By Bruce Hyer
The forest industry has been aerial spraying the herbicide glyphosate for decades. Glyphosate is a somewhat selective herbicide that kills many broad-leaved plants while having less effect on evergreens. The rationale is that after spruces and jack pines are cut, hardwoods like poplar and birch compete with young conifers for sunlight and nutrients.
There are concerns with glyphosate. Environment North proposes that forestry companies seek alternatives to aerial spraying of glyphosate on Crown lands in Northern Ontario. About 50,000 hectares were sprayed in Ontario in 2015 and in 2016.
The concerns with glyphosate fall into three areas: effects on non-human species, humans and economics.
Non-human effects include wildlife (including moose) that are declining along with loss of biodiversity and critical habitats.
Effects on humans include cultural, health and economics. Indigenous people and other harvesters of wild fruits, including blueberries, are concerned about the loss of food and
commerce. A recent scientific study in B.C. found glyphosate in new shoots and berries of plants that survived an aerial herbicide application one year prior.
Human health risks from glyphosate continue to be hotly debated. There may be a variety of unintended effects — unexpected, hidden, wonderful, nasty, or deadly. They are all effects.
A “safe” pesticide could be a formulation that if used according to directions would meet the following criteria:
• Not likely to cause death or acute toxicity, and
• Not toxic due to chronic exposure.
A widely used (but incredibly simplistic) means of assessing acute toxicity is to find the “LD50” (the lowest dose that kills 50 per cent of the test population of animals). LD50 charts tell you nothing about non-lethal acute effects or the effects of chronic low doses, which can be far more serious than acute toxicity.
There are four classes of chronic effects to humans or other animals that should be of particular concern to us all:
a) Developmental (or teratogenic, such as birth defects or fetal death)
c) Genetic (mutations, DNA damage)
d) Carcinogenesis (cancer-producing, can sometimes require up to one-quarter of a lifetime.)
A common myth: “If you eat enough of anything, it will give you cancer . . .” A substance either is a cancer initiator, or promoter (or both) or not. Some carcinogens have no dose without risk and others may have a low-dose threshold below which there might be no risk.
After decades of use, glyphosate is too cheap and familiar to receive adequate regulation. In 2017, glyphosate was approved for continued use by Health Canada despite strong opposition by many groups (including the Canadian Physicians for the Environment) due to probable cancer and wildlife effects.
A variety of published scientific reports show that glyphosate is toxic in many ways. Some are worrisome.
An epidemiological study of Ontario farmers showed that glyphosate exposure increased risk of late spontaneous abortions and premature births. Some recent analyses reviewing a number of studies suggest an association between glyphosate use and the risk of a cancer called non-Hodgkin lymphoma. In 2018, Monsanto was forced to pay $289 million in damages in just one lawsuit — and there are hundreds, potentially thousands, of other lawsuits pending. Monsanto has allegedly manipulated scientific evidence thereby downplaying the health risks of their glyphosate-based products.
Lastly, there are economic issues. One alternative to aerial spraying is manual thinning of hardwood competition by forest workers thus creating employment.
Quebec banned herbicide use on Crown land in 2001. British Columbia has reduced glyphosate use from 16,000 to 10,000 hectares in recent years and is considering a number of forestry practices to use less glyphosate and create more diverse and resilient forests, better able to withstand pests, fires and climate change.
Dozens of foresters and economists have been asked repeatedly over the years “What forest species will produce the forest products of the future in 60-100 years?” Nobody knows! We may just be killing the species and forestry jobs of our grandchildren’s future.
Bruce Hyer is a board member of Environment North and has a history in pesticide regulation and policy. Column supplied by Environment North.