A packed crowd at the East Otago Events Centre wanted answers from officials about the effect of lead in the water at Waikouaiti and Karitane.

Whether they feel they got them is less certain.

Hundreds of people flowed into the centre in Waikouaiti ahead of last night's meeting. There was standing room only at the venue and people lined the walls.

The meeting was called by Public Health South.

Residents wanted to know if they should eat vegetables from their gardens and if it was safe for animals to drink the water. They wanted to know if eggs from the area were safe.

These were not areas of expertise for the panel, but they suggested people avoid harvesting their vegetables for a couple of weeks until more was known.

National Poisons Centre director and medical toxicologist Adam Pomerleau said everybody had lead present in their bodies from background exposure.

It was a cumulative toxin.

"We aim to keep lead exposure as low as we can."

Restlessness simmered through the crowd.

Otago Regional Council chairman Andrew Noone said the panel of officials and council representatives sensed residents' frustration.

When he asked people to look forward, rather than back, the crowd murmured.

"Your reassurance doesn't mean much," one person said.

"We're pretty bloody angry about the whole situation," another said.

One resident said it was disconcerting that information from officials kept changing.

"Many of us lack trust in what is being said to us."

Karitane residents such as Jane Schofield wanted tanks tested.

Dunedin Mayor Aaron Hawkins said the city council was committed to supporting the community and focused on getting to the bottom of the problem.

"I appreciate that this is a distressing time," he said.

DCC infrastructure services committee chairman Cr Jim O'Malley, a scientist, said the council had taken samples since July to assess the integrity of pipes and possible corrosion.

An elevated level of lead was immediately evident at one site.

O'Malley said a high reading from a December 8 sample — a result sent to the council on December 18 but not noticed until January 7 when a staff member returned from leave — was followed by results that were not of concern.

"What we think we're looking at is what might be best described as a pulse," he said.

It appeared that the water was fine most of the time, he said.

But results were unpredictable and it was therefore considered not safe to allow drinking of the water to continue.

The council has stepped up the frequency of sampling.

Towns around the country did not test for heavy metals frequently, O'Malley said.

Jack said it was unclear from intermittent spikes in lead readings whether there could have been significant exposure.

Babies, children and pregnant women were most at risk to the effects of lead exposure, Jack said.

ESR (the Crown Research Institute) has concluded the risk of lead exposure through the Waikouaiti drinking water system is likely to be low.

It was not known yet whether there had been long-term exposure, Jack said. "The thing with children we are concerned about is long-term development."

Blood tests of lead levels would shape understanding about whether there had been long-term exposure.

Symptoms of elevated lead levels in adults can include tiredness, mood changes, impaired memory, sleeplessness, irritability, headaches and joint pain.

Gastrointestinal symptoms can include lack of appetite, nausea, diarrhoea, constipation, stomach pains and weight loss.

Young children may not show symptoms, but lead exposure over time may affect their development.

Lead in mothers can be passed on to unborn babies and to infants through breast milk.