Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:8:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 8 (pt 1/2)
Character Range: 1538970–1542067

8   40              110  300  530  810  1500

3.6.3         Calculation of soil quality guidelines for fresh zinc contamination based on lowest observed effect concentration and 30% effect concentration toxicity data, and based on 50% effect concentration toxicity data
In addition to calculating SQG(NOEC & EC10) values, two other sets of SQGs corresponding to two other levels of protection were generated. T hese were the SQG(LOEC & EC30), which indicate concentrations above which moderate toxic effects would occur and the SQG(EC50), which indicate concentrations above which marked toxic effects would occur.

3.6.3.1         Calculation of soil-specific added contaminant limits
The Zn SQG(LOEC and EC30) and SQG(EC50) and associated ACL values were calculated using the methodology, except the input data for the SSD was changed to the appropriate type (Table 1). This data is presented in Tables 24 and the raw data can be found in Appendix A. These measures of toxicity were not available in all instances, so, to maximise the data available to calculate SQG(LOEC and EC30) and SQG(EC50) values, the available toxicity data was converted to these measures using conversion factors. The NBRP (cited in Heemsbergen et al. 2008) derived a set of conversion factors for Cu and Zn (Table 17). These experimentally-based conversion factors were used rather than the generic conversion factors presented in Heemsbergen et al. (2008), which is consistent with the approach recommended in the  methodology for deriving SQGs. Table 18 shows the ACL(LOEC & EC30) and ACL(EC50) values for the Australian reference soil (that is, a pH of 6 and a CEC of 10 cmolc/kg) with areas of ecological significance, urban residential/public open space and commercial/industrial land uses. The set of soil-specific Zn ACL(LOEC & EC30) and ACL(EC50) values for each land use are presented in Tables 19 and 20.

Table 17. Conversion factors used to convert various measures of toxicity for cations such as copper and zinc. The conversion factors were obtained from unpublished data from the Australian National Biosolids Research Program and were cited by Heemsbergen et al. (2008).
Data being converted          Conversion factor
NOEC or EC10 to EC50          x 3
NOEC or EC10 to LOEC or EC30  x 1.5
LOEC or EC30 to EC50          x 2

Table 18. Zinc (Zn) added contaminant levels based on lowest observed effect concentration and 30% effect concentration data (ACL(LOEC & EC30)), and based on 50% effect concentration data (ACL(EC50)) for the Australian reference soil with various land uses.
Land use                             ACL(LOEC& EC30) values  ACL(EC50) values
                                     (mg/kg added Zn)        (mg/kg added Zn)
Areas of ecological significance     40                      80
Urban residential/public open space  160                     290
Commercial/industrial                250                     450

Table 19. Soil-specific added contaminant limits based on lowest observed effect concentration and 30% effect concentration toxicity data (ACL(LOEC & EC30), mg/kg)