The construction industry is a major source of pollution, responsible for around 4% of particulate emissions, more water pollution incidents than any other industry, and thousands of noise complaints every year. Although construction activities also pollute the soil, the main areas of concern are: air, water and noise pollution.

Air Pollution

Construction activities that contribute to air pollution include: land clearing, operation of diesel engines, demolition, burning, and working with toxic materials. All construction sites generate high levels of dust (typically from concrete, cement, wood, stone, silica) and this can carry for large distances over a long period of time. Construction dust is classified as PM10 – particulate matter less than 10 microns in diameter, invisible to the naked eye.

Research has shown that PM10 penetrate deeply into the lungs and cause a wide range of health problems including respiratory illness, asthma, bronchitis and even cancer. Another major source of PM10 on construction sites comes from the diesel engine exhausts of vehicles and heavy equipment. This is known as diesel particulate matter (DPM) and consists of soot, sulphates and silicates, all of which readily combine with other toxins in the atmosphere, increasing the health risks of particle inhalation.

Diesel is also responsible for emissions of carbon monoxide, hydrocarbons, nitrogen oxides and carbon dioxide. Noxious vapours from oils, glues, thinners, paints, treated woods, plastics, cleaners and other hazardous chemicals that are widely used on construction sites, also contribute to air pollution.

Water Pollution

Sources of water pollution on building sites include: diesel and oil; paint, solvents, cleaners and other harmful chemicals; and construction debris and dirt. When land is cleared it causes soil erosion that leads to silt-bearing run-off and sediment pollution. Silt and soil that runs into natural waterways turns them turbid, which restricts sunlight filtration and destroys aquatic life.

Surface water run-off also carries other pollutants from the site, such as diesel and oil, toxic chemicals, and building materials like cement. When these substances get into waterways they poison water life and any animal that drinks from them. Pollutants on construction sites can also soak into the groundwater, a source of human drinking water. Once contaminated, groundwater is much more difficult to treat than surface water.

Noise Pollution

Construction sites produce a lot of noise, mainly from vehicles, heavy equipment and machinery, but also from people shouting and radios turned up too loud. Excessive noise is not only annoying and distracting, but can lead to hearing loss, high blood pressure, sleep disturbance and extreme stress. Research has shown that high noise levels disturb the natural cycles of animals and reduces their usable habitat.

Measures to Prevent Pollution

Good construction site practice can help to control and prevent pollution. The first step is to prepare environmental risk assessments for all construction activities and materials likely to cause pollution. Specific measures can then be taken to mitigate these risks:

• To prevent erosion and run-off, minimise land disturbance and leave maximum vegetation cover.
• Control dust through fine water sprays used to dampen down the site.
• Screen the whole site to stop dust spreading, or alternatively, place fine mesh screening close to the dust source.
• Cover skips and trucks loaded with construction materials and continually damp down with low levels of water.
• Cover piles of building materials like cement, sand and other powders, regularly inspect for spillages, and locate them where they will not be washed into waterways or drainage areas.
• Use non-toxic paints, solvents and other hazardous materials wherever possible
• Segregate, tightly cover and monitor toxic substances to prevent spills and possible site contamination.
• Cover up and protect all drains on site .
• Collect any wastewater generated from site activities in settlement tanks, screen, discharge the clean water, and dispose of remaining sludge according to environmental regulations.
• Use low sulphur diesel oil in all vehicle and equipment engines, and incorporate the latest specifications of particulate filters and catalytic converters.
• No burning of materials on site.
• Reduce noise pollution through careful handling of materials; modern, quiet power tools, equipment and generators; low impact technologies; and wall structures as sound shields.

Pressure to Clean Up

The UK Environment Agency and other government bodies are putting increasing pressure on construction companies to reduce pollution and conform to environmental regulations. In the past the pollution fines have been low and environmental regulations slack, and it could have been perceived as cheaper to pollute than to prevent pollution. This situation is now changing, and enforcement of environmental regulations is not only very expensive but can be irreversibly damaging to the reputation of a firm. Measures to reduce and control pollution are relatively inexpensive and cost-effective, and the construction industry needs to incorporate these into an environmental management strategy. By employing these practices, the construction industry is well positioned to clean up its act. Find out more about ecofriendly construction methods.

Source – Sustainablebuild.co.uk

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Flooding from Hurricane Harvey actually warped Earth’s crust

Harvey’s 275 trillion pounds of water was a heavy weight to carry.

Harvey as it intensified into a hurricane. (Photo: NOAA)

Who knew that slicing bagels was the fifth most treacherous task in the kitchen?

“Approach love and cooking with equal abandon,” advises the Dalai Lama, but emergency room doctors beg to differ. Although spending time in the kitchen can be magic for the soul, it can be brutal for the body. Most of us know we are supposed to handle razor-sharp knives and searing hot pans with care — but we persist in misusing them, not to mention all of the other dangers awaiting us in the kitchen. Consider the following:

1. Playing with fire

FEMA reports that cooking equipment, most often a range or stovetop, is the leading cause of reported home fires and home fire injuries in the United States. The agency, which notes that the leading cause of fires in the kitchen is unattended cooking, offers some tips for avoiding being a statistic:

• Stay in the kitchen when you are frying, grilling or broiling food. If you leave the kitchen for even a short period of time, turn off the stove.
• If you are simmering, baking, roasting or boiling food, check it regularly, remain in the home while food is cooking, and use a timer to remind you that you’re cooking.
• Keep anything that can catch fire — potholders, oven mitts, wooden utensils, paper or plastic bags, food packaging, towels or curtains — away from your stovetop.
• Keep the stovetop, burners and oven clean.
• Keep pets off cooking surfaces and nearby countertops to prevent them from knocking things onto the burner.
• Wear short, close-fitting or tightly rolled sleeves when cooking. Loose clothing can dangle onto stove burners and catch fire if it comes into contact with a gas flame or electric burner.

2. Contact burns from equipment

The oven is magic. No longer do we have to sear our food on an open fire like our ancestors did; we have a nifty box that keeps the heat contained and cooks our food to perfection. But all that heat combined with metal components and cookware leads to loads of burns. Quick tips (which are obvious, but good to keep in mind): Always use oven mitts, replace them when they’re old; don’t use a wet towel as an oven mitt; don’t reach your arm in to check baked goods, pull out the rack to test; don’t touch the stovetop; and stir simmering food with a wooden spoon, not a metal one, which will get hot.

3. Food burns

Some of the worst kitchen burns come from hot food, so avoid scalding yourself by following these rules:

• Use back burners when possible, or turn pot and pan handles in towards the counter when on the stove so that they can’t be knocked into and over by a passerby.
• Use a potholder when removing tops from cooking food to prevent the dreaded steam burn.
• Take caution with hot foods in the blender; they have a tendency to explode and splatter.
• Keep liquid away from hot oil; it will cause the oil to splatter.
• It may sound obvious, but always take extreme care with super hot food; it’s dangerous. For example, burn doctors hate instant soup because so many children end up in the hospital with serious burns from the hot broth and noodles from tipped instant soup cups.

Take the time to clean up spills as they happen. (Photo: wernimages/Shutterstock)

Up to four Queensland coalmines could be closed

UP TO FOUR Queensland coalmines could be closed after they allegedly failed their dust monitoring obligations.

The allegations relate to Glencore’s Oaky North and Oaky No.1 in central Queensland, along with Anglo’s Moranbah North and Grosvenor.

State Mines Minister Anthony Lynham said the underground mines had failed to meet their obligations during the second quarter of this year.

“I have been advised that the levels of non-compliance vary. However in my view, any failure to meet their safety and health obligation is not acceptable,” he said.

Source – The Morning Bulletin

Black lung disease: Tougher coal dust monitoring needed, new report finds

Tougher coal dust monitoring standards are needed in Australia to prevent the “unacceptable” spread of the deadly black lung disease, a new study has found.

In Queensland, there are seven cases of the disease, which was thought to have been eradicated three decades ago.

A clinical focus published on Monday in the Medical Journal of Australia recommended an industry-funded screening program for at-risk workers every three years and mandatory reporting of cases to a register.

Co-author of the report, Associate Professor Deborah Yates, said one tougher standard of exposure limit was also needed in Australia to help eradicate the disease.

Current coal dust exposure limits vary between states and show considerable variations of monitoring protocols between sites.

In Queensland, 3 milligrams of coal dust per metre cubed is allowed, whereas in New South Wales it is 2.5mg.

“And there have been calls nationally and internationally by occupational hygiene and medical experts to reduce that level to as low as one milligram per metre cubed,” Dr Yates said.

“It is unacceptable that any new cases of [pneumoconiosis] should be occurring in Australia in 2016.”

The report found NSW had probably been more stringent when it came to the regulation and implementation of screening.

Dr Yates, from Sydney’s St Vincent’s Hospital, said there had been recent reports which suggested a potential decline in exposure control could be behind the resurgence.

Dr Yates said a study by the Queensland Mines Inspectorate found long-wall miners were exposed to equal amounts or greater than the coal dust exposure limit.

The article comes two months after a Senate committee called for a national coal dust exposure standardand an industry fund to cover medical costs.

Better ventilation, dust suppression needed

Steve Smyth from the Construction, Forestry, Mining and Energy Union (CFMEU) wanted independent monitoring.

He also said the cutting speed of machines needed to be slowed down as well as having better ventilation, water spraying and dust suppression.

“Workers being able to feel they can raise concerns around safety, and not be disciplined or action taken against them, which is occurring now,” he said.

Queensland Resources Council chief executive Michael Roche said the industry was shocked by the resurgence of the disease.

He said the first step was prevention and if there was non-compliance with dust levels it was appropriate the Mines Inspectorate act and enforce the regulations.

“Our top priority is the health and safety of mine workers,” Mr Roche said.

Source – ABC.net

Dust Monitoring Equipment – providing equipment, services and training in dust fallout management to the mining industry.

The Mechanics of the Ear: How Hearing Works

Having a basic understanding of how hearing works can make treating hearing loss a less stressful process. Look for a hearing care provider or audiologist who offers workshops, educational resources, or uses tools that provide the patient clarity and control over the quality of their care.

Below are the basic elements of how sounds are received and interpreted as hearing.

• The outer ear collects sound waves and directs them into the external auditory canal.
• The ear canal carries sound waves to the eardrum (tympanic membrane).
• Sound waves cause the eardrum to vibrate.
• The bones in the middle ear (malleus, incus, and stapes) pick up vibrations from the  eardrum.
• The bones in the middle ear amplify the sound and transmit it to the inner ear.
• Vibrations pass through the oval window to the inner ear, setting the fluid inside the cochlea in motion.
• Special nerve cells (hair cells within the cochlea) then turn the sound waves into electrical impulses.
• The auditory nerve sends these electrical impulses to the brain’s central auditory cortex, where it is processed as sound.

Ringing in your Ears?

Are you hearing ringing, whistling, hissing, buzzing, or pulsing sounds?
You may be suffering from tinnitus. (Pronounced: tin-NIGHT-us or TIN-it-us.)

What is Tinnitus?

Tinnitus is a medical condition characterized by persistent ringing in one or both ears which can only be heard by the affected individual. It has also been described as whistling, hissing, buzzing, or pulsing in the ear.

These sounds may come and go; however, most experience symptoms 24 hours a day, seven days a week. The effects range from a slight annoyance to a severe disruption of everyday life. In fact, tinnitus is the number one complaint from United States Veterans and grows at 18 percent per year, and the American Tinnitus Association estimates that over 50 million Americans experience symptoms from tinnitus.

In many cases the distressing combination of tinnitus and hearing loss can be relieved with hearing aid technology. While worn, hearing aids can restore environmental sounds and help reduce the effects of tinnitus.

Other tinnitus treatment options are available through hearing care providers and audiologists including Tinnitus Retraining Therapy (TRT) and Tinnitus Retraining Instruments (TRI).

TRT combines low-level, steady background noises played through a device with counseling. It “retrains” the way a patient hears, helping them ignore the symptoms of tinnitus. TRI’s may be used in conjunction with TRT when deemed appropriate. These instruments fit within the ear and produce a faint but audible sound that can alleviate the symptoms of tinnitus.

Although there isn’t a single cure for tinnitus, many reputable hearing care providers and audiologists are experienced at providing individual solutions on a case-by-case basis. If ringing in your ears bothers you, please schedule an appointment with your provider to begin creating goals and solutions to improve your quality of life.

Hearing Loss – Source – HearingLoss.com

Dust Monitoring Equipment – providing equipment, services and training in dust fallout management to the mining industry.

Seventeen of Australia’s 20 dustiest coal mines, including the entire top nine, were in Queensland, according to the federal government’s latest National Pollution Inventory.

The data, which covered emissions in the 2015-16 financial year, showed the Peak Downs mine was the biggest generator of airborne pollution, with 30,576 tonnes of PM 10 particulates (10 micrometres or less in diameter) entering the atmosphere near Moranbah.

The Blackwater mine (28,135 tonnes) was second, with another Moranbah mine – Goonyella Riverside – third with 22,336 tonnes.

Blackwater produced the most PM 2.5 particulates (2.5 micrometres or less in diameter) in Australia, with 480 tonnes, followed by Peak Downs (418 tonnes) and Saraji, near Dysart, with 403 tonnes.

Clean Air Queensland spokesman Michael Kane said the nine mines in the national top 10 accounted for 40 per cent of the state’s industrial air pollution and something had to be done.

“The level of air pollution caused by the coal industry in Queensland is unacceptable and continues virtually unregulated,” he said.

“The re-emergence of black lung in Queensland coal workers highlights the problems we are facing in holding the government and the coal industry accountable.”

Black lung disease, once thought to have been eradicated, has had a resurgence in Queensland, with the CFMEU blaming poor dust management at mine sites.

The resurgence has prompted a government inquiry, which has heard details of systemic failures in the management and diagnosis of the disease, more formally known as coal miner’s pneumoconiosis.

“It is not just miners being exposed to elevated concentrations of coal dust,” Mr Kane said.

“Communities throughout the Queensland are being exposed to undisclosed and unregulated fine particle pollution concentrations.

“In south-east Queensland alone we have a situation where 40,000 children are attending school within one kilometre of millions of tonnes of uncovered coal trains as they make their way to the Brisbane port.”

Mr Kane said there needed to be more stringent dust mitigation regimes to protect the public from coal dust.

“We don’t need another inquiry or study, we need action,” he said.

“I think it’s clear that communities are facing a similar situation to workers in regards to regulatory failure on air pollution. I am very concerned about the tens of thousands of Queenslanders who live near coal mines, stockpiles, coal ports and uncovered coal transports.

“(Environment) Minister (Steven) Miles needs to significantly expand the state’s air pollution monitoring network, improve community access to monitoring data, review the pollution licences held by coal mines and other major polluters, and demand best practice pollution controls such as covering coal wagons and stockpiles.”

Dr Miles was not available for comment, but a Department of Environment and Heritage Protection spokeswoman said the NPI was not a measure of community exposure to pollutants.

“Many additional factors, including weather conditions and distance from emission sources, influence ambient air quality – the air-pollutant levels people are exposed to,” she said.

“In Queensland, ambient air quality is measured by the Queensland government’s statewide network of 28 fixed air-monitoring stations.”

The spokeswoman said “significant” air monitoring had been done around coal transport rail lines.

“Coal loads are covered with veneer prior to transport, a biodegradable substance that forms a crust on top of coal loads to prevent coal dust being blown off,” she said.

“Air monitoring has demonstrated that Queensland is meeting ambient air quality objectives adjacent to rail lines.”

The monitoring of mine sites themselves, the spokeswoman said, was performed by the mine operators.

“Air monitoring required under environmental authorities is designed to inform on off-site risks to air quality,” she said.

“It is not intended to address workplace health and safety issues such as black lung. Black lung disease is a workplace health and safety issue dealt with at a workplace level.”

Queensland Resources Council chief executive Ian Macfarlane said the overall figures were much less dramatic.

“Over the past two years, the NPI data has shown both national and Queensland emissions have been steadily reducing in both PM 2.5 and PM 10,” he said.

“Queensland has a rigorous and transparent system of compliance with dust monitoring levels and companies implement stringent measures to reduce emissions.

“The top priority is the health and safety of mine workers and the resources sector is committed to their protection.”

Coal Dust Polluters – Source – Sydney Morning Herald

Dust Monitoring Equipment – providing equipment, services and training in dust fallout management to the mining industry.

Image copyrightGETTY IMAGES

Airborne dust is normally seen as an environmental problem, but the lack of it is making air pollution over China considerably worse.

A new study suggests less dust means more solar radiation hits the land surface, which reduces wind speed.

That lack of wind in turn leads to an accumulation of air pollution over heavily populated parts of China.

The researchers found that reduced dust levels cause a 13% increase in human-made pollution in the region.

Sands from the Gobi

Hundreds of millions of people across China continue to be impacted by air pollution from factories and coal-fired power plants.

Studies suggest that the dirty air contributes to 1.6 million deaths a year, about 17% of all mortalities.

But this new research says that the human-induced pollution is being made worse or better by naturally occurring dust that blows in from the Gobi desert.

Using models to simulate 150 years of wind and dust patterns in the region, the researchers found that the dust deflects significant amounts of sunlight.

Without it, more heat from the Sun hits the land. Differences in the temperatures between land and sea cause the winds to blow. Without the dust, the land warms up more and that changes the temperature differential with the sea leading to weaker breezes – and more air pollution.

Image copyrightGETTY IMAGES

“There are two dust sources. One is the Gobi and the other is the highlands of north-west China, but we found the Gobi had much more influence,” said lead author Yang Yang, from the Pacific Northwest National Laboratory in Washington State, US.

“Less dust in the atmosphere causes more solar radiation to reach the surface. It weakens the temperature difference between the land and the sea and impacts the circulation of the winds and causes a stagnation over eastern China and that causes an accumulation of air pollution.”

Small change, big impact

The decreases in dust emissions are considerable, varying by almost a third. The impact on winds speeds are quite small by comparison, a reduction of barely more than one-tenth of one mile per hour.

However, when this takes place on a large scale over a wide region, the small change in speed means a 13% increase in the amount of air pollution over eastern China during the winter.

Another study has recently shown a link between declining Arctic sea ice and a major air pollution event in China in 2013.

The authors of the new study believe that both theories could be true.

“Our study has the same mechanism: the weakening of winds causes more pollution, and what is behind this needs to be studied,” said Yang Yang.

“We have two views on this kind of weakening of wind. They found the sea ice, we found the dust-wind interaction can also lead to weakening of the wind. I think both of them are important.”

The researchers believe that the study may inform broader questions about how natural and human-created aerosols interact.

Many parts of the world, in addition to China, are now suffering from increased levels of air pollution and understanding how dust, winds and emissions work together may help limit some of the worst impacts of dirty air.

One of the key lessons from this study is that the absence of dusty conditions could mean the air you are breathing is worse for you, not better.

“You’re damned if you do, damned if you don’t,” said Prof Lynn Russell from the Scripps Institution of Oceanography in California.

“Dust emissions can impair visibility, but they are not so harmful in terms of air quality,” she told BBC News.

“If it’s not a dusty year, you may be happy and spending more time outdoors because you don’t have this dust in the way, but you are actually going out to spend more time in more toxic air.”

The study has been published in the journal Nature Communications.

Lack of dust makes China’s air pollution much worse – Source – BBC.com

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Most current plastics are made from oil, which is unsustainable. However, scientists from the Centre for Sustainable Chemical Technologies (CSCT) at the University of Bath have developed a renewable plastic from a chemical called pinene found in pine needles.

Pinene is the fragrant chemical from the terpene family that gives pine trees their distinctive “Christmas smell” and is a waste product from the paper industry.

The researchers hope the plastic could be used in a range of applications, including food packaging, plastic bags and even medical implants.

Making renewable plastics from trees

Degradable polyesters such as PLA (polylactic acid) are made from crops such as corn or sugar cane, but PLA can be mixed with a rubbery polymer called caprolactone to make it more flexible. Caprolactone is made from crude oil, and so the resulting plastic isn’t totally renewable.

The researchers publishing their results in the journal Polymer Chemistry, used pinene as the raw material to make a new type of plastic that can be used in the place of caprolactone.

Helena Quilter, PhD student at the CSCT, explained: “We’re not talking about recycling old Christmas trees into plastics, but rather using a waste product from industry that would otherwise be thrown away, and turning it into something useful.

“So if we can make a plastic from sustainable sources, it could make a big difference to the environment.”

Replacing fossil fuels

Professor Matthew Davidson, Director of the CSCT and Whorrod Professor of Sustainable Chemical Technologies, added: “This research is part of a wider project that looks at using bio-based chemicals like pinene as a sustainable starting material for making a range of useful products, in the place of petrochemicals. This reduces our reliance on fossil fuels and provides a renewable feedstock that has the potential to revolutionise the chemical industry.”

The project, funded by the Engineering and Physical Sciences Research Council (EPSRC), is also investigating using other terpenes, such as limonene from citrus fruit, as a substitute for petrochemicals to make a range of products from plastics to pharmaceuticals.

The research is still at the early stages – only a few grams have been made so far—but the scientists aim to scale up the process to produce larger quantities in the near future.
Read more at: https://phys.org/news/2017-01-scientists-plastic-christmas-trees.html#jCp

How orange peel could replace crude oil in plastics

Orange juice, both delicious and nutritious, is enjoyed by millions of people across the world every day. However, new research indicates that it could have potential far beyond the breakfast table. The chemicals in orange peel could be used as new building blocks in products ranging from plastics to paracetamol – helping to break our reliance on crude oil.

Today’s society is totally reliant on the chemicals and materials that are obtained from our diminishing supply of fossil fuels. As such, there is an increasing global focus on the development of renewable chemical feedstocks from a variety of sustainable sources such as sugarcane and fatty acids in the production of biofuels. And the chemically rich essential oils contained within waste citrus peels are another such source that is being investigated with real zest.

This is promising, as the orange juice industry uses highly inefficient and wasteful juicing processes, with almost 50% of the fruit thrown away. This gives a real opportunity, then, to develop a sustainable supply of chemicals from the diverse and plentiful molecules locked within the peels.

Limonene – a versatile building block

Recent figures estimate around 20m tonnes of citrus is wasted each year. As some 95% of the oil extracted from these waste rinds is made up of limonene molecules, a colourless liquid hydrocarbon known as C₁₀H₁₆, this waste could yield around 125,000 tonnes of limonene a year.

Current extraction methods rely on distillation, passing steam through the waste solids and simply collecting the resulting oil. But recently, researchers at the University of York began investigating microwave extraction techniques as a greener alternative. The team simply placed orange peel and an organic solvent into a microwave and heated for 30 minutes. Within the peel, the water molecules start to boil, rupturing the cells and allowing the limonene to leach out. The results are favourable; the process is much faster, less energy intensive, produces a higher quality of limonene and in a yield twice as good as conventional methods.

But what is it that makes limonene so useful? As a simple hydrocarbon, it shares many similarities with the chemicals we obtain from fossil fuels, such as its liquid nature and boiling point. Therefore the technology we currently use on petrochemical feedstocks can be directly used on limonene to turn it into useful products. We can do this by exploiting limonene’s two carbon double bonds for a variety of chemical transformations.

Renewable plastics

Perhaps limonene’s greatest potential is as a building block for the polymer industry. Chemists are always looking for new ways to join molecules into long polymer chains so they can be used in a range of products, such as the polypropylene (a chain of propylene molecules) fibres that we use in carpets, or polyethylene (a chain of ethylene molecules) for making plastic bottles.

Back in 2006, scientists at Cornell University first showed the how fruitful this strategy could be. By reacting limonene oxide – a limonene molecule including an oxygen atom – with carbon dioxide in an alternating pattern, they could create polyesters, used in many woven or knitted fabrics. This groundbreaking work has been followed up in recent years through a variety of other polymer-forming reactions. This has included other forms of polyesters by replacing carbon dioxide with alternative building blocks.

Polyurethanes are a family of synthetic polymers that have found their ways into many of our homes from foam cushions to shoe soles. Currently the raw materials are obtained from fossil fuels, however limonene-based replacements have been recently identified. For instance, researchers in Germany have produced a family of new polyurethane-like plastics with limonene at the centre. The properties and hardness of these materials could be easily tuned to make a range of household products.

The development of limonene-based materials does not stop at everyday consumer products. Advanced optical materials have been recently been prepared by using limonene as a binder to make thin luminescent films.

The production of medicines from limonene may also one day be a reality. My team at the University of Bath is investigating the production of paracetamol using limonene’s carbon skeleton at its core. Through a series of chemical transformations combined with state-of-the-art engineering, we hope to turn waste orange peels into this widely used pain relief drug.

Hurdles to overcome

Limonene certainly has the potential to become an important component of a bio-based chemical industry. The field however is still in its infancy with no commercial limonene-based plastics on the marketplace. Issues that need to be addressed include a finding a reliable supply and greener processing – many of the above processes for manufacturing polymers using limonene still require petrochemicals as additives.

Limonene and its wider family (called terpenes) are only one piece of the renewable feedstocks puzzle. For example polylactic acid, a sustainable polymer derived from corn starch has been commercially available for the past decade primarily as disposable packaging. Other plastic building blocks have being sourced from plant materials such as Coca Cola’s PlantBottle technology. These alternative renewable sources can contain large amounts of oxygen atoms giving the resulting polymers different but complementary properties to limonene-based plastics.

The availability of limonene is also dictated by the weather in Florida and Brazil and by our desire to drink orange juice. Even if all of the currently available limonene from citrus waste was made into polymers it wouldn’t make a dent in global levels of plastic production.

However, if we could make the most of all the citrus that gets wasted, the amount of available limonene would increase. More efficient extraction methods will also boost availability as will advances in biotechnology. My team is also investigating how to modify bacteria to feed off municipal waste and excrete limonene as its only product. These sort of advances may be a way off but they are important first steps to breaking our dependence on crude oil – molecules such as limonene will no doubt be a bright part of our future.

Read more at: https://phys.org/news/2015-09-orange-crude-oil-plastics.html#jCp

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