Study underway to improve understanding of the health risk of swimming in rivers

Date:  18 December 2019

With thousands of New Zealanders heading to their favourite swimming spots in rivers around the country, the Ministry for the Environment is funding research to better understand the relationship between the presence of pathogens in freshwater and people getting sick.

The Quantitative Microbial Risk Assessment (QMRA) pilot study will confirm the best method to establish the link between levels of disease-causing organisms and indicators of them (such as E. coli) in New Zealand rivers to determine the health risks to people in contact with fresh water.

Swimming in summer is a part of the kiwi way of life and we want people to enjoy our rivers without fear of getting sick. Ministry for the Environment recognises that we need reliable information to be able to properly advise people of any of the potential health risks.

Being able to use our lakes and rivers safely is an issue that affects everyone, which is why Ministry for the Environment is working with research institutes (ESR, NIWA and Massey University) and regional councils to determine the best way to provide the data.

Councils will collect around 80 samples for scientists to analyse across 16 freshwater sites throughout New Zealand this summer. The results, expected in June 2020, would inform the development of a larger-scale QMRA study, which if funded, would take around three years to complete.

The current recreational freshwater public health guidelines are based on a similar study conducted over 20 years ago. The way we use land and manage our waste has changed significantly over that time so it is possible the presence of pathogens and indicators has also changed. A comprehensive QMRA study would confirm if the science that those guidelines are based on is still fit-for-purpose.