Plastic, plastic, everywhere: but the smaller particles hidden beneath the surface may be the greater threat.
You can’t see it from satellites. You can’t see it by plane. You’d be hard pressed to notice it even by boat. But there’s a modern-day monster lurking just beneath the ocean surface, and its effects could haunt us all.
This monster, sometimes known as the ‘Great Pacific garbage patch’, is a heavy concentration of plastic particles whose extent may vary with the currents but is estimated to lie somewhere between the size of Texas and that of the entire continental United States. Actually, there are many such patches on our planet. They form where ocean currents from the north and south converge in ‘subtropical gyres’ when these currents carry debris from boats and from the shoreline. The reason these patches aren’t easily visible despite their huge areas and the large amounts of plastic they contain – up to five kilograms per square kilometre – is that this plastic is mostly in the form of very small particles less than two millimetres in diameter. That’s partly because larger objects – plastic bags, bottles, containers and so on – are rapidly broken up into smaller pieces by the combined forces of sunlight, salty water, storms and sealife. But an even bigger problem, perhaps, is the plastic that begins small in the first place.
The first synthetic plastic was Parkesine, forged in a time and place that were right at the heart of the industrial age, Birmingham in 1856. But it was between the 1920s and 1950s, especially when cheap and versatile materials were needed in quantity to facilitate the Second World War and the recovery from its devastation, that an explosion in the varieties of plastic available took place, mainly produced from oil. Since then, their use has increased worldwide year on year, and they have become an integral part of the fabric of both the industrialised world and the poorer regions wither the influence of industry has spread. Those who provide plastic products to these regions seldom provide the means to dispose of it, and it’s not difficult to see how large quantities of plastic reach the oceans from the shores of Africa and Asia when even in our own country – where regulations and recycling are widespread – rivers and beaches are lined with litter.
Indeed, so pervasive is plastic that we often use it without even realising. Many cosmetic products – from face-scrubs to toothpastes – are impregnated with tiny plastic beads, and our clothes and furniture are laced with plastic fibres. It’s just these sorts of imperceptible pieces of plastic that are the most likely to make it into our water systems, washed down the sink or exuded by washing machines.
But don’t make the mistake of thinking that just because they’re small these plastic pieces are harmless. Far from it: in fact, in many ways plastic becomes more dangerous the smaller it gets, mainly because it becomes more ingestible. The danger posed to humans by the build-up in our bodies of synthetic toxins that have rubbed off our furniture or food and drinks packaging remains uncertain, but some of these chemicals may be linked to cancers, heart disease and birth and development defects. Unfortunately, their proliferation is too recent for us to be certain.
In the oceans, though, it’s the effect on wildlife that’s most concerning. Ocean gyres are naturally quite nutrient-poor, which makes it quite likely that the concentration of plastic pieces exceeds that of microscopic plankton in many cases. Many fish live on plankton, and if they eat the plastics instead and absorb them into their tissues not only their own health but also that of other animals right up the food chain – including humans that catch and eat fish – will suffer. Sea-birds are sometimes found to have died from starvation with full stomachs, having filled up on indigestible plastic instead of fish. It’s because these materials aren’t naturally occurring and sometimes take thousands of years to break down into their safer constituent elements that chaos ensues when they’re released without consideration into the environment.
Ironically, though, what’s most worrying to scientists is not that the oceans’ plastic islands are growing, but that their size, over the last couple of decades at least, has been remarkably stable. This is dangerous because the amount of plastic produced and discarded in the world has continued to increase over this period, and it’s not as though the routes by which it escapes into the oceans have suddenly been blocked. This leaves us with a worrying quandary: where exactly is all that plastic going? If it’s not building up on the ocean surface, and currents aren’t carrying substantial quantities back to shore, the most likely explanation is that it’s being eaten in vast quantities, either carried to the ocean floor in the dead bodies of a plethora of poisoned sea-life, or being broken down by bacteria into still smaller fragments. The latter could be good news, if those fragments are small enough to be harmless. But more likely, the bacteria don’t break it down beyond the molecular level, in which case it could be seeping into the flesh of fish in larger quantities than previously thought, a lurking danger that could be poisoning future fish, birds and humans for generations to come.