What we know:
• Waikouaiti-Karitane water tested 90 times since July 2020.
• Six tests show elevated lead levels.
• First test results showing elevated lead levels in August.
• Elevated lead levels at Waikouaiti Golf Club (4 times), Karitane Bowls Club (1), Waikouaiti raw water reservoir (1).
• No-drink notice issued Feb 2 (after reservoir test result received Jan 29).
• Two test results emailed to DCC on Dec 18 not opened until Jan 7.
• DCC changes email procedures.
The highest level of lead in the water in Waikouaiti was almost 40 times acceptable levels - not four times as previously reported by the Dunedin City Council.
Meanwhile, Mayor Aaron Hawkins has welcomed the Ministry of Health's announcement that blood tests would be made available to 1500 residents in Waikouaiti and nearby Karitane.
The DCC said this afternoon a result recorded at Waikouaiti Golf Club on December 8 was .39 milligrams per litre, which was four times the amount reported by a staff member in an interview with RNZ.
This meant it was almost 40 times the acceptable level of 0.01mg/L and not four times.
The December 8 test results were emailed to the council on December 18, but because a staff member was on holiday it was not until January 7 that council first learned of the results.
On December 8 there was also a smaller spike - but still above the acceptable level at the bowling club.
However, a sample taken from Waikouaiti township's main street returned a result well below acceptable limits on that same day.
The council acknowledged the lower figure was incorrectly stated in a radio interview.
Director-General of Health Ashley Bloomfield earlier today revealed Waikouaiti and Karitane residents will be offered blood lead level testing as early as next week.
On Tuesday afternoon the council advised Karitane and Waikouaiti residents not to drink tap water after testing at the Waikouaiti raw water reservoir showed elevated levels of lead.
Testing near the end of the supply line had previously showed intermittent spikes in lead since August last year, but officials decided the public did not need to be warned until this month.
The reservoir test result revealed there could be contamination at the water source.
Speaking at today's Covid-19 briefing, Dr Bloomfield said he had been updated about the situation after Ministry of Health officials spoke to the Dunedin City Council, Public Health South and the organisation which carried out testing of the water.
He had been told the 1500 residents in the townships north of Dunedin would be offered blood lead level testing to provide assurance.
Dr Bloomfield said this was the right thing to do.
"They are just working through the logistics of doing that, standing that up next week."
This was being led by Southern District Health Board Medical Officer of Health Dr Susan Jack.
Symptoms to watch out for
Dr Jack said yesterday people could experience acute symptoms if consuming high levels of lead.
"In young children and babies, low levels don't cause any obvious illness.
"But higher levels can cause symptoms like vomiting or stomach pains or difficulty sleeping, and low chronic levels may cause an impact on children's development," she said.
Adults' gastrointestinal and nervous systems could be affected, she said, and chronic lead poisoning could cause mood changes, headaches, tingling, numbness, nausea and diarrhoea, or constipation.
Council welcomes blood tests
The Dunedin City Council said this afternoon the tests were aimed at determining the impact, if any, of intermittent spikes in lead levels detected in drinking water in recent months.
Chief executive Sandy Graham said the council had been in regular contact with its independent drinking water assessor and Public Health South officials, and had followed expert advice throughout.
"Our staff are working hard to get to the bottom of what has caused the contamination issue and how it resolve it."
Staff remained focused on ensuring affected communities had access to a safe and adequate water supply while working to find the source of the contamination
This included deploying water tankers to the affected communities and having staff on hand to answer questions.
The council was also working with an independent technical expert on the response and sampling plans, as well as identifying the source of contamination.
Mayor Aaron Hawkins said the Ministry's announcement provided reassurance for residents.
"The Dunedin City Council will continue to follow expert public health advice, as we have done to date. We will provide whatever support is asked of us from the Ministry of Health and other health authorities."
Practice 'inundated' with calls
East Otago Health practice manager Jane Roberts said the practice had been inundated with calls since the news broke on Tuesday.
"We've been fielding a lot of calls, probably twice as many."
She estimated that since lunchtime yesterday, 20 to 25 people had been referred to Dunedin for blood lead level testing.
Test results had been fast-tracked and would be returned within 48 hours, she was told.
"We are waiting on these results so we can let the community know of the situation."
The Ministry of Health has set up an incident management team to ensure it was getting updates.
The main concern about lead was over the effect it could have on the neurodevelopment of children. But this was associated with long exposure and the length of exposure was not yet known.
The tests would give authorities a better idea about the situation.
Dr Ashley Bloomfield said he did not have enough information to comment on the Dunedin City Council's performance after finding elevated lead levels.
He was asked if he been briefed about the situation.
"I have, and I asked the team this morning for a briefing and they have been on the phone with the public health unit down there and the city council and the organisation that does the water testing, Dr Bloomfield replied.
"What they are planning to do is to offer blood lead testing to the populations of the two places affected ... which I think is absolutely the appropriate thing to do."
DCC infrastructure services general manager Simon Drew said six water samples out of 90 in the past six months showed elevated lead levels.
Four were recorded at the Waikouaiti Golf Club near the end of the supply line, one at the Karitane Bowls Club and one at the Waikouaiti reservoir.
The first of those was received on August 13, 2020.
Officials thought regular sampling showed no evidence of a continuing problem, until results of a January 20 test from the reservoir were received on Friday last week, prompting Tuesday's notice.
- additional reporting Grant Miller and Emma Perry