Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:5:p3
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 5 (pt 3/5)
Character Range: 1196589–1199527

uncertainty and also to identify the most sensitive exposure assessment parameters.

This may guide further studies and field activities to reduce the uncertainty.

5.4              Toxicity assessment
As part of the Definitive ERA, it may be useful to review the currency of the toxicity data used in the derivation of the generic EILs.  A detailed review of the literature since the EILs were derived should be conducted to update the toxicological profile of each contaminant of concern and mixtures of the contaminants. If there is additional data then it should have its quality and appropriateness assessed using the data quality assessment method in Schedules B5b and B5c. The acceptable quality data should then be added to the toxicity data used to derive the current EILs and new generic or soil-specific EILs derived using the method in Schedules B5b and B5c.

Alternatively, or in addition, the toxicity of each contaminant of concern and mixtures of the contaminants of concern may be measured directly. Such toxicity testing can be particularly useful where a site is contaminated by numerous contaminants and assessing the impact of the mixture from individual EILs is not straightforward, or where a site is contaminated by chemicals for which EILs do not exist, although in this case appropriately adapted data from similar studies may also be used.

Toxicity tests for a range of soil and terrestrial species have been developed by various regulatory and international agencies, for example, the American Society for Testing and Materials (ASTM), the International Standards Organisation (ISO 1993, 1995), the Organisation of Economic Cooperation and Development (OECD 1984a, 1984b), Environment Canada (EC 2004, 2005) and the United States Environmental Protection Agency (US EPA). Such standardised methods are generally preferred though at some sites it may be more appropriate to use endemic species for which there are no standardised toxicity test methods. The use of such tests is appropriate providing the methods used are based on standardised toxicity tests that have been modified to suit the test species and/or site conditions. The species to be used in site-specific toxicity tests and the experimental design should be based on information provided by the problem identification, receptor identification and exposure assessment components of the Definitive ERA.

Where toxicity testing is undertaken as part of a toxicity assessment, it is crucial that the end points measured are ecologically relevant. This includes tests with end points such as growth and reproduction rather than just biochemical changes that may or may not be adverse. The suitability of such non-standardised tests can be determined using the method in Schedules B5b and B5c, which assesses the quality of terrestrial toxicity data in terms of experimental design, analytical and statistical techniques used, and whether appropriate