Glyphosate's impact on farming systems

Farmers have been applying glyphosate based herbicides (GBH), commonly known as Roundup on their pastures, silage and forage for several years. GBH’s dry out the feed and increase the metabolisable energy, they’re considered a useful harvest aid. But it may be a minor benefit, and perhaps, more likely a detriment to the sensitive systems that underpin soil and stock health.

This popular tool may need revisiting, if we take recently released hard data into account. There are significant reasons why you might want to pull back from applying GBHs like Roundup to your pastures and stockfeed. It’s got to do with your soil microbiome and your mammalian microbiome, your livestock health and your economic outlook.

In June 2015 the International Agency for Research on Cancer (IARC) declared glyphosate a probable carcinogen, noting that there was strong evidence the chemical was genotoxic. Many of the studies considered in this metastudy involved the full formulation. Every farmer knows the full formulation, and many off-patent mixes, are considerably more toxic than the active ingredient.

The studies used by regulatory agencies, including the US EPA, European Food Safety Authority, WHO/FAO, APVMA and NZ EPA, that arrive at critical endpoints that go on to establish daily exposure levels (Eg. ADI and RfD) and permitted rates on agricultural crops and weeds - are private, remain unpublished and never peer reviewed in the public domain. The studies are also narrower in focus and do not take into account the full formulation consumers and applicators are exposed to.

The carcinogenicity studies used by these agencies in the last twenty years to arrive at the 'low toxicity' finding for glyphosate, simply cannot compete with the breadth and variety of studies considered by the IARC to establish the glyphosate is a 'probable carcinogen' finding.

This message is very difficult to get through to farmers and pesticides applicators. The agricultural media is reluctant to discuss this fact.  

Regulators rely on old protocols and old science.

International regulators, including the Environmental Protection Agency (EPA), never consider the full formulation when they evaluate the toxicity of pesticides in risk assessment. It is not just POEA, many ingredients in the formulation add to toxicity. What lets our farmers down - who may be exposed to glyphosate on a weekly basis – is that the EPA has repeatedly ignored published science indicating harm at very low levels – and used unpublished studies directly supplied by the chemical manufacturer to arrive at critical exposure levels. There’s a lack of rigorous science underpinning regulatory actions that places trade health before long term farm health. As risk assessment occurs only rarely, (for example the last glyphosate reregistration occurred in 1993), it is critical that regulatory actions reflect modern knowledge.  A 2015 scientist consensus statement clearly noted ‘Regulatory estimates of tolerable daily intakes for glyphosate in the United States and European Union are based on outdated science.’

Simply put, our farmers, at the coalface, deserve more.

A quick glance at the NPIC Fact sheet can help clarify just how outdated the science is, that is used to arrive at exposure levels. The Fact Sheet advises the chronic reference dose (RfD) for glyphosate is 1.75 mg/kg/day (RfD). The study that was used to establish this level is a private, unpublished Monsanto study, known as ‘Rodwell DE; Tasker EJ; Blair M; et al. (1980). The EPA used this study in the September 1993  Reregistration Eligibility Decision Document Case 0178 (Glyphosate). Note that this unpublished 1980 study, was already then, 13 years old. Since 1993 there has been a cartload of published and peer reviewed science demonstrating that GBH’s are much more toxic than previously considered.

As of 2016, the EPA has been sitting on the current registration review for seven years – the docket was opened for submissions in 2009. Science released since 2009 should be considered, but there is no promise of this. The delay, for this chemical regularly sprayed on staple food crops and along drains that lead to drinking water sources, reflects the politicisation of chemical. Children are widely exposed as glyphosate is used as a harvest aid on food crops. The time taken appears to many, to be unconscionable, particularly when re-registrations occur only rarely.

The NPIC today advises the acceptable daily intake (ADI) is 1 mg/kg day, derived from the 2004 World Health Organisation JMPR toxicological evaluation of glyphosate. The study that established this is a private, 1993 Cheminova paid study.

Somewhat astonishingly, the USA’s maximum permitted level in drinking water is 700ppb (0.7 mg/L), making the US a world leader in permitted exposure levels.

Many farmers may express dismay that, in addition to drinking water, glyphosate has been found in beer at concerning levels. All the old studies held with regulators assumed glyphosate would be ‘fully excreted’ – but constant exposure via food and water today results in chronic exposures over a lifetime.

For years, control of supplying scientific studies directly between manufacturer and risk assessment agency has quietly… worked. But as industry has, naturally, extended product use, from a pipecleaner, a weedkiller to a desiccant and harvest aid higher exposure levels have resulted and the product has become more conspicuous.

To many, it is not a broken system, it is a system that works conveniently well. By limiting toxicity by only considering the active ingredient, by industry controlling the studies submitted in risk assessment, reregistration has been a smooth process. Particularly if regulatory agencies are emasculated with insufficient staff and resources to barely approve new chemicals, let alone time to review older, off patent products using commercially confidential formulations.

But safe risk assessment is a different thing altogether. Twenty first century science can, and should be taking into account full formulations, endocrine disruption; systemic feedback loops, digestive system effects, and critically, effects of exposure at the delicate levels the population is exposed to.

Because we can. Yet none of this is happening. It’s archaic.

Do GBHs affect stock health and impact fertility?

While my own farming family probably will consider themselves bulletproof, the following information may strike a raw nerve because livestock health is economic health. The health effects as a result of GBHs on stockfeed have never been studied.

The USA pegs MRLs for stockfeed at about 400mg/kg. Usually permitted maximum levels are just a little bit higher than trials indicate, as protocol demands.

Industry (pesticides manufacturer) studies reveal that current exposures are harmful. (Studies produced by independent scientists with no financial conflicts demonstrate that the situation is more serious.)

A journey through old industry studies held with USA EPA, the World Health Organisation and the European Commission reveals decreased pregnancy rate, litter size, survival rate and increased dystocia, abortions, and reabsorptions.  These studies indicate lower growth rates (from diarrhoea, soft stools, decreased food consumption); increased gastrointestinal disturbances/congested stomach; changes in liver (organ weight increases); salivary glands; and stomach mucosa and bladder epithelium (histology). The studies recorded eye cataracts; focal tubular dilation of the kidneys and heart malformations (dilated heart, interventricular septal defect).

When industry supplied these studies, it was not common practice to apply glyphosate on stockfeed. (It was before residue levels were increased in 2006).

A European NGO has queried how GBH’s can contribute to birth defects, but farm based impacts – direct risk to the farmer and the farm, are rarely considered.

There has been a lot of discussion about reproduction rates. When older farmers are advised of current repro rates they’re surprised. While many factors must be taken into account, research looking at GBH on feed and fertility impact is all but non-existent. Published studies have demonstrated since 1995 that GBHs impact fertility, and I have questioned why no research has been conducted on this issue. Questions are surfacing regarding how glyphosate may impact the fusarium fungi that produces the harmful and estrogenic zearalenone toxin. It is difficult to get these questions in mainstream agricultural media.

Scientists have noted the ‘consistent association between previous glyphosate use and Fusarium infections.’ Many papers have called for more research to understand how glyphosate impacts soil fungal communities and alters plant resistance to pathogens including fusarium. 

When faced with the unvarying drawl of agribusiness to ‘feed the planet’ it would seem the casual disregard in evaluating causes of disease - crop failure and disease growth – the reluctance to commit significant public monies to independent research funding and low prioritisation of soil science, is staggering in its moronic-ness. It fits the same narrowness as the constant call for a cancer cure without financial commitment nor intention to prevent it in the first place. Our genes and plant genes, haven’t changed that much. It’s the environment, stupid.

The IARC also concluded that there was strong evidence that GBH’s are genotoxic - cell damaging and could affect DNA. Of course, a substances’ ability to impact herd epigenetics (genetic expression) and affect resultant offspring is naturally, of concern to farmers.

US media and research institutions have steered clear of investigating impacts of full formulation toxicity (Eg.Roundup) and herd health. Research on stock health is rare. In Europe, a team at the University of Leipzig demonstrated there is reason to be cautious regarding glyphosate and its formulations. European scientists have investigated gut dysbiosis, and considered glyphosate impact on animal health and nutrition.

A 2009 study demonstrated how glyphosate reduces essential mineral nutrient availability in plants. A 2015 study of dairy cows clearly found that glyphosate was toxic to the normal metabolism of dairy cows. A 2013 study discussed that strong biocides like glyphosate could explain the observed increase in levels of C. botulinum associated diseases, and that glyphosate in particular could be the significant predisposing factor that is associated with the increase in C. botulinum mediated diseases in cattle. A 2014 study demonstrated that glyphosate caused dysbiosis which favoured the production of the botulinum neurotoxin in the rumen. The authors stated ‘We believe that glyphosate will have a greater influence on cattle herd health in the near future due to increasing application rates of glyphosate to crops and much higher residual levels especially in glyphosate-resistant GM crops.’

Soil Health – new research.

New studies are demonstrating that glyphosate negatively impacts underground arbuscular mycorrhizal fungi (AMF) networks. AMF plays critical roles aiding nutrient uptake for over 80% of plants, improving soil quality, water retention and contributing to erosion prevention. Historically, it is considered that as AMF are shielded below ground, and don’t receive a direct application of glyphosate based herbicides, AM fungi have been protected.

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A 2014 study by Zaller et al using Roundup Speed (glyphosate active ingredient 7.2 g l−1) noted 'We found a 40% reduction of mycorrhization after Roundup application in soils amended with the mycorrhizal fungi G. mosseae. This is in contrast to what we hypothesized, based on the allegedly fast biodegradation of the herbicide and the very plant-specific mode of action. '

Please note, this study was of the formulation. Another 2011 study found that the same AMF strain was not affected. However it only researched effects of the active ingredient.

Results demonstrating impacts of glyphosate on earthworms have been mixed, but Zaller et al also found ‘Interestingly, earthworms significantly increased glyphosate leaching only in absence of AMF, while in presence of AMF earthworms tended to decrease glyphosate leaching. It remains to be tested whether this is due to glyphosate uptake and accumulation by AMF or whether these AMF hyphae might have been consumed by earthworms thus protecting glyphosate from leaching.’

It is always complex.  Perhaps what this study did was demonstrate just how narrow the focus of earlier studies have been.

US patent no.7771736 B2 (2010) advises how glyphosate formulations affect cell viability of plant based pathways – it is an antiprotozoal agent. Yet protozoa play an important role in mineralizing nutrients, making them available for use by plants and other soil organisms. This has not been studied in great depth to assess economic impact. 

It is also worth considering a 2011 Chinese study by Sheng et al which used Roundup Weathermax (450 g active in-gredient·ha–1). This study detected a shift in the identity of dominant AMF species but did not detect an overall reduction.

Little research has focussed on AMF spore viability.  A 2012 Argentinian grassland study found that even at the lower rates, ‘spore viability in herbicide untreated soils was between 5.8- and 7.7-fold higher than in treated soils’. Furthermore, ‘root colonization was significantly lower in plants grown in glyphosate treated soil than in untreated ones.’

A latter 2013 grassland study by the same authors advised that ‘glyphosate application can damage AMF directly (through contact with spores and external hyphae) or indirectly through the changes it generates on host plants.’ Spore viability was reduced only when the soil was directly treated with glyphosate.

When it comes to earthworms, again due to variable environments and inputs, we are in early stages of understand impact. A recent 2015 study was extremely definite, however. The scientists, including J.G. Zaller demonstrated ‘that the surface casting activity of vertically burrowing earthworms (Lumbricus terrestris) almost ceased three weeks after herbicide application, while the activity of soil dwelling earthworms (Aporrectodea caliginosa) was not affected. Reproduction of the soil dwellers was reduced by 56% within three months after herbicide application. Herbicide application led to increased soil concentrations of nitrate by 1592% and phosphate by 127%, pointing to potential risks for nutrient leaching into streams, lakes, or groundwater aquifers.’

This study used the full formulation of Roundup.

We have been aware that pesticides can negatively alter the reproductive output of earthworms (Eisenia fetida) for some time. However the relationship of the glyphosate metabolite AMPA to earthworms has rarely been studied. This 2015 study came to the conclusion that persistent AMPA impacts juveniles, reducing earthworm size, which may limit their beneficial role.

How glyphosate based herbicides affects farmer health

Most farmers understand that glyphosate is a broad spectrum organic phosphate chelator that immobilizes positively charged minerals (such as manganese, cobalt, iron, zinc, copper, etc.) Glyphosate damages the gut biota, as it harms the critical plant based Shikimate pathway (contained in gut based bacteria, fungi, algae, parasites) essential for the synthesis of essential aromatic amino acids.

Our cells can't make aromatic amino acids because they don't have this pathway.  Stephanie Seneff advises ‘the aromatics are very important molecules, biologically, including being precursors to all the neurotransmitters (serotonin, dopamine, adrenalin) as well as the B vitamin folate, thyroid hormone, the hormone melatonin, and the skin tanning agent melanin.’

Glyphosate based herbicides - what can they do to farmers and their families? :

1.            Suppresses beneficial bacteria in the gut, impacting the immune system.

2.            Chelator which reduces access to mineral nutrients (Mg, Cu, Zn etc)

4.            Act as an environmental trigger and contribute to increased prevalence of genetic disease. Once the microbiome and gut breaks down individuals kick into whatever illness or disease they are predisposed to.  Autoimmune and allergic disease development (pathogenesis) involves 3 factors which may act like dominoes.  a) Exposure to environmental triggers and b) Loss of intestinal barrier function - gut permeability (leaky gut); then you become ill according to c) Genetic predisposition.

5.            Probably cause cancer including non-hodgkins lymphoma

6.            Contribute to liver and kidney problems including Chronic Kidney Disease CkD

7.            Affect the hormone (endocrine) system and may contribute to hormone related cancers

8.            Contribute to depression due to gut dysbiosis (90% of serotonin is made in the gut).

9.            A new classification in Europe would warn that glyphosate “may cause damage to organs through prolonged or repeated exposure”

Many farmers, particularly in orcharding and cropping, on retirement, acknowledge the cost of chemicals to their health, whether it’s a struggle with Parkinsons, skin conditions, depression, new cancers. Of course, rarely are non-chemical systems put forward by the farming media that surrounds them, or industry bodies. There appears no alternative. To the average farmer, there appears too much economic risk associated with moving away from chemicals. So instead, they get sick.


Economic Health: Residues in food.

Farmers are all too familiar with increased regulation surrounding chemical use in, for example, the dairy shed, the potential for chemicals to get into the system via teat sprays and so on. This is happening because food safety is moving from not just microbial hygiene. It now takes into account chemical hygiene.

Simply put, mums want safe food. It’s one of the reasons demand for organic is surging.

Mothers are waking up to the fact that kids who are healthier, are eating real food – not processed, not with added chemicals, just the same stuff that their grandparents grew up on. This is an international revolution. Food processors are waking up and changing decades old patterns to remain appealing to the kitchen dollar.

In fact as PwC states ‘High-profile food safety and quality scandals are damaging public trust in the food industry and increasing consumers’ concerns about their food.

With the ubiquity of social media and increasing media and public interest, more food scares are turning into damaging scandals – pushing governments and food companies to improve standards.’

The difference is now, these mums can test for glyphosate content in food product. Scientists are finding glyphosate in breast milk and in urine, even breakfast foods.  It’s proven to get through the placental barrier, and the Environmental Protection Authority acknowledged last year it may test food products. Glyphosate has evaded food testing for so long, because industry tests have quietly ensured regulators considered the chemical ‘of low toxicity,’ thus avoiding public testing in food and groundwater.

Slowly, ever so slowly, we are realising immune health is at the centre of health – human and plant. We now know soil microbes, like human microbes function as an immune system and help prevent (plant) diseases from developing. Yet profoundly, dismayingly - much of the media that surrounds farmers prevents access to the facts – the growing pile of hard data that supports the reality that multiple chemicals on food are not regulated safely, and cannot be proven to be safe.

The knowledge that consumer concern is driving safer food production, whether to reduce chemical exposure or increase nutritional content. This delay leaves food production systems on the back foot and farmers not knowing why no-one wants their glyphosate sprayed sugar beets or their conventionally produced, glyphosate treated grain based milk production systems.

International scrutiny leaves exporters vulnerable and the public exposed – which is why agile countries are adopting safer food production systems, while others can’t sell their commodity product. All countries deserve risk assessment that is internationally competitive and fits with international best practice.

Profoundly, we need risk assessment that places the health interests of both the regular user (the farmer) and the most vulnerable citizen (from the elderly to a pregnant mother) above trade based interests.

Tainted product gives foreign markets the opportunity to reject or downprice product. Risk assessment must be impeccable.

It’s about time the economic impact of this toxic endocrine disruptor and probable carcinogen was fully assessed. Glyphosate is simply the tip of a massive chemical iceberg that has not been scrutinised for its toxic cost to earth systems, it's potential to degrade soils and cause intergenerational harm to stock and human health.

In the meantime, there is enough scientific evidence across the board to make it worth questioning your own and your livestocks’ exposure to this demonstrably harmful product, and asking the question – what is the long term risk of this on our food?

I welcome any conversations to discuss this issue further.