Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:10:p3
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 10 (pt 3/4)
Character Range: 1749695–1753407

fetida          467           700           1400
Earthworm                    E. Andrei               25.4          79.5          159
Glutamic acid decomposition                          55            400           800
Grass                                                200           500           600
Indian mustard               Brassica juncea         500           750           1100
Lettuce                      L. sativa               500           387           775
Nitrogenase                                          <<50          <<50          <<50
Nitrogen mineralisation                              172           302           626
Nitrogenate formation                                50            200           500
Oat                          A. sativa               339           508           1016
Perennial ryegrass           L. perenne              3333          5000          10000
Radish                       R. sativus              500           387           775
Respiration                                          36.3          114           139
Rye                          Secale cereale          233           350           700
Urease                                               71.2          122           205

In order to maximise the use of the available toxicity data, conversion factors provided in Schedule B5b were used to permit the inter-conversion of NOEC, LOEC, EC50, EC30 and EC10 data. The conversion factors used are presented in Table 17.

10.4          Normalisation relationships
There are only three published normalisation relationships for Cr (III) toxicity (Sivakumar & Subbhuraam 2005). They all relate the toxicity of Cr (III) to survival of E. fetida and are presented in Table 84. These are all based on clay content. The logarithmic form of normalisation relationship 1 was used to normalise the E. fetida and E. andrei toxicity data. This relationship was not applied to the toxicity data of the other species/microbial processes as they do not belong to the same organism type (that is, soft-bodied invertebrate) as the earthworm. This approach is consistent with the method recommended in Schedule B5b and adopted in the various EU ecological risk assessments that have been conducted for metals (EC 2008a; EC 2008b; LDA 2008).
Table 84. Normalisation relationships for the toxicity of trivalent chromium (Cr (III)) to soil invertebrates. The relationship used to normalise the toxicity data is in bold. All equations from Sivakumar & Subbhuraam (2005).
Species/soil process                                               Y Parameter  X parameter(s)
E. fetida                                                          log EC50     -5.46 clay content + 1905.93
                                                                                (r2 = 0.92)
-5.75 clay content – 10.62 pH + 1980.46 (r2 = 0.92)
-3.59 clay content + 4.16 pH + 65.83 soil N + 1748.22 (r2 = 0.95)

10.5          Sensitivity of organisms to trivalent chromium
Figure 10 shows the SSD (that is, the cumulative distribution of the geometric means of species sensitivities to Cr (III)) for all species for which Cr (III) toxicity data was available). Due to the limited amount of Cr (III) toxicity data and the fact that the data was not normalised (and thus soil properties affect the values), it is difficult to draw conclusions regarding the relative sensitivity of plants, invertebrates and soil processes to Cr (III). Given the lack of data and the overlaps in the sensitivity of the organism types, all the Cr (III) toxicity data was used to derive the SQGs.
Figure 10. The SSD (plotted as a cumulative frequency against added trivalent chromium (Cr (III)) concentration) of