posted in the Sydney Morning Herald June 21, 2011
Plastic resin pellets collected at Watermans Beach pellets in August 2010.Millions of tiny plastic resin pellets, some containing harmful chemicals, which litter Western Australia's southern beaches, are thought to be contributing to the "inevitable" wipe out of the world's marine species.
A report from the International Programme on the State of the Ocean, held at Oxford University, has found that overfishing and ocean pollution is killing fish, sharks, whales and other marine species far faster than predicted, and could result in a catastrophic extinction event.
The international panel of marine experts said that conditions in today's oceans were comparable to conditions during "every previous major extinction of species in Earth's history" and there was a "high risk of entering a phase of extinction of marine species unprecedented in human history".
Volunteers sorting and recording marine debris collected at Binningup Beach during the 2010 South West Beach Cleanup.Alex Rogers, scientific director of IPSO, said when considering the cumulative effect of fertiliser run-offs, plastics, chemical pollutants, acidification and overfishing of the sea, "the implications became far worse than we had individually realised".
Among these dangerous pollutants are plastic resin pellets, used in the manufacture of plastic drink bottles and other plastic ware.
Made up of different chemicals, they absorb pesticides and industrial chemicals found in the ocean and form concentrated toxic pills for unsuspecting marine life, according to Tangaroa Blue Ocean Care Society officer Wally Smith.
He said that among the more hazardous impacts the pellets could have, when accumulated in high doses, was creating hormone disruption and possible infertility.
One plastic polymer widely studied for its impact on hormones, more specifically on the creation of oestrogen, was Bisphenol A (BPA).
It was found to be almost as potent as a person's natural hormones back in the 1930s, but by the '50s it was also discovered that BPA molecules could be synthesised into a hard durable plastic, now found everywhere, Mr Smith said.
"BPA is a fairly well-studied example of the transfer of oestrogenic chemicals from plastics into the human body and this is the process occurring in natural environments as well," he said.
"Although studies directed at the actual transfer of chemicals from the plastic into marine creatures is limited."
A variety of chemicals, many oestrogenic, also get mixed into the polymer to give it the desired properties of colour, flexibility, UV resistance and so on, he said.
"These chemicals are never fully fixed in the polymers and migrate to the surface and escape," he said.
"So some of the chemicals in discarded plastic quickly escape into the air or water and enter the food web."
The chemicals found on plastic resin pellets in the Cape Naturaliste to Cape Leeuwin area several years ago were found to be low but did include PCBs (industrial chemicals), DDT derivatives (pesticide), and HCH (pesticides) - all of which were hormone disruptors.
"No tests have occurred since then and the more appropriate testing regime in our view would be a local monitoring program over time covering a number of locations on the West Australian coast," Mr Smith said.
"The tendency in Australia is to wait for overseas studies to prove these chemicals are affecting sea life.
"This is unfortunate as we are now beginning to get an idea of the scale of marine plastic pollution and how extensive micro-pollutants such as plastic resin pellets are."
These pellets can be found in the thousands, and sometimes millions, on a single WA beach.
The pellets are often difficult to detect due to their size and colour against the sand and could take lifetimes to sift out of the continually varying seashore.
However the South-West coastal clean-up action group, Tangaroa Blue, has been collecting and recording these pellets in a bid to trace their movements and potential hazardous affect on marine life.
"We know some come from the Perth metropolitan area while others are carried here by ocean currents from distant countries," Mr Smith said.
"Changing ocean acidity and temperature will affect the rate of release of chemicals from plastic and the subsequent toxicity of those chemicals.
"This kind of change may well speed up and magnify the impacts on marine life."
Tangaroa Blue is holding its annual West Australian Beach Cleanup Event on October 15 and 16.