Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1
Character Range: 1755228–1756799

1          2.5       5             ≥10
NOEC       AES       4             6    7    9
           UR        35            45   60   75
           C/I       65            90   110  140
LOEC       AES       25            30   40   50
           UR        75            100  130  160
           C/I       120           170  210  270
EC50       AES       9             10   15   20
           UR        110           150  190  230
           C/I       220           300  375  470

AES = Areas of ecological significance
UR = urban residential/public open space
C/I = commercial/industrial land uses.

10.6.2     Calculation of ambient background concentration values for fresh trivalent chromium contamination
For sites with no history of Cr (III) contamination, the method of Hamon et al. (2004) is recommended to estimate the Cr ABC. Technically this method predicts total Cr but under aerobic soil conditions the vast majority of Cr will be present as Cr (III). It is therefore appropriate to use the Hamon et al (2004) method to estimate Cr (III) ABC values. The equation to predict the Cr ABC is:

log Cr conc (mg/kg) = 0.75 log Fe content (%) + 1.242            (equation 12)

Examples of the ABC values predicted by this equation are presented in Table 86. Predicted ABC values for Cr (III) range from approximately 3 to 160 mg/kg in soils with iron concentrations between 0.1 and 20%.

Table 86. ABCs for chromium (Cr) predicted using the method of Hamon et al. (2004) (equation 12 above).
Fe content (%)  Predicted Cr ABC (mg/kg)
0.1             3
0.5             10