Soil Contaminant Standards

The NES sets out the methods for setting applicable numerical standards for contaminants in soils that are protective of human health. The NES provides guidance in the form of soil contaminant standards by reference to the “Methodology for Deriving Standards for Contaminants in Soil to Protect Human Health.”  Specific standards are allocated for 12 contaminants, called “priority contaminants”, including including metals such as arsenic and lead, and organic contaminants such as DDT and dioxin.  If the land in question falls within an identified “expose scenario” then these standards apply.  If it does not fall within an “exposure scenario” the applicable “priority contaminant” standard is the most appropriate out of the exposure scenario standard or the standard level derived using the methodology in the above mentioned document.  For non-priority contaminants the NES directs the methodology for practitioners deriving the applicable contaminant standard is be found in an alternate document, the “Contaminated Land Management Guidelines No. 2–Hierarchy and Application in New Zealand of Environmental Guideline Values”. ⁴²⁶⁰

An “exposure scenario” is a combination of an exposure pathways (the way in which exposure occurs such as ingestion, dermal absorption or consumption of vegetables grown in contaminated soil) typical of a particular activity in which exposure to soil is likely to occur. ⁴²⁶¹  In short the five “exposure scenarios” identified identify situations where exposure to contaminated soil is likely as a result of the previous and proposed future use of the land, for example the sue of former agricultural land as a reserve.

External documents are able to be incorporated by reference into an NES.  These can be used to determine and set standards and requirements.  For example, a contaminant standard or a procedural monitoring requirement. Key documents incorporated by reference into the NES contaminated soil regulations are:

Contaminated Land Management Guidelines No. 1 - Reporting on Contaminated Sites in New Zealand (Revised 2011). 

• This guideline includes checklists for reporting requirements for contaminated sites and for the removal of petroleum underground storage tanks, which are available as separate documents.                                           

Contaminated Land Management Guidelines No 2 - Hierarchy and Application in New Zealand of Environmental Guideline Values (Revised 2011).

• This guideline outlines principles and basis for a hierarchy of environmental guideline values as contained in reference documents is described and the hierarchy established. This hierarchy determines the order in which guideline values contained in those reference documents should be used in a contaminated site assessment. It will be of use to environmental consultants and landowners undertaking contaminated site investigations, and to council staff involved in reviewing contaminated site assessment reports.

Contaminated Land Management Guidelines No 5 - Site Investigation and Analysis of Soils (Revised 2011).

• This guideline provides best practice for the sampling and analysis of soils on sites where hazardous substances are present or suspected in soils in New Zealand, and guidance on the principles governing the interpretation of the data obtained.

Guidelines for assessing and managing petroleum hydrocarbon contaminated sites in New Zealand (Revised 2011).

• This guideline provides information on the assessment and management of sites contaminated with petroleum hydrocarbons.

Methodology for Deriving Standards for Contaminants in Soil to Protect Human Health (2011)

• This technical reference outlines a risk-based methodology for deriving soil contaminant concentrations.

Hazardous Activities and Industries List (2011)

• A compilation of activities and industries that are considered likely to cause land contamination resulting from hazardous substance use, storage or disposal.

Last updated at 2:09PM on February 8, 2018