Sealing of poisonous sites urged

Contaminated sites could be sealed in the future, after a new report showing that a variety of toxins might have been released into the air and water during the experimental clean-up of the Mapua toxic site.

Parliamentary Commissioner for the Environment Jan Wright on Monday released her long-awaited report on the $12 million remediation of the former Fruitgrowers Chemical Company site.

Dr Wright said that while soil was successfully treated at the site - which had been considered the most contaminated in New Zealand - operations from September 2004 until November 2005 were not well run.

"This may have led to some dioxins and other toxins being discharged during the clean-up process," she stated.

Her report said that if dioxins were emitted into the air, the amount could have been insignificant. However, inadequate monitoring systems meant the monitoring data had little value.

Her in-depth report showed that groundwater and sediment were contaminated by copper added during the treatment process, and the groundwater at the site still has elevated levels of organochlorine pesticides.

"This copper is not toxic to people, but is not good for the estuary," she said.

Dr Wright said a small risk still existed that soil at the site might have some residual mercury contamination. She said further soil sampling needed to be done before building could begin.

The Parliamentary Commissioner for the Environment was asked to investigate the Mapua clean-up in 2006 after residents living near the site and workers said the three-year clean-up had affected their health.

A separate investigation by health authorities and the Department of Labour into the health effects of the clean-up will be released later this year.

Dr Wright said that in hindsight, remediation of the site in the middle of a residential area and next to a sensitive estuary was a "high-risk strategy".

She said lessons could be learned from the lengthy clean-up, which cost twice as much as budgeted and ran months longer than anticipated. "Sealing up contaminated sites, for example, may well be safer for people and better for the environment than trying to clean them up."

Large volumes of a wide range of agricultural chemicals were manufactured and stored at the Mapua site over several decades. The clean-up started in September 2004 and was completed last year.

The report makes several recommendations for public agencies to implement to improve the management of other contaminated sites.

Among them is a recommendation that the Minister for the Environment establish a way of appointing a pool of independent, technically expert environmental auditors to help with the management and remediation of contaminated land, and develop guidelines for when an accredited auditor might be needed.

Dr Wright said public agencies such as the Environment Ministry needed to respect technical expertise and have their own technical experts if they were to take on operational projects like the Mapua clean-up.

The commissioner will issue a second report on the Mapua site later this year once final clean-up data is available from the Environment Ministry.

Copies of the report are available on www.pce.govt.nz.

KEY POINTS
Clean-up planned to take 18 months but took three years.

Initial budget $6.5 million. Actual cost about $12 million.

People may have been exposed to a range of toxins and dioxins as well as mercury compounds, especially between September 2004 and November 2005.

Ground water and estuary sediment have been contaminated by copper used in the treatment process.

Resource consent conditions flawed.

A number of potential breaches of resource consent conditions found.

The Tasman District Council could have enforced resource conditions more strongly.

Groundwater monitoring shows contaminants including DDT, lindane, nitrate and ammoniacal nitrogen exceeding consent levels.

Contaminants in water discharged into Waimea Inlet and nearby wells potentially affected the estuary, water quality and human health.

The Environment Ministry took no effective action to reduce contaminant discharges in ground water or find their source, despite requests from the TDC and advice from the site auditor.