Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:5:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 5 (pt 2/4)
Character Range: 1550112–1553544

SQGs in recently contaminated soils (that is, contamination is <2 years old), an equivalent set of levels was derived for soils where the contamination is aged (that is, it has been present for ≥2 years). The Zn SQG(NOEC & EC10), SQG(LOEC & EC30) and SQG(EC50) for aged sites were calculated using the methods set out in Schedule B5b and this Schedule, the only difference being that laboratory toxicity data based on freshly spiked soils or soils that had not been leached were multiplied by an ageing/leaching factor. A factor (3 for Zn) was developed by Smolders et al. (2009) that accounted for ageing and leaching of various metals. This ageing and leaching factor (ALF) has been incorporated into the methodology to derive the Flemish soil quality guidelines (VLAREBO 2008). Therefore, the raw toxicity data (Appendix A) for Zn that was generated using freshly spiked and non-leached soils was multiplied by this conversion factor and the geometric means for each species and soil process recalculated (Tables 21–23). It should be noted that the values in Tables 21–23 are not simply the data from Tables 2–4 multiplied by 3, as the correction factor was not applied to all the data (for example, data from the field-based NBRP was not adjusted).

3.7.2         Calculation of soil quality guidelines for aged zinc contamination based on no observed effect concentration and 10% effect concentration toxicity data

3.7.2.1         Calculation of added contaminant limits for aged zinc contamination based on no observed effect concentration and 10% effect concentration toxicity data
The lowest geometric mean of the age-corrected toxicity data for each species/soil microbial process that was used to derive the aged ACL(NOEC & EC10) values is presented in Table 21 for soil processes, Table 22 for soil invertebrate species and Table 23 for plant species. The conversion of the fresh toxicity data to account for ageing/leaching and the resulting toxicity values are presented in Appendix A.

Table 21. The geometric mean values of the aged and age-corrected zinc (Zn) toxicity data (expressed in terms of added Zn) for soil processes.
Soil process           Geometric means (mg/kg added Zn)
                       EC10 or NOEC                      EC30 or LOEC  EC50
Acetate decomposition  561                               841           1681
Amidase                363                               545           1091
Ammonification         295                               443           885
Arylsulphatase         868                               1303          2605
Glucose decomposition  274                               1169          2904
Nitrate reductase      168                               252           504
Nitrification          455                               706           930
Phosphatase            2022                              3033          6066
Respiration            313                               470           940

Table 22. The geometric mean values of the aged and age-corrected zinc (Zn) toxicity data (expressed in terms of added Zn) for soil invertebrate species.
Invertebrate species  Geometric means (mg/kg added Zn)
Common name           Scientific name                   EC10 or NOEC  EC30 or LOEC  EC50
Earthworm             A. caliginosa                     669           823           1172
Earthworm             A. rosea                          1172          1221          1308