18 Feb 2021

High levels of lead in children: More analysis of blood required to assess effects - expert

7:50 pm on 18 February 2021

Elevated lead levels in the blood of children is concerning, but more work needs to be done to understand the cause or any potential effects, a professor of toxicology says.

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The presence of elevated levels of lead in children is worrying but people should not panic, an expert says (File image). Photo: 123RF

Blood tests have found unsafe levels of lead in some east Otago residents - including a number of children.

Last night, Southern District Health Board Medical Officer of Health Susan Jack confirmed to RNZ some results have come back above internationally recognised safe levels.

Almost 1400 residents in and around Waikouaiti, Karitane and Hawksbury Village have been tested since traces of lead up to 40 times the acceptable level were found in their water supply.

Canterbury University toxicology professor Ian Shaw said any level of lead in the blood was concerning, but it did not immediately translate into serious health effects.

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Professor Ian Shaw. Photo: University of Canterbury

"The really important thing, particularly if it's above the internationally accepted levels, is whether that level is maintained or not," he said.

"A single spike in blood isn't going to be a huge problem. But if that level is maintained for a period of time, then the longer the period of time the worse the problem, and the higher the level, the worse the problem.

"What will have to be done is to take some sequences of blood samples and measure them to see if the level is consistent or not."

The presence of the elevated levels in children was further worrying but people should not panic, he said.

"It's certainly worse for tamariki, simply because their brains are still developing, their nervous system is still developing and the younger they are, the worse it is. Lead has an effect on the development of the nervous system, so they'd certainly be a target group we need to look at very closely.

"But we mustn't run away with the idea that everybody's going to get brain damage if they've got a level of lead that's higher than the international standard, because it doesn't mean that at all. And the effects that lead can have on individuals vary tremendously from individual to individual. That's due to the fact that some people excrete lead much more quickly than others, so it's not possible from a level to predict what might happen but we do know that raised lead levels are a bad thing."

Public Health South and the Dunedin City Council will host another public meeting in Waikouaiti on 5 March.

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