A health warning issued on Wednesday (December 4) for Lake Ngā Roto, has now been escalated to ‘extreme risk’ after further testing.

The National Public Health Service is urging people to avoid all recreational water activity at Lake Ngā Roto, due to a significant rise in the cyanobacteria (blue green algae) concentration.

Waikato Medical Officer of Health Dr Liz Becker says repeat testing this week has confirmed that there has been a highly significant rise in cyanobacterial levels.

As a result, the alert remains in place. Recent test results returned a 1,203 mm3/L, far higher than the Guideline Value of 1.8 mm3/L.

“The cyanobacteria currently in the lake may produce toxins which are extremely harmful and may cause serious illnesses,” Dr Becker says.

It is strongly advised not to undertake any recreational use of the lake where there could be skin contact or swallowing of lake water.

Avoid all recreation on the lake including kayaking, fishing, boating and swimming.

“Dog owners should prevent their dogs from drinking or swimming in the water, as dogs are particularly sensitive to cyanobacteria and its related toxins,“ she says.

If you have used Lake Ngā Roto recently and have any of the following symptoms:

  • a rash
  • skin and eye irritation 
  • allergy symptoms such as hayfever and asthma or
  • possibly stomach upsets including diarrhoea and vomiting

Please seek medical attention such as contacting your GP. 

Please note, these symptoms may not appear until sometime after contact with the affected water.

If you have any health problems that have developed after exposure to any of the lakes with health warnings, please ring National Public Health Service - Waikato on (07) 838 2569.

ENDS