Spotlight on weedkiller
Use of popular weedkiller Roundup has been called into question again after a landmark court case in the US.
The San Francisco jury granted US$289 million to a groundskeeper who said his lymphoma resulted from years of applying Monsanto’s trademarked Roundup herbicide, which did not include adequate warning of its links to cancer.
The decision prompted Environment Minister Eugenie Sage to ask the Environmental Protection Agency (EPA) to consider adding Roundup to a list of hazardous substances up for reassessment.
Dr Fiona Thomson-Carter, general manager of New Zealand's EPA's Hazardous Substances Group, said there is "no change to the science behind our current position, which is products containing glyphosate remain safe to use when you follow the instructions on the products label".
New Zealand scientists argued the US ruling shouldn't prompt a knee-jerk ban of Roundup here.
"Herbicide use is seldom exposure to just one specific product - and the dose, duration, type, and frequency of exposure is relevant to any potential risk," Associate Professor Brian Cox, a cancer epidemiologist at the University of Otago told the NZ Herald.
"A sudden reaction to one case in one US law court, that has not yet gone to the appeal court, is not an appropriate method of developing health policy in New Zealand."
There is debate over whether or not Roundup causes cancer. Massey University Centre for Public Health Research Professor John Potter told The AM Show that glyphosate — a key ingredient in Roundup - has officially been designated a "probable carcinogen" by the cancer research arm of the World Health Organisation: the International Agency for Research on Cancer (IARC). He said councils that use the weed killer on verges, greens and schools should reconsider their use, as should wider agriculture businesses that use it.
However, Dr Belinda Cridge, a toxicologist from the University of Otago, told the SMC the IARC definition means glyphosate may cause cancer, but there is no evidence of cause and effect and it may only do so only under the right conditions and exposures. Red meat is also listed by IARC as a "probable carcinogen". She said the IARC reviews are "based on good scientific evidence" but that "wider factors are critical to determining full risk".
The SMC gathered expert reaction to the court result and Environment Minister's response.
She acknowledged: "it is very difficult to model and track all possible interactions" of the additives in Roundup and it might be that the combination of these chemicals contributes to cancer — but this isn't something that's been tested yet.
"It's important to consider the whole picture. Roundup isn’t, and has never been, a safe panacea for all weed control. Scientists continue to learn more and more about this chemical and its effects. However, the alternative options aren’t very appealing and many are much much worse for both people and the environment."