Health outcomes for Mapua residents near former toxic site

Thursday 7 November 2013

Study of health outcomes for Mapua residents near former toxic site released

A new University of Otago study of health outcomes for residents living near a formerly contaminated site in Mapua, near Nelson, has found no evidence that remediation work led to exposure to levels of dioxins or other toxic chemicals that posed a significant health risk.

Study Principal Investigator Associate Professor David McBride says the study did however strongly suggest that there were significant social health* effects linked to the remediation process.

The former Fruitgrowers Chemical Company site in Mapua had been classified as New Zealand’s ‘most contaminated’ and soil remediation at the site began in 2004 and was completed in 2008.

Previous testing had indicated that dioxins were released into the environment during the remediation work, although an environmental model predicted the associated risk to public health would be low.

The latest study, which compared health outcomes for local Mapua residents with their counterparts in a similar area of Nelson, involved a survey and blood testing of a small number of residents, particularly those closest to the clean-up site.

The researchers analysed blood samples to measure exposures of the residents to dioxins, non-dioxin-like PCBs and organochlorine pesticides (OCPs) compared with a control group in the Nelson suburb of Tahunanui.

No evidence was found of elevated exposures or physical ill-health in Mapua linked to the remediation process, but the survey suggested that it had significant social health effects for those who resided or worked nearby, says Associate Professor McBride.

The results demonstrated that any perceived risks of chemical hazards are multidimensional and extend to psycho-social health and wellbeing, he says.

“One of our key findings was that toxic site remediation can be a contentious process and community involvement should be subject to detailed planning, and consultation should be robust and continuous.”

In the case of those surveyed in Mapua, more than 60 per cent of residents reported not being consulted about the remediation. Issues also arose for those residents who were consulted with doubts expressed about how objective the information provided was.

The study report noted that trust, or its loss, towards the agencies responsible for the remediation process was an issue that was raised by all participants.

“A key ‘take home’ message from this research is that a successful remediation process is essentially one in which the community has faith that the site has been decontaminated, not only because scientific processes have been observed, but also because the community trusts those in charge of the communication and the information they are being given,” he says.

The research represents the first multidisciplinary investigation into health effects induced by exposure to chemicals in New Zealand and involved a physician, a social anthropologist and health geographer, two epidemiologists, a psychologist and a biostatistician.

Researchers shared findings from the study and answered questions at a community meeting in Nelson last night.

*Social health relates to psychosocial processes impacting health.

About the Mapua Epidemiological Study:

Associate Professor David McBride of Otago’s Department of Preventive and Social Medicine led a multidisciplinary team comprising departmental colleague Dr Kirsten Lovelock, the University of Auckland’s Drs Kim Dirks and David Welch and Dr Daniel Shepherd of AUT University. They received a Health Research Council of New Zealand and Ministry of Health partnership research grant to undertake the work.

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