Holiday Warning – Health Threat Posed By Canterbury Rivers

Scientific testing of popular Canterbury fishing and swimming rivers has produced disturbing findings, including the presence of dangerous disease-causing bacteria and antibiotic resistant E. coli. 

Fish and Game commissioned the independent testing after anglers raised concerns about the potential risk of infection they were running due to river pollution and the increasing number of dairy cows in Canterbury.

The tests samples were collected from the Ashley, Selwyn and Rangitata rivers in May and September and tested by Massey University’s Institute of Agriculture and Environment.

Above Right: Sediment gathered from the Ashley River for Testing by Massey University.

The findings show the presence of E. coli, antibiotic resistant E. coli and a dangerous strain of bacteria called shiga toxin-producing E. coli or STEC. 

STEC infection is a notifiable disease in New Zealand.  It is a strain of E. coli which produces shiga toxin and can cause severe disease, including bloody diarrhea and kidney failure.

The two most common E. coli strains found in the testing only come from ruminants, such as cows.

Experts consulted by Fish and Game say the test results show all these harmful organisms are present at levels that may impact on human health.

Fish and Game New Zealand chief executive Martin Taylor says the results are disturbing.

“We undertook the testing based on local anglers’ concerns and began with samples taken from above and below the biggest farms on the Ashley, Selwyn and Rangitata rivers,” Mr Taylor says.

“What we found in the first tests was so alarming, we actually did a second round of testing to confirm the findings, as well as consulting health authorities to get their expert opinions.

“The results suggest these organisms are now common in our water ways - if this is the case, then it certainly is concerning from a public health standpoint,” he says.

Martin Taylor says with the holiday season about to begin, the test results are a wakeup call.

“In plain language, the results indicate swimming in these rivers could be like playing Russian roulette with the health of you and your family. 

“What we have found indicates the proper authorities urgently need to undertake more testing to establish the extent of the problem, along with action to ensure people are kept safe.”

Martin Taylor says the testing shows that the contamination of Canterbury waterways is primarily due to intensive dairy farming.

“The scale of dairying in Canterbury is staggering.  The region has 1.3 million cows and each of them produces around 68 litres of effluent a day.  This means 32 billion litres of effluent is introduced into the environment each and every year,” he says.

“Unfortunately, while some of it is captured by effluent systems, or taken up in soil, much of it sits on the land until it is washed into waterways. 

“The result for the average person wanting to go for a swim in their local river or stream is they just can’t be sure it is safe if there are dairy farms close by.”

Martin Taylor says the problem isn’t confined to Canterbury.

“These test results show that the sheer number of cows on the Canterbury Plains and in areas like Southland and Taranaki are creating not just environmental problems but also human health issues.

“This is not an attack on dairy farmers, many of whom are doing the right thing by the environment.  However, as an industry it needs to do much better,” Mr Taylor says.

“Regional and district councils also need to be doing a much better job of enforcing the rules and protecting our waterways and the New Zealanders who use them.

“We are looking forward to Federated Farmers representatives claiming this is a beat up, that the tests are wrong, these dangerous organisms aren’t from cows or some other such argument in attempt to minimise the huge impact their industry is having on human health.

“The simple fact is that in 2017, New Zealand voters demonstrated they are fed up with having their waterways polluted.

“The coalition government has responded with a freshwater programme to improve water quality but our test results show that programme must urgently make fundamental changes to land use,” Martin Taylor says.

Frequently asked questions about E.coli

You can download the results here.

The test locations information is here.