Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:20:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 20 (pt 1/3)
Character Range: 1340291–1343273

20        <18      <165     <40      <56      <29      <62

2.4.9.2         Organic contaminants
Most organic contaminants of interest to contaminated sites are xenobiotics, hence they have no natural background concentration. Notable exceptions to this include lipids and fats, hormones (for example, oestrogen, testosterone), fatty acids, alcohols, hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and dioxins. Therefore, ABCs will have to be generated by direct measurement or a default ABC of zero could be assumed (Crommentuijn et al. 2000b). There are no equivalent models to that of Hamon et al. (2004) available for organic contaminants.

For dioxins, regional ABC values are available (Muller et al. 2004) and could be used or, alternatively, site-specific assessments could be conducted. For other pyrogenic organic contamination (for example, PAHs), a site-specific assessment should be conducted to determine if the measured concentrations are background concentrations for that region. If a site-specific assessment is conducted, then the upper 80th percentile of the ABCs should be used as the background as per the Australian and New Zealand WQGs (ANZECC & ARMCANZ 2000). However, even if they are considered ABCs, this does not imply that there is no risk to terrestrial biota.

2.4.10     Calculation of the EIL
If biomagnification is not considered, then the EIL for a contaminant is calculated as follows:
EIL = ABC + ACL      (equation 7)
where ABC is the ambient background concentration (mg/kg) and ACL is the added contaminant limit (mg/kg).
If biomagnification is considered and is significant for that contaminant, then the EIL is calculated as follows:
EIL = ABC + ACLBM        (equation 8)
where ACLBM is the contaminant added limit that accounts for biomagnification.

2.4.11     The reliability of the EIL
Classifying the EIL based on the amount and type of toxicity data is important to provide users with an indication of the reliability of the EIL values and also for prioritising future re-assessments of EILs. Methods for determining the reliability of TVs were developed and used in the Australian and New Zealand WQGs (ANZECC & ARMCANZ 2000; Warne 2001) and this formed the basis of the soil EIL reliability assessment system. The number of data points, the type of toxicity data, the number of species/soil processes for which there is data, and whether or not there are normalisation relationships are all used to assess the reliability. The three classes of EIL reliability are high, moderate and low. The requirements for an EIL to receive these classifications are provided below.

High reliability:
    * The toxicity database contains sufficient toxicity data for the SSD approach and at least one normalisation relationship (that is, relationships that describe the effects of soil characteristics on toxicity) is available.
Moderate reliability:
    * The toxicity database meets the minimum data requirements for the SSD approach