A recent study carried out on scallop shells has shown that in only a few hours, billions of plastic nanoparticles can seep into the mollusk’s organs.
We know that in our oceans, plastic decomposes into ever tinier fragments so that it eventually forms nanoparticles of less that a thousandth of a millimetre in diameter. The impact of these plastic particles on marine life remains even today relatively unknown and with limited research studies. However a team of researchers from the University of Plymouth have been looking into scallop shells assimilation of these nanoparticles of plastic. The details of their study has been published in the journal Environmental Science & Technology.
Billions of plastic nanoparticles absorbed in a few hours
“For this experiment; we had to develop an entirely new scientific approach,” explained Maya Al-Sid-Cheikh from the University of Plymouth and principal author of the study. Researchers then made plastic nanoparticles in a laboratory. They then radiolabelled the nano-plastics so that they could follow them inside the mollusk’s body. These mollusks were exposed to concentrations of plastic that is similar to what is found in the oceans today. The results showed that these plastic nano-particles could be quickly adsorbed by the a marine organism. In fact, the nanoparticles seem to have spread around the mollusk’s body in just a few hours.
After six hours of exposure to be more precise, researchers noted the presence of billions of plastic nanoparticles in the mollusk’s intestines. These particles measured only 250 nm in diameter, or 0.00025 mm. Often containing polystyrene which is a common plastic found in seawater. Smaller particles, measuring 24 nm, also dispersed into the rest of the body, especially into muscles. The scallops were then plunged into clean water. It then took about 14 days for the smaller particles to disappear. However the larger particles were still present 48 days later.
Evaluating the impact on human health
“Understanding whether plastic particles are absorbed across biological membranes and accumulate within internal organs is critical for assessing the risk these particles pose to both organism and human health,” stated Ted Henry a professor of Environmental Toxicology at the University of Heriot-Watt, Edinburgh. The novel use of radiolabelled plastic particles pioneered in Plymouth provides the most compelling evidence to date on the level of absorption of plastic particles in a marine organism.
Overtime this novel method could allow researchers to label nanoparticles so that they can analyse their absorption by other organisms. The better we understand the problem, the better we are able to deal with the problem. This is a step in the right direction as according to Greenpeace, the equivalent of a bin lorry of rubbish gets dumped into the ocean every minute!