Horticultural soils in North Shore City

Our interactive viewer contains historical aerial photographs that may indicate a horticultural activity once occupied a site. Please read the below information before accepting the conditions of use and accessing the viewer.

Background

North Shore City has a long history of commercial market gardens, orchards and glasshouses which spread north following construction of the harbour bridge.

Intensive horticulture however makes plants more susceptible to attack by numerous pests subsequently chemicals are used to protect crops. Over time this can lead to an accumulation of pesticide residues in surrounding soils.

In 2001, the Auckland Regional Council and the Auckland District Health Board undertook a sampling programme of 43 horticultural sites within the Auckland region. The results of this sampling programme were that pre 1975 horticultural activity resulted in the presence of harmful levels of chemical residues on 69 per cent of horticultural sites.

Following the receipt of this report North Shore City Council initiated a desktop study using old aerial photographs to identify any properties within North Shore City boundaries that may have been used for horticultural purposes prior to 1975.

Following the mapping of historical horticultural sites Council has undertaken testing of land that it administers (such as roads and reserves) that were historical horticultural sites. More than 400 soil samples were tested at council-owned sites across the city. Of the 67 sites previously used for horticultural purposes, only five were found to have elevated levels of horticultural spray chemicals remaining in the soil. ARC-approved remediation work is underway at all these sites, which will ensure there is no risk to public health.

Currently agreed regional guideline levels are being used as the basis for council's approach. It is understood that the Ministry for the Environment is continuing to research the introduction of national guideline levels for contaminants. Should guideline levels change then council's approach may also change if need be.

Information on LIMs

The Local Government and Official Information Act provides for council to annotate (tag) a LIM (Land Information Memorandum) where there is known information that is considered of relevance to the landowner. Given that information held on historical horticultural activities is not specific enough to be shown on selected LIMs the statement on all LIMs generally highlights previous activities and general land-based hazards and reads as follows:

"Attention should be given to land-based hazards including land instability, soil contamination, dumping and previous activities that may be unknown to council that could affect the current or your intended use of the site.

There may be broad scale information related to these land-based hazards that is not specific enough to be shown on this LIM but that may be of interest to you. Should you wish to further satisfy yourself on this matter it is suggested that a search be undertaken of the council's website www.northshorecity.govt.nz regarding information held on previous activities established and/or operating on the site.

It is also recommended that a search be undertaken of the council's property file. Please note that a schedule of fees and charges applies for property file searches. Inquiries can also be made into information held by other organisations such as, but not limited to, the Auckland Regional Council."

This website contains historical aerial photographs that may indicate that a horticultural activity once occupied your site. In order to determine whether chemical residues are actually present the soil on your property would need to be tested.

Public health implications

The Auckland District Health Board has released the attached information sheet providing advice for sites previously used for horticultural purposes to minimise peoples' exposure to contaminants.

Health information for people to minimise exposure to contaminants in soil (PDF 31KB)

Testing the Soil

Owners of private properties will not be required by North Shore City Council to undertake soil testing unless there is further building or development proposed for the site. In these situations we have responsibilities under the Resource Management Act to manage the effects of soil contamination. The assessment of the effect of soil contamination may require the applicant to undertake a soil test.

In that case property owners will need to pay for the soil test and ensure that the testing is correctly undertaken in accordance with the attached Auckland Regional Council soil testing protocol.

Look in the Yellow Pages under ‘Environmental Consultants' for a list of professional organisations that can undertake this soil testing. It is advisable to seek more than one quote.

Site investigation and soil sampling protocol (PDF 117KB)

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