Wetenschap - 27 september 2012

Mussels don't like plastic

Arno van 't Hoog

Plastic nanoparticles demand extra energy from mussels. Particles may pass from mussels to humans.

Plastic pollution takes many forms, from empty bottles and bags to micro- and nanoplastics - tiny particles no more than a couple of millimetres in size. Such particles are formed when larger waste matter gets broken down and they are in sewer water, where they come from wear and tear to synthetic clothing in the wash and from residues of cosmetics.
Wageningen researchers led by Bart Koelmans studied the effect these particles have on life in the water. In a research involving mussels, the researchers recreated plastic pollution in the lab using polystyrene balls 30 nanometres (30 millionths of a millimetre) in diameter. Adding these particles to seawater causes the mussels to slow down their filter activities to get rid of the plastics. Koelmans: 'That takes energy for the mussels and must therefore happen at the expense of their growth.'
The particles can also be found in the mussels afterwards, which means shellfish eaters including humans could ingest them. But Koelmans does not want to draw far-reaching conclusions about that at this point. For that, too little is known yet about the concentrations of nanoplastics in the environment. 'We cannot yet estimate the degree of risks. For that you also need to look at the total concentrations of nanoparticles found in the environment. Both natural sources and road traffic generate root particles that float in the water.'