Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:20:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 20 (pt 1/14)
Character Range: 1296790–1299812

20        Were the incubation conditions and duration stated?                                                                                                                     3, 1 or 0
          Total score
          Total possible score for the various types of data and contaminants: 102
          Quality score (%) (Total score /102 * 100)
          Quality class (H ≥80%, A 51%–79%, U ≤ 50%)a

a H = high quality, A = acceptable quality and U = unacceptable quality.

Each experimentally derived toxicity datum should have its quality assessed by the data quality assessment scheme (Table 7), which asks 20 questions, with marks awarded depending on the answer to the questions. The quality score for each datum is determined by expressing the total score obtained as a percentage of the maximum possible score. The toxicity data is then classified into three classes depending on the quality score. Data with a quality score ≤50%, between 51% and 79% and ≥80% were classed as unacceptable (U), acceptable (A), and high (H) quality respectively. Only acceptable and high quality data should be used to derive EILs.

Only toxicity data expressed as either added or total soil concentrations should be used to derive EILs. There is considerable evidence both from overseas (Smolders et al. 2003; Smolders et al. 2004; Oorts et al. 2006; Zhao et al. 2006) and within Australia (Broos et al. 2007; Warne et al. 2008b) that chemical extract concentrations; for example, calcium chloride, ammonium nitrate and soil solution extracts, are not necessarily better measures of bioavailability than total concentrations for inorganic contaminants where contamination occurred in soluble forms. Furthermore, there is also considerably more toxicity data expressed as total metal concentration, and there is regulatory acceptance and understanding of this concentration measure.

2.4.2         Standardisation of the toxicity data
By this point in the methodology, the available toxicity data has been collated or models used to derive estimates and the data has been assessed for its appropriateness and quality. The obtained data requires standardisation in terms of four factors:
    1. measures of toxicity
    2. the toxicity expressed in terms of added concentrations
    3. duration of exposure
    4. use of toxicity data for endemic or overseas species.
Please note that this is not the normalisation step that accounts for the effect that soil characteristics have on toxicity values.

2.4.2.1         Measures of toxicity
There are many different measures of toxicity. The most frequently used toxicity measures to derive EQGs are NOECs and EC/LC50-type data. However, not all studies report these particular measures of toxicity; for example, the toxicity may be reported as an EC25 or an LC40. Therefore, in order to maximise the data available to derive EILs, it may be necessary to estimate the reported toxic effect.

A number of studies (Moore & Caux 1997; US EPA 1991; Hoekstra &Van Ewijk 1993) have shown that