Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:8:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 8 (pt 2/5)
Character Range: 1682345–1685695

491 mg/kg. This value was higher than the limit based on direct exposure of soil organisms of 333 mg/kg.

Thus, it is apparent that Pb does not pose a biomagnification risk to terrestrial ecosystems. This finding is consistent with the findings for aquatic ecosystems that Pb does not biomagnify (Eisler 1988; Suedel et al. 1994; Demayo et al. 1982; Vighi 1981; Lu et al. 1975;  Henney et al. 1991) and is the conclusion reached by the EU Pb ecological risk assessment (LDA 2008). Therefore, only direct toxic effects to soil organisms were considered in the derivation of the SQGs.

8.3              Toxicity data
All the available Pb toxicity data was reported with both the total concentration and ambient background concentration, therefore the data could be converted to added concentrations. A total of ninety-six toxicity measures were available for Pb. These were for eight plant species, five species of soil invertebrates and six microbial processes (Table 62). Thus, this met the minimum data requirements recommended by Heemsbergen et al. (2008) to use the BurrliOZ SSD method (Campbell et al. 2000). Table 62 shows the geometric means of toxicity values of each species or soil microbial process that were used to derive the SQGs for Pb. The raw toxicity data used to generate the species geometric means is presented in Appendix G. In the vaxt majority of cases the geometric means of the toxicity data increase from NOEC or EC10 to LOEC or EC30 to EC50 values. However, for F. candida, Raphanus sativa, A. sativa, P. tedea and L. Sativa, the EC50 values were lower than the LOEC and EC30 data. This reflects the fact that the Pb toxicity data was not normalised for soil properties and the toxicity tests were conducted in soils with a variety of physicochemical properties.

In order to maximise the use of the available toxicity data, conversion factors recommended in Schedule B5b to permit the inter-conversion of NOEC, LOEC, EC50, EC30 and EC10 data were used (Table 17).
Table 62. Geometric means of the toxicity of lead (Pb) (expressed in terms of added Pb) to soil invertebrates, plants and soil microbial processes.
Test species         Geometric mean (mg/kg)
Common name          Scientific name                NOEC or EC10  LOEC or EC30  EC50
Invertebrates
Earthworm            Dendrobaena rubida             129           194           387
Earthworm            Eisenia andrei                 -             1500          3410
Earthworm            E. fetida                      761           2026          3829
Earthworm            L. rubellus                    1000          1500          3000
Springtail           F. candida                     1797          3749          1866
Microbial processes
Soil process         ATP                            -             -             3018
Soil process         Denitrification                250           500           750
Soil process         Nitrification                  337           505           1010
Soil process         N-mineralisation               447           1095          1342
Soil process         Respiration                    655           982           1964
Soil process         Substrate induced respiration  1733          2600          5200
Plants
Radish               Raphanus sativus               100           500           300
Oat                  A.