Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:2:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 2 (pt 1/3)
Character Range: 1332679–1335740

2                                              50
<5 species                                     3                                       10
Field data/data of model ecosystems                                                    10

      N/A = not applicable

2.4.8         Accounting for secondary poisoning and biomagnification
Secondary poisoning can occur if contaminants accumulate from the ambient environment (for example, soil) into the tissue of organisms (bioaccumulation) that are then consumed by other organisms and the concentration in tissue increases in the journey up the food chain (for example, soil, earthworms, birds and predatory birds). In such a situation, the species at most risk are the species higher in the food web (the predators). Examples of contaminants that biomagnify and have shown adverse effects on predators include DDT, cadmium and PCBs (Morrissey et al. 2005; Jongbloed et al. 1996; Luoma & Rainbow 2008). Biomagnification and secondary poisoning should only be addressed for contaminants that show biomagnification potential.

Secondary poisoning should be addressed for residential EILs. Residential areas cover a large area and can harbour many birds and small land species that can potentially be at risk from contaminants that biomagnify. For site-specific risk assessment, secondary poisoning EILs may not be relevant for contaminated sites of limited area.

The vast majority of ecotoxicological data is derived from direct exposure from the ambient environment and not from food. Thus, if a contaminant biomagnifies, then normal toxicity data and EILs derived using such data may underestimate the impact the contaminant has on the environment and communities. Therefore, a more protective measure is needed for biomagnifying contaminants.

If an SSD approach were used to derive the EIL for contaminants that biomagnify, the level of protection (that is, percentage of species and/or soil processes to be protected) should be increased by 5%, i.e. to 85% (or to 90% if <8 taxonomic species or functional processes are used). This approach is consistent with that used in the Australian and New Zealand WQGs (ANZECC & ARMCANZ 2000) to deal with secondary poisoning.

If the EIL were derived using the AF approach, then a BMF will have to be applied in order for the EIL to account for biomagnification.

The ACL for biomagnification will be calculated by:
     (equation 6)
If there is sufficient BMF data available for an organic contaminant, then the 80th percentile of these values should be used in equation 6 above. For those organic contaminants that have no BMF values, BMF values for organic contaminants with similar chemical structures should be collated and then a specific percentile value could be adopted. The percentile of BMF values to be used is set at 80%.

For inorganic contaminants, grouping of BMF values is not recommended and biomagnification should be dealt with on an individual chemical basis.

For organic contaminants, the BMF values depend on the Kow of the contaminant and increase