Tag Archives for Mercury
A tale of two valleys: Latrobe and Hunter regions both have coal stations, but one has far worse mercury pollution
Larissa Schneider, Australian National University; Anna Lintern, Monash University; Cameron Holley, UNSW; Darren Sinclair, University of Canberra; Neil Rose, UCL; Ruoyu Sun, and Simon Haberle, Australian National UniversityWe know coal-fired power stations can generate high levels of carbon dioxide, but did you know they can be a major source of mercury emissions as well?
Our new research compared the level of mercury pollution in the Hunter Valley in New South Wales and the Latrobe Valley in Victoria.
And we found power stations in the Latrobe Valley emit around 10 times more mercury than power stations in the Hunter Valley. Indeed, the mercury level in the Latrobe Valley environment is 14 times higher than what's typically natural for the region.
So why is there such a stark difference between states? Well, it has a lot to do with regulations.
Following a NSW requirement for power stations to install pollution control technology, mercury levels in the environment dropped. In Victoria, on the other hand, coal-fired power stations continue to operate without some of the air pollution controls NSW and other developed countries have mandated.
To minimise the safety risks that come with excessive mercury pollution, coal-fired power stations in all Australian jurisdictions should adopt the best available technologies to reduce mercury emissions.
A dangerous neurotoxin
Mercury is a neurotoxin, which means it can damage the nervous system, brain and other organs when a person or animal is exposed to unsafe levels.
Coal naturally contains mercury. So when power stations burn coal, mercury is released to the atmosphere and is then deposited back onto the Earth's surface. When a high level of mercury ends up in bodies of water, such as lakes and rivers, it can be transferred to fish and other aquatic organisms, exposing people and larger animals to mercury that feed on these fish.
The death of coal-fired power is inevitable — yet the government still has no plan to help its workforce
Mercury does not readily degrade or leave aquatic environments such as lakes and rivers. It's a persistent toxic element — once present in water, it's there to stay.
The amount of mercury emitted depends on the type of coal burnt (black or brown) and the type of pollution control devices the power stations use.
The Latrobe Valley stations in Victoria burn brown coal, which has more mercury than the black coal typically found in NSW. Despite this, Victorian regulations have historically not placed specific limits on mercury emissions.
In contrast, NSW power plants are required to use "bag filters", a technology that's used to trap mercury (and other) particles before they enter the atmosphere.
While bag filters alone fall short of the world's best practices, they can still be effective. In fact, after bag filters were retrofitted to Hunter Valley's Liddell power station in the early 1990s, mercury deposition in the surrounding environment halved.
Mercury deposited in sediments of Lake Glenbawn (left) in the Hunter Valley and Traralgon Railway Reservoir (right) in the Latrobe Valley.
The best available technology to control mercury emissions from coal-fired power plants is a combination of "wet flue-gas desulfurization" (which removes mercury in its gaseous form) and bag filters (which removes mercury bound to particles).
This is what's been adopted across North America and parts of Europe. It not only filters out mercury, but also removes sulphur dioxide, nitrogen oxides and other toxic air compounds.
Using lake sediments to see into the past
Lake sediments can capture mercury deposited from the atmosphere and from surrounding areas. Sediments that contain this mercury accumulate at the bottom of lakes over time — the deeper the sediment, the further back in time we can analyse.
We took sediment samples from lakes in the Latrobe and Hunter valleys, and dated them back to 1940 to get a historical record of mercury deposition.
This information can help us understand how much naturally occurring mercury there was before coal-fired power stations were built, and therefore show us the impact of burning coal.
Lake Narracan: one of the lakes we sampled sediments from, near a coal-fired power station in Latrobe Valley.
Larissa Schneider, Author provided
From these records, we found the adoption of bag filters in the Hunter Valley corresponded with mercury depositions declining in NSW from the 1990s.
In contrast, in Victoria, where there's been no such requirement, mercury emissions and depositions have continued to increase since Hazelwood power station was completed in 1971.
What do we do about it?
In March, the Victorian government announced changes to the regulatory licence conditions for brown coal-fired power stations. Although mercury emissions allowances have been included for the first time, they're arguably still too high, and there's no requirement to install specific pollution control technologies.
There's a risk this approach won't reduce mercury emissions from existing levels. Victoria should instead consider more ambitious regulations that encourage the adoption of best practice technology to help protect local communities and the environment.
Loy Yang power station, Victoria's largest, burns brown coal which contains more mercury.
Another vital step toward protecting human health and the environment from mercury is for the federal government to ratify the Minamata Convention on Mercury, an international treaty to protect human health and the environment from mercury.
Despite signing the convention in 2013, the Australian government is yet to ratify it, which is required to make it legally binding in Australia.
Ratifying the convention will oblige state and federal governments to develop and implement a strategy to reduce mercury emissions, including from coal-fired power stations across Australia. And this strategy should include rolling out effective technologies — our research shows it can make a big difference.
The authors acknowledge Lauri Myllyvirta from the Centre for Research on Energy and Clean Air for her contributions to this article.
Hazelwood power station: from modernist icon to greenhouse pariah
Larissa Schneider, DECRA fellow, Australian National University; Anna Lintern, Lecturer, Monash University; Cameron Holley, Professor, UNSW; Darren Sinclair, Professor, University of Canberra; Neil Rose, Professor of Environmental Pollution and Palaeolimnology, UCL; Ruoyu Sun, Associate Professor, and Simon Haberle, Professor, Australian National University
July 12, 2021 by particularkev	Categories: Air Pollution, Australia, Electricity, Hunter Valley, Latrobe, New South Wales, Pollution, Victoria	| Tags: article, Australia, coal-fired, electricty, Hunter Valley, Latrobe Valley, Mercury, New South Wales, NSW, pollution, power station
Ban on toxic mercury looms in sugar cane farming, but Australia still has a way to go
Phil / CC BY (https://creativecommons.org/licenses/by/2.0)
Larissa Schneider, Australian National University; Cameron Holley, UNSW; Darren Sinclair, University of Canberra, and Simon Haberle, Australian National University
This month, federal authorities finally announced an upcoming ban on mercury-containing pesticide in Australia. We are one of the last countries in the world to do so, despite overwhelming evidence over more than 60 years that mercury use as fungicide in agriculture is dangerous.
Mercury is a toxic element that damages human health and the environment, even in low concentrations. In humans, mercury exposure is associated with problems such as kidney damage, neurological impairment and delayed cognitive development in children.
Australia emits mercury at double the global average
The ban will prevent about 5,280 kilograms of mercury entering the Australian environment each year.
But Australia is yet to ratify an international treaty to reduce mercury emissions from other sources, such as the dental industry and coal-fired power stations. This is our next challenge.
Prime Minister Scott Morrison visiting a sugar cane farm in 2019. Mercury-containing pesticides will be banned.
Cameron Laird/AAP
A mercury disaster
Mercury became a popular pesticide ingredient for agriculture in the early 1900s, and a number of poisoning events ensued throughout the world.
They include the Iraq grain disaster in 1971-72, when grain seed treated with mercury was imported from Mexico and the United States. The seed was not meant for human consumption, but rural communities used it to make bread, and 459 people died.
In the decades since, most countries have banned the production and/or use of mercury-based pesticides on crops. In 1995 Australia discontinued their use in most applications, such as turf farming.
Emissions of the element mercury are a threat to human health and the environment.
Despite this, authorities exempted a fungicide containing mercury known as Shirtan. They restricted its use to sugar cane farming in Queensland, New South Wales, Western Australia and the Northern Territory.
According to the sugar cane industry, about 80% of growers use Shirtan to treat pineapple sett rot disease.
But this month, the Australian Pesticides and Veterinary Medicines Authority cancelled the approval of the mercury-containing active ingredient in Shirtan, methoxyethylmercuric chloride. The decision was made at the request of the ingredient's manufacturer, Alpha Chemicals.
Shirtan's registration was cancelled last week. It will no longer be produced in Australia, but existing supplies can be sold to, and used by, sugar cane farmers for the next year until it is fully banned.
Workers and nature at risk
Over the past 25 years, Australia's continued use of Shirtan allowed about 50,000 kilograms of mercury into the environment. The effect on river and reef ecosystems is largely unknown.
What is known is that mercury can be toxic even at very low concentrations, and research is needed to understand its ecological impacts.
The use of mercury-based pesticide has also created a high risk of exposure for sugar cane workers. At most risk are those not familiar with safety procedures for handling toxic materials, and who may have been poorly supervised. This risk has been exacerbated by the use itinerant workers, particularly those from a non-English speaking background.
South Sea Islanders hoeing a cane field in Queensland, 1902. Cane workers have long been exposed to mercury.
Further, in the hot and humid conditions of Northern Australia, it has been reported that workers may have removed protective gloves to avoid sweating. Again, research is needed to determine the implication of these practices for human health.
To this end, Mercury Australia, a multi-disciplinary network of researchers, has formed to address the environmental, health and other issues surrounding mercury use, both contemporary and historical.
Australia is yet to ratify
The Minamata Convention on Mercury is a global treaty to control mercury use and release into the environment. Australia signed onto the convention in 2013 but is yet to ratify it.
Until the treaty is ratified, Australia is not legally bound to its obligations. It also places us at odds with more than 100 countries that have ratified it, including many of Australia's developed-nation counterparts.
Australia's outlier status in this area is shown in the below table:
Accession, acceptance or ratification have the same legal effect, where parties follow legal obligations under international law.
Mercury-based pesticide use was one of Australia's largest sources of mercury emissions. But if Australia ratifies the convention, it would be required to control other sources of mercury emissions, such as dental amalgam and the burning of coal in power stations.
The three active power stations in the Latrobe Valley, for example, together emit about 1,200 kilograms of mercury each year.
The coal-burning Mount Piper Power station near Lithgow in NSW. Government efforts to reduce mercury emissions should focus on coal plants.
David Gray/Reuters
Time to look at coal
If Australia ratified the Minamata Convention, it would provide impetus for a timely review and, if necessary, update of mercury regulations across Australia.
Emissions from coal-fired power stations in Australia are regulated by the states through pollution control licences. Some states would likely have to amend these licences if Australia ratified the convention. For example, Victorian licences for coal-fired power stations currently do not include limits on mercury emissions.
Pollution control technologies were introduced at Australian coal plants in the early 1990s. But they do not match state-of-the-art technologies applied to coal plants in North America and Europe.
Why won't Australia ratify an international deal to cut mercury pollution?
Australian environment authorities have been examining the implications of ratifying the convention. But progress is slow.
The issue of mercury emissions does not attract significant public or political attention. But there is a global scientific consensus that coordinated international action is needed.
The pesticide phase-out and ban is an important step. But Australia still has a way to go.
Larissa Schneider, DECRA fellow, Australian National University; Cameron Holley, Professor, UNSW; Darren Sinclair, Professor, University of Canberra, and Simon Haberle, Professor, Australian National University
June 27, 2020 by particularkev	Categories: Australia, Farming	| Tags: agriculture, Australia, ban, farming, Mercury, sugar cane, toxic | Leave a comment
Mercury pollution from decades past may have been re-released by Tasmania's bushfires
Tasmania's fires may have released mercury previously absorbed by trees.
AAP Image
Larissa Schneider, Australian National University; Kathryn Allen, University of Melbourne, and Simon Haberle, Australian National University
Tasmania's bushfires may have resulted in the release of significant amounts of mercury from burnt trees into the atmosphere. Our research shows that industrial mercury pollution from decades past has been locked up in west Tasmanian trees.
Mercury occurs naturally in Earth's crust. Over the past 200 years, industrial activities have mobilised mercury from the crust and released it into the atmosphere. As a consequence, atmospheric mercury concentrations are now three to four times higher than in the pre-industrialisation era.
Mining is the largest source of the global atmospheric mercury, accounting for 37% of mercury emissions. When Europeans first arrived in Australia, there was, of course, no Environmental Protection Act in place to limit emissions from industrial activities. In western Tasmania, where mining has occurred for more than a century, this meant mercury was being released without control into the local atmosphere until changes in technology, market conditions, and later, regulation, conspired to reduce emissions.
Because mercury is also very persistent in the environment, past mining activity has generated a reservoir of mercury that could be released to the atmosphere under certain conditions. This is a concern because even small amounts of mercury may be toxic and may cause serious health problems. In particular, mercury can threaten the normal development of a child in utero and early in its life.
Tree rings can reveal past mercury contamination
How much mercury has been released into the Australian environment and when has remained largely unknown. However, in a new study we show how mercury levels in Tasmania have dramatically changed over the past 150 years due to mining practices. Long-lived Huon pine, endemic to western Tasmania, is one of the most efficient bioaccumulators of mercury in the world. This makes it a good proxy for tracking mercury emissions in western Tasmania. If concentrations of mercury in the atmosphere are high in a given year, this can be detected in the annual ring of Huon pine for that year.
Mercury pollution from past mining practices in western Tasmania has left a lasting environmental legacy. The sampled trees contained a significant reservoir of mercury that was taken up during the peak mining period in Queenstown. Changes in mercury concentrations in the annual rings of Huon pine are closely aligned with changes in mining practices in the region.
Increased concentrations coincide with the commencement of pyritic copper smelting in Queenstown in 1896. They peak between 1910 and 1920 when smelting was at its height. In 1922, concentrations begin to decline in parallel with the introduction of a new method to separate and concentrate ores. This method required only one small furnace instead of 11 large ones. In 1934, a new dust-collection apparatus was installed in the smelter's chimney, coinciding with the further decrease in mercury concentrations in nearby Huon pine.
Temporal tree rings of Huon pine, revealing historical mercury pollution.
Author provided
Toxic elements or compounds taken up by vegetation can also be released back into the local environment. Bushfires that burn trees that have accumulated mercury may release this mercury as vapour, dust or fine ash, potentially exposing people and wildlife to the adverse effects of mercury. It is estimated that bushfires release 210,000kg of mercury into the global atmosphere each year. As these fires become more frequent and ferocious in Australia, mercury concentrations in the atmosphere are likely to increase. Mercury released by bushfires can persist in the atmosphere for a year, allowing for long-distance transportation depending on wind strength and direction. This means that mining activity from over a century ago may have regional implications in the near future. The Tasmanian fires in December-February burned almost 200,000 hectares, including areas around Queenstown.
It is not currently possible to know how much mercury has been released by these recent fires. Our results simply highlight the potential risk and the need to better understand the amount of mercury taken up by vegetation that may one day be released back to the atmosphere via bushfires.
Re-release of historical mercury emissions by bushfires.
Dry lightning has set Tasmania ablaze, and climate change makes it more likely to happen again
Although there is no simple way to remove bio-accumulated mercury from trees, the history of mercury contamination recorded in tree rings provides important lessons. Decreased uptake of mercury after upgrades to the Queenstown copper smelter operations demonstrates the positive impact that good management decisions can have on the amount of mercury released into the environment.
To control mercury emissions globally, the United Nations Environment Programme (UNEP) has developed the Minamata Convention on Mercury. Its primary goal is to protect human health and the environment from the negative effects of mercury. Australia has signed the convention and but has yet to ratify it. Once ratified, Australia would be required to record sources of mercury and quantify emissions, including those from bushfires.
But to do this, the government must first be able to identify environmental reservoirs of mercury. Our study, the first of its kind in the Southern Hemisphere, shows that the long-lived Huon pine can be used to for this purpose. Further work to determine what other tree species record atmospheric emissions of mercury and other toxic elements in other regions of Australia is required.
Larissa Schneider, DECRA fellow, Australian National University; Kathryn Allen, Academic, Ecosystem and Forest Sciences, University of Melbourne, and Simon Haberle, Professor, Australian National University
April 16, 2019 by particularkev	Categories: Air Pollution, Australia, Bushfires/Wildfires, Tasmania	| Tags: article, Australia, bushfires, Mercury, pollution, released, Tasmania | Leave a comment
Mercury from the northern hemisphere is ending up in Australia
Mercury pollution, often released from gold mining and coal power stations, is a global problem.
Jenny Fisher, University of Wollongong; Dean Howard, Macquarie University; Grant C Edwards, Macquarie University, and Peter Nelson, Macquarie University
Mercury pollution has a long legacy in the environment. Once released into the air, it can cycle between the atmosphere and ecosystems for years or even decades before ending up deep in the oceans or land.
The amount of mercury in the ocean today is about six times higher than it was before humans began to release it by mining. Even if we stopped all human mercury emissions now, ocean mercury would only decline by about half by 2100.
To address the global and long-lasting mercury problem, a new United Nations treaty called the Minamata Convention on Mercury came into effect last month. The treaty commits participating countries to limit the release of mercury and monitor the impacts on the environment. Australia signed the Convention in 2013 and is now considering ratification.
Read more: Why won't Australia ratify an international deal to cut mercury pollution?
Until now, we have only been able to guess how much mercury might be in the air over tropical Australia. Our new research, published in the journal Atmospheric Chemistry and Physics, shows that there is less mercury in the Australian tropics than in the northern hemisphere – but that polluted northern hemisphere air occasionally comes to us.
A global problem
While most of mercury's health risks come from its accumulation in ocean food webs, its main entry point into the environment is through the atmosphere. Mercury in air comes from both natural sources and human activities, including mining and burning coal. One of the biggest mercury sources is small-scale gold mining – a trade that employs millions of people in developing countries but poses serious risks to human health and the environment.
Small-scale gold mining is an economic mainstay for millions of people, but it releases mercury directly into the air and water sources.
Once released to the air, mercury can travel thousands of kilometres to end up in ecosystems far away from the original source.
Measuring mercury in the tropics
While the United Nations was gathering signatures for the Minamata Convention, we were busy measuring mercury at the Australian Tropical Atmospheric Research Station near Darwin. Our two years of measurements are the first in tropical Australia. They are also the only tropical mercury measurements anywhere in the Maritime Continent region covering southeast Asia, Indonesia, and northern Australia.
We found that mercury concentrations in the air above northern Australia are 30-40% lower than in the northern hemisphere. This makes sense; most of the world's population lives north of the Equator, so most human-driven emissions are there too.
More surprising is the seasonal pattern in the data. There is more mercury in the air during the dry season than the wet season.
The Australian monsoon appears to be partly responsible for the seasonal change. The amount of mercury jumps up sharply at the start of the dry season when the winds shift from blowing over the ocean to blowing over the land.
In the dry season the air passes over the Australian continent before arriving at the site, while in the wet season the air usually comes from over the ocean to the west of Darwin.
Howard et al., 2017 (modified)
But wind direction can't explain the whole story. Mercury is likely being removed from the air by the intense rains that characterise the wet season. In other words, the lower mercury in the air during the wet season may mean more mercury is being deposited to the ocean and the land at this time of year. Unfortunately, there simply isn't enough information from Australian ecosystems to know how this impacts local plants and wildlife.
Fires also play a role. Mercury previously absorbed by grasses and trees can be released back to the atmosphere when the vegetation burns. In our data, we see occasional large mercury spikes associated with dry season fires. As we move into a bushfire season predicted to be unusually severe, we may see even more of these spikes.
Air from the north
Although mercury levels were usually low in the wet season, on a few days each year the mercury jumped up dramatically.
To figure out where these spikes were coming from, we used two different models. These models combine our understanding of atmospheric physics with real observations of wind and other meteorological parameters.
Both models point to the same source: air transported from the north.
Australia is usually shielded from northern hemispheric air by a "chemical equator" that stops air from mixing. This barrier isn't static – it moves north and south throughout the year as the position of the sun changes.
A few times a year, the chemical equator moves so far south that the top end of Australia actually falls within the atmospheric northern hemisphere. When this happens, polluted northern hemisphere air can flow directly to tropical Australia.
We observed 13 days when our measurement site near Darwin sampled more northern hemisphere air than southern hemisphere air. On each of these days, the amount of mercury in the air was much higher than on the days before or after.
Tracing the air backwards in time showed that the high-mercury air travelled over the Indonesian archipelago before arriving in Australia. We don't yet know whether that mercury came from pollution, fires, or a mix of the two.
The highest mercury is observed when the air comes from the northern hemisphere.
To effectively reduce mercury exposure in sensitive ecosystems and seafood-dependent populations around the world, aggressive global action is necessary.
The cross-boundary influences on mercury that we have observed in northern Australia highlight the need for the type of multinational collaboration that the Minamata Convention will foster.
Our new data establish a baseline for monitoring the effectiveness of new actions taken under the Minamata Convention. With the first Conference of the Parties having taken place last week, hopefully it will only be a matter of time before we begin to see the benefit.
Jenny Fisher, Senior Lecturer in Atmospheric Chemistry, University of Wollongong; Dean Howard, , Macquarie University; Grant C Edwards, Senior lecturer, Macquarie University, and Peter Nelson, Pro Vice Chancellor (Research Performance and Innovation), Macquarie University
October 3, 2017 by particularkev	Categories: Australia, Pollution	| Tags: article, Australia, hemisphere, Mercury, northern, pollution | Leave a comment
Robyn Schofield, University of Melbourne
A report released this week by advocacy group Environmental Justice Australia presents a confronting analysis of toxic emissions from Australia's coal-fired power plants.
The report, which investigated pollutants including fine particles, nitrogen oxides and sulfur dioxide, also highlights our deeply inadequate mercury emissions regulations. In New South Wales the mercury emissions limit is 666 times the US limits, and in Victoria there is no specific mercury limit at all.
This is particularly timely, given that yesterday the Minamata Convention, a United Nations treaty limiting the production and use of mercury, entered into force. Coal-fired power stations and some metal manufacturing are major sources of mercury in our atmosphere, and Australia's per capita mercury emissions are roughly double the global average.
In fact, Australia is the world's sixteenth-largest emitter of mercury, and while our government has signed the Minamata convention it has yet to ratify it. According to a 2016 draft impact statement from the Department of Environment and Energy:
Australia's mercury pollution occurs despite existing regulatory controls, partly because State and Territory laws limit the concentration of mercury in emissions to air […] but there are few incentives to reduce the absolute level of current emissions and releases over time.
Mercury can also enter the atmosphere when biomass is burned (either naturally or by people), but electricity generation and non-ferrous (without iron) metal manufacturing are the major sources of mercury to air in Australia. Electricity generation accounted for 2.8 tonnes of the roughly 18 tonnes emitted in 2015-16.
Mercury in the food web
Mercury is a global pollutant: no matter where it's emitted, it spreads easily around the world through the atmosphere. In its vaporised form, mercury is largely inert, although inhaling large quantities carries serious health risks. But the health problems really start when mercury enters the food web.
I've been involved in research that investigates how mercury moves from the air into the food web of the Southern Ocean. The key is Antartica's sea ice. Sea salt contains bromine, which builds up on the ice over winter. In spring, when the sun returns, large amounts of bromine is released to the atmosphere and causes dramatically named "bromine explosion events".
Essentially, very reactive bromine oxide is formed, which then reacts with the elemental mercury in the air. The mercury is then deposited onto the sea ice and ocean, where microbes interact with it, returning some to the atmosphere and methylating the rest.
Once mercury is methylated it can bioaccumulate, and moves up the food chain to apex predators such as tuna – and thence to humans.
As noted by the Australian government in its final impact statement for the Minamata Convention:
Mercury can cause a range of adverse health impacts which include; cognitive impairment (mild mental retardation), permanent damage to the central nervous system, kidney and heart disease, infertility, and respiratory, digestive and immune problems. It is strongly advised that pregnant women, infants, and children in particular avoid exposure.
Read more: Climate change set to increase air pollution deaths by hundreds of thousands
Australia must do better
A major 2009 study estimated that reducing global mercury emissions would carry an economic benefit of between US$1.8 billion and US$2.22 billion (in 2005 dollars). Since then, the US, the European Union and China have begun using the best available technology to reduce their mercury emissions, but Australia remains far behind.
But it doesn't have to be. Methods like sulfur scrubbing, which remove fine particles and sulfur dioxide, also can capture mercury. Simply limiting sulfur pollutants of our power stations can dramatically reduce mercury levels.
Ratifying the Minamata Convention will mean the federal government must create a plan to reduce our mercury emissions, with significant health and economic benefits. And because mercury travels around the world, action from Australia wouldn't just help our region: it would be for the global good.
In an earlier version of this article the standfirst referenced a 2006 study stating Australia is the fifth largest global emitter of mercury. Australia is now 16th globally.
Robyn Schofield, Senior Lecturer for Climate System Science and Director of Environmental Science Hub, University of Melbourne
August 17, 2017 by particularkev	Categories: Air Pollution, Australia, Pollution	| Tags: air pollution, Australia, average, double, emissions, global, Mercury | Leave a comment
April 18, 2015 by particularkev	Categories: Mercury, Space, video	| Tags: Mercury, space, video | Leave a comment