assessing water quality. Further refinement of the trigger values may be needed to take account of local conditions, especially for aquatic ecosystems and particularly in places, or for issues, requiring priority action.
Trigger levels that have been locally refined must still protect the environmental value and drive local protection or improvement of water quality. This should be consistent with the approach advocated by the ANZECC 2000 Guidelines of focusing on the actual issue (or process) that is a risk or potential risk to the environmental value(s). The selection of the indicator and derivation of the trigger value should trigger action or investigation before the environmental value is compromised.
The key indicators and trigger values used here are examples of some of
the indicators listed in the ANZECC 2000 Guidelines. Key indicators for each environmental value
are listed below.
Downstream impacts
Planning and management decisions need to recognise that activities and decisions made upstream affect water quality downstream. Where this involves cumulative impacts for nutrients and sediments, the best approach may be to develop load targets for the catchment (see ANZECC 2000 Guidelines).
Water Quality Objectives
Meeting water quality levels suitable for local ecosystems is generally the basis for
protecting the other environmental values, which are the uses people have for water.
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Aquatic ecosystems
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Maintaining or improving the ecological condition of waterbodies and
their riparian zones over the long term |
Where the objective applies
- This objective applies to all natural waterways.
- High level protection of aquatic ecosystems applies to waters in and immediately
upstream of national parks, nature reserves, state forests, drinking water catchments and
high-conservation-value areas. This reflects their largely unmodified aquatic ecosystems,
value in providing natural sources of high-quality drinking water, and high levels of
recreational use.
- Even in areas greatly affected by human use, continuing improvement is needed towards
healthier, more diverse aquatic ecosystems.
- Water quality in artificial watercourses (e.g. drainage channels) should ideally be
adequate to protect native species that may use them, as well as being adequate for the
desired human uses. However, full protection of aquatic ecosystems may not be achievable
in the short-term in some artificial watercourses.
- Artificial watercourses should meet the objectives (including protection of aquatic
ecosystems) applying to natural waterways at any point where water from the artificial
watercourse flows into a natural waterway.
Examples of key indicators and their numerical criteria (default trigger values)
The following table includes examples of some of the key water quality indicators and related numerical criteria (default trigger values) selected from the ANZECC 2000 Guidelines, relevant to assessing and monitoring the health of aquatic ecosystems. To use and interpret these guidelines, see supporting information below and the ANZECC 2000 Guidelines. The booklet "Using the ANZECC Guidelines and Water Quality Objectives in NSW" explains key terminology and concepts used in the guidelines, in the context of NSW policy.
Aquatic ecosystems |
Indicator |
Numerical criteria (trigger values) |
Total phosphorus |
- Upland rivers: 20 µg/L
- Lowland rivers: 25 µg/L for rivers flowing to the coast; 50 µg/L for rivers in the Murray-Darling Basin
- Lakes & reservoirs: 10 µg/L
- Estuaries: 30 µg/L
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Total nitrogen |
- Upland rivers: 250 µg/L
- Lowland rivers: 350 µg/L for rivers flowing to the coast; 500 µg/L for rivers in the Murray-Darling Basin
- Lakes & reservoirs: 350 µg/L
- Estuaries: 300µg/L
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Chlorophyll-a |
- Upland rivers: not applicable
- Lowland rivers: 5 µg/L
- Lakes & reservoirs: 5 µg/L.
- Estuaries: 4 µg/L.
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Turbidity |
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Salinity (electrical conductivity) |
- Upland rivers: 30–350 µS/cm
- Lowland rivers: 125–2200 µS/cm
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Dissolved oxygen |
- Upland rivers: 90–110%
- Lowland rivers: 85–110%
- Freshwater lakes & reservoirs: 90–110%
- Estuaries: 80–110%
Note: Dissolved oxygen values were derived from daytime measurements.
Dissolved oxygen concentrations may vary diurnally and with depth.
Monitoring programs should assess this potential variability. |
pH |
- Upland rivers: 6.5–8.0
- Lowland rivers: 6.5–8.5
- Freshwater lakes & reservoirs: 6.5–8.0
- Estuaries: 7.0–8.5
Changes of more than 0.5 pH units from the natural seasonal maximum or
minimum should be investigated. See supporting information |
Temperature |
See ANZECC 2000 Guidelines, table 3.3.1. |
Chemical contaminants or toxicants |
See ANZECC 2000 Guidelines, chapter 3.4 and
table 3.4.1. |
Biological assessment indicators |
This form of assessment directly evaluates whether management goals for ecosystem protection are being achieved (e.g. maintenance of a certain level of species diversity, control of nuisance algae below a certain level, protection of key species, etc). Many potential indicators exist and these may relate to single species, multiple species or whole communities. Recognised protocols using diatoms and algae, macrophytes, macroinvertebrates, and fish populations and/or communities may be used in NSW and interstate (e.g. AusRivAS). |
Supporting information
- The ANZECC 2000 Guidelines advocate a risk-based approach to water
quality assessment and management. That is, the intensity of assessment of
current water quality status or impacts on water quality should reflect the
risk of impacts on the achievement/protection of the water quality
objective.
- Trigger values are the numeric criteria that if exceeded indicate potential for harmful environmental effects to occur. The default trigger values provided in ANZECC 2000 Guidelines are essentially conservative and precautionary. If they are not exceeded, a very low risk of environmental damage can be assumed. If they are exceeded, further investigation is "triggered" for the pollutant concerned. Assessing whether the exceedance means a risk of impact to the Water Quality Objective requires site-specific investigation, using decision trees provided in the Guidelines.
- For Protection of Aquatic Ecosystems in NSW, the ANZECC 2000 Guidelines provide default trigger values for major physico-chemical stressors in Tables 3.3.2 and 3.3.3 (pages 3.3-10 & 11) and for Toxicants in Table 3.4.1 (page 3.4-5).
- Note for turbidity trigger values: In general values in the lower part of the range will be found in rivers and streams during low flows and/or in more vegetated catchments. Waters of the Clyde River in particular tend to have turbidity values below 5 NTU and where these levels exist they should be maintained. Values in the higher part of the range will be found in rivers and streams in high flows and lower in the catchment (particularly inland catchments). For lakes and reservoirs, in general the higher values will be found in waterbodies that are shallow or in areas with dispersive soils.
- Note that pH varies naturally. Whilst 6.5-8.5 is the default trigger range, values outside this range should be investigated to assess whether they reflect natural variation. For example, some streams in sandstone areas have natural pH ranges as low as 4.5.
- The approach to protecting the aquatic ecosystem should consider the whole range of
interacting factors - such as variability of water quality over time, sediment interactions,
river flow, local geology, land use, the needs of sensitive habitats, and people's uses
for water.
- Assessing ecosystem health also requires using a range of indicators and considering
local modifying factors-such as basalt soils that result in naturally higher nutrient
levels, or estuary opening patterns that affect water quality. However, information on a
full range of indicators may not be available from regular monitoring.
- Although modified, many non-pristine environments contain important aquatic ecosystems.
Well-functioning aquatic ecosystems also benefit people using these waters, such as by
reducing blue-green algal blooms.
- Reducing diffuse pollutant loads during rainfall and runoff periods should be a key focus for
improving water quality. It is also important in managing longer term impacts, such as
sedimentation and polluted sediments.
- The choice of toxicant indicators for use in each management situation is related to
known past or current activities. Impacts are detected by measuring water, sediment or
biota. Natural sources should also be considered.
- Protecting aquatic ecosystems requires mimicking natural river flow patterns as closely
as possible (see Section 5).
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Visual amenity
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Aesthetic qualities of waters |
Where the objective applies
- The objective applies to all waters, particularly those used for aquatic recreation and
where scenic qualities are important.
Examples of key indicators and their numerical criteria
Indicators used to assess and monitor visual amenity are summarised in the table.
Visual amenity |
Indicator |
Numerical criteria (trigger values) |
Visual clarity and colour |
Natural visual clarity should not be reduced by more than 20%.
Natural
hue of the water should not be changed by more than 10 points on the Munsell Scale.
The natural reflectance of the water should not be changed by more than 50%.
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Surface films and debris |
Oils and petrochemicals should not be noticeable as a visible film on the
water, nor should they be detectable by odour. Waters should be free from floating
debris and litter. |
Nuisance organisms |
Macrophytes, phytoplankton scums, filamentous algal mats, blue-green
algae, sewage fungus and leeches should not be present in unsightly amounts. |
Supporting information
- Visual amenity will be improved by protecting aquatic ecosystems and improving
stormwater management.
- Visual amenity also needs to be protected to maintain water quality for primary and
secondary contact recreation.
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Secondary contact recreation
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Maintaining or improving water quality for activities such as boating
and wading, where there is a low probability of water being swallowed |
Where the objective applies
- This objective applies to all waters but may not be achievable for some time in some
areas.
- Secondary contact recreation applies in waterways where communities do not require water
quality of a level suited to primary contact recreation, or where primary contact
recreation will be possible only in the future.
Examples of key indicators and their numerical criteria
Indicators used to assess and monitor water for secondary contact recreation are summarised in the
table.
Secondary contact recreation |
Indicator |
Numerical criteria (trigger values) |
Faecal coliforms |
Median bacterial content in fresh and marine waters of < 1000 faecal
coliforms per 100 mL, with 4 out of 5 samples
< 4000/100 mL (minimum of 5 samples taken at regular intervals not exceeding one
month). |
Enterococci |
Median bacterial content in fresh and marine waters of < 230
enterococci per 100 mL (maximum number in any one sample: 450-700 organisms/100 mL). |
Algae & blue-green algae |
< 15 000 cells/mL |
Nuisance organisms |
Use visual amenity guidelines. Large numbers of midges and aquatic
worms are undesirable. |
Chemical contaminants |
Waters containing chemicals that are either toxic or irritating to the
skin or mucous membranes are unsuitable for recreation. Toxic substances should not
exceed values in tables 5.2.3 and 5.2.4 of the ANZECC 2000 Guidelines. |
Visual clarity and colour |
Use visual amenity guidelines. |
Surface films |
Use visual amenity guidelines. |
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Primary contact recreation
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Maintaining or improving water quality for activities such as swimming
in which there is a high probability of water being swallowed |
Where the objective applies
- This objective applies in the immediate future to waters within and immediately upstream
of recognised recreation sites. For many other waters, this is a long-term objective.
- Secondary contact recreation levels should apply in areas where primary contact
recreation, such as swimming, is unlikely to be achieved in the immediate future, owing to
pollution.
Examples of key indicators and their numerical criteria
Indicators used to assess and monitor water for primary contact recreation are summarised in the
table.
Primary contact recreation |
Indicator |
Numerical criteria (trigger values) |
Turbidity |
A 200 mm diameter black disc should be able to be sighted horizontally
from a distance of more than 1.6 m (approximately 6 NTU). |
Faecal coliforms |
Beachwatch considers waters are unsuitable for swimming if:
- the median faecal coliform density exceeds 150 colony forming units
per 100 millilitres (cfu/100mL) for five samples taken at regular
intervals not exceeding one month, or
- the second highest sample contains equal to or greater than 600 cfu/100mL
(faecal coliforms) for five samples taken at regular intervals not
exceeding one month.
ANZECC 2000 Guidelines recommend:
- Median over bathing season of < 150 faecal coliforms per 100 mL, with
4 out of 5 samples < 600/100 mL (minimum of 5 samples taken at regular intervals not
exceeding one month).
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Enterococci |
Beachwatch considers waters are unsuitable for swimming if:
- the median enterococci density exceeds 35 cfu/100mL for five samples taken at regular
intervals not exceeding one month, or
- the second highest sample contains equal to or greater than 100 cfu/100mL
(enterococci) for five samples taken at regular intervals not
exceeding one month.
ANZECC 2000 Guidelines recommend:
- Median over bathing season of < 35 enterococci per 100 mL (maximum
number in any one sample: 60-100 organisms/100 mL).
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Protozoans |
Pathogenic free-living protozoans should be absent from bodies of fresh
water. (Note, it is not necessary to analyse water for these pathogens
unless temperature is greater than 24 degrees Celsius). |
Algae & blue-green algae |
< 15 000 cells/mL |
Nuisance organisms |
Use visual amenity guidelines.
Large numbers of midges and aquatic
worms are undesirable. |
pH |
5.0-9.0 (see supporting information) |
Temperature |
15°-35°C for prolonged exposure. |
Chemical contaminants |
Waters containing chemicals that are either toxic or irritating to the
skin or mucus membranes are unsuitable for recreation. Toxic substances should not
exceed the concentrations provided in tables 5.2.3 and 5.2.4 of the ANZECC
2000 Guidelines 2000. |
Visual clarity and colour |
Use visual amenity guidelines |
Surface films |
Use visual amenity guidelines |
Supporting information
- Maintain water quality in all areas where water quality levels for swimming are
currently achieved.
- The immediate focus should be on improving swimming water quality at recognised
recreation sites, with an emphasis on meeting targets during the bathing season.
- Over the longer term, water quality will need to improve to meet swimming objectives at
more locations.
- Bacterial water quality tests are used to indicate the possible presence of human
pathogens. DEC considers that the use of faecal coliforms and enterococci as
indicators provides a suitable expression of the disease risks presented by
contaminated bathing waters and allows for international comparisons to be made.
It will, however, monitor closely scientific developments in
this area.
- Achieving water quality levels that are safe for swimming will also result in safer
water quality for non-potable uses in homesteads.
- Note that pH in ambient waterbodies varies naturally across the landscape and with time. The goal should be to retain the natural range of pH.
- The National Health and Medical Research Council released new guidelines for recreational water quality in 2005. However, these have not yet been adopted for use in NSW. Contact Beachwatch or NSW Health public health units for current information on recommended guidelines.
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Livestock water supply
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Protecting water quality to maximise the production of healthy
livestock |
Where the objective applies
- This objective applies to all surface and groundwaters used to water stock.
Examples of key indicators and their numerical criteria
Indicators used to assess and monitor water for livestock water supply are summarised in the
table.
Livestock water supply |
Indicator |
Numerical criteria (trigger values) |
Algae & blue-green algae |
An increasing risk to livestock health is likely when cell
counts of microcystins exceed 11 500 cells/mL and/or
concentrations of microcystins exceed 2.3 µg/L expressed as
microcystin-LR toxicity equivalents. |
Salinity (electrical conductivity) |
Recommended concentrations of total dissolved solids in
drinking water for livestock are given in table 4.3.1 (ANZECC 2000
Guidelines). |
Thermotolerant coliforms (faecal coliforms) |
Drinking water for livestock should contain less than 100
thermotolerant coliforms per 100 mL (median value). |
Chemical contaminants |
Refer to Table 4.3.2 (ANZECC 2000 Guidelines) for heavy
metals and metalloids in livestock drinking water.
Refer to Australian Drinking Water Guidelines (NHMRC and NRMMC 2004) for information regarding pesticides and other organic contaminants, using criteria for raw drinking water.
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Supporting information
- Poor water quality can limit livestock productivity.
- This objective is generally attainable if aquatic ecosystems are protected.
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Irrigation water supply
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Protecting the quality of waters applied to crops and pasture |
Where the objective applies
- This objective applies to all current and potential areas of irrigated crops, both
small- and large-scale.
- Local requirements for irrigation water quality, such as salinity, apply.
Examples of key indicators and their numerical criteria
Indicators used to assess and monitor water for irrigation water supply are summarised in the
table.
Irrigation water supply |
Indicator |
Numerical criteria (trigger values) |
Algae & blue-green algae |
Should not be visible. No more than low algal levels are desired to
protect irrigation equipment. |
Salinity (electrical conductivity) |
To assess the salinity and sodicity of water for irrigation
use, a number of interactive factors must be considered including
irrigation water quality, soil properties, plant salt tolerance, climate,
landscape and water and soil management. For more information, refer to
Chapter 4.2.4 of ANZECC 2000 Guidelines. |
Thermotolerant coliforms (faecal coliforms) |
Trigger values for thermotolerant coliforms in irrigation
water used for food and non-food crops are provided in table 4.2.2 of the
ANZECC Guidelines |
Heavy metals and metalloids |
Long term trigger values (LTV) and short-term trigger
values (STV) for heavy metals and metalloids in irrigation water are
presented in table 4.2.10 of the ANZECC 2000 Guidelines. |
Supporting information
- Long-term effects of irrigation with saline water on soils need to be
considered.
- A major consideration for irrigation water supply is the sodium adsorption ratio (SAR),
which indicates the level of excess sodium in the water. If the SAR is high, the water may
have an adverse effect on soil structure, even though the total salinity of
the water may be
low.
- A variety of plant pathogens can be distributed by irrigation water
including nematodes,
fungi, viruses and bacteria. However, in the absence of sufficient data, there are no
guidelines for controlling plant pathogens.
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Homestead water supply
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Protecting water quality for domestic use in homesteads, including
drinking, cooking and bathing |
Where the objective applies
- The objective applies to all homesteads that draw water from surface and groundwaters
for domestic needs, including drinking water.
- The NSW Health Department advises that water for domestic use in homesteads should
comply with the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004) at the point of use, regardless of source.
Examples of key indicators and their numerical criteria
Key indicators for drinking water quality at the point of use in the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004) are set out below. Monitoring should also be considered for health-related parameters of local concern. Communities should refer to the Australian Drinking Water Guidelines (and updates) [www.nhmrc.gov.au/publications/synopses/eh19syn.htm] for information on
additional parameters.
Homestead water supply |
Indicator |
Numerical criteria (trigger values) |
Blue-green algae |
Recommend twice weekly inspections during danger period for storages with history of algal blooms. No guideline values are set for cyanobacteria in drinking water. In water storages, counts of < 1000 algal cells/mL are of no concern. >500 algal cells/mL - increase monitoring.
>2000 algal cells/mL - immediate action indicated; seek expert advice.
>6500 algal cells/mL - seek advice from health authority
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Turbidity |
5 NTU; <1 NTU desirable for effective disinfection; >1 NTU may shield some micro-organisms from disinfection. (see supporting information) |
Total dissolved solids |
< 500 mg/L is regarded as good quality drinking water based on taste. 500-1000
mg/L is acceptable based on taste.
>1000 mg/L may be associated with excessive scaling, corrosion and unsatisfactory
taste. |
Faecal coliforms |
0 faecal coliforms per 100 mL (0/100 mL). If micro-organisms are detected
in water, advice should be sought from the relevant health authority. See also the
Guidelines for Microbiological Quality in relation to Monitoring, Monitoring Frequency and
Assessing Performance in the Australian Drinking Water Guidelines (NHMRC & ARMCANZ 2004). |
pH |
6.5-8.5 (see supporting information) |
Chemical contaminants |
See Guidelines for Inorganic Chemicals in the Australian Drinking
Water Guidelines (NHMRC & NRMMC 2004). |
Supporting information
- For an individual water supply, the emphasis should be on selecting the best quality
source water available, and on protecting its quality by the use of barrier systems and
maintenance programs. Whatever the source (ground, surface or tank water), householders
should assure themselves that the water is safe to drink.
- Information on the quality of surface or groundwater may be available from state and
local governments conducting monitoring programs. If not, individuals should consider
having the water tested for the indicators above and any key health characteristics identified as being of local
concern. Where raw water quality does not meet the requirements of the Australian
Drinking Water Guidelines (NHMRC & NRMMC 2004), a point-of-use device may be needed to treat the water.
- The NSW Private Water Supplies Guidelines provide information regarding monitoring and treatment of private supplies serving the public. These are available from NSW Health.
- In many cases it will not be possible for water at individual homesteads to comply with
the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004) without some form of treatment. Many homesteads traditionally take drinking water untreated from local streams. Even in pristine areas there are health risks associated with this practice. The Government recommends that drinking water, including water for cooking and bathing, is at least disinfected before use.
- Effective communication and education strategies may be needed to ensure that
householders understand that when water is not of a potable quality, precautionary
measures should be taken (e.g. avoiding ingestion, boiling drinking water). Such water may
be of sufficient quality to be used for washing clothes, gardening, toilet-flushing and
other non-potable uses.
- Many homesteads rely on tank water for drinking and cooking. The enHealth Council's Guidance on the Use of Rainwater Tanks (enHealth 2004) is endorsed by the NSW Health Department and provides useful information on the safe operation of rainwater tanks. Information is also available in the NSW Health Rainwater Tanks Brochure (PDF 98KB, from www.health.nsw.gov.au/pubs/r/pdf/rainwater020067.pdf ).
- Turbidity and pH in ambient waters are likely to vary outside the criteria above. Treatment at the point of use is likely to be necessary to achieve criteria above. It is advisable to maintain pH within this range to protect plumbing and fittings from corrosion and scale.
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Drinking water - Disinfection only, or
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Drinking water - Clarification and
disinfection
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Drinking water - Groundwater
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Refers to the quality of drinking water drawn from the raw surface and
groundwater sources before any treatment |
Where the objectives apply
- These objectives apply to all current and future licensed offtake points for town water
supply and to specific sections of rivers that contribute to drinking water storages or
immediately upstream of town water supply offtake points. The objective also applies to
subcatchments or groundwaters used for town water supplies.
Examples of key indicators and their numerical criteria
Key indicators for raw water for drinking water supply that is to undergo coarse screening only are listed below. These indicators are drawn from the National Health and Medical Research Council Australian Drinking Water Guidelines (NHMRC & NRMMC 2004).
Note that a wide range of treatment technologies are available (e.g. coagulation,
flocculation, filtration, ion exchange, reverse osmosis, carbon adsorption columns) that
enable the production of acceptable drinking water from almost any raw water. The ANZECC
2000 Guidelines do not specify criteria for the many types of water quality that
could be involved.
Refer to the NSW Groundwater Protection Policy, (DLWC 1998b) for information on
the management of groundwater quality.
All drinking water should comply with the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004) at the point of use. Refer to the Summary in the Australian
Drinking Water Guidelines.
Drinking water |
Indicator |
Numerical criteria (trigger values) |
Blue-green algae |
Recommend twice weekly inspections during danger period for storages with history of algal blooms.
>500 algal cells/mL - increase monitoring.
< 2000 algal cells/mL - water may be used for potable supply.
>2000 algal cells/mL - immediate action indicated; seek expert advice.
>6500 algal cells/mL - seek advice from health authority.
>15 000 algal cells/mL - may not be used for potable supply except with full water treatment, which incorporates filtration and activated carbon.
Source: Australian Drinking Water Guidelines (NHMRC & NRMMC 2004).
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Turbidity |
Site-specific determinant. |
Salinity (electrical conductivity) |
<1500 µS/cm > 800 µS/cm causes a deterioration in taste. |
Faecal coliforms* |
0 faecal coliforms per 100 mL (0/100 mL) |
Total coliforms* |
95% of samples should be 0 coliforms/ 100 mL throughout the year. Up to
10 coliform organisms may be accepted occasionally in 100 mL.
Coliform organisms should not be detected in 100 mL in any two consecutive samples. |
Dissolved oxygen |
> 6.5 mg/L (> 80% saturation) |
pH |
6.5-8.5 |
Chemical contaminants |
See ANZECC 2000 guidelines, section 6.2.2. |
* Values given are NHMRC criteria for raw waters before disinfection or clarification. Raw waters can have concentrations of faecal coliforms above the NHMRC criteria, even in pristine ecosystems. Slightly greater faecal coliform or total coliform contamination, may therefore be acceptable in raw waters that are to be disinfected before delivery to the consumer. (Faecal coliform criteria used in Victoria have suggested that for raw waters requiring only low-level treatment, natural background levels of 95% of samples should have <10 faecal coliforms/100 mL. For high-level treatment, 95% of samples should have <100 faecal coliforms/100 mL.) For a full discussion of drinking water system management and criteria, see the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004).
Supporting information
- Refer to the summary of guideline values in the Australian Drinking Water Guidelines (section 10.8)
- While the Australian Drinking Water Guidelines 2004 do not recommend a specific raw water quality for treatment, the Framework for Management of Drinking Water Quality has been developed as a preventative risk management approach for the management of water quality from catchment to consumer.
- The Guidelines advocate "barrier systems" involving catchment management, appropriate treatment and monitoring to verify quality.
- The focus is on improving the quality of raw drinking water sources to protect public
health and minimise treatment costs. In some cases, this will require controlling or
removing pollutants from dedicated drinking water subcatchments, from upstream of river
offtakes and from groundwater systems used for drinking water.
- Protection of zones upstream of raw water or reservoir inlets is essential, but may be
feasible only over limited distances. The location and size of offtake zones will need to
be defined based on further local community consultation. Upstream conditions will also
need to be considered (e.g. existing land use, pollutant sources, climatic and river flow
factors).
- The existence of an offtake zone acts as an indication of the need to protect drinking
water at the point of supply and to identify upstream threats to those supplies.
- Some waterbodies used as a raw drinking water source may provide water of high quality
that needs only disinfection before use. These waterbodies should be regarded as having a
high environmental value and should be protected.
- Many town water supplies rely on pumping groundwater from aquifers or river alluvium.
- Water quality tests for faecal coliform bacteria are used as an indicator of the
possible presence of human pathogens. Improved tests are being developed.
- The NSW Health Private Water Supplies Guidelines provide information regarding monitoring and treatment of private supplies serving the public.
- It is advisable to maintain pH within the range above at the point of supply, to protect plumbing and fittings from corrosion and scale.
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Aquatic foods (cooked)
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Refers to protecting water quality so that it is
suitable for the production of aquatic foods for human consumption and
aquaculture activities. (Note: The ANZECC 2000 Guidelines lists this
environmental value as Aquaculture and human consumption of aquatic
foods) |
Where the objective applies
- The objective applies to all waters where aquatic foods are taken for
non-commercial and commercial harvesting.
Examples of key indicators and their numerical criteria
Indicators used to assess and monitor water quality so that it is suitable
for the production of aquatic foods are summarised in
the following table. Other indicators are listed in the ANZECC 2000 Guidelines
and Food Standards Code (ANZFA 1996 and updates available at www.anzfa.gov.au).
Aquatic foods |
Indicator |
Numerical criteria (trigger values) |
Algae & blue-green algae |
No guideline is directly applicable, but toxins present in blue-green
algae may accumulate in other aquatic organisms. |
Faecal coliforms |
Guideline in water for shellfish: The median faecal coliform
concentration should not exceed 14 MPN/100mL; with no more than 10% of the samples
exceeding 43 MPN/100 mL. Standard in edible tissue: Fish destined
for human consumption should not exceed a limit of 2.3 MPN E Coli /g
of flesh with a standard plate count of 100,000 organisms /g. |
Toxicants (as applied to aquaculture
activities) |
Metals:
- Copper: less than 5 µgm/L.
- Mercury: less than 1 µgm/L.
- Zinc: less than 5 µgm/L.
Organochlorines:
- Chlordane: less than 0.004 µgm/L (saltwater
production)
- PCB's: less than 2 µgm/L.
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Physico-chemical indicators (as applied to
aquaculture activities) |
- Suspended solids: less than 40 micrograms per litre (freshwater)
- Temperature: less than 2 degrees Celsius change over one hour.
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Supporting information
- To protect the health of human consumers of aquatic foods (whether derived
from aquaculture, commercial, recreational or indigenous fishing) the ANZECC
2000 Guidelines are intended to be used in conjunction with the Food
Standards Code (ANZFA 1996 and updates available at www.anzfa.gov.au).
- The indicators are to assist managers to minimize the exposure of human
consumers of aquatic food species (eg recreational fishermen) to
bacteria-borne disease. In the case of commercial harvesting and cultured
species the relevant requirements of NSW SafeFoods and the NSW Shellfish
Projects Operations Manual need to be met. Also NSW Health recommends
against the consumption of raw shellfish harvested on a non-commercial
basis. All such shellfish should be thoroughly cooked to kill pathogens and
minimize the risk of food poisoning. Cooking, however, cannot remove the
risk of algae toxins or chemical contaminants.
- There is a need to identify all aquatic food sources to ensure that appropriate
management is in place to protect the human consumer.
- The condition of the waterway must be suitable for both individual species and their
habitats and must protect consumers from chemical contaminants that may accumulate in the
tissues of aquatic foods or from human pathogens. Many waterways in NSW produce aquatic
foods that are suitable for eating after cooking.
- NSW Health should be consulted about issues that have a direct public health impact and
concerns about the safety of aquatic foods should be brought to the attention of local
public health units.
- The potential for members of the public, including those in Aboriginal communities, who
gather shellfish for subsistence or non-commercial purposes to be exposed to pathogens by
eating raw shellfish needs to be considered.
- The potential presence of microbial pathogens (faecal bacteria, viruses, Cryptosporidium),
algal and biotoxins and chemical contaminants needs to be considered when assessing the
risks associated with shellfish consumption. In addition, an understanding
of the catchment and actual and potential pollution sources that may impact
on the water quality is essential.
- Water quality tests for faecal coliform bacteria are used as an indicator of the
possible presence of human pathogens. Improved tests are being developed.
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Industrial water supplies
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The high economic value of water taken from rivers and lakes for use by industry needs recognition in water quality planning and management. It has been identified as an important environmental value through community consultation.
As industry water supply needs are diverse, relevant water quality criteria are not summarised here and the ANZECC 2000 Guidelines do not provide guidance on the water quality needed for various industries. Sources of water used for industry invariably have other environmental values, which mostly need water of a higher quality than that needed by industry. Further, individual industries generally have the capacity to monitor and treat the available water resources to meet their own needs.
This page was published 1 May 2006