Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:6:p3
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 6 (pt 3/5)
Character Range: 1617397–1620235

its ability to volatilise, DDT can be subject to long-distance transport. In fact, a global distillation hypothesis was developed and has widely been accepted as the explanation of the presence of DDT and its metabolites and other persistent organic pollutants in polar ecosystems, which have no nearby industrial point sources or non-point sources. Because of this global transport of DDT, it could be argued that there is an ABC. As the DDT toxicity studies did not provide any estimate of the ABC for DDT either at the sites or in the soils that were used, this could not be accounted for in deriving the limits for DDT. Therefore, a default ABC for DDT of 0 mg/kg was adopted.

6.6.1         Calculation of generic soil quality guidelines for fresh DDT contamination based on no observed effect concentration and 10% effect concentration toxicity data
The situation for DDT was that:
    * it biomagnifies and this needs to be accounted for in deriving the SQG
    * there was sufficient toxicity data to use the BurrliOZ software
    * the data could not be normalised to the Australian reference soil as there were no normalisation relationships available for DDT
    * the toxicity data could not be expressed in terms of added concentrations
    * an ABC of 0 was used.
Therefore, a single value was generated by BurrliOZ (Campbell et al. 2000) for each of the three land uses. The output was the SQG(NOEC & EC10) for each particular land use and no soil-specific SQGs could be calculated. As DDT biomagnifies, the SQGs must take this into account. The methodology for deriving SQGs (Schedule B5b) for biomagnifying contaminants is to increase the level of protection (% of species to be protected) by 5% for soils for urban residential/public open space and commercial/industrial land uses to 85% and 65% of species respectively. For areas of ecological significance land uses no increase in the level of protection is recommended (Schedule B5b) as the default level (that is, for non-biomagnifying contaminants) is already 99% protective of species. The methodology was adopted and the resulting SQG(NOEC & EC10) values are presented in Table 43.
Table 43. Soil quality guidelines based on no observed effect concentration and 10% effect concentration toxicity data (SQG(NOEC & EC10)) for DDT in freshly contaminated soils with different land uses.
Land use                             SQG(NOEC & EC10)
                                     (mg total DDT/kg soil)
Areas of ecological significance     1a
Urban residential/public open space  70b
Commercial/industrial                250c

a to protect 99% of species, b to protect 85% of species, c to protect 65% of species.
It should be noted that if a site-specific ABC for DDT is determined (and there is sufficient justification for this ABC to be used instead of the default