Thor

I was in my seventh year (1970) and just in infant's school when my class did a project on the great maritime explorer and adventurer Thor Heyerdahl. 

He had just completed another epic sea journey in little more than a buoyant mud hut called Ra following on from his perhaps even more epic sea journey on his Kon Tiki raft in the late 1940's. 

There was a lot for us young children to learn about the actual boat, how he survived the months at sea, the practicalities of eating, getting fresh water and of course, of great interest to developing minds - how he went to the toilet. 

We made models of vessels that we would hope, ourselves, to sail around the great oceans aboard but our resources of loo rolls, milk cartons and margarine containers did have severe creative limitations.

What I do not remember being told about and I realise this  only now in my 51st year was Heyerdahl's recording of his shock and dismay at the amount of pollution that he came across every day of his journey.

He had seen early signs of the use of the oceans as a dumping ground on his first rafting but the increase in waste and debris over the ensuing 20 to 25 years he found heartbreaking. 

So how bad is the problem now, another near half century on? 

Current estimates are that the amount of plastic found in the world's oceans is around 8.8 million tons.

An aid to assist in visualising this figure is that it would translate into five carrier bags full of the stuff for every foot of the whole of the earth's coastline. 

Most of the debris consists not of obvious bulky items of bottles, containers, packaging, wrappers, etc but of small plastic particles averaging 5mm x 5mm x 1mm which are suspended at or just below the surface. The problem is lurking there but is impossible to detect by aircraft or satellite and may not be detectable even by boaters or divers amongst it. 

The particles in being light are very mobile and become trapped and re-circulated in the main currents of the great oceans. 

There are garbage patches in the Pacific, Indian Ocean and North Atlantic with not only pelagic plastics but chemical sludge and other pollutants. 

The size of the Pacific Garbage Patch is unknown but has been estimated from sampling from 270,000 square miles (the size of Texas) to more than 5,800,000 square miles which is, staggeringly, twice the size of the continental United States. 

In 2009 an Oceanography Vessel found that plastic debris was present in 100 consecutive samples taken at various depths and using different net sizes along a 1700 mile trawl through the Garbage Patch. 

Unlike organic debris which biodegrades the plastic tends to disintegrate into ever smaller pieces while remaining a polymer. As the flotsam photodegrades yet smaller and smaller it forms a concentrated soup near the ocean surface and is readily ingested by aquatic organisms. It is not far from this point to a risk of the plastic entering the human food chain. 

Those plastics which do decompose are not the end of the problem as toxic chemicals are released including PCB's and derivatives of polystyrene. In many of the sampled areas the overall concentration of plastics was found to be seven times greater than natural zooplankton. 

Concerns have been expressed that the layer of pollution prevents light reaching into the oceans and the debris is also able to absorb toxins with potential to poison anything that eats it. 

A clean-up coalition was formed in 2008 in the Pacific Region to try to identify methods to safely remove plastic and persistent organic pollutants. Commercial scale collection and recycling is an option and research has been undertaken on the potential to use the surface currents to let the debris drift to specifically designed points thereby keeping running costs at virtually zero but with efficiencies making for good projections of profitability from such an operation. 

On a very small scale but actually up and running is the crafting of a soap dish made from recycled ocean plastic from beaches in Hawaii. Artist Groups use trash from the Garbage Patch to create clothing coining the new term of trashion. 

The emphasis has tended to be on trying to cope with current concentrations of rubbish but active sources of the problem are well known around the Pacific Basin and where the other gyres of marine debris are to be found. 

The majority of the plastic comes from five countries, China, Indonesia, Sri Lanka, The Phillipines and Vietnam. These nations appear to lack any real concerted waste management programmes  resulting in resorting to disposal into the sea. The United States are an example of a country with a defined environmental policy and although not at all squeaky clean in contributing 77,000 tonnes (compared with 2.4 million tons from China) it is equally shocking that this is thought to mainly come from littering.

I conclude with recollections of my school project on Thor Heyedahl way back in 1970. 

We as innocent children were not to know or appreciate then what we were, as part of the human race, storing up in terms of environmental impact and ecological hazard. Pollution and Climate change were not prominent in our infantile studies or to be honest of any interest or concern whatsover. We were far more fascinated and enthralled by trying to imagine drifting about on a raft and all adventurous things like that.