Underwater Australia
Daily Archives for March 19, 2019
Research Check: do we need to worry about glyphosate in our beer and wine?
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.
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.
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.
The summer bushfires you didn’t hear about, and the invasive species fuelling them
Author provided
Christine Schlesinger, Charles Darwin University and Barry Judd, Charles Darwin University
In January 2019, fires burned across a 100-kilometre length of the iconic Tjoritja National Park in the West MacDonnell Ranges, from Ormiston Gorge nearly to the edge of Alice Springs.
These fires affected an area comparable to the recent Tasmanian fires, but attracted relatively little national attention. This is partly because the fires in Tasmania were so unusual – but we believe the fires in central Australia were just as unexpected.
Read more:
Dry lightning has set Tasmania ablaze, and climate change makes it more likely to happen again
In the past, fires of this magnitude have tended to come after heavy rain that powers the growth of native grasses, providing fuel for intense and widespread fires. But our research highlights the new danger posed by buffel grass, a highly invasive foreigner sweeping across inland Australia and able to grow fast without much water.
Far from being pristine, Tjoritja and the Western MacDonnell Ranges are now an invaded landscape under serious threat. Our changing climate and this tenacious invader have transformed fire risk in central Australia, meaning once-rare fires may occur far more often.
Buffel grass in Australia
Buffel grass is tough and fast-growing. First introduced to Australia in the 1870s by Afghan cameleers, the grass was extensively planted in central Australia in the 1960s during a prolonged drought.
Introductions of the drought-resistant plant for cattle feed and dust suppression have continued, and in recent decades buffel grass has become a ubiquitous feature of central Australian landscapes, including Tjoritja.
Buffel grass has now invaded extensive areas in the Northern Territory, Queensland, Western Australia and South Australia and is spreading into New South Wales and Victoria. It was legally recognised as a key threat in 2014, but so far only South Australia has prohibited its sale and created statewide zoning to enforce control or destruction.
Buffel grass crowds out other plants, creating effective “monocultures” – landscapes dominated by a single species. In central Australia, where Aboriginal groups retain direct, active and enduring links to Country, buffel grass makes it hard or impossible to carry out important cultural activities like hunt game species, harvest native plant materials or visit significant sites.
But buffel grass isn’t only a threat to biodiversity and Indigenous cultural practices. In January the Tjoritja fires spread along dry river beds choked with buffel, incinerating many large old-growth trees. Much like the alpine forests of Tasmania, the flora of inland river systems has not adapted to frequent and intense fires.
We believe the ability of the fires to spread through these systems, and their increased intensity and size, can be directly attributed to buffel grass.
Fire and buffel grass
Because of the low average rainfall, widespread fires in central Australia have been rare in the recorded past, only following unusual and exceptionally high rainfall.
This extreme rain promoted significant growth of native grasses, which then provided fuel for large fires. There could be decades between these flood and fire cycles. However, since the Tjoritja (previously West MacDonnell Ranges) National Park was established in the 1990s, there have been three large-scale fires in 2001, 2011 and 2019.
What has changed? The 2001-02 and 2011-12 fires both came after heavy rainfall years. In fact, 2011 saw one of the biggest La Niña events on record.
Climate change predictions suggest that central Australia will experience longer and more frequent heatwaves. And although total annual rainfall may stay the same, it’s predicted to fall in fewer days. In other words, we’ll see heavy storms and rainfall followed by long heatwaves: perfect conditions for grass to grow and then dry, creating abundant fuel for intense fires.
Author provided
If central Australia, and Tjoritja National Park in particular, were still dominated by a wide variety of native grasses and plants, this might not be such a problem. But buffel grass was introduced because it grows quickly, even without heavy rain.
The fires this year were extraordinary because there was no unusually high rainfall in the preceding months. They are a portent of the new future of fire in these ecosystems, as native desert plant communities are being transformed into dense near-monocultures of introduced grass.
The fuel that buffel grass creates is far more than native plant communities, and after the fire buffel grass can regenerate more quickly than many native species.
So we now have a situation in which fuel loads can accumulate over much shorter times. This makes the risk of fire in invaded areas so high that bushfire might now be considered a perpetual threat.
Changing fire threat
In spinifex grasslands, traditional Aboriginal burning regimes have been used for millennia to renew the landscape and promote growth while effectively breaking up the landscape so old growth areas are protected and large fires are prevented. Current fire management within Tjoritja “combines traditional and scientific practices”.
However, these fire management regimes do not easily translate to river environments invaded by buffel grass. These environments have, to our knowledge, never been targeted for burning by Aboriginal peoples. Since the arrival of buffel grass, there is now an extremely high risk that control burns can spread and become out-of-control bushfires.
Even when control burns are successful, the rapid regrowth of buffel grass means firebreaks may only be effective for a short time before risky follow-up burning is required. And there may no longer be a good time of year to burn.
Read more:
How invasive weeds can make wildfires hotter and more frequent
Our research suggests that in areas invaded by buffel grass, slow cool winter burns – typical for control burning – can be just as, or more, damaging for trees than fires in hot, windy conditions that often cause fires to spread.
Without more effective management plans and strategies to manage the changing fire threat in central Australia, we face the prospect of a future Tjoritja in which no old-growth trees will remain. This will have a devastating impact on the unique desert mountain ranges.
We need to acknowledge that invasive buffel grass and a changing climate have changed the face of fire risk in central Australia. We need a coordinated response from Australia’s federal and state governments, or it will be too late to stop the ecological catastrophe unfolding before us.
The authors acknowledge the contribution of Shane Muldoon, Sarah White, Erin Westerhuis, CDU Environmental Science and Management students, and NT Parks and Wildlife staff to the research at experimental sites and ongoing tree monitoring in central Australia.
Christine Schlesinger, Senior Lecturer in Environmental Science and Ecology, Charles Darwin University and Barry Judd, Professor, Indigenous Social Research, Charles Darwin University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
How to neutralise your greenhouse gas footprint
Andrew Blakers, Australian National University
With time running out for us to make deep reductions in greenhouse emissions, you may well be wondering what you personally can do to minimise your own greenhouse footprint.
The average greenhouse emissions per Australian are the equivalent of 21 tonnes of carbon dioxide per year. How can you offset or neutralise your personal share of these carbon emissions in the most cost-effective way?
Read more:
We can be a carbon-neutral nation by 2050, if we just get on with it
There are some places where the government is willing to take the necessary action on your behalf. The ACT government, for example, is on track to eliminate greenhouse gas emissions generated within Canberra by 2045, and indeed by 2020 will make its own electricity sector carbon-neutral.
The latter feat was achieved by contracting several new zero-emission solar and wind farms to produce renewable electricity equivalent to Canberra’s consumption. Canberra retail electricity prices continue to be among the lowest in Australia.
Take advantage of solar and wind
If you don’t live in Canberra, you need another way to neutralise your emissions. Fortunately, the cost of solar photovoltaic (PV) and wind power have both fallen rapidly. Australia has long been in the midst of a boom in rooftop PV, and many Gigawatts of ground-mounted PV and wind farms are being built around the country. This has put Australia on track to reach 50% renewable electricity in 2024. Each Megawatt hour (MWh) of electricity generated by renewables reduces electricity from coal by a similar amount, and therefore avoids about 0.9 tonnes of carbon dioxide emissions.
https://datawrapper.dwcdn.net/7Gd1z/2/
The above pie chart, based on federal government data, shows the various sources of Australian greenhouse emissions in 2017. Electricity production is the largest source and can be neutralised by substituting PV and wind for coal and gas. Emissions from electricity use in commerce and industry, the land sector, industrial processes and high temperature heat is largely beyond your control, however, so it’s perhaps best to focus your attention closer to home.
Cost-effective action
However, putting solar panels on your roof, switching to an electric car, and substituting electric heat pumps for gas water and space heating can (or soon will) be cost-effective steps that you can take to reduce your greenhouse footprint. And in the long term, these will either pay for themselves or even end up saving you money.
Read more:
‘Renewable energy breeding’ can stop Australia blowing the carbon budget – if we’re quick
A 10-kilowatt solar PV system installed on your roof will produce about 14 MWh of electricity per year. Since coal power stations produce 0.9 tonnes of carbon dioxide per MWh this save about 12 tonnes of CO2 emissions per year.
To offset your 21 tonnes of CO2 per year, you would therefore need to install 15kW of solar PV capacity for each person who lives in your house. So if four people live in your house, you would need a 60kW solar system.
But a typical rooftop PV system now has a rating of 5-15kW, and many homes lack the roof space needed to install a larger system. Ways to address this are described below.
Road to success
A typical car produces about 190 grams of CO2 per kilometre of travel, and the average Australian car travels 15,500 km per year, thus producing 3 tonnes of CO2.
Moderately priced electric cars are expected to be widely available in the early 2020s, which can travel about 6,000 km for each MWh of electricity consumed.
Once the premium for an electric vehicle drops below about A$10,000, the lifetime cost of an electric car (including buying, maintaining and charging it) will be competitive with conventional cars.
A 2kW PV panel on your house roof will produce enough electricity for 16,000km of electric car driving per year, thus offsetting your entire emissions from motoring (3 tonnes of CO2), assuming you drive an average amount each year and previously drove a conventional model.
Off the gas
Most natural gas use within a home is for water and space heating. Gas can readily be replaced by electric heat pumps, which move heat from the air outside the home into your hot water tank or reverse cycle air conditioning system. Heat pumps typically move four units of heat for each unit of electricity consumed and can be readily powered by rooftop solar panels, supplemented by electricity from the grid.
For the average household, replacement gas with heat pumps can readily reduce household greenhouse gas emissions by up to 5 tonnes per year, at lower lifecycle cost than using gas. Replacement of gas cookers with electric induction cookers allows elimination of gas altogether from the home.
Fly less
Limiting air travel is one of the most effective tactics to cut your personal emissions. Short-haul flights or flights with few passengers increase the emissions intensity per passenger. A mostly full return trip from Australia to London (34,000km) will typically generate about 4 tonnes of CO₂ per passenger.
When you do decide to fly, think about how you can offset the emissions directly. Adding 1kW to your rooftop PV system can offset one return trip to London for one person every 3 years.
Read more:
Why our carbon emission policies don’t work on air travel
Will it pay for itself?
Now that we’ve looked at these various strategies, let’s now consider a family home with three occupants and one car. A 10kW PV system on the roof can make a substantial reduction in their greenhouse footprint by offsetting 14 tonnes of CO2 per year. Switching to an electric car saves 3 tonnes per year and substituting electric heat pumps for gas saves a further 1- 5 tonnes per year.
An additional 5 kW of rooftop PV is needed to neutralise an average amount of air travel, and to power the electric car and heat pumps. This 15kW system would cost about A$20,000 up front and would last 25 years. However, rooftop PV systems are now so cheap compared with the retail electricity tariff that the money invested is generally recovered within 10 years.
The total emissions savings estimated above are about 25 tonnes per year, per household, which is still significantly short of the 63 tonnes (on average) that this family emits. To be fully carbon-neutral, one option is for the family to invest in a wind or solar farm.
The required share of a wind farm or solar farm is about 10 kW or 20 kW respectively per three-person family, noting that a 3MW wind turbine produces nearly double the amount of electricity per year of a 3MW PV farm (single axis tracking), which in turn produces 40% more electricity per year than an equivalent amount of roof-mounted solar panels.
The up-front cost of this investment would be about A$25,000 per family, and it would return a steady income sufficient to repay the initial outlay (with interest) over the 25-year lifetime of the system.
So in summary, assuming that you have the means to meet the (not insubstantial) upfront costs, doing your part to preserve a living and vibrant planet for our children ultimately has a low or even negative net cost.
Andrew Blakers, Professor of Engineering, Australian National University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Kevin's Walk on the Wild Side 