Anti-avian ingenuity: the numerous ways to minimise airport bird strikes

The widespread installation of wind turbines over the past three decades has generated a new ecologically unfriendly phenomenon, namely wild birds being killed by turbine sails. Although it could cause maintenance issues - and of course it's not good news for the birds themselves, the increasing density of air travel means far higher numbers of bird strikes are likely to occur in the much smaller turbines of jet engines, predominantly around airports.

I've previously written about how urban environments appear to generate wildlife somewhat smarter than rural equivalents. In contrast, airports seem to be a very poor choice for birds to inhabit, suggesting that the loss of natural environments coupled with the relatively undeveloped land around airport perimeters is causing birds to congregate in such precarious places.

It's somewhat ironic that such an environmentally unfriendly technology as air travel is inadvertently providing habitats for wild birds, but as urban sprawl increases animals are forced to live wherever they can find, even areas as seemingly unsuitable as runway taxiways and safety areas. As aircraft increase in size and speed but decrease in engine noise, it may be that aviation technology is contributing to the problem. In addition, waterfowl are attracted by the fresh water storage ponds found near runways for use in firefighting or drainage. Therefore, despite the noise, pollution, changes to local weather patterns and the obstacles in the form of the aircraft themselves, airports worldwide have found themselves becoming home to or visited by flocks of numerous bird species.

With over forty bird strikes every day, the cost to the global airline industry surpasses US$1 billion per year. So what is being done to reduce or remove this threat? The range of options is both ingenious and proof that birds are a formidable opponent, so here is a brief summary of popular methods:

1. Removing food and water sources
2. Audio repellents
3. Chemical repellents
4. Fake fire and pyrotechnics
5. Baited traps
6. Real and fake predators
7. Removing and culling birds

1) Reducing bird foodstuffs involves a variety of techniques that aren't exactly the height of eco-friendliness. Any vegetation that might be a food source for local bird species, such as fruit- or seed-bearing trees and bushes may be removed. One step further is to replace any grass areas with a non-local variety that is less attractive to native birds.

A substantially less environmentally-friendly approach has been the regular use of insecticides to remove food sources for insectivorous birds and even distributing poison to remove potential raptor prey such as rabbits. Open water storage ponds within airports have been netted to prevent waterfowl from landing on them, but camouflage has also been developed specifically to minimise the attractiveness of large bodies of water.

2) Some airports such as Singapore's Changi play bird distress and/or raptor calls to scare birds away. A less subtle method has been the regular discharge of loud sounds generated by sonic cannon such as propane exploders. However, evidence suggests that birds soon become accustomed to these.

3) As an antithesis to the removal of food sources described above, adding chemical repellents to airport vegetation is now being used. Since 2010, New Zealand airports have been using a a locally-developed grass, which contains an endophyte fungus that reduces insect numbers and makes birds sick. This may prove to be easier to implement than natural chemical repellents imported from agribusiness, such as methyl anthranilate and anthraquinone, which require sophisticated, ongoing and locally-tailored programmes to maintain effectiveness.

4) Although it might sound high-tech, the use of wind-blown metallic streamers that simulate fire have been found to only fool birds for short periods. Likewise, the use of lasers, flare launchers and other live pyrotechnic devices serve to acclimatise local wildfowl to sudden noise and light. After all, the birds are already congregating around noisy aircraft for much of the day!

5) For airports frequented by raptors, live prey such as pigeons can serve as bait for sophisticated traps that notify staff once they have been triggered. The problem then is where to release the bird of prey so that it doesn't return to the original area.

6) The opposite of the previous method is to swamp the locality with trained predators, from dogs to raptors, in order to convince birds to nest elsewhere. The predators don't have to always be live, either: in the USA, fake coyotes have been used in wetlands to keep birds away from flight paths.

7) If all other methods fail, there are several time-consuming alternatives that could be used as a last resort. Firstly, birds can be caught and moved to regions far from airports. Naturally, this requires collaboration with wildlife experts and/or rangers. As a guaranteed solution, culling may also be allowed, although this is hardly going to endear most people to a sector that, essential though it is, has a rather poor environmental record.

One potential smart solution for civilian aviation has been developed for the Royal Netherlands Air Force, which involves constant radar monitoring of wildfowl so that pilots can adjust their take-off and landing flight paths. Apart from lack of the technology at airports, each airport would need long-term trials to determine the appropriate adjustments with regard to local bird populations and their behaviour.

From what I've learnt while researching this issue, there is probably no single solution suitable for all airports; a suite of methods is required, tailored for each one depending on the local landscape, climate and of course bird species - the latter being wily and unpredictable adversaries. Clearly, there's a long way to go if such drastic solutions as culling the birds themselves and poisoning the wider ecosystem are seen as valid options. It looks as if more research is required before the danger to both airliners and birds can be reduced, although I doubt if it could ever be completely eliminated; nature is just too unpredictable!

Lift to the stars: sci-fi hype and the space elevator

As an avid science-fiction reader during my childhood, one of the most outstanding extrapolations for future technology was that of the space elevator. As popularised in Arthur C. Clarke's 1979 novel, The Fountains of Paradise, the elevator was described as a twenty-second century project. I've previously written about near-future plans for private sector spaceflight, but the elevator would be a paradigm shift in space transportation: a way of potentially reaching as far as geosynchronous orbit without the need for rocket engines.

Despite the novelty of the idea: a tower stretching from Earth - or indeed any planet's surface - to geosynchronous orbit and beyond; the first description dates back to 1895 and writings of the Russian theoretical astronautics pioneer Konstantin Tsiolkovsky. Since the dawn of the Space Age engineers and designers in various nations have either reinvented the elevator from scratch or elaborated on Tsiolkovsky's idea.

There have of course been remarkable technological developments over the intervening period, with carbyne, carbon nanotubes, tubular carbon 60 and graphene seen as potential materials for the elevator, but we are still a long way from being able to build a full-size structure. Indeed, there are now known to be many more impediments to the space elevator than first thought, including a man-made issue that didn't exist at the end of the nineteenth century. Despite this, there seems to be a remarkable number of recent stories about elevator-related experiments and the near-future feasibility of such a project.

An objective look at practical - as opposed to theoretical - studies show that results to date have been decidedly underwhelming. The Space Shuttle programme started tethered satellite tests in 1992. After an initial failure (the first test achieved a distance of a mere 256 metres), a follow up six years later built a tether that was a rather more impressive twenty kilometres long. Then last year the Japanese STARS-me experiment tested a miniature climber component in orbit, albeit at a miniscule distance of nine metres. Bearing in mind that a real tower would be over 35,000 kilometres long, it cannot be argued that the technology is almost available for a full-scale elevator.

This hasn't prevented continuous research by the International Space Elevator Consortium (ISEC), which was formed in 2008 to promote the concept and the technology behind it. It's only to be expected that fans of the space elevator would be enthusiastic, but to my mind their assessment that we are 'tech ready' for its development seems to be optimistic to the point of incredulity.

A contrasting view is that of Google X's researchers, who mothballed their space elevator work in 2014 on the grounds that the requisite technology will not be available for decades to come. While the theoretical strength of carbon nanotubes meets the requirements, the total of cable manufactured to date is seventy centimetres, showing the difficulties in achieving mass production. A key stopping point apparently involves catalyst activity probability; until that problem is resolved, a space elevator less than one metre in length isn't going to convince me, at least.

What is surprising then is that in 2014, the Japanese Obayashi Corporation published a detailed concept that specified a twenty-year construction period starting in 2030. Not to be outdone, the China Academy of Launch Vehicle Technology released news in 2017 of a plan to actually build an elevator by 2045, using a new carbon nanotube fibre. Just how realistic is this, when so little of the massive undertaking has been prototyped beyond the most basic of levels?

The overall budget is estimated to be around US$90 billion, which suggests an international collaboration in order to offset the many years before the completed structure turns a profit. In addition to the materials issue, there are various other problems yet to be resolved. Chief among these are finding a suitable equatorial location (an ocean-based anchor has been suggested), capturing an asteroid for use as a counterweight, dampening vibrational harmonics, removing space junk, micrometeoroid impact protection and shielding passengers from the Van Allen radiation belts. Clearly, just developing the construction material is only one small element of the ultimate effort required.

Despite all these issues, general audience journalism regarding the space elevator - and therefore the resulting public perception - appears as optimistic as the Chinese announcement. How much these two feedback on each other is difficult to ascertain, but there certainly seems to be a case of running before learning to walk. It's strange that China made the claim, bearing in mind how many other rather important things the nation's scientists should be concentrating on, such as environmental degradation and pollution.

Could it be that China's STEM community have fallen for the widespread hype rather than prosaic reality? It's difficult to say how this could be so, considering their sophisticated internet firewall that blocks much of the outside world's content. Clearly though, the world wide web is full of science and technology stories that consist of parrot fashion copying, little or no analysis and click bait-driven headlines.

A balanced, in-depth synthesis of the relevant research is often a secondary consideration. The evolutionary biologist Stephen Jay Gould once labelled the negative impact of such lazy journalism as "authorial passivity before secondary sources." In this particular case, the public impression of what is achievable in the next few decades seems closer to Hollywood science fiction than scientific fact.

Of course, the irony is that even the more STEM-minded section of the public is unlikely to read the original technical articles in a professional journal. Instead, we are reliant on general readership material and the danger inherent in its immensely variable quality. As far as the space elevator goes (currently, about seventy centimetres), there are far more pressing concerns requiring engineering expertise; US$90 billion could, for example, fund projects to improve quality of life in the developing world.

That's not to say that I believe China will construct a space elevator during this century, or that the budget could be found anywhere else, either. But there are times when there's just too much hype and nonsense surrounding science and not enough fact. It's easy enough to make real-world science appear dull next to the likes of Star Trek, but now more than ever we need the public to trust and support STEM if we are to mitigate climate change and all the other environmental concerns.

As for the space elevator itself, let's return to Arthur C. Clarke. Once asked when he thought humanity could build one, he replied: "Probably about fifty years after everybody quits laughing." Unfortunately, bad STEM journalism seems to have joined conservatism as a negative influence in the struggle to promote science to non-scientists. And that's no laughing matter.

Concrete: a material of construction & destruction - and how to fix it

How often is it that we fail to consider what is under our noses? One of the most ubiquitous of man-made artifices - at least to the 55% of us who live in urban environments - is concrete. Our high-rise cities and power stations, farmyard siloes and hydroelectric dams wouldn't exist without it. As it is, global concrete consumption has quadrupled over the past quarter century, making it second only to water in terms of humanity's most-consumed substance. Unfortunately, it is also one of most environmentally-unfriendly materials on the planet.

Apart from what you might consider to be the aesthetic crimes of the bland, cookie-cutter approach to International Modernist architecture, there is a far greater issue due to the environmental degradation caused by the concrete manufacturing process. Cement is a key component of the material, but generates around 8% of all carbon dioxide emissions worldwide. As such, there needs to be a 20% reduction over the next ten years in order to fulfil the Paris Agreement - yet there is thought there may be a 25% increase in demand for concrete during this time span, particularly from the developing world. Although lower-carbon cements are being developed, concrete production causes other environmental issues as well. In particular, sand and gravel extraction is bad for the local ecology, including catastrophic damage to the sea bed.

So are there any alternatives? Since the 1990's, television series such as Grand Designs have presented British, New Zealand and Australian-based projects for (at times) extremely sustainable houses made from materials such as shipping containers, driftwood, straw bales, even shredded newspaper. However, these are mostly the unique dream builds of entrepreneurs, visionaries and let's face it, latter-day hippies. The techniques used might be suitable for domestic architecture, but they are impractical at a larger scale.

The US firm bioMASON studied coral in order to develop an alternative to conventional bricks, which generate large amounts of greenhouse gases during the firing process. They use a biomineralisation process, which basically consists of injecting microbes into nutrient-rich water containing sand and watching the rod-shaped bacteria grow into bricks over three to five days.  It's still comparatively early days for the technology, so meanwhile, what about applying the three environmental ‘Rs' of Reduce, Reuse and Recycle to conventional concrete design and manufacturing?

1 Reduce

3D printers are starting to be used in the construction industry to fabricate building and structural components, even small footbridges. Concrete extrusion designs require less material than is required by conventional timber moulds - not to mention removing the need for the timber itself. One common technique is to build up shapes such as walls from thin, stacked, layers. The technology is time-effective too: walls can be built up at a rate of several metres per hour, which may induce companies to make the initial outlay for the printing machinery.

As an example of the low cost, a 35 square metre demonstration house was built in Austin, Texas, last year at a cost of US$10,000 - and it only took 2 days to build. This year may see an entire housing project built in the Netherlands using 3D-printed concrete. Another technique has been pioneered at Exeter University in the UK, using graphene as an additive to reduce the amount of concrete required. This greatly increases both the water resistance and strength compared to the conventional material, thus halving the material requirement.

2 Reuse

Less than a third of the material from conventionally-built brick and timber structures can be reused after demolition. The post-war construction industry has continually reduced the quality of the building material it uses, especially in the residential sector; think of pre-fabricated roof trusses, made of new growth, comparatively unseasoned timber and held together by perforated connector plates. The intended lifespan of such structures could be as little as sixty years, with some integrated components such as roofing failing much sooner.

Compare this to Roman structures such as aqueducts and the Pantheon (the latter still being the world's largest unreinforced concrete dome) which are sound after two millennia, thanks to their volcanic ash-rich material and sophisticated engineering. Surely it makes sense to use concrete to construct long-lasting structures, rather than buildings that will not last as long as their architects? If the reuse of contemporary construction materials is minimal (about as far removed as you can get from the traditional approach of robbing out stone-based structures in their entirety) then longevity is the most logical alternative.

3 Recycle

It is becoming possible to both recycle other waste into concrete-based building materials and use concrete itself as a secure storage for greenhouse gases. A Canadian company called CarbonCure has developed a technique for permanently sequestering carbon dioxide in their concrete by converting it into a mineral during the manufacturing process, with the added benefits of increasing the strength of the material while reducing the amount of cement required.

As for recycling waste material as an ingredient, companies around the world have been developing light-weight concrete incorporating mixed plastic waste, the latter comprising anywhere from 10% to 60% of the volume, particularly with the addition of high density polyethylene.

For example New Zealand company Enviroplaz can use unsorted, unwashed plastic packaging to produce Plazrok, a polymer aggregate for creating a concrete which is up to 40% lighter than standard material. In addition, the same company has an alternative to metal and fibreglass panels in the form of Plaztuff, a fully recyclable, non-corroding material which is one-seventh the weight of steel. It has even been used to build boats as well as land-based items such as skips and playground furniture.

Therefore what might appear to be an intractable problem appears to have a variety of overlapping solutions that allow sustainable development in the building and civil engineering sector. It is somewhat unfortunate then that the conservative nature of these industries has until recently stalled progress in replacing a massive pollutant with much more environmentally sound alternatives. Clearly, green architecture doesn't have to be the sole prerogative of the driftwood dreamers; young entrepreneurs around the world are seizing the opportunity to create alternatives to the destructive effects of construction.

Sonic booms and algal blooms: a smart approach to detoxifying waterways

A recent report here in New Zealand has raised some interesting issues around data interpretation and the need for independent analysis to minimise bias. The study has examined the state of our fresh water environment over the past decade, leading to the conclusion that our lakes and rivers are improving in water quality.

However, some of the data fails to support this: populations of freshwater macro invertebrates remain low, following a steady decline over many decades. Therefore while the overall tone of the report is one of optimism, some researchers have claimed that the data has been deliberately cherry-picked in order to present as positive a result as possible.

Of course, there are countless examples of interested parties skewing scientific data for their own ends, with government organisations and private corporations among the most common culprits. In this case, the recorded drop in nitrate levels has been promoted at the expense of the continued low population of small-scale fauna. You might well ask what use these worms, snails and insects are, but even a basic understanding of food webs shows that numerous native bird and freshwater fish species rely on these invertebrates for food. As I've mentioned so often the apparently insignificant may play a fundamental role in sustaining human agriculture (yes, some other species practice farming too!)

So what is it that is preventing the invertebrates' recovery? The answer seems to be an increase in photosynthetic cyanobacteria, or as is more commonly - and incorrectly known - blue-green algae. If it is identified at all, it's as a health food supplement called spirulina, available in smoothies and tablet form. However, most cyanobacteria species are not nearly as useful - or pleasant. To start with, their presence in water lowers the oxygen content, so thanks to fertiliser runoff - nitrogen and phosphorus in particular - they bloom exponentially wherever intensive farming occurs close to fresh water courses. Another agriculture-related issue is due to clearing the land for grazing: without trees to provide shade, rivers and streams grow warmer, encouraging algal growth. Therefore as global temperatures rise, climate change is having yet another negative effect on the environment.

Most species of cyanobacteria contain toxins that can severely affect animals much larger than fresh water snails. Dogs have been reported as dying in as little as a quarter of an hour from eating it, with New Zealand alone losing over one hundred and fifty pet canines in the past fifteen years; it's difficult to prevent consumption, since dogs seem to love the smell! Kiwis are no stranger to the phylum for other reasons, as over one hundred New Zealand rivers and lakes have been closed to swimmers since 2011 due to cyanobacterial contamination.

Exposure to contaminated water or eating fish from such an environment is enough to cause external irritation to humans and may even damage our internal organs and nervous system. Drinking water containing blue-green algae is even worse; considering their comparable size to some dogs, it is supposed that exposure could prove fatal to young children. Research conducted over the past few years also suggests that high-level contamination can lead to Lou Gehrig's disease, A.K.A. amyotrophic lateral sclerosis, the same condition that Stephen Hawking suffered from.

What research you might ask is being done to discover a solution to this unpleasant organism? Chemicals additives including copper sulphate and calcium hypochlorite have been tried, but many are highly expensive while the toxicity of others is such that fish and crustacean populations also suffer, so this is hardly a suitable answer.

A more elegant solution has been under trial for the past two years, namely the use of ultrasound to sink the blue-green algae too deep to effectively photosynthesise, thus slowly killing it. A joint programme between New Zealand and the Netherlands uses a high-tech approach to identifying and destroying ninety per cent of each bloom. Whereas previous ultrasonic methods tended to be too powerful, thereby releasing algal toxins into the water, the new technique directly targets the individual algal species. Six tests per hour are used to assess water quality and detect the species to be eradicated. Once identified, the sonic blasts are calibrated for the target species and water condition, leading to a slower death for the blue-green algae that avoids cell wall rupture and so prevents the toxins from escaping.

Back to the earlier comment as to why the report's conclusions appear to have placed a positive spin that is unwarranted, the current and previous New Zealand Governments have announced initiatives to clean up our environment and so live up to the tourist slogan of '100% Pure'. The latest scheme requires making ninety percent of the nation's fresh water environments swimmable by 2040, which seems to be something of a tall order without radical changes to agriculture and the heavily polluting dairy sector in particular. Therefore the use of finely target sonic blasting couldn't come a moment too soon.

Our greed and short-sightedness has allowed cyanobacteria to greatly increase at the expense of the freshwater ecosystem, not to mention domesticated animals. Now advanced but small-scale technology has been developed to reduce it to non-toxic levels, but is yet to be implemented beyond the trial stage. Hopefully this eradication method will become widespread in the near future, a small victory in our enormous fight to right the wrongs of over-exploitation of the environment. But as with DDT, CFCs and numerous others, it does make me wonder how many more man-made time bombs could be ticking out there...

Amphibian Armageddon and killed-off kauri: the worldwide battle against fighting fungi

I recently wanted to visit the Ark in the Park, an open sanctuary in the Waitakere Ranges west of Auckland that uses constant predator control to protect native plants and animals. However, I was stopped by a sign stating that Te Kawerau a Maki, the Maori of the district, have placed a rāhiu or prohibition on entering the forest. Although not legally binding, the rāhui is intended to stop people walking through the area and spreading infection, serving in place of any notice by the New Zealand Government or Auckland City Council, since the latter two bodies have failed to take action. Perhaps this inactivity is because the infection does not directly affect humans or farming. Instead a fungus-like pathogen is killing the native kauri Agathis australis, one the largest tree species on Earth.

Known to live for over a thousand years and grow to over fifty metres tall, the largest kauri are seen by Maori as the lords of New Zealand's northern forests. Yet since 2009 the microscopic water mould Phytophthora agathidicida has been causing kauri dieback at an ever-increasing rate. Surveys in the Waitakeres show that most of the infected areas are within ten metres of walking paths and therefore the mould is being spread by visitors to the lowland forests who fail to thoroughly clean their shoes with the supplied disinfectant spray. In a truly David versus Goliath battle between the miniscule mould and giant trees, introduced species such as possums and pigs are aiding the former by accidentally spreading the minute spores.

Auckland Council reported last winter that the amount of affected kauri has reached 19 percent, meaning a doubling in scale in only five years. Since there is no cure for infected kauri, some scientists are now predicting the extinction of this magnificent tree in the near future. The combination of the pathogen's microscopic size with its rain-based activation after dormancy means there are currently no methods that can prevent the infection from spreading. In a way, the rāhui may just slow down the inevitable. Considering the immense kauri are home to a unique ecosystem of epiphytes, orchids and associated symbiotic organisms, the future flora and fauna of kauri-free forests may well be markedly different from the Waitakeres as they are today.

I've previously discussed the ubiquity of the unsung fungi and how prominent they are even within totally man-made environments. It seems surprising that New Zealand's authorities, so keen to preserve native birds and reptiles, are failing to take any action to at least buy time for the kauri; perhaps they have already deemed extinction as unavoidable and not worth spending public funds on.

The kauri are far from being the only organisms currently threatened by fungi or their kin. Over the past decade more than thirty snake species in the eastern and mid-western United States have started succumbing to what has been termed Snake Fungal Disease. The culprit is thought to be a soil-based fungus called Ophidiomyces ophiodiicola, with a similar organism now also thought to be affecting snakes in the United Kingdom and mainland Europe. Research suggests that up to ninety percent of infected snakes die from the condition, so clearly if humans and their vehicles play unwitting hosts to the microscopic fungal spores, the future for the world's snake population looks depressing. Although many people might not like snakes, ecosystems without them may see an explosion in the numbers of their prey animals, including rodents; to say the least, this would not bode well for crop farmers!

Perhaps the best-known of the global fungal-caused epidemics is the amphibian-decimating Chytridiomycosis, whose affects were initially recognised twenty years ago but may have started much earlier. As its spores can live in water, the responsible Batrachochytrium fungi are ideally situated to infect about one-third of all frog, toad, newt and salamander species. Again, it is thought that man has inadvertently caused the problem, as the African clawed frog Xenopus laevis is an immune carrier of the fungus and has been exported worldwide since the 1930's.

Another contributor may be climate change, as amphibian-rich forests experience temperature variations that are ideal for the chytrid fungi to proliferate in. As a final nail in the coffin - and as with bees and Colony Collapse Disorder - pesticides may play a key role in the epidemic. Agrochemicals are shown to lower the amphibian immune response and so increase their susceptibility to infection. However, the situation isn't completely hopeless: here in New Zealand, researchers at the University of Otago have used chloramphenicol, an antibiotic eye ointment, to cure infected Archey's frogs (Leiopelma archeyi). This species is already critically endangered even without the chytrid epidemic; hopefully, the cure will prove to be the saviour of other amphibian species too. This would be just as well, considering the dangerous side effects found in other treatments such as antifungal drugs and heat therapy (the latter involving temperature-controlled environments that are lethal to the pathogen).

During the past decade, over five million North American bats have been killed by white-nose syndrome, which is caused by the fungus Pseudogymnoascus destructans. Again, humans have inadvertently spread the pathogen, in this case from Eurasia, where the bat species are immune to it, to North America, where they are most definitely susceptible. The bats are only affected during hibernation, which makes treating them difficult, although brief exposure to ultraviolet light has been shown to kill the fungus. This may prove to be a cure to infected colonies, although how the UV could be administered without disturbing the cave-roosting populations will take some figuring out.

It appears then that a combination of manmade causes (international travel, climate change and chemical pollution) is creating a field day for various tiny fungi or fungus-like organisms, at the expense of numerous species of fauna and flora. The culprits are so small and pervasive that there is a little hope of preventing their spread. Therefore if conventional cures cannot be found, the only hope for the likes of the kauri might be the use of genetic engineering to either give the victim resistance or to kill off the pathogen. This science fiction-sounding technology wouldn't be cheap and its knock-on effects unknown – and potentially disastrous. The former technique would presumably not be any use to the existing populations, only to the germ line cells of the next generation. Whatever happens, our short-sighted approach to the environment is certainly starting to have major repercussions. A world without the magnificent kauri, not to mention many amphibian, reptile and mammal species, would be a much poorer one.

PET projects: can nature destroy plastic pollution?

One of key markers of the Anthropocene - the as yet unofficial term for a human-impacted global environment - is the deposition of manmade pollutants on land and in the oceans. A prominent component of these pollutants is plastic-based consumer waste; as I mentioned in March 2010, the UK was then using 17.5 billion plastic bags each year. Happily, the introduction of a charge on lightweight plastic shopping bags in the UK has reduced usage by a fantastic 85%. Various nations have introduced similar or even better legislation, but unfortunately in that key polluter the USA only California has had any success in overcoming corporate lobbying. The situation in Trump's America looks unlikely to change any time soon, since several states have even prohibited such bans at a county level!

Therefore, despite the best endeavours of some nations, most recently Kenya, around 80 million tonnes of polyethylene-based packaging and bags are still being produced worldwide each year. The amount that is recycled varies considerably from nation to nation, with the US Environmental Protection Agency recording only 12% of America's plastic as being recycled. As a result, it is estimated that about 12 million tonnes of plastic is annually deposited in the oceans, with even deep-sea species found to have been contaminated.

We've all seen images of beaches on the most remote, uninhabited islands smothered by tiny, multicoloured pieces of plastic, but apart from being unsightly, what are the potential dangers to the global ecosystem and humans in particular? By ingesting plastics, animals risk either choking or starving to death, or being poisoned by chemicals leaching from the material. Even if the latter doesn't quickly kill the critter (which could be anything from sea birds to turtles to baleen whales), substances such as Bisphenol A can build up in their system. In addition to the damage caused to the animals themselves, toxins can upset a species' reproductive cycle. For instance, some of the leached chemicals mimic estrogen, potentially inhibiting development of male offspring.

Of course, with such a range of species being affected, isn't it feasible that there will be knock-on effects to the human food chain? Even if there aren't obvious reductions in commercially-caught species, there is a high likelihood that wider food webs could be severely altered - and not for the good - or even that we on the verge of ingesting copious amounts of microscopic plastic particles. Even people who never eat seafood won't be able to avoid it, since animal feed may contain contaminated fishmeal.

It isn't just the obvious items that are the key pollutants, either: plastic microbeads (i.e. less than 1mm along their longest side) are prominent in rinse-off personal care products. Whoever invented them clearly has zero environmental credentials, bearing in mind there's no ability to recycle or reuse them; in fact, about 8 quadrillion microbeads get washed down the plug hole every day.  The World Trade Organisation is making some inroads into their removal - here in New Zealand their manufacture and sale will be banned by the middle of next year - but research has found they are already pretty much ubiquitous in the environment wherever these products are in use.

Therefore it makes sense to tackle the problem as soon as possible. Since some countries are reticent to implement legislation, or like China and India are having difficulties enforcing it, there is much to be said for seeking ways to degrade plastic waste in the most efficient way possible. Research over the past decade has revealed an astonishing conclusion: only about 1% of the expected amount of waste material has been found in the oceans. Either it is rapidly being buried in the sea bed, or more likely, something is breaking it down. Is this possible? Last year, a team of Japanese researchers found a microbe called Ideonella sakaiensis that is able to digest polyethylene terephthalate (PET), which is used in such mass-produced items as drink bottles. This suggests that there may be marine microorganisms with a taste for human waste, diligently destroying our plastic rubbish and preventing even worse effects on ocean life.

The Japanese research hints that it may be possible to use vats of these microbes to break down at least waste PET and then recycle it, with a much greater efficiency than is currently possible. Without interference, PET is thought to take between four hundred and one thousand years to completely degrade, presumably depending on the shape and thickness of the item. In contrast, Ideonella is able to digest the material in only six weeks. About 56 million tonnes of PET, mostly for bottles, is produced each year. Here in New Zealand, less than half of this material is recycled, the first (conventional) PET recycling plant having started work in August. So there's plenty of scope for a natural solution, should it become usable on an industrial scale.

This begs the question: are there any other critters with similar capabilities?  Last month a team at Texas Tech University reported that caterpillars of the pantry moth Plodia interpunctella have been able to thrive on polyethylene. Research showed that their digestive system contains various species of bacteria - different from the gut microbes in caterpillars that eat natural foods - which are capable of breaking down the plastic. However, what worries me is that if these microbes become selected for in the wild, will this change have the same sort of disastrous result that the inadvertent artificial selection of MRSA has had?

Some worm species are known to eat natural polymers similar to man-made plastics, such as the beeswax in hives, and so have been tested for their ability to break down plastic as well. Further research is required to determine whether the work is being done by microbes in the worms' digestive systems, but one issue with worm-digested plastic is that by-products include the toxic ethylene glycol. Apart from bacteria, Chinese researchers using plastic waste from Pakistan have found that the fungus Aspergillus tubingensis can degrade polyester polyurethane. After some years of disappointing results in mycoremediation (the use of fungi to break down man-made materials) this may prove to be a breakthrough.

The big question then is has nature done it again? After all, it does have about three and a half billion years' head start on the human race. Plastic waste is clearly a big issue and for the majority of humanity who live away from the sea (or rubbish dumps, for that matter) it's fairly easy to think "out of sight, out of mind". However, it pays to highlight the potential danger of changing ecosystems on a global scale, including the extinction of unseen and unknown species, including microbes that are vital to maintaining stability. I've previously mentioned the problems with concentrating on a few key 'poster' organisms at the expense of those that may play a pivotal role - now, or in the future - to our nutritional, pharmaceutical or technological needs. Therefore we need to be certain that the solution won't be as bad as the problem, when it comes to using nature itself to destroy the waste we unthinkingly generate. Surely a good compromise would be to minimise the amounts of plastic rubbish we generate in the first place?

Water, water, everywhere: the hidden holism of H2O

Like other northern regions of New Zealand, the summer of 2017 saw Auckland residents facing City Council requests to conserve water, as well as a hosepipe ban in effect during March and April. It therefore seems ironic that the water shortage occurred at the same time as flooding in the west of the city; thanks to a tropical downpour - one of several so far this year - the equivalent of an entire month's rain fell over a day or two. Clearly, water shortages are going to become an ever-increasing issue, even in nations with well-developed infrastructure.

The British historian of science James Burke, writer-presenter of The Day the Universe Changed, also made three television series called Connections 1, 2 and 3 (in 1978, 1994 and 1997 respectively) which examined the historical threads linking scientific and technological advances with changes in other areas of society. Therefore I'd like to take a similarly holistic approach to the wonderful world of water consumption and see how it ties into the world in general.

Although the statistics vary - it's difficult to assess with any great precision - there are published figures suggesting that the populace of richer nations use up to 5000 litres of water each per day, mostly hidden in food production. Many websites now supply details of the amount of water used to grown certain crops and foodstuffs, so you can easily raise your guilt level simply by comparing your diet to the water involved in its generation; and that's without considering the carbon mileage or packaging waste, either!

I've previously discussed the high environmental cost of cattle farming, with both dairy and beef herds being prominent culprits in water pollution as well as consumption. However, there are plenty of less-obvious foodstuffs proven to be notorious water consumers, for example avocado and almonds. Although the latter might be deemed a luxury food, much of the global supply is now used to make almond milk; with consumption increasing up to 40% year-on-year, this is one foodstuff much in demand.

Even though it is claimed to require much less water than the equivalent volume of dairy produce, almond farming is still relevant due to the massive increase in bulk production, especially in California (home to 80% of the global almond harvest). The reasons for the popularity of almond milk are probably two-fold: firstly, the public is getting more health-conscious; and secondly, a reduction or abstention in dairy produce is presumed to lessen food allergies/intolerance. These obviously link to prominent concerns in the West, in the form of high-calorie/low-exercise diets leading to mass obesity and over-use of cleaning chemicals in the home, preventing children from developing good anti-microbial resistance. Clearly, there is a complex web when it comes to water and the human race.

Even for regions chronically short of water such as California, more than three-quarters of fresh water usage is by agriculture. In order to conserve resources, is it likely that we may soon face greater taxes on commercially-grown water-hogging produce and bans on the home-growth of crops that have a low nutrition to water consumption ratio? I've recently read several books discussing probable issues over the next half century with the humble lettuce appearing as a good example of the latter.

Talking of which, the wet and windy conditions in New Zealand of the past year - blamed at least partially on La Niña - have led to record prices for common vegetables: NZ$9 for a lettuce and NZ$10 for a cauliflower, even in major supermarket chains. British supermarkets were forced to ration some fruit and vegetables back in February, due to their Mediterranean growers suffering from storms and floods. This suggests that even for regions with sophisticated agricultural practices there is a fine line between too much and too little fresh water. Isn't it about time that the main food producers developed a more robust not to mention future-proof infrastructure, considering the increased impact that climate change is likely to have?

The world is also paying a heavy price for bottled water, a commercial enterprise that largely breaks all boundaries of common sense. In the USA alone it costs several thousand times the equivalent volume of tap water and there are some reports that there may be chemical leaching from reusing plastic bottles. As you might expect, there is also an extremely high environmental cost. This includes the fossil fuels used by bottling plants and transportation, the lowering of the water table (whose level is so critical in areas utilising less sophisticated farming technologies) and the impact of plastic waste: the USA only recycles about 23% of its plastic water bottles, resulting in 38 billion bottles dumped each year at a cost of around US$1 billion. All in all, bottled water for nations with highly developed infrastructure seems like an insane use of critical resources.

Although accelerated population growth has become a widespread fear, there are indicators that later this century the global figure may peak at around nine billion and then level off. Increasing urbanisation is seen a primary cause for this and not just in developing nations; Auckland for example (New Zealand's largest city by far) experienced 8% population growth in the seven years from 2006. A larger population obviously requires more food, but a more urban and therefore generally better educated, higher income populace tends to demand access to processed, non-local and above all water-intensive foods. China is the touchstone here, having seen a massive increase in fish and meat consumption over the past half century; the latter has risen from 8 million tons per year in 1978 to over 70 million tons in recent years.

It has been claimed that 70% of industrial waste generated in developing nations is dumped into water courses, meaning that there will be a massive cost for environmental clean-up before local sources can be fully utilised. The mass outbreak of E-coli in Hawke's Bay, New Zealand, in February this year shows that even developed nations are having difficulty maintaining water quality, whilst there has been a shocking admittance of lead contamination above safe levels in 41 American states over the past three years. Does this mean bottled water - heretofore the lifeline of Western tourists abroad - is becoming a necessity in the West after all?

Some might argue that thanks to global warming there will be more water available due to the melting of polar caps and glaciers, which after all contain almost two-thirds of the world's fresh water resources. However, these sources are mostly located far from high-density populations and upon marine contamination they require energy-demanding desalination technology. It's small comfort that current estimates suggest that by 2025 about 14% of the global population will rely on desalination plants for their fresh water needs.

In the West we tend to take clean, safe water completely for granted but thanks to the demands of living in a society run on rampant consumerism - coupled with poor science education - everyday decisions are being made that affect the environment, waste critical resources and damage our own health. Pundits are predicting that water will be the new oil: liquid gold, a precious commodity to be fought over, if necessary. Surely this is one resource that all of us can do something to support, whether it is cutting down on water-intensive foodstuffs, using tap rather than bottled water, or simply turning off a tap sooner than usual!

Mopping up spilt milk: pollution in the New Zealand dairy sector

It's been slow to dawn on New Zealanders, but for a country that prides itself on a '100% Pure' image our environmental pollution record is fairly appalling - and shows few signs of alleviation. Politicians who point to the large percentage of the nation's electricity generation coming from renewable sources, not to mention the slow but sturdy growth in hybrid vehicles, are completely missing the point: it has been claimed that over half of New Zealand's greenhouse gas emissions emanate from agri business.

Although the quantity of sheep in the country has plummeted from a 1982 peak of around 70 million to less than 30 million last year, cattle numbers continue to rise. There are about 3.6 million livestock on beef farms and circa 6.5 million dairy cattle. The latter sector generates twenty percent of New Zealand's exports and seven percent of its GDP, so it forms a substantial component of the kiwi economy. But with plans to double the country's dairy production by 2025, the term 'sustainable development' appears to be, well, unsustainable.

Since cattle create as much waste product as fourteen humans, it's not difficult to imagine some of the more obvious forms of dairy pollutant, smell and all. As New Zealand dung beetles are primarily forest dwellers there have been trials of introduced dung beetle species to help clean up the waste, with a reduction in nitrous oxide emissions from the soil and a lowering of cattle disease as side benefits. However, pastoral poo is only one element in the catalogue of pollutants caused by dairy farming.

Last summer I was taken to an outdoor swimming hole not far from Wanganui, consisting of a rectangular concrete-lined pool situated on the edge of a forest. I was informed that children had swam there until a decade or so, but no more: several signs warned that the water is contaminated and no longer safe for humans. This story has been repeated throughout New Zealand, with agriculture being by far the most common culprit. It isn't just artificial environments that have this problem; reports suggest that within the past twenty years about two-thirds of monitored swimming areas within rivers have become too polluted. And that's just for people; there's far less concern for the effects on river fauna and flora.

Although environmentalists have been issuing warnings for years, not enough has been done to alleviate this problem. Last month approximately five thousand inhabitants of Havelock North were taken ill due to tap water contaminated by campylobacter. The source was a series of bores which the director of the Infectious Diseases Research Centre at Massey University, Professor Nigel French, put down to pollution from sheep and cattle. Sources of contamination could include carcases of dead livestock, as well as faecal matter getting into waterways that provide the source of unchlorinated - and therefore at risk - tap water.

In fact, the outbreak appears to be the tip of the iceberg. Despite some hundreds of cases of illegal effluent discharge brought against New Zealand farmers each year, many more escape prosecution. It has to be said this seems to be a regular occurrence for the Ministry for Primary Industries, judging by the recent reports of their waiving prosecutions for commercial fishing vessels caught flouting bycatch and dumping laws. Turning a blind eye seems to be the order of the day when it comes to protecting food production - or at least the food producers. This philosophy seems to be driven by those who clearly have little understanding of the complexity - and at times fragility - of food webs. Not so much short-term thinking as profound myopia!

In addition to the organic matter there are chemical pollutants that can find their way into water supplies situated close to farms. Since the 1990s, the New Zealand Ministry for the Environment has been monitoring ground water for nitrates and has found levels substantially above those recommended for drinking water. Although chemical fertiliser has been blamed in addition to livestock effluent, environmental mapping suggests the latter is the primary cause, since the polluted areas heavily coincide with the widest-scale dairy production.

As well as polluting waterways dairy farmers have also been caught stealing billions of litres of water each year from rivers and aquifers, especially in the Canterbury region. Whilst not a form of pollution per se, this is obviously somewhat lacking in the environmentally-friendly stakes. The deforestation of low-lying plains for cattle grazing is also a source of pollution, as the lack of tree roots, besides allowing greater flooding, can generate increased run-off into rivers. This polluted water can lead to algal blooms, lowering oxygen levels and so endangering freshwater fish. That might not sound of any great concern except to diehard anglers, but for any whitebait fans, four of the five Galaxiidae species whose young form this delicacy are now said to be threatened.

The systematic destruction of forests to make way for pastoral land use has been repeatedly raised as a concern not just by environmental organisations but by the New Zealand Ministry of Agriculture and Forestry (MAF) itself. Their 2006 report claimed close to half a million hectares of the nation's forests were at risk of conversion to land for cattle grazing.

In addition, overseas forests are also affected: since 2008 the amount of palm kernels imported into New Zealand as a dairy cattle feed supplement has doubled to over 2 million tons per annum. This accounts for about twenty-five percent of global production and comes at the expense of destruction of rainforests in nations including Indonesia and Malaysia. Although the state-owned farm company Landcorp Farming Ltd is in the process of moving to a different supplement over the next year or so, the dairy giant Fonterra has not announced similar intentions. What's wrong with those guys: a surfeit of Milton Friedman in their formative years?

Having covered solids and liquids, it's time to move on to gas. As I've mentioned on various occasions, methane is a primary greenhouse gas. It was therefore shocking to discover that per capita, New Zealand has the greatest annual methane emission rate worldwide, accounting for over forty percent of the country's greenhouse gas emanations. The methane emission from dairy cattle alone has continually increased over the past quarter century, although the amount reported varies from ten percent to a whopping fifty percent or so. Perhaps that's not surprising, considering cattle can each generate up to 500 litres of methane per day!

There is some recent cause for hope, with various trials under way to reduce bovine emissions. These range from vaccination to selective breeding to diets bases on forage rape, with the latter showing that the change in feed affects fermentation - and therefore reduces methane production - in sheep. However, it wouldn't hurt to see the Government funding more research in this matter: one widely-reported paper last year was Massey University's The New Zealand Dairy Farming: Milking Our Environment for All its Worth, which received much criticism from the dairy sector when it was revealed to consist primarily of a student thesis.

It's very easy to become depressed with such deleterious effects coming from just one sector. Of course no nation can afford to rest on its laurels: we cannot turn the clock back. The halcyon image of bucolic ruralism is a myth perpetrated by those who have never worked on the land and farmers deserve the benefits of modern technology in their work as much as anyone. The development of sophisticated tools and software can aid the dairy sector in preserving the environment. as long as there is enough public money to support this eco-friendly research. But Government funding for this type of sustainable development appears to be sadly lacking. Doesn't it make sense that those who run God's Own Country should try a little harder to prove that the 100% Pure tagline isn't just marketing spin?

Beetlemania: can eating insects help save the environment?

Christmas - along with Thanksgiving for Americans - has probably got to be the most obvious time of the year when Westerners over-indulge in animal protein. However, this meatfest comes at a severe cost to the planet, as anyone who is environmentally aware is likely to know. Although many people have started making changes to mitigate climate change and pollution, compared to say recycling and reducing your carbon footprint, cutting down on meat seems to be far more challenging.

Actor and former California Governor Arnold Schwarzenegger has suggested Americans should have one or two meat-free days each week, but that's easier said than done in a continent raised on heaped platefuls of red meat. It isn't as if switching from cattle, sheep and goat to more unusual species would help either, as recent research confirms the likes of kangaroo and reindeer as sources of high methane emissions too. As a side note, it isn't just meat consumption that needs to be reduced; there's also dairy farming to consider. Does anyone really like soya milk? Mind you, I haven't tried almond milk yet...

United Nations reports suggest that greenhouse gas emissions from farming, primarily due to livestock and artificial fertilisers, have almost doubled in the past half century. As you might expect,these are likely to continue increasing at a similar rate over the next fifty years. In addition, vast tracts of Amazonian rainforest - amongst other unspoilt natural habitats - are being destroyed to make way for cattle grazing. At around three million acres lost each year, there's obviously not much in the way of sustainability about this particular development!

So is there any good news in all this culinary doom and gloom? Both Europe and especially North America have recently seen a profusion of companies marketing manufactured foods intended as meat replacements that are derived from of all things…insects. These products range from burgers to crackers and usually offer little appearance or taste to indicate their source material. Is it possible that the future for developed nations could include the delights of grasshopper goulash and wormicelli pasta?

It isn't as strange as it sounds. Over a quarter of mankind routinely eats insects from several thousand species as part of their traditional diet, usually with the source animal obvious in the presentation. This makes sense for developing nations, since wild insects can be caught en masse, farmed bugs fed on cheap waste material that can't be converted into conventional animal feed - and of course they require comparatively little water. Although the material isn't being converted to highly processed foodstuffs, Thailand - with over 20,000 insect farms - is an example of a nation currently increasing its insect consumption.

The species used in the new ‘hidden' insect foods varies widely, with crickets prominent on the menu. It isn't as straightforward as just killing the wee beasties and grinding them into powder, but many of the new American and European companies are conducting extensive research, developing mechanised processes that bode well for industrial-scale production.

The nutritional analysis shows promise to say the least, with some Hymenoptera species containing up to three times the protein yield of domestic cattle. The vitamin and mineral statistics are pretty good too, sometimes exceeding both farmed mammals and birds as well as plant staples such as soya beans. Not bad, considering that bug farming should prove to be at least four times as efficient as cattle husbandry.

Whether a trendy novelty can become mainstream remains to be seen, since the fledgling industry faces more than just the ‘yuck' factor. As with much cutting-edge technology, legislation has yet to catch up: there could be issues around safety concerns, with short shelf life, uncaught impurities or pollutants and allergic reactions all potential factors that could inhibit widescale production.

Bug protein isn't the only dish on the table (see what I did there?) as there are even more sophisticated approaches to reducing the environmental degradation caused by meat production. One well-publicised technique has been the cultivation of animal flesh in-vitro. However, it's only been a couple of years since the (nurturing? propagation?) of the first petri dish burger and so the process is still prohibitively expensive. By comparison, insects (bees and butterflies excepted) are not currently in short supply.

As a someone who hasn't eaten any land-based flesh for over a quarter of a century - and yes, I try to be careful with which aquatic species I consume - I suppose I have a fairly objective opinion about this matter. It does seem to make environmental sense to pursue processed insect protein as a replacement for domesticated mammal and bird species, but how often has logic taken a backseat to prejudice and the irrational? I look forward to near future developments, not least the massive brand campaigns that will no doubt be required to convert the Western public to the likes of Cricket crackers and Wormer schnitzel. Look out turkeys, your Christmases could be numbered...

Nanosilver: the future may be tiny and shiny, but is it safe?

A few years' ago I bought some socks containing nanosilver in the hope of reducing foot odour - or more specifically a lingering smell in shoes - I am not proud. Strangely, moving to a warmer, more humid climate since then has greatly reduced the problem, rather more so than the nanosilver, which was frankly useless. But soon after buying the less-than-super socks I started thinking about just what I had done. After all, you don't usually consider yourself in close proximity to amounts of silver around one billionth or so of a metre in size...

In the case of nanosilver, it has long been recognised as an anti-bacterial agent and fungicide too, hence the sock idea. I've already discussed smart materials elsewhere but felt this particular example deserved a post by itself. So just how efficient was the nanosilver anyway? According to studies in 2008 and 2009, up to one third of the metal is washed out at the first laundering. Hardly a long-term solution then! So what happens to the silver that disappears down the washing machine waste pipe? Could the nanoparticles get into the water supply if not removed in treatment plants, evading capture due to the minuteness of their size? I just had to find out!

It seems that silver-impregnated socks are just the tip of the iceberg, with all sorts of products in recent years taking advantage of its anti-bacterial capability. Everything from washing machines to vacuum cleaners has appeared, some removed from the market, if only a temporary basis, due to growing health concerns. But is the use of nanosilver just a fad, with little scientific evidence to support its alleged efficacy? In 2006 the New Zealand manufacturer Fisher and Paykel announced that there was no point incorporating nanosilver into their washing machines since a 20 degrees Celsius wash cycle using detergent would remove over 99 per cent of bacteria anyway! The same, year, the US Environmental Protection Agency claimed that it would introduce some nanotechnology-related legislation, although there seems to have been limited action in the meantime, to say the least.

Meanwhile other nations carry on regardless and allow if anything a greater than ever range of products with little attempt to investigate either their efficacy or ecological impact. Although found in some genuine anti-bacterial medical products, colloidal silver (that is, 1-1000 nanometre-sized silver particles in solution) is now being aggressively marketed after several decades in the doldrums. Claims for its use range from the mildly optimistic (in, for example, toothbrushes) to obvious quackery (a cure for AIDs, would you believe?) Clearly the manufacturers of alternative medicines have found a new weapon for their arsenals. But since gold is the only inert metal when it comes to ingestion - think gold flakes in vodka - just how safe is silver in any form of consumed product?

Starting with the assumption that there are no known cases of death by 'medicinal' products containing silver it might appear that consumers are just wasting their money, but there are plenty of other issues if you consider the bigger picture. Which in this case is the planetary ecosystem. Firstly, any overuse of household antibacterial agents can reduce children's immunity, although silver-based products are probably small fry compared to the myriad of cleaning sprays, gels and wipes aimed to keeping the family home 'safe from germs'. And since silver cannot differentiate between useful/symbiotic and harmful/disease-causing bacteria, the application is more akin to machine gun fire - with its consequences of 'collateral damage' - than a precision-targeted solution.

Next, the natural variation in the bacterial gene pool can lead to the sort of problems that hospitals are now facing with the likes of the MRSA 'superbug', namely that killing 99.9% of bacteria leaves the remaining 0.1% to form the one hundred per cent of the next, completely immune generation. A perfect example of inadvertent natural selection. Or should that be unintended artificial selection? However you define it, we are now starting to pay the price for thoughtless use (and frequent overuse) of our war against microbes.

Finally, back to my original question as to what happens to the ever-increasing amount of nanosilver washed down the drains from the likes of our socks (and the washing machines themselves). According to recent Swiss research, circa 95% of waste water nanosilver ends up as silver sulphide and is therefore relatively harmless. So need I have worried about where the material was ending up? Well, 5% on a global scale could still be considered a substantial amount, and since sewage sludge can end up being dumped on farm land - 3 to 4 million tonnes per year in the UK alone - could there be residual consequences on the soil bacteria, fungi, earthworms and of course farm produce destined for human consumption? Even a subtle shift in the microbial population could have a profound effect on the ecosystem and therefore the human food chain, if you want to be purely selfish about it.

This latter may sound like unsubstantiated scaremongering, but considering the history of research, often industry-sponsored, that has downplayed or even denied the dangers of nicotine, leaded petrol, DDT and various others, might it be too soon to say that the risk is non-existent? The lack of scientific evidence, combined with the poor efficacy of products such as my impregnated socks, suggest that fashionable capitalism is the primary reason behind much of the use of nanosilver. As we all know, mindlessly following others can lead to all sorts of problems. If there's a lesson here, it’s think before you shop: if you want to buy something small, shiny and made of silver, there are plenty of tried and trusted alternatives!