What does ‘risk’ mean?
The risk is of getting sick when swimming, surfing or otherwise being exposed to freshwater or seawater. The guidelines that Environment Canterbury use are based on fixed levels of risk, which in turn are based on overseas guidelines (which have been confirmed by New Zealand studies). Overseas investigations have settled on a maximum acceptable level of risk for marine waters of 19 in every 1000 bathers contracting an illness. For freshwaters the accepted level of risk is 8 in every 1000 bathers contracting an illness. Even when beaches and rivers meet the guidelines there will still be a health risk associated with recreational activities in the sea. Because scientists are not directly measuring the pathogens, it is not possible to say there is zero risk to public health, especially where there are known inputs of human and animal faeces. If tested waters exceed the acceptable level of risk, the public is advised that the area is unsuitable for recreational activities.
