Berlin: The seas are littered with large quantities of microplastic particles -- plastics in small bits and pieces -- endangering the lives of marine creatures, says a report.
Plastic bottles washed ashore are as much a part of the coast as the sound of seagulls. What the eye does not see are the innumerable ultra-small plastic objects that float on the water, are washed on to the beach or settle on the seabed.
Scientists refer to these as "microplastic particles" whose diameter is less than five mm. Majority of these particles are smaller than grains of sand or tips of needles, says the journal, Environmental Science & Technology.
Scientists in Germany, with British and Chilean colleagues, have analysed all published studies on this topic and proposed standardised guidelines for the recording and characterization of microplastic particles in the sea.
"The particles are swallowed by organisms and absorbed via the digestive tract. It has been possible, for example, to detect them in the tissue of mussels or other animals," says Lars Gutow, a biologist at the Alfred Wegener Institute for Polar and Marine Research.
Toxic substances also attach to particles in the sea which then enter the food chain and can, therefore, be dangerous to humans, says a statement by Alfred Wegener Institute.
Gutow and his colleagues from the Universidad Catolica del Norte in Chile and the School of Marine Science and Engineering in Plymouth, United Kingdom, have jointly addressed the question as to how greatly the oceans of the world are polluted with microplastic particles.
The biologists analysed 68 scientific publications on this subject.
"Microplastic particles reach the seas in different ways. A large share is accounted for by so-called plastic pellets used as a raw material in the manufacture of plastic products such as computer housings and other everyday articles," says Gutow.
"If these pellets are handled carelessly, during ship-loading for example, many may be blown away by the wind and fall into the sea."
Microplastic particles are also to be found in cosmetics and cleaning agents.
"Small plastic particles are used as `abrasives` in many peeling products. They then reach the sea via sewage water and rivers," says Gutow.
Finally, every plastic bottle and every plastic bag floating on the sea disintegrates into countless microparticles. "It can take years for larger plastic parts to disintegrate primarily through physical processes. The sun`s ultraviolet radiation makes the plastic brittle. It is then broken down into ever smaller parts from the waves and friction processes," says Gutow.