People jumping into lakes and rivers along the Waitaki Valley this weekend are being warned they could end up with more than a cool dip - gastroenteritis is also a possibility.
Environment Canterbury, Waitaki District Council and Public Health South yesterday issued a reminder that runoff carried pollutants such as effluent and nutrients into streams and rivers.
Otago/Southland Medical Officer of Health Dr Marion Poore said recent water quality results from ECan showed high levels of faecal indicator bacteria at Loch Laird, just below the Benmore Dam, and Lake Aviemore, just downstream.
Loch Laird is high because of the release of water from the dam, and combined with recent rainfall it was likely contaminants had been washed into the loch from the lake shore.
It should be noted that the results only provided a snapshot of water quality at the time the samples were taken, Dr Poore said.
People wanting to enter the water should always take note of the daily conditions when considering whether the water was safe.
"We can't monitor every stretch of water, so it's wise for people to learn to be aware of the signals that the water may not be ideal for some activities."
In freshwater, these included intensive farming in the surrounding catchment area, industries immediately upstream, recent rainfall and the colour of the water, she said.
If the water was murky - "if you can't see your toes" - there was a higher risk the water was polluted.
Dr Poore said contaminated water increased the risk of stomach bugs, in particular.
"The main health problem is gastroenteritis.
"This causes diarrhoea, vomiting, abdominal cramps, fever and can be highly infectious.
"Usually people are sick for two or three days . . . good hand hygiene is essential to avoid passing it on to others."
The best management was to drink plenty of fluids, use paracetamol to relieve cramps or fever, and rest.
People with gastroenteritis who worked in child care centres, health workplaces, or as food handlers needed to stay away from work until 48 hours after symptoms had completely resolved.
People wishing to check water quality monitoring results can find the latest information on the ECan site, www.ecan.govt.nz.
