Site-specific guidelines and Body-burden responses
The new risk-based water quality guidelines published jointly by the
Australian and New Zealand Environment and Conservation Council (ANZECC)
and the Agricultural and Resource Management Council of Australia and
New Zealand. The ANZECC (2000) guidelines differ from the earlier
(ANZECC 1992) guidelines in the method for derivation of numeric
criteria and in provision for use of a range of management approaches.
Implementation of the new guidelines presents challenges in relation to
the Resource Management Act (RMA) 1991 and Hazardous Substances and New
Organisms (HSNO) Act 1996.
One of the key features of the new guidelines is the provision of a
framework where users can refine the guidelines to suit their local
environment, i.e., develop site-specific guidelines. This marks a
significant move away from the 1992 guidelines where a single number was
advocated across not only different ecosystems, but also the huge
diversity of landscapes found in Australia and New Zealand.
The main purpose of the guidelines is "to provide an authoritative
guide for setting water quality objectives required to sustain current,
or likely future, environmental values (uses) for natural and
semi-natural water resources in Australia and New Zealand". The
guidelines are not mandatory standards; however, they should become an
authoritative reference for water quality management, especially for
The focus is on the issues.
The new guidelines recommend you choose an issue (e.g., toxicity) and
then work out the environmental processes that contribute to it, rather
than focusing on a single indicator (e.g., copper). Once this has been
done, you can decide which water quality indicators to use and what
guidelines to follow. The guidelines have been divided up into different
issues with 'packages' of indicators related to each issue. Some
examples of guideline packages include: effects due to toxicants in
sediments; effects due to temperature changes; and effects due to pH
There are more ecosystems.
Rather than lumping aquatic ecosystems into freshwater and marine,
the new guidelines now recommend up to six ecosystem types: upland
rivers and streams, lowland rivers, freshwater lakes and reservoirs,
wetlands, estuaries, and coastal and marine. These categories will
probably be refined even further as more information comes to hand.
Three types of ecosystem conditions are also now recognised, each with
its own level of protection: high conservation/ecological value systems;
slightly to moderately disturbed systems; and highly disturbed systems.
The guidelines can be applied to local conditions.
Unfortunately it is not possible to have a universal set of specific
guidelines that will apply equally to all the different ecosystems in
New Zealand and Australia. The ANZECC has, however, developed a series
of risk-based decision frameworks where we will be able to refine the
guidelines to suit local environmental conditions, i.e., make the
guidelines site-specific. These frameworks are based on guideline
'trigger values' which are concentrations of a chemical or nutrient that
have the potential to cause a problem if exceeded, and so trigger a
management response. If the level of a particular chemical or nutrient
does not meet the water quality guidelines (i.e., exceeds the trigger
values), one has the option of getting more information to determine
whether the trigger values are suitable or whether they need to be
changed. It may be more time consuming refining the guideline trigger
values, but one may also produce more realistic management guideline
How do trigger values translate to the RMA?
Trigger values for chemical stressors are provided for differing levels
of nominal aquatic community protection (e.g., 99%, 95%, 75%). Guidance
has been provided (Hickey & Pyle 2001) in interpreting the trigger
value thresholds relative to the RMA narrative guidelines. The trigger
values for 99% protection relate to the narrative "no adverse
effects" and would apply to protection of pristine areas, with a
95% value applying to a "no significant adverse effect"
guideline. Further discussion is provided in that publication relating
to the situations applicable to implementation of trigger values for
lower protection levels.
What is the relevance to contaminated sites?
Contaminated sites represent a wide range in their potential for
leaching of chemicals to the receiving environment. For this reason,
they frequently require site-specific considerations for management and
implementation of monitoring programmes. For example, contaminant
exposure by aquatic organisms may occur through various routes. These
include continuous release to a riverine environment, resulting in
chronic exposure conditions, or discharge relatively high concentrations
during rainfall events, resulting in acute (short-term) exposures. The
ANZECC guidelines provide trigger values for chronic exposure (but not
acute exposure) and provide guidance on other approaches such as
toxicity testing and biological monitoring.
How do I get more information?
The New Zealand Ministry for the Environment operates a frequently asked
questions section of their web page (www.mfe.govt.nz) relating to the
These guidelines provide an authoritative reference for
water quality management in New Zealand - particularly for toxic
contaminants - and are a big step forward in helping us manage water
A comprehensive document providing guideline values for
toxicants, physical and chemical stressors, etc. Includes guidelines for
sediment quality, agricultural water use, biological indicator methods,
Available in printed form or to download from the MfE web site in
ANZECC. (1992). Australian water quality guidelines for fresh and marine
waters. Australian and New Zealand Environment and Conservation Council,
ANZECC & ARMCANZ. (2000). Australian and New Zealand guidelines for
fresh and marine water quality. October 2000. National Water Quality
Management Strategy Paper No 4, Australian and New Zealand Environment
and Conservation Council & Agriculture and Resource Management
Council of Australia and New Zealand, Canberra, Australia.
Hickey, C.W.; Pyle, E. (2001). Derivation of water quality guideline
values for heavy metals using a risk-based methodology: An approach for
New Zealand. Australian Journal of Ecotoxicology 7: 137-156.