28 Oct 2020

Auckland Harbour Bridge report into contamination released

3:35 pm on 28 October 2020

A reserve next to the Auckland Harbour Bridge that is at the centre of heavy metal residue concerns has been given the OK by Auckland Council in a just-released health assessment.

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Photo: RNZ / Katie Todd

This follows local residents' concerns they were not told about heavy metal and hydrocarbon contamination discovered there 10 years ago.

The council ordered an independent assessment be done in 2011 for land at the north end of the Auckland Harbour Bridge at Te Onewa Pā-Stokes Point Reserve. But it has not released this till now.

The report says relatively high lead or hydrocarbons were found in a few instances, but not many. It also judged exposure for children and adults by considering the results of tests done for the Transport Agency in 2010-11.

"Evaluation of the risk estimates against those applicable in New Zealand indicates that as a whole, contaminant levels do not pose an unacceptable risk to human health," said the assessment by engineering consultants Tonkin and Taylor.

It helped that the reserve was not used much, and that the council had covered over the soil most contaminated by hydrocarbons.

The area "is safe for the public to use and enjoy", council director of regulatory services Craig Hobbs said in a statement today.

Following the 2011 study, Hobbs said the council recommended the Transport Agency Waka Kotahi do another assessment "before seeking permission to test residential properties".

"Waka Kotahi concluded based on the evidence available that residential properties adjacent to the Auckland Harbour Bridge would have acceptable contaminant concentrations," it said.

No private properties were tested.

The council had no authority to carry out tests on private land or record anything on LIMs if a public health risk was not found, but property owners could get tests done, Hobbs said.

Neither the council, NZTA or Auckland Regional Public Health advised local residents of any of the testing or studies on public land in 2010-12.

The 2011 study did not discuss copper or zinc, as it concluded only lead and the carcinogenic benzo(a)pyrene were potential risks to human health.

Zinc is a threat to plants and marine life.

The source of the lead and hydrocarbons was fill imported to the site years ago, and possibly leaching from an old coal-tar footpath. And to a lesser extent bridge maintenance work by painters, and vehicle emissions, the study said.

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