Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:8:p4
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 8 (pt 4/5)
Character Range: 1688265–1691145

are no useful normalisation relationships available for Pb, so the toxicity data was not normalised to the Australian reference soil, nor were soil-specific SQGs derived.

8.5              Sensitivity of organisms to lead
The SSD for the Pb NOEC toxicity data is presented in Figure 8. There was only toxicity data for 19 different species/microbial processes and the available data has not been normalised; therefore, the distribution reflects the variability in sensitivity of the organisms and the effect of soil properties. There was insufficient data to make a robust assessment of the relative sensitivity of the groups of organisms. However, the distributions of all three types of organisms overlap, so it was considered appropriate to use all the toxicity data to derive the SQGs.
Figure 8. The species sensitivity distribution of fresh lead (Pb) contamination (plotted as a cumulative frequency of the Pb NOEC toxicity data against soil Pb concentration) for soil invertebrates, plants and microbial processes.

8.6              Calculation of soil quality guidelines for fresh lead contamination
There was NOEC and EC10, LOEC and EC30, and EC50 Pb toxicity data so ACLs and SQGs could be derived using each of these datasets. These were generated using the same general methods as for Cu.

8.6.1         Calculation of soil quality guidelines for fresh lead contamination based on NOEC and 10% effect concentration toxicity data

8.6.1.1         Calculation of soil-specific added contaminant limits
There were no normalisation relationships available for Pb and therefore the NOEC and EC10 toxicity data was not normalised, nor could soil-specific ACL values be derived. The single numerical output from the SSD analysis for each land use became the generic (not soil-specific) ACL for that land use and these are presented in Table 63.

Table 63. Generic ACL (mg/kg) values based on NOEC and 10% effect concentration toxicity data (EC10) for fresh lead (Pb) contamination in soil with various land uses.
Land use                             ACL(NOEC & EC10) (mg/kg)
Areas of ecological significance     40
Urban residential/public open space  130
Commercial/industrial                220

8.6.1.2         Calculation of ambient background concentration values
For sites with no history of contamination, the method of Hamon et al. (2004) is recommended to estimate the ABC. The equation to predict the Pb ABC is

log Pb conc (mg/kg) = 1.039 log Fe content (%) + 0.118    (equation 9)

Examples of the ABC values predicted by this equation are presented in Table 64. Predicted ABC values for Pb range from approximately 0.1 to 30 mg/kg in soils with iron concentrations between 0.1 and 20%.
Table 64. Lead (Pb) ABCs predicted using the method of Hamon et al. (2004) (see equation 9 above).
Fe content (%)  Predicted ABC (mg/kg)
0.1             0.1
0.5             0.6