Roundup, the farmer’s and backyard gardener’s harmless friend … or not? The most ubiquitous of weed killers, most likely there’s some in your garage or shed right now. Over the past forty years users and consumers have been told it is harmless; it breaks down in the soil quickly; it’s as safe as salt; and weed resistance is not an issue.

Well, that’s what Monsanto claimed about its glyphosate-based herbicide. Research from around the world is now contradicting that complacency. The World Health Organisation has warned glyphosate is a probable carcinogen and warns New Zealand producers to keep glyphosate residues out of food.

Roundup™ was the first glyphosate based herbicide on the market in 1974. Since Roundup™ went off patent there are hundreds of similar spray formulations, which make it the most widely used herbicide/pesticide on the planet.

Glyphosate is used extensively in Hawke’s Bay to dry off grain crops and kill pastures before they are sown with crops like tomatoes, squash or onions. It is used to spray between the vines in vineyards, by councils to control the roadsides, and people happily spray it on the driveway wearing only jandals. How wise is this? Have we been naïve about the safety of this ubiquitous spray?

At the recent Food Matters lectures in Havelock North, two world-leading experts discussed what they are seeing in the field and in the human genetics lab regarding glyphosate herbicide use.

Dr Don Huber is an Emeritus Professor of Plant Pathology from Purdue University in the USA. He is also a Defense Department expert in biosecurity threats. In his talk he highlighted that it takes about 10 to 20 years for half of the glyphosate to breakdown in the soil. He documented dozens of examples of severe plant and animal mineral deficiencies caused by glyphosate use. He is particularly concerned about the failure of seed crops, infertility in animals and birth defects in humans ranging from autism to anencephaly, where the baby is born without a brain.

Dr Gilles-Eric Seralini of the CRIIGEN bio-molecular lab in Caen, France, discussed his 2012 experiment with rats. Some were fed glyphosate-sprayed food; others were fed non-GMO and non-glyphosate food. This study was unusual because it was not funded by Monsanto who makes Roundup™ and because it looked at all indicators of rat health over the life of the rats. The rats were researched for two years rather than the usual three month study.

What they found was that rats fed glyphosate-sprayed food died earlier, had kidney and liver damage, and developed massive breast and testicular tumours. The pressure from Monsanto and the biotech industry to retract the journal article was immediate and intense. In an unprecedented move, the editor was fired and the article was retracted. Seralini’s research was again evaluated and cleared by an independent panel of world experts in this type of experiment and stands as valid.

These serious health effects are being confirmed by numerous studies overseas. In mid-March, the World Health Organization’s cancer research arm, IARC, officially pronounced glyphosate a “probable carcinogen”. Dr Gloria Swanson of Seattle Washington has created a series of graphs charting the correlation between glyphosate use in the USA and the official incidence rates of 32 major degenerative disorders like Alzheimer’s, Parkinson’s, diabetes, autism and infertility. There is a strong correlation for every disorder. The correlation for autism is the strongest.

But we’re here in clean, green healthy NZ, right? So, why should we care about this? In Auckland both glyphosate and its derivative AMPA have been found in marine sediment in the Waitemata Harbour and Hauraki Gulf. This is believed to have come largely from the spraying of urban roadside weeds.

Glyphosate residues are found in animal foods that contain genetically modified grains that are heavily sprayed with glyphosates and these residues filter through into human food.

Glyphosates have been found in the blood and urine of agricultural workers, indicating absorption, and one study has found increased chromosomal damage to residents after glyphosates are sprayed.

Our premium markets are quickly becoming savvy about the impacts that glyphosate residues have on their health and fertility and they would prefer not to have it in their food. Very low concentrations of glyphosate have been shown to disrupt hormones in humans, which is the first step towards development of cancer. The levels of glyphosate in food are much higher than that. Our markets will increasingly be willing to pay premiums for organic or low-glyphosate residue food.

Making matters worse, the actual active glyphosate in the herbicide may only be part of the problem. The surfactant or ‘sticker’ used to keep the spray on the plant is a particularly nasty chemical. It is truly toxic, but USA EPA regulations don’t require those sorts of ‘inert ingredients’ to be safetyevaluated in the pesticide application and most governments around the world have followed suit. Because of our higher rainfall conditions, NZ formulations have more of this toxin than most other countries and here it can be as high as 15% to 17% of the total volume of some glyphosate sprays.

Moreover, glyphosate use has farming disadvantages. Glyphosate used on fields, even several years previous, has been shown to substantially reduce the minerals available to plants and make them more susceptible to pests and fungal diseases. So, more costly sprays are needed to get the crop to maturity with less profit to farmer.

Dr Huber said in his Havelock North lecture: “I consider glyphosate to be the most serious threat to human health introduced in the 20th century.” When asked for the best alternative when an herbicide really is needed, he replied, “Paraquat! … Well, it breaks down quickly in the soil and it is so toxic that people treat it with respect and protect themselves,” he said to the shocked audience.

So how can we get ourselves out of this situation and move toward better market returns and better health?

It will probably help to remember what we were doing in agriculture before 1974 and the introduction of Roundup™. We disked in pastures and waited a bit longer for the grass residues to breakdown before planting. We could do that again, as well as plant diverse, flowering cover crops between the vines and mow or disk them periodically. We could use gas cylinder flame weeders on our pathways and use lawn clippings for mulch around the base of shrubs or trees.

There are remediation approaches to help de-activate and eventually decompose glyphosate residues in the soil. Coincidentally enough, they involve pretty much the same things as biological agriculture programmes: get your calcium and magnesium levels up; add manganese, copper and zinc through foliar spray nutrition. And do whatever it takes to lift humus formation and microbe diversity in your soil, because it’s the soil microbes that ultimately detoxify glyphosate and produce the flavourful, spray-free, nutrient-dense food we all want.

If we’re serious about being an international food bowl of the highest quality and about food tourism, we need to look seriously at what we can do to reduce glyphosate use.

“That’s not particularly convenient,” you might say. But consider the alternatives. Cancer isn’t convenient either. Not being able to conceive is devastating. Having an autistic child or looking after a parent with Alzheimer’s is heartbreaking.

No one wants that for themselves. And our overseas food markets certainly don’t.

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