Concentrations that occur naturally in a geographic area are considered local background concentrations.
- Surface water
If substances at a site are above the numerical soil or water quality standards and are thought to be local background concentrations, an application to establish a local background concentration can be made to the ministry.
When a local background concentration is established, it effectively replaces the CSR environmental quality standards for the determination of a contaminated site (CSR Section 11(3) or the remediation standard (CSR Section 18).
The applicant must establish a local background concentration prior to applying for:
- Approval in Principle
- Certificate of Compliance
- Determination of Contaminated Site
- Scenario 3 release notice under the site identification process
Applications to establish a local background concentration must be accompanied by a Contaminated Sites Service Application (CSSA) (Online) as described on the Apply for services page.
During site investigation, naturally occurring concentrations of substances may be identified in groundwater in excess of the CSR numerical standards.
If this is suspected, Protocol 9: Establishing Local Background Concentrations in Groundwater (PDF, 400KB) provides options for establishing local background concentrations at a site.
The ministry has developed soil and groundwater databases that may be used at sites where local background concentrations are above the CSR numerical soil or water standards.
Further information on the data and databases themselves can be found on the Background concentrations databases page.
During site investigation, naturally occurring concentrations of substances may be identified in sediment, vapour, or surface water in excess of the CSR numerical standards.
If this is suspected, an application under Protocol 6: Applications with Approved Professional Recommendations and Pre-approvals (PDF, 406KB) can be prepared for ministry review.
The information on this web page does not replace the legislative requirements in the EMA or its regulations and it does not list all provisions for contaminated site services.
If there are differences between this information and the Act, Regulation, or Protocols, the Act, Regulation, and Protocols apply.