Land may be contaminated in a number of ways, but mainly as a result of the manufacture, transport, storage, use or disposal of hazardous substances. Industrial activity is the predominant cause, but commercial, agricultural and residential land uses or activities can also result in contamination. Contamination of an area of land may, in turn, result in contamination of other land, sediment, air, groundwater or surface water, both at the source of contamination and at locations remote from the source through migration of the hazardous substances.
The significance of land contamination (ie, the actual and potential adverse effects or risks it poses) varies according to:
- the concentrations of hazardous substances present, or whether they are present at all
- the scale, history, nature and location of hazardous substances relative to potential receptors (ecosystems, plants, animals, people)
- the presence of an exposure pathway between the hazardous substance and a potential receptor (eg, how a person might come into contact with a hazardous substance). Exposure pathways include direct contact, ingestion, absorption, inhalation or contact with vapours.
Contaminated land is defined in the RMA, as amended in 2005, as land of one of the following kinds:
(a) if there is an applicable national environmental standard on contaminants in soil, the land is more contaminated than the standard allows; or
(b) if there is no applicable national environmental standard on contaminants in soil, the land has a hazardous substance in or on it that:
(i) has significant adverse effects on the environment; or
(ii) is reasonably likely to have significant adverse effects on the environment.
Section 30(1)(ca) of the RMA assigns the following function to regional councils:
... the investigation of land for the purposes of identifying and monitoring contaminated land.
Section 31(1)(b)(iia) of the RMA gives territorial authorities the function of:
... the prevention or mitigation of any adverse effects of the development, subdivision, or use of contaminated land.
Regional councils and territorial authorities have functions for controlling the use of land for the purposes of prevention or mitigation of any adverse effects of the storage, use, disposal or transportation of hazardous substances. Local authorities may also gain information about potentially contaminating activities through their responsibilities under the Hazardous Substances and New Organisms Act 1996 and the Health Act 1956. Territorial authorities may hold land contamination information to fulfil their responsibilities under the Building Act 2004 regarding Project Information Memoranda (PIMs) and under the Local Government Official Information and Meetings Act 1987 for Land Information Memoranda (LIMs).
2.1 Information management system components
Any information system used by local authorities to manage land contamination information will consist of three components:
- a physical or electronic database or register ('the register')
- a technical procedure for classifying and registering a site (site classification)
- administrative procedures for information management (information management protocols).
The information management protocols have been further subdivided into recommendations for data transfer and release, and procedures defining good practice for data management and security. The register is described below, and site classification and information management protocols are detailed in chapters 3, 4 and 5.
2.2 The register
The register is that part of a set of physical files or electronic databases that stores site classification information relating to identifiable parcels of land. A site is an area of land, as defined by legal descriptions or part of a legal description. Site investigation refers to the collection of information about that area of land.
Regional councils and territorial authorities both need access to land contamination information to undertake their functions. This guideline recommends a single master register for each region, for greater accuracy and to avoid duplication of effort. We assume that the regional councils will hold master registers, in view of their functions under the RMA. Most regional councils already hold a considerable amount of information within dedicated regional registers. As holders of master registers, regional councils would be responsible for reviewing new information and for determining how sites are classified and described, initially or during reviews.
Nothing in this guideline precludes individual territorial authorities from holding a register for their district or city, with an up-to-date copy being held by the regional council. The important elements of registers are accuracy of data and processes, including information sharing and release, regardless of who administers the register. If a territorial authority and the regional council for a particular region agree that the territorial authority will maintain their own register, the recommended systems set out in this guideline should be modified accordingly. This arrangement will not alter the overall objectives of the guideline.
Additional information about a site may be held on property files and in electronic forms outside the register. This may include other databases used to manage site information, as well as detailed investigations, assessment reports and correspondence. However, until a site is entered onto the register (see chapter 3), such information is not considered to be part of the register, even if it refers to site contamination.
This guideline provides rules and procedures that all regional councils and unitary authorities can adopt, with sufficient flexibility to allow for differences within and between regions in how the recommendations are adopted. A particular database design or kind of software is not prescribed. The approach in this guideline applies irrespective of the actual means of information storage - whether in a sophisticated electronic database or a paper-based system.
If electronic, the register may be shared between local authorities with appropriate authorisations for altering data. A shared register would facilitate access to live, accurate information and lessen the need for requests and transfers of information between local authorities.
2.3 Information management principles
This guideline is based on the following principles for managing information.
- Transparency - the purpose and procedures of site information collection, storage and management are clearly documented.
- Consistency - the procedures described in this guideline are applied in all situations.
- Fairness - site owners are given the opportunity to review, and object to or correct, information about to be placed on, or already held on, the register.
- Quality - information will be verified in a timely manner.
- Security - access to the register to view, add, alter or release information will only be given to authorised local authority officers.
- Accountability - an audit trail will be kept of additions and changes to the register, information sharing with territorial authorities, and releases to other parties.
These principles are very important, because the entry of a particular site on a register may materially affect the ability of the owner to use or sell the property. Incorrect information may expose a local authority, or other parties, to legal liability.