Holding back the tide in a sea of plastic
Spanish conservation biologist Renaud de Stephanis describes the tip of an iceberg that is made up of human-generated waste: “It was as if it had a rock inside its intestines. Nothing could get through. There was so much plastic that it finally exploded.” The sperm whale he found in March 2012 on a beach south of the city of Granada was one isolated victim of the mismanaged plastic waste being blown by the wind from landfills into the sea. According to the researcher at the Estacion Biologica de Donana, “the sea is full of rubbish.” Over a period of decades, items made of nearly indestructible plastics are weakened by UV and ground up into tiny microplastic beads that have so far been found in the digestive tracts of 663 marine species. “And that is what we end up eating,” says de Stephanis succinctly.
A growing problem
Recent studies show that harmful chemicals like DDT or polychlorinated biphenyls (PCBs) accumulate in non-degradable microplastics at levels over a million times higher than those in sea water. And these toxins are regularly taken up by fish, turtles, shellfish and seabirds. About 80% of the constantly growing problem comes from plastic waste disposed of on land. Every year, an estimated 20 million tonnes of non-recycled plastic waste joins the 140 million tonnes of plastic garbage that have accumulated at the flat-water centres of five gigantic ocean gyres (see map, p. 18). Dubbed the Great Pacific Garbage Patch, the largest of these – which lies between Hawaii and California – is over twice the size of Germany. Though it can’t be seen by satellite, the diffuse soup of microplastics poses a huge danger to the maritime environment. According to figures released by the US Environmental Protection Agency (EPA), ingested plastics kill a million seabirds and 100,000 sea mammals each year. Most of it originally comes from the partially-degraded packaging materials and plastic bags that make up a little over a third of annual global plastics production.
Biotech to the rescue?
At the current stage, only a few pioneers are thinking about how they can turn the problem into an opportunity. A team of microbiologists, biotechnologists and chemists from twelve institutions and seven SMEs for instance are in the midst of the €4m FP7 “Bioclean“ project. “We need to be ambitious,” says coordinator Fabio Fava from the University of Bologna. “Our idea is to develop biotech processes that help degrade durable polymers like PE, PP, PVC and polystyrene into simpler products that can be reused in chemical synthesis.” Turning plastic waste heading for landfills or composting facilities into value-added products without releasing additional carbon dioxide is clearly more attractive commercially than incinerating them. “We have already isolated some microbes that perform better on some of the plastics than any microorganisms described so far in the literature,” says Fava. By 2015, his team wants to use the microbes in a 30-litre pilot-scale bioreactor to generate compounds from plastic waste that are useful for the chemical industry. The team is also investigating whether they can use the specialist microbes to degrade (micro)plastics litter in industrial compositing plants. Elsewhere, partners from Crete are testing the ability of the microorganisms to reduce plastic waste in the Aegean Sea.
Read the full background on the plastics problem in our print magazine!
- Global Market projection for biobased and biodegradable plastics
- Overview of the market for bioplastics
- The political viewpoint: bans and taxes worldwide
- Interview on sustainability with the founder of the Zero Emissions Research and Initiatives (ZERI) and CEO of Novamont Gunter Pauli
- Market opinions from bioplastics and environment experts