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Executive Summary

This guideline document is the second in a series of documents on contaminated land management to be produced by the Ministry for the Environment. This guideline document has been developed to ensure the consistent selection and application of the environmental guideline values most commonly used in contaminated site assessments in New Zealand. It will be of use to environmental consultants and landowners undertaking contaminated site investigations, and to council staff involved in reviewing contaminated site investigation reports.

The principles and basis for a hierarchy of environmental guideline values as contained in reference documents, including those documents most commonly used by contaminated site practitioners in New Zealand, 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. The hierarchy is:

  1. New Zealand documents that derive risk-based guideline values
  2. rest-of-the-world documents that derive risk-based guideline values
  3. New Zealand documents that derive threshold values
  4. rest-of-the-world documents that derive threshold values.

The Environmental Guideline Value (EGV) database has been developed as a companion to this guideline. It contains the guideline values provided in the reference documents and discussed here, and can be accessed from the Ministry for the Environment’s website.

The database should be used with care as reference documents are revised and superseded by the various regulatory agencies that publish them. However, although these reference documents may change over time, the hierarchy itself will not change.

In all situations users of the guideline document and the EGV database should refer to the reference documents for the derivation and applicability of any guideline value to be used in assessing a contaminated site. Users are also cautioned against using the EGV database simply as a series of look-up tables: it is important to be fully conversant with the derivation of any guideline values that are applied in a contaminated site assessment.

The information presented here does not aim to provide a step-by-step process on how to select a suitable guideline value, or how to apply the criteria in assessing the effects of contamination and contaminants on the environment. The aim is to provide guidance only. There may be circumstances where strict adherence to the document and the guideline values in the EGV database is not appropriate. Using this document to apply guideline values to any site should be made only after considering all of the specific site conditions and circumstances.

Neither this document nor the EGV database is intended to replace the original reference documents. Users of both sources are advised in all situations to refer to these reference documents for the latest derivation and application of the guideline values contained in the documents.

A list of website links and addresses to the reference documents discussed in this guideline document and used in the EGV database is provided at the end of this document.