Workshop Report 28

Regulatory use of SSDs in Australia and New Zealand

Michael Warne
DSITIA Science Delivery, Australia

Author: Warne MStJ1, Batley GE2, Braga O3, Chapman JC4, Fox D5, Hickey C6, Stauber JL2, and Van Dam R7.


1.Water Quality and Investigations, Environmental Monitoring and Assessment Science, Science Delivery, Department of Science, Information Technology, Innovation and the Arts, Brisbane, Queensland, Australia.
2.Centre for Environmental Contaminants Research, CSIRO Land and Water, Lucas Heights, NSW, Australia.
3.Department of Sustainability, Environment, Water, Population and Communities, Canberra, Australia.
4.Office of Environment & Heritage, Lidcombe, NSW, Australia.
5.Environmetrics, Melbourne, Victoria, Australia.
6.National Institute of Water and Atmospheric Research (NIWA), Hamilton, New Zealand.
7.Environmental Research Institute of the Supervising Scientist, GPO Box 461, Darwin, NT, Australia.

Australia and New Zealand, along with many other countries, use risk-based approaches to manage and regulate chemicals in the environment. A key component of the risk approach has been the use of species sensitivity distribution (SSD) methods. SSDs are central to the Australian and New Zealand approach to managing the quality of various environmental compartments (water, sediment and soil), of additives to soils (biosolids and mineral fertilisers) and in conducting environmental risk assessments. Australia and New Zealand developed a new SSD method called BurrliOZ (
) that uses the distribution from the Burr Type III family of statistical distributions that best fits the sensitivity data. This method can therefore provide a good fit to many more datasets than can SSD methods that use a single statistical distribution. The Australian and New Zealand Guidelines for Fresh and Marine Water Quality (
) were released in 2000 and are currently undergoing a review. This is examining the framework used to derive the guidelines (called trigger values). Key recommendations arising from the review are: increasing the types and sources of data that can be used; working with industry to permit the use of commercial-in-confidence toxicity data; increasing data requirements; improving the software used to calculate trigger values; increasing the rigour of site-specific trigger values; improving the method for assessing the reliability of the trigger values; providing guidance of measures of toxicity and toxicological endpoints that may, in the near future, be appropriate for trigger value derivation. A new set of sediment quality guidelines and new trigger values for a number of existing metals will be derived. In addition, trigger values for a range of organic chemicals focussing on pesticides, pharmaceuticals and personal care products will be derived. Finally, a weight of evidence approach is being included into the guidelines. These changes will improve the number and quality of the trigger values that can be derived and will increase end-users’ ability to understand and implement the guidelines in a scientifically rigorous manner.

The water quality guidelines are generic - a single value that applies to all waterways. The only exception being the trigger values of some metals that can be modified using hardness algorithms. In contrast, the Australian guidelines for contaminants in contaminated soils and in biosolids, are wherever possible, soil-specific. That is a matrix of guidelines are generated for each contaminant depending on the values of various soil physico-chemical properties known to modify toxicity. This presentation discussed the ways that SSDs are used in Australia and New Zealand and the proposed changes arising from the current review of the Australian and New Zealand water quality guidelines.