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Background concentration

An estimate of the natural concentration of a substance (element, compound or mixture) that would exist in the absence of any anthropogenic input, usually on a regional, sub-regional or catchment basis. For chemical elements in soils, the background concentration is expected to show some broad-scale variation depending on the nature of the geochemical parent materials.

A site is considered to be above background concentrations when the concentration of a contaminant is clearly higher than its background concentration. In determining this, reference may be made to factors such as the upper confidence limit (95% UCL) of the background concentration, the number of samples collected and their representativeness, observed or expected variability associated with sampling and analysis, and applicable guideline values.

Contaminated land
Defined by section 2 of the Resource Management Act 1991 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
Hazardous substance
Defined by section 2 of the Hazardous Substances and New Organisms Act 1996 as any substance:
a) With one or more of the following intrinsic properties:
i) explosiveness
ii) flammability
iii) a capacity to oxidise
iv) corrosiveness
v) toxicity (including chronic toxicity)
vi) ecotoxicity, with or without bioaccumulation; or
b) Which on contact with air or water (other than air or water where the temperature or pressure has been artificially increased or decreased) generates a substance with any one or more of the properties specified in paragraph (a) of this definition.
Land Information Memorandum (LIM)
A document issued (normally on payment of a fee) by a territorial authority, which gives information on any land within the territorial authority district. The LIM information will include (among other information) any building consents or other authorisations applying to buildings on the land and special features of the land concerned, including potential erosion, subsidence or inundation, or the likely presence of hazardous contaminants (Local Government Official Information and Meetings Act, Section 44A). Anyone may apply for a LIM.
Project Information Memorandum (PIM)
A report issued by a territorial authority prior to the issuing of a building consent. It lists any requirements under any other Acts other than the Building Act. It also includes information likely to be relevant to the proposed building work, such as special features of the land concerned, including potential natural hazards or the likely presence of hazardous contaminants (Building Act 2004).
A physical or electronic database to store site classification information and other information on identifiable parcels of land. Local authorities may refer to their registers by specific names (eg, 'selected land-use register').
The probability that an adverse outcome will occur in a person, a group, or an ecological system that is exposed to a particular dose or concentration of a hazardous substance; ie, it depends on both the level of toxicity of the hazardous substance and the level of exposure (after ANZECC, 1992).
An area of land, as defined by a legal description(s) or part of a legal description.
Site classification
A system for placing sites into categories based on the information that is held by a local authority.
The adverse effects caused by a toxin (poison) that, when introduced into or absorbed by a living organism, destroys life or injures health.