Blood testing for lead contamination in the Otago towns Karitane and Waikouaiti. Photo: RNZ/Dom Thomas

Almost two months after residents in villages north of Dunedin discovered their drinking water was contaminated with unsafe levels of lead, the advice not to use tap water is still in place. Dr Francisco Barraza asks if we will ever be able to trust in the drinking water there again.

Since the ‘do not drink tap water’ notification was issued on February 2, 2021 in Waikouaiti, Karitane and Hawkesbury, serious concerns arose in these communities about possible health risks, particularly to children and those with compromised health.

After the first public meeting organised by the Dunedin City Council (DCC) on February 5, health concerns increased due to the limited information available. For me, as both an affected local resident and someone with expertise in the areas of health and environmental issues, I was struck by how the community’s response changed from the perception of a possible problem to the recognition of a potential serious risk. During that meeting, I remembered the words of my epidemiology professor who had repeatedly reminded us, as students, to carefully prepare what we wanted to say to people in situations such as these to avoid scaring them.

It was also a sobering time personally to realise that you and your family might have been exposed to a harmful pollutant in a fundamental resource as drinking water.

After the darkness comes the light. We recently had a second public meeting organised by the council showing good results from the blood tests and that plenty of work had been undertaken to mitigate possible lead contamination.

In my opinion, Waikouatiti, Karitane and Hawkesbury communities felt a sense of relief after learning there was not a major health problem in the community due to high levels of lead in the drinking water supplied by the council.

Contrary to the first meeting, the communities passed from a perception of living in a toxic place to one in which they had been exposed to a few episodes of contaminated water without a demonstrable health consequence.

It was also good news to learn the council is close to starting a major upgrade of local water treatment. This upgrade will improve drinking water quality, and it will rectify the bad taste of the water, a concern that has existed in the community for years.

Is this the end of the story? The answer is, no.

Not all the questions have been answered, for example:

– What was the source of pollution? DCC staff are working to answer this question. They have hired external experts to assess this problem and try to identify if the contamination came from a single or multiple sources and if it was natural or produced by human activity/behaviours.

– How will they control future contamination episodes? The DCC is still working to measure toxic components in the drinking water already supplied. That means people might be exposed again if a yet-to-be-identified pollution source releases harmful lead levels in the water. In the last meeting, it was mentioned that the purchase and installation of a new monitor would control the input of water from the river.

– Finally, the most important question not yet answered is when can people drink/use water from their taps?

The last question, which is linked to questions of trust in the water supplied, reveals the largest challenge to the Council and to all the professionals working to fix this problem. As an informed citizen, in order to trust in the water quality, it is good to find the source of pollution, but it is more fundamental to implement adequate controls of the final drinking water before it is supplied to avoid future exposure to contaminated water.

The second point has yet to be addressed. In this case, the testing methodology currently used by the DCC does not allow us to assess the water quality before it is supplied to or drunk by communities.

In other words, if the DCC had implemented adequate control of the drinking water (before it is supplied and drunk), it would not have been necessary to perform more than a thousand blood tests. Indeed, the DCC would have been able to issue the warning notification before the communities were exposed.

Will the council be able to guarantee the quality of the drinking water before it is supplied? As an environmental and health professional and a resident of one of the affected communities, the answer to this question will determine whether I can trust the water my family, friends, and neighbours will be drinking.

Dr Francisco Barraza is a researcher in environmental health and climate change, in the University of Otago' School of Geography.

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