5.3 Contaminated Land*
Background and Explanation
Historical records show hazardous substances that may contaminate soils have probably been used, stored or disposed of at over 3,300 locations throughout the Region. This figure excludes sites that may have been contaminated as a result of the use of production land (e.g. sheep dip sites or elevated levels of pesticides in soils at orchards) and sites where hazardous wastes have been disposed of illegally.
Only 191 of these 3,300 sites have been investigated, and an even smaller number of these have been remediated or actively managed to minimise risk to site users, the community and the wider environment. Specific examples of prominent contaminated sites that have had significant adverse effects within the Region include the:
- Waikato Carbonisation Plant at Rotowaro
- Tui Mine above Te Aroha
- Hamilton Timber Treatment
- Hamilton Gasworks Site.
Contaminated land is not always a large industrial site. Contamination of ground water with petroleum products, mainly from leaking underground fuel storage tanks, is a problem in the United States and Europe and is increasingly being recognised as a threat in New Zealand. A number of underground fuel storage tanks in the Waikato Region have leaked, contaminating soil and both surface and ground water.
Where remediation has occurred1 it has generally been to levels that national or international guidelines identify as being safe for the current or proposed land use or for specified uses of water (e.g. livestock watering purposes but not potable use).
This Chapter focuses on contaminated land, especially those sites that have not yet been investigated or remediated. Chapter 5.2 addresses the risk that future discharges of contaminants onto or into land may contaminate soils.
Functions for the Management of Contaminated Land
Territorial authorities are responsible for controlling land use on contaminated land. This means that Waikato Regional Council must develop objectives, policies and methods for managing both passive and active discharges from contaminated land. Territorial authorities will need to consider, in terms of district plans and building consents, the suitability of some sites for a range of activities given the degree and effects of soil contamination on the site.
Other organisations such as the Ministry of Health (under the Health Act 1956) and the Department of Labour (under the Health and Safety in Employment Act 1992) also have functions that relate to the management of contaminated land. These functions are, however, very limited in their scope.
This Chapter provides clarity as to how Waikato Regional Council will respond to issues associated with discharges from contaminated land. By defining Waikato Regional Council’s response to the issue, other agencies may also be better placed to develop their own responses to the issues.