Guidance is provided here on some details of the amended NEPM.
About the NEPM amendment
The Standing Council on Environment and Water (SCEW) amended the National Environment Protection (Assessment of Site Contamination) Measure 1999 (the NEPM) on 16 May 2013.
The health investigation levels (HILs) for 2,4,5-T and 2,4-D are derived in Schedule B7, Appendix A4 of the NEPM with full details of the toxicological review. You can also see them in the summary calculation table in Appendix C. The units have always been reported as mg/kg for both these substances.
The health screening levels (HSLs) in the NEPM trigger the duty to notify the EPA of site contamination under section 60 of the Contaminated Land Management Act 1997 if levels of selected petroleum hydrocarbons meet or exceed the HSLs along with the other criteria required under section 60(3).
The NSW EPA considers it is appropriate to apply HSL land-use category D (commercial/industrial) to assess potential vapour intrusion for multi-storey buildings with residential uses at ground level and where a car park exists in a basement, subject to the HSL application restrictions detailed in the NEPM and in Technical Report No. 10 - Health screening levels for petroleum hydrocarbons in soil and groundwater published by the CRC for Contamination Assessment and Remediation of the Environment (E Friebel and P Nadebaum 2011).
The ecological Investigation levels (EILs) and ecological screening levels (ESLs) are still ‘single point’ criteria, However, although not explicitly stated, the information provided in Schedule B1 intends to allow for statistics to be applied to both human health and ecological criteria. The statistics are calculated for a relevant ‘area’ based on the conceptual site model, taking into account the receptors present.
Further guidance about ecological assessment is provided in Section 3.4.2 of Schedule B1.
Correct ecological screening level for benzo[a]pyrene (BaP) and xylene
The correct ESL is 1.4 mg/kg for BaP in both coarse and fine soil. There was an error in the review paper, which has been corrected.
The correct ESL for xylene is in Table 1B(6) of Schedule B1. The author’s explanatory papers are in the NEPM toolbox.
No. While the NEPM only provides EILs for a limited number of analytes, it also provides the methodology to develop EILs for other analytes, such as those for which phytoxicity-based investigation levels have been included in the site auditor guidelines.
Spreadsheets and database of calculated ecological investigation levels
Spreadsheets for calculating EILs are available in the NEPM toolbox.
There is not a database of calculated EILs, but you can use available data as long as it is relevant and appropriate references can be found.
A distinction should be made between
- uncontaminated natural materials from a known local source such as clay and sand used for levelling or landscaping purposes (‘clean fill’), and
- heterogeneous fill of unknown origin
While an ambient background concentration (ABC) could be calculated through sampling and analysis for clean fill of known origin and date of emplacement, it is not appropriate to calculate or derive an ABC for other types of fill.
Fresh and aged lead
The EIL spreadsheet in the NEPM toolbox presents the added contaminant limits (ACLs) for fresh and aged lead as ‘generic EILs’ without the option to estimate the ambient background concentration. This is a flaw in the spreadsheet. The lead EIL can be calculated as per the procedure in Schedule B1, Section 2.5.10 (EIL = ABC + ACL) or refer to Schedule B5c which contains several sample calculations for lead.
Note that there is also an error in Schedule B5c, Section 126.96.36.199. The worked Example 1 (SQG based on LOEC and EC30) shows the ABC for lead as 150 mg/kg for an old suburb with low traffic volume in South Australia. This should read 30 mg/kg and is displayed correctly as such in Table 67 on page 76.
Added contaminated limit for copper
Organic carbon data is not needed to determine the ACL for copper. only pH and cation exchange capacity (CEC) are required. Refer to Appendix F in Schedule B5c for a more detailed explanation.
The groundwater investigation levels (GILs) in the NEPM refer to Guidelines for managing risks in recreational waters 2008. There is currently no intention to approve these guidelines under section 105 of the CLM Act. However, it is expected that site auditors and consultants will use the most recent version of guidelines in their contaminated sites work.
Toluene in groundwater
Does the criterion for toluene of 300 ug/L in the Guidelines for assessing service station sites (EPA 1994) still apply?
The NEPM does not present a GIL for toluene for fresh and marine waters, but it does include a GIL for drinking water. The NEPM notes that additional GILs applicable to industrial, agricultural and recreational uses are provided in other documents as referenced in Table 5 of Schedule B1. The NEPM does not present a groundwater HSL for vapour intrusion because it is not limiting.
The Australian water quality guidelines 2000 include low reliability trigger values for toluene. These guidelines are approved by the EPA under section 105 of the CLM Act. You can consider whether they are appropriate for application to a site, for example, is 95% protection level appropriate?).
The management limits for petroleum hydrocarbons are applied after considering relevant ESLs and HSLs.
Guidelines for the NSW site auditor scheme (2nd edition) state the most sensitive use on a mixed-use site should be considered. The NEPM provides a more pragmatic approach consistent with land use changes on a site. The revised site auditor guidelines will adopt the approach suggested in the NEPM.
In general, the presence of asbestos does not mean a site must notified to the EPA under section 60 the CLM Act. Sites may be regulated under the CLM Act where the EPA determines that there is ‘significant contamination’ of land, such as where the scale and nature of the contamination is giving rise to actual or potential harm to human health or the environment. This could occur where there are elevated levels of asbestos fibres in air and the responsible party is not addressing the source of the risk.
The missing table of recommendations for PCBs was inadvertently omitted from the final version of the NEPM but has been included in the errata list that is now available.
An appropriate reference to the amended NEPM would be National Environment Protection (Assessment of Site Contamination) Measure 1999 (April 2013), NEPC 2013, Canberra.
An example of how to distinguish between the original and amended NEPM in a report could be to reference the amended measure as ‘National Environment Protection (Assessment of Site Contamination) Measure 1999 (April 2013)’ and the original as ‘National Environment Protection (Assessment of Site Contamination) Measure 1999 (1999)’.