Pohara contamination a mystery


Pohara Beach needs to be cleaned up after water quality testing showed that bacteria counts at the popular Golden Bay swimming beach exceeded national safety standards five times last summer.

Tasman District Council environmental staff monitor water quality at 11 popular river swimming holes and beaches throughout the summer and results of last summer’s tests showed that Pohara is the only problem area. Five samples from Pohara exceeded the guidelines with two of them so bad that council erected warning signs at the beach from January 10-20.

Although there were another six contaminated samples taken at other sites during the testing, council resource scientist Trevor James says they were nearly all associated with high rainfall which washes animal waste into the streams and rivers. One contaminated sample taken from the Top Rocks site in the Takaka River in dry weather was thought to be caused by cattle swimming the river.

Water contaminated with animal and human waste can contain a range of bacteria that can enter the body through mouth, ears or nose. It can cause gastro-enteritis and respiratory health effects or more serious diseases like hepatitis A, campylobacteria or samonella.

Council environment and planning manager Dennis Bush-King says he is generally pleased with the results that show Kaiteriteri Beach and Mapua Leisure Beach were graded good and Rabbit Island Main Beach was graded very good during all weather. The river sites were all graded good for all weather.

However, Dennis says Pohara, which was only graded fair, has been a problem for a number of years with unpredictable spikes in bacteria levels. Council conducted extensive testing of sewage and stormwater pipes in Pohara last summer but did not find any obvious source of faecal contamination.

Dennis says council will be conducting more exhaustive “genetic” testing at Pohara this spring and summer to try and find out what is causing the contamination.

“We will try to determine if it’s a microbiological source or a septic tank issue. It could be bovine or it could be human.”