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Clean-up of the Mapua contaminated site

Boundary of Mapua site.
Boundary of Mapua site.

Flourishing grass now covers seaside land at Mapua, near Nelson, which was previously New Zealand’s worst contaminated site – a legacy of decades of pesticide pollution by its former owners, the Fruitgrowers Chemical Company (FCC).

By the middle of 2009, it is hoped the site auditor will have assessed the site as fit for the proposed future recreational, residential and commercial uses by the Mapua community.

The Ministry for the Environment helped fund an investigation of the site – now owned by Tasman District Council (TDC) – and the vast majority of the $12 million clean-up project. Following the withdrawal of the original project manager, the Ministry took responsibility for making sure the project did not stall. It took over the clean-up resource consents, and managed the project from 2004 through to the last soil being cleaned in 2007.

The clean-up posed significant challenges, including the sheer amount of contamination, and the site’s location sandwiched between a residential area and a sensitive marine ecosystem.

Though the clean-up has turned a highly toxic site into a real asset for the Mapua community, the Ministry has been criticised for aspects of its handling of the project. Reports by the Department of Labour and local medical officer of health are pending. The Ministry acknowledges there were hiccups along the way, but these must be expected in contaminated site projects of this scale.

After Clean up
After clean-up
During Clean Up
During clean-up

The Ministry accepts it could have done some things better as it cleaned up the site. A review of the Ministry’s handling of the project by expert Australian environmental consultant Chris Bell has identified valuable lessons for the Ministry, and delivered recommendations for the future of contaminated site clean-ups in New Zealand.

The Ministry is grateful for the ongoing support of the Mapua community, and looks forward to being able to report back in mid-2009 when the independent site auditor has completed their work. This process is underway.

Because of its severity, the legacy of FCC’s pollution will always be present to some degree, and the site will require ongoing management and monitoring. But New Zealand’s worst contaminated site is now unrecognisable from the toxic eyesore it was five years ago.

Background to the project (excerpt from the Bell Report)

FCC opened a pesticide formulation factory at Mapua in 1932.  In 1945 the manufacture of organochlorine pesticides began, and in 1958, organophosphorus formulation was introduced.    By the time the FCC operations closed down in 1988, more than a hundred chemicals had been used and formulated on site.  While this history resulted in a complex and heterogeneous site, it is not unusual for such sites remediated elsewhere in the world. 

During this period, housing was developed on the peninsula south of the site, including on properties on the boundaries of the site.  Commercial properties were developed to the north of the site.

After Clean up
After clean-up

The management of a site with these characteristics, whether by treatment and remediation, or by containment, is inevitably associated with significant but manageable risks.

Tasman District Council is the local authority which has responsibilities under the Resource Management Act.

In the mid-90s, site investigations were conducted, leading to the development of a resource consent application for a containment strategy.  In 1997 a resource consent hearing granted a consent for this purpose.  The Royal Forest and Bird Protection Society appealed this decision, in part on the grounds that containment was not the preferred response.  The government also expressed its view that the preferred strategy was remediation, not containment.  In 1999 the Government decided to assist TDC with funding, research and advice, delivered in part by the Ministry.

After a number of technology assessments, and field trials on the subject soil, TDC awarded the contract to Thiess, using the remediation technology of Environmental Decontamination Ltd in 2001. 

Thiess carried out further site characterisation and investigations, leading to a resource consent application in 2003 for remedial works.  Greenpeace and the Royal Forest and Bird Protection Society appealed the conditions, and the consent was granted with amendments in November 2003.  The amendments included the establishment of a Peer Review Panel to oversee the ‘Proof of Performance’ of the selected remediation technology.

In August 2004, Thiess Services withdrew from the project and the Ministry became the consent holder, assuming responsibility for the project.

The last batch of contaminated soil was treated in July 2007, and in November 2007 the resource consents expired and the site became the responsibility of TDC.

Last updated: 5 January 2009