Bacteria hazard at beaches

Signs were erected at one of Auckland's most popular beaches last week, warning swimmers to stay out of the water. Browns Bay, on the North Shore, has been plagued with problems of wastewater overflow but the latest culprit is a type of seaweed that turned the nearby creek black.

Council spokesman Paul Thompson said test results received last Friday revealed unsafe levels of pollution at the beach.

Officials originally thought oil had been poured into the stormwater system but further testing showed it was a type of seaweed.

Signs warning swimmers of the problem were erected immediately, but were taken down yesterday after further testing showed the problem had cleared.

However, Browns Bay is not the only beach swimmers should keep an eye on this summer.

Last week's flooding in Auckland's Mission Bay and regular flooding on the Coromandel Peninsula highlight the problems faced by swimmers at some of our more polluted beaches.

While most coastal beaches have good water quality, local and regional councils recommend swimmers be wary of the risks posed at some beaches by heavy rain run-off.

Other Auckland beaches that often exceed the recommended safe levels of pollution include Home Bay, Cox's Bay and Okahu Bay.

Local and regional councils around the North Island carry out regular testing of coastal swimming spots for enterococci bacteria.

The bacteria indicates the presence of faecal matter when it occurs in high levels. It can cause stomach illnesses, skin, eye and ear infections.

Auckland City, North Shore City and Rodney District test water quality weekly at 64 beaches and lakes from October to April.

Results are regularly updated on council websites.

Auckland City tests 17 sites, including four on Waiheke and three on Great Barrier Island.

Environmental health manager Chris Dee said Auckland's beaches were good compared with other international cities.

Despite official assurances that Okahu Bay is generally safe, Auckland iwi Ngati Whatua is concerned about its quality.

"All the run-off coming from Tamaki Dr and all the construction in the area is combining and getting into the sediment," said spokesman Ngarimu Blair. The tribe would eventually like to collect seafood from the bay.

Waitakere City Council tests 20 of its most popular beaches weekly between November and March, including Bethells, Piha and Karekare, while Environment Waikato monitors 26 popular swimming beaches, including Hot Water Beach and Raglan.

The Northland Regional Council conducts weekly tests at 75 coastal sites including Tutukaka, the Hokianga Harbour and Mangawhai.

- HERALD ON SUNDAY