Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:2:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 2 (pt 2/3)
Character Range: 1335488–1338416

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 to 10 for organic contaminants having a log Kow of 5–8. For inorganic contaminants, the Kow values of the contaminant should not be used but the literature should be searched for BAF or BMF for terrestrial species, or fish if no terrestrial data is available. If BMF values are not available for an inorganic contaminant or a group of organic chemicals, a conservative biomagnification factor should be used. The biomagnification factors for organic contaminants, from the European technical guidance for risk assessment (ECB 2003), which are shown in Table 14 below, should be used.
Table 14. Default BMF values for organic substances that correspond to the logarithm of the octanolwater coefficients and the BCFs adapted from ECB (2003).
log Kow of contaminant  BCF (fish)   BMF
<4.0                    <2,000       1
4.05                   2,0005,000  2
58                     >5,000       10
>89                    2,0005,000  3
>9                      <2,000       1

2.4.9         Calculation of the ambient background concentrations
To calculate a site-specific EIL, ABCs for soils should be determined, as the ACL is based on added toxicity values. If possible, the ABCs should be directly measured at a clean reference site with a comparable soil type to the site being examined. However, such sites are not always available or easy to identify.

2.4.9.1         Inorganic contaminants
For metal contaminants, if reliable ABCs cannot be measured, then either the estimation method of Hamon et al. (2004) or collations of ABC values such as Olszowy et al. (1995) could be used. The equations for calculating ABC values are presented in Table 15 below. Estimates of ABCs for several metals based on example soil iron or manganese concentrations (determined by aqua regia digestion) are presented in Table 16 below. To use the Hamon et al. (2004) method, it is necessary to ascertain that the iron and manganese concentrations of the soil at the site in question are not elevated by co-contamination—these elements are normally determined in chemical analysis of soils to determine total metal concentrations and therefore minimal extra cost is involved. These Hamon et al. (2004) relationships are based on soils from sites with no known history of contamination apart from farming.

Therefore, this approach would be suitable for predicting the ABC in otherwise uncontaminated areas including new suburbs; that is, suburbs less than 20 years old (Olszowy et al. 1995). In fact, for the inorganic contaminants where comparison is possible, the ABC values predicted by the Hamon et al. (2004) method are very similar to the 25th percentile of the ABC values for