Thursday, October 14, 2010

Plastics in the oceans debate comes to qualified consensus Plastics in the oceans debate comes to qualified consensus

“Reduce, reuse, recycle” sums up the common ground reached by an environmental campaigner, an oceanographer and a senior plastics industry representative in a debate on marine plastic litter hosted by the Royal Geographical Society (RGS) at its London headquarters last night.

Panellists were David de Rothschild, leader of the trans-Pacific Plastiki expedition on a boat made from plastic bottles ( 22 March), Dr Simon Boxall of the National Oceanography Centre, Southampton, and Peter Davis, Director General of the British Plastics Federation (BPF). In the chair was Peter Shukman, BBC science and environment correspondent.

Dr Boxall outlined salient scientific findings on the marine litter problem evident in all five oceanic gyres (north and south Pacific, north and south Atlantic, and Indian Ocean). The circulation time in each gyre is around six years; around 40% of gyre litter is lost on each cycle to the single global deep-water circulation system. Thus “the problem knows no boundaries, and covers the entire planet.”

Boxall said that bulk retrieval of current marine litter is not feasible – “basically, we’re stuck with it”, and efforts must concentrate on preventing future littering.

According to Boxall, on the macroscopic scale, plastic bags cause disproportionate problems in the oceans – they are transported by wind as well as currents, mimic the food prey of wildlife such as albatrosses and turtles, and are usually fatal when ingested.

He noted that marine pollution surveys do not pick up on microscopic plastic particles; which in some locations outnumber phytoplankton and zooplankton – causing foodchain problems. Plastic dust is detectable in UK coastal waters. “The good news,” said Boxall, is that globally there has been no significant increase in particle count from 1986 to 2008.”

Finally, Boxall observed that bisphenol A (BPA) leaching from plastics is significantly soluble in seawater at 30°C, and that the pollutants PCB and DDT are absorbed by spongelike plastic particles.

David de Rothschild denounced the use of what he described as “dumb single-use plastics”, citing as particular bêtes-noires retail plastic bags and water bottles, and styrofoam cups. He advocated that plastic food packaging be drastically reduced by the widespread adoption of farmers’ markets, and the retention of current plastics distribution chains to handle more sustainable alternatives – but queried whether the plastics industry is truly motivated to implement sustainability measures which would harm its own livelihood.

Peter Davis noted that marine plastic litter is now firmly on media and plastics industry agendas – but not regarded as important by most governments. Climate change and overpopulation would surely increase environmental pressure on the oceans.

Davis denied that the plastics industry has no incentive to address waste and pollution through reuse and recycling, commenting “We [in the industry] regard used plastics as a resource, not as waste – we want them back for recycling!”

As evidence of industry commitment, he cited progress with the Plastics 2020 Challenge to divert plastics from landfill in order to reduce climate change impact, address the energy deficit, and achieve a step change in the efficient use of resources. Operation Cleansweep is dealing with loss and waste of raw material pellets, with health and safety as well as resource benefits.

While applauding plastic bag re-use schemes, Davis noted that that bags form “a tiny proportion” by weight of the total plastics waste stream. He endorsed eliminating excess packaging, but noted that an appropriate minimum is necessary since “64m UK citizens need three safe, fresh meals per day, delivered via a 24-hour supply chain.”

On marine BPA pollution, Davis noted “a clean bill of health” for the chemical from the European Food Standards Agency (, 4 October).

A lively session of questions from the audience of several hundred RGS members and guests followed. Asked about the potential of biodegradable plastics, the panel noted that the relevant bacteria are killed by a saline environment, so biodegradation must happen before the waste reaches the sea. Peter Davis cautioned that, excellent as biodegradables are, they only suit a limited range of applications.

A questioner asked whether there are viable alternatives to plastic for farmers packing foodstuffs – and how these would be received by the market (especially the supermarkets).

The panel agreed that dumping of rubbish by multinational companies on poor countries (e.g. on the West African coast) must cease, through political pressure or otherwise.

Asked why recycling symbols on packaging are not explained to consumers, the panel responded that the code is intended mainly for local authorities and recycling contractors – but that consumer education could only be beneficial.

The panel concluded that marine littering would best be tackled through behavioural change – for instance:

• education and enforcement against littering by beach visitors, illegal dumping at sea and poor port management

• refundable deposits on plastic drinks bottles, analogous to previous common practice with glass bottles

• stronger measures against fishermen losing or dumping tackle at sea

• diverting and composting the high proportion of biodegradables which currently go to landfill

• much more consistent recycling by local authorities, spreading best practice to the worst performers

• coastal clean-up initiatives.

No comments:

Post a Comment