Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:5:p9
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 5 (pt 9/10)
Character Range: 168639–171498

with individual gardens. Prior to industrial use, the whole site was filled from 0 to 1 m with imported clay/soil fill of uniform characteristics.
Response
The site was assessed by a detailed sampling program based on a well-documented site history and no contamination of concern was found below 2 m. Based on site history, CrVI was included in the sampling and analysis but not detected. Representative samples of site soils were analysed for cation exchange capacity (CEC), clay content and pH to assist with ecological assessment.
For the purposes of illustration, the generalised geometric mean (GM) data shown below is assumed to be sufficient from a statistical basis to describe and evaluate the condition of the site. All relevant contaminants of concern were identified and the original surface stratum has uniform characteristics across the site. Hot spots, if present, would need to be considered separately.
Step 1: Document soil results and select HILs
Depth (m)  Cu     Zn     Ni     CrIII  CEC        pH        % Clay
           mg/kg  mg/kg  mg/kg  mg/kg  (cmol/kg)  pH units  %
01        540    890    660    1100   9          6.0       10
12        170    470    380    400    17         6.5       12
HIL A      6,000  7,400  400    N/A    -          -         -

Note: N/A= not applicable due to the low human toxicity of CrIII.
   Shaded and bold font for sample value indicates HIL exceeded.
Step 2: Tier 1 health risk assessment
    1. Are site values greater than HILs? YES, elevated Ni level requires further health risk assessment.
Step 3: Tier 1 ecological risk assessment
  2.       Determine site EILs (EIL = ABC + ACL) or use the EILs spreadsheet in the ASC NEPM Toolbox.
  3.       Determine the added contaminant limits (ACLs)
   Examination of the site history indicates that the contamination has been present for over 2 years and therefore ACLs for aged contamination are appropriate. To determine site ACLs, refer Table 1B(1) for Zn, Table 1B(2) for Cu and Table 1B(3) for CrIII and Ni. Establish the site ACL for the appropriate land use and with consideration of the soil-specific pH, clay content or CEC as required. Select the nearest ACL value in the CEC table. The ACL for Cu may be determined by pH or CEC and the lower of the determined values should be selected for EIL calculation.

Site ACLs (mg/kg)  Depth (m)  Cu   Zn   Ni   CrIII
01                190        400  170  400
12                210        590  270  400

  4.       Measure the ambient background (ABC) at an appropriate reference location.

    * 01 m clay/soil fill, sampled from filled area at rear of property known to be unaffected by subsequent industrial activity.
    * 12 m, sample of uncontaminated strata from adjacent site.

ABC (mg/kg)  Depth (m)  Cu  Zn   Ni  CrIII
01          4          65  2    7
12          1.5        8