‘One sip can kill’: why a highly toxic herbicide should be banned in Australia


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Nedeljka Rosic, Southern Cross University; Joanne Bradbury, Southern Cross University, and Sandra Grace, Southern Cross UniversityThere’s a weedkiller used in Australia that’s so toxic, one sip could kill you. It’s called paraquat and debate is brewing over whether it should be banned.

Paraquat is already outlawed in many places around the world. The Australian Pesticides and Veterinary Medicines Authority has been reviewing paraquat’s use here for more than two decades, and its final decision is due later this year.

We are medical and environmental scientists, and have researched the harmful effects of paraquat, even when it’s used within the recommended safety range. We strongly believe the highly toxic chemical should be banned in Australia.

The potentially lethal effects on humans are well known. In Australia in 2012, for example, a farmer died after a herbicide containing paraquat accidentally sprayed into his mouth. And our research has found paraquat also causes serious environmental damage.

Brown dead plants
Paraquat is used to spray crops, but can harm humans and wildlife.
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Paraquat: the story so far

Paraquat is the active ingredient in Gramoxone, among other products. It has been used since the 1950s, mostly to control grass and weeds around crops such as rice, cotton and soybeans.

Paraquat is registered as a schedule 7 poison on the national registration scheme, meaning its use is strictly regulated.

Suppliers of paraquat say it should not be banned, insisting herbicides containing it are safe for people and the environment when used for their intended purpose and according to label instructions.

Farmers have also argued against a ban, saying it would force them to use more expensive, less effective alternatives and reduce crop yield.

Paraquat has been banned in more than 50 countries, including the United Kingdom, China, Thailand and European Union nations. However, it’s still widely used by farmers in the developing world, and in Australia and the United States.




Read more:
Ban on toxic mercury looms in sugar cane farming, but Australia still has a way to go


Paraquat bottles with Thai language label
Paraquat is now banned in Thailand, among other nations.
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A chemical peril

Paraquat is a non-selective herbicide, which means it kills plants indiscriminately. It does so by inhibiting photosynthesis, the process by which plants convert sunlight into chemical energy.

Paraquat stays in the environment for a long time. It’s well known for causing collateral damage to plants and animals. For example, even at very low concentrations, paraquat has been found to harm the growth of honey bee eggs.

Exposure to living organisms can occur by spray drift or when paraquat is sprayed on crops then reaches surface and underground sources of drinking water.

Paraquat can have unintended consequences for biological organisms and the environment, particular in waterways. Our recent paper summarised the evidence of the harmful effects of paraquat at realistic field concentrations.

We found evidence that paraquat can severely inhibit healthy bacterial growth in aquatic environments, which in turn affects nutrient cycling and the decomposition of organic matter.

The research also shows paraquat can distort tropical freshwater plankton communities by negatively impacting metabolic diversity and reducing phytoplankton growth.

In fish, paraquat has been found to lead to a death rate of common carp three times higher than the weed it is used to control.

Common carp in the wild
Research shows paraquat kills common carp at a higher rate than the weed it’s meant to control.
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‘One sip can kill’

In addition to the environmental effects, of course, paraquat is highly toxic to humans. A small accidental sip can be fatal and there is no antidote.

The US Centers for Disease Control and Prevention says paraquat is a leading cause of fatal poisoning in parts of Asia, the Pacific Islands, and South and Central Americas.

Paraquat enters the body through the skin, digestive system or lungs. If ingested in sufficient amounts, it causes lung damage, leading to pulmonary fibrosis and death through respiratory failure. The liver and kidney can also fail.

Several recent incidents in Australia demonstrate the risks of paraquat poisoning due to human error, even within the current strict regulations.

According to news reports, the Queensland farmer poisoned by paraquat in 2012 was filling a pressure pump to control weeds on his property. The unit cracked and paraquat sprayed over his body and face, entering his mouth.

In 2017, an adult with autism took a sip from a Coke bottle used to store paraquat. The bottle had been left in a disabled toilet at a sports ground in New South Wales. The man was initially given 12 hours to live, but fortunately recovered after two weeks in hospital.




Read more:
Pesticides and suicide prevention – why research needs to be put into practice


chemical being poured into pressure pump container
A Queensland farmer died in 2012 after paraquat accidentally sprayed in his face when he filled a pressure pump.
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Paraquat: not worth the risk

There’s a growing awareness of the threats posed by global chemical use. In fact, a paper released this week suggests the potential risk to humanity is on a scale equivalent to climate change.

Paraquat is no doubt an effective herbicide. However, in our view, the risks it poses to humans and the environment outweigh the agricultural benefits.

Current regulation in Australia has not prevented harm from paraquat. It’s time for Australia to join the movement towards a global ban on this toxic chemical.




Read more:
The real cost of pesticides in Australia’s food boom



Editor’s note: the article has been updated to reflect the fact products other than Gramoxone also contain paraquat.The Conversation

Nedeljka Rosic, Senior Lecturer, Southern Cross University; Joanne Bradbury, Senior Lecturer, Evidence Based Healthcare, Faculty of Health, Southern Cross University, and Sandra Grace, Professor, Southern Cross University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Research Check: do we need to worry about glyphosate in our beer and wine?



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Research out of the US tested different varieties of beer and wine for the presence of glyphosate – but there’s lots to consider when interpreting the findings.
From shutterstock.com

Ian Musgrave, University of Adelaide

Glyphosate is back in the news again. The common weed killer, which has previously attracted controversy for its possible link to cancer, has been found in beer and wine.

Researchers in the US tested 15 different types of beer and five different types of wine, finding traces of the pesticide in 19 out of the 20 beverages.

So how much should we be worried? Hint: not at all. The amount detected was well below a level which could cause harm. And there are insufficient details in the methods section to feel confident about the results.




Read more:
Stop worrying and trust the evidence: it’s very unlikely Roundup causes cancer


How was this study conducted?

One of the first things I do when evaluating a piece of research is to check the methods – so how the researchers went about collecting the data. What I found didn’t fill me with confidence.

The authors say they set up their experiment based on a technique called a mass spectroscopy method. This methodology has been used to measure the quantities of glyphosate in milk (but not alcoholic drinks). Mass spectroscopy is a very sensitive and specific method, and the authors quote the concentrations that can be reliably detected in milk with this approach.

But the method they actually used is called enzyme linked immunosorbent assay (ELISA). Importantly, you can’t use the concentrations that can be reliably detected with the mass spectroscopy to describe ELISA sensitivity. They’re not compatible.

Glyphosate is the pesticide which makes up many weed killers.
From shutterstock.com

ELISA is sensitive, but typically not as sensitive as mass spectroscopy, which uses an entirely different physical method to measure glyphosate.

ELISA also has issues of cross contamination. Biological samples for glyphosate measurement, whether ELISA or mass spectroscopy, need careful sample preparation to avoid cross-reaction with any other materials in the sample such as the common amino acid glycine, which looks quite similar to glyphosate and is present in much higher quantities. But the authors didn’t give any detail about the sample preparation used.

These issues make it difficult to be confident in the results.

We’ve seen this before with claims of detection of glyphosate in breast milk, which could not be duplicated. So given the lack of detail around the methodologies used, we should be cautious about taking these figures at face value.

What did they find?

For the sake of argument, let’s accept the researchers’ values and take a look at what they mean.

The highest level of glyphosate they measured was 51.4 parts per billion in one wine (in most of the beverages they found much less). That’s equivalent to 0.0514 miligrams per litre (mg/L).

The authors cite California’s Office of Environmental Health Hazard’s proposed “No Significant Risk Level” for glyphosate consumption of 0.02 mg/kg body weight/day. The limits are based on body weight, so a heavier person can be exposed to more than a person who weighs less, taking into account body volume and metabolism.

This is much lower than the EU Food Safety Authorities’ and Australia’s regulatory allowable daily intake of 0.3 mg/kg body weight/day.

But again, for argument’s sake, let’s use the Californian proposed limits and look at the wine in which the researchers measured the highest amount of glyphosate. With those limits, an average Australian male weighing 86kg would need to drink 33 litres of this wine every day to reach the risk threshold. A 60kg person would need to drink 23 litres of this wine each day.




Read more:
Drink, drank, drunk: what happens when we drink alcohol in four short videos


If you’re drinking 33 litres of wine a day you have much, much bigger problems than glyphosate.

Alcohol is a class 1 carcinogen. Those levels of alcohol consumption would give you a five times greater risk of head, neck and oesophageal cancer (and an increased risk of other cancers). The risk of glyphosate causing cancer is nowhere near these levels. The irony is palpable.

This isn’t even taking into account the likelihood of dying of alcohol poisoning by drinking at this level – which will get you well before any cancer.

And that’s using the highly conservative Californian limits. Using the internationally accepted limits, an average adult male would have to drink over 1,000 litres of wine a day to reach any level of risk.

So how should we interpret the results?

The report does not contain a balanced representation of the risks of glyphosate.

They cite the International Agency for Research on Cancer’s finding of glyphosate as class 2 (probably) carcinogenic (alcohol is class 1, a known carcinogen).

But they don’t mention the European Food Safety authority finding that glyphosate posed no risk of cancer, or the WHO Joint Meeting on Pesticide Residues report showing no significant cancer risk to consumers under normal exposure.

They cite a paper on glyphosate supposedly increasing the rate of breast cancer cell growth, but not the papers that find no such thing.

They don’t cite the most important study of human exposure, the Agricultural Health Study which is the largest and longest study of the effect of glyphosate use. This study found no significant increase in cancer in highly exposed users.




Read more:
Research Check: can even moderate drinking cause brain damage?


The “report” claiming that there is glyphosate in wine and beer provides inadequate information to judge the accuracy of the claimed detection, and does not put the findings in context of exposure and risk.

Even taking their reported levels at face value, the risk from alcohol consumption vastly outweighs any theoretical risk from glyphosate. Their discussion does not fairly consider the evidence and is weighted towards casting doubt over the safety of glyphosate.

So you may enjoy your beer and wine (in moderation), without fear of glyphosate.

Blind peer review

This is a fair and accurate assessment of the study and its findings. That said, it is prudent for the scientific community to remain attentive to changes within the food supply and issues of potential risk to public health. Considering the increasing use of glyphosate by the food industry, we need continued diligence in this area. – Ben Desbrow


Research Checks interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one or more academics not involved with the study, and reviewed by another, to make sure it’s accurate.The Conversation

Ian Musgrave, Senior lecturer in Pharmacology, University of Adelaide

This article is republished from The Conversation under a Creative Commons license. Read the original article.

New research suggests common herbicides are linked to antibiotic resistance



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New Zealand researchers have found that the active ingredients in commonly-used weed killers like Round-up and Kamba can cause bacteria to become less susceptible to antibiotics.
from http://www.shutterstock.com, CC BY-ND

Jack Heinemann

Antibiotics are losing their ability to kill bacteria.

One of the main reasons for the rise in antibiotic resistance is the improper use of antibiotics, but our latest research shows that the ingredients in commonly-used weed killers like Round-up and Kamba can also cause bacteria to become less susceptible to antibiotics.

Herbicides induce gene activity

Already, about 700,000 deaths are attributable each year to infections by drug-resistant bacteria. A recent report projected that by 2050, 10 million people a year will die from previously treatable bacterial infections, with a cumulative cost to the world economy of $US100 trillion.

The bacteria we study are potential human pathogens. Seventy years ago pathogens were uniformly susceptible to antibiotics used in medicine and agriculture. That has changed. Now some are resistant to all but one or two remaining antibiotics. Some strains are resistant to all.


Read more: Drug resistance: how we keep track of whether antibiotics are being used responsibly


When bacteria were exposed to commercial herbicide formulations based
on 2,4-D, dicamba or glyphosate, the lethal concentration of various antibiotics
changed. Often it took more antibiotic to kill them, but sometimes it took less.
We showed that one effect of the herbicides was to induce certain genes that they all carry, but don’t always use.

These genes are part of the so-called “adaptive response”. The main elements of this response are proteins that “pump” toxins out of the cell, keeping intracellular concentrations sublethal. We knew this because the addition of a chemical inhibitor of the pumps eliminated the protective effect of the herbicide.

In our latest work, we tested this by using gene “knockout” bacteria, which had been engineered to lose just one pump gene. We found that most of the effect of the herbicide was explained by these pumps.

Reduced antibiotic use may not fix the problem

For decades we have put our faith in inventing new antibiotics above the wisdom
of preserving the effectiveness of existing ones. We have applied the same invention incentives to the commercialisation of antibiotics as those used with mobile phones. Those incentives maximise the rate of product sales. They have saturated the market with phones, and they saturate the earth with antibiotic resistant bacteria.

Improper use of antibiotics is a powerful driver of the widespread resistance.
Knowing this naturally leads to the hypothesis that proper and lower use will make the world right again. Unfortunately, the science is not fully on the side of that hypothesis.

Studies following rates of resistance do generally find a decrease in resistance to specific drugs when their use is banned or decreased. However, the effect is not a restoration of a pre-antibiotic susceptibility, characterised by multi-year effectiveness of the antibiotic. Instead, resistance returns rapidly when the drug is used again.

This tells us that once resistance has stablised in populations of bacteria, suspended use may change the ratio of resistant to susceptible but it does not eliminate resistant types. Very small numbers of resistant bacteria can undermine the antibiotic when it is used again.

Herbicides and other pollutants mimic antibiotics

What keeps these resistant minorities around? Recall that bacteria are very
small, but there are lots of them; you carry 100 trillion of them. They are also found deep underground to high up in the atmosphere.

Because antibiotics are so powerful, they eliminate bacteria that are susceptible and leave the few resistant ones to repopulate. Having done so, we now have lots of bacteria, and lots of resistance genes, to get rid of, and that takes a lot of time.

As our work suggests, the story is even more complicated. We are inclined to think of antibiotics as medicine and agrichemicals, hand soaps, bug sprays and preservatives as different. Bacteria don’t do this. To them, they are all toxic.

Some are really toxic (antibiotics) and some not so much (herbicides). Bacteria are among the longest lived organisms on earth. Nearly four billion years of survival has taught them how to deal with toxins.

Pesticides as antibiotic vaccines

Our hypothesis is that herbicides immunise the bacteria from more toxic
toxins like antibiotics. Since all bacteria have these protections, the use of widely used products to which they are exposed is particularly problematic. So these products, among others, might keep bacteria ready for antibiotics whether or not we are using them.

We found that both the purified active ingredients and potential inert ingredients in weed killers caused a change in antibiotic response. Those inert ingredients are also found in processed foods and common household products. Resistance was caused below legally allowed food concentrations.

What does this all mean? Well for starters we may have to think more carefully about how to regulate chemical commerce. With approximately eight million manufactured chemicals in commerce, 140,000 new since 1950, and limited knowledge of their combination effects and breakdown products, this won’t be easy.

The ConversationBut neither is it easy to watch someone die from an infection we lost the power to cure.

Jack Heinemann, Professor of Molecular Biology and Genetics

This article was originally published on The Conversation. Read the original article.

Herbicide: RoundUp & Amphibians


The link below is to an article reporting on how RoundUp is altering the morphology of some tadpoles.

For more, visit:
http://www.matternetwork.com/2012/4/weed-killer-can-alter-shape.cfm