Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:7:p3
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 7 (pt 3/4)
Character Range: 1632900–1635824

that predicts the toxicity of a single contaminant to a single species using soil physicochemical properties (for example, soil pH and organic carbon content). Normalisation relationships are used to account for the effect of soil characteristics on toxicity data. Thus, when toxicity data is normalised the effect of soil properties on the toxicity should be removed, so the resulting toxicity data should more closely reflect the inherent sensitivity of the test species.

Eighteen normalisation relationships were reported in the literature for Cu toxicity and an additional two were derived as part of this study (Table 50), giving a total of 20 normalisation relationships. Six were developed for Australian soils (Broos et al. 2007; Warne et al. 2008a; Warne et al. 2008b) and fourteen have been derived for European soils (Oorts et al. 2006a; Rooney et al. 2006; Criel et al. 2008; EC 2008a). Eight of the relationships were for plants, six for soil invertebrates, and six for microbial functions (Table 50).

The choice of normalisation relationships to be used to normalise the toxicity data was based on (1) regional relevance, (2) whether they are based on field- or laboratory-based toxicity data; preference is given to field-based relationships as they provide better estimates of toxicity in the field (Warne et al. 2008b), (3) providing a conservative SQG—normalisation relationships with lower gradients will provide lower normalised toxicity values and thus lower SQGs (EC 2008a), (4) the quality of the relationship as indicated by the coefficient of determination ( r2), and (5) the number of species to which the relationships apply.

Thus, whenever there were appropriate Australian normalisation relationships, these were applied to Australian toxicity data and the same rule applied to European normalisation relationships.

Of the Australian relationships, number 1 was not used as an equivalent field-based relationship for Australian soils was available (relationship 3) and relationship 2 was not used as ultimately it is the amount of harvestable food that is most important when considering crops. The best relationship developed by Broos et al. (2007) for substrate induced nitrification, (SIN) (relationship 4) was based on EC50 and pH. However, to be consistent with all the other normalisation relationships developed, the data was re-analysed using the logarithm of the EC50 data, which resulted in relationship 5, used in this Schedule. Relationship 7 was not used as relationships not explaining at least 60% of the variation are not considered appropriate for normalisation (Warne et al. 2008b). Relationship 3 was used to normalise all the Australian plant toxicity data and relationship 5 was used to normalise all the Australian microbial process toxicity data.

Of the European relationships, 8 rather than 7 was used for barley as it contained fewer parameters and had a marginally