Past horticultural land use information on LIMs

In 2001, Auckland Regional Council and Auckland District Health Board undertook a research project into the effect on soil of past horticultural activity.

The study aimed to assess the extent of residual contamination in soils from the past activity.

The study involved sampling 43 horticultural and agricultural sites in the Auckland region. Only one site within Auckland City’s boundaries was tested.

The study concluded that historic horticultural activity resulted in comparatively elevated levels of contaminants on approximately 45 per cent of the sites. The remainder of the sites showed acceptable levels.

Auckland City then undertook a desktop study to identify which properties in Auckland city may have been used in the past for horticultural purposes. Aerial photographs of the city, taken in the 1940s and 1950s, were studied.

The desktop study resulted in a list of 1,172 properties (1,155 privately owned properties or owned by other government agencies and 17 owned by Auckland City) that may, in the past, have been used for horticultural purposes.

Auckland City has a responsibility to disclose information it has about a property. The possibility of past horticultural activity is being put onto the land information memorandum (LIM) files of the private properties.

Auckland City will be writing directly to the affected property owners.

The 17 properties owned by Auckland City, all parks and reserves, have been tested. Five properties showed isolated areas of pesticide residue, consistent with regular maintenance activities such as weed control. The residues are evident in areas that are inaccessible to the public or where recreational activity is unlikely.

John Duthie, group manager, City Planning, says: “It is important to remember that all land within an urban environment is likely to have background levels of various substances from past activity on the land. This is an issue for all councils in New Zealand.”

Similar studies have been undertaken in Tasman and Waikato.

There are no known immediate health risks to affected property owners. The Auckland District Health Board advises that it is sensible to follow standard hygiene practices such as washing hands after gardening and cleaning children’s hands and faces after they have been playing outside.

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