Textile microfibres from washing machines accumulating in ocean floors

Tiny, extremely fine fibres, that come from waste waters of washing machines, are accumulating on sea floors and may adversely affect marine life, a study warns.

Researchers from University of Barcelona in Spain and University of Plymouth in the UK analysed the amount of coloured fibres -- which vary between 3 to 8 millimetres (mm) and are extremely fine, with less than a 0.1 mm diameter -- in south European marine floors, from the Cantabrian Sea to the Black Sea.

The results, published in the journal PLOS ONE, show the dominance of cellulosic fibres over synthetic polymers, and highlight that several oceanographic processes pile and transport microfibres to marine hollows.

The findings could help design effective management strategies to reduce the emission of microfibres with a potential negative effect on the marine ecosystems.

Microfibres are one of the most common microplastics in the marine environment, but such a deep study had not been carried out so far in a large area.

Researchers analysed soil samples from 42 and 3,500 metres deep in 29 stations in southern European seas. The results show that higher densities of fibre are found in the Cantabrian Sea, followed by the Catalan seas and the Alboran Sea, respectively, while lower densities are in the western Mediterranean and the Black Sea.

The study also shows distance in deep seas is not a barrier to the accumulation of microfibres, since about 20 per cent of these particles are accumulated in the open sea beyond 2,000 metres deep.

"Textile microfibres seem to concentrate at the bottom of submarine canyons, while the quantity in the slope is significantly lower," said Anna Sanchez Vidal, from University of Barcelona.

"This suggests microfibres, probably coming from the ground (a washing machine can release up to 700,000 microfibres to waste waters in one use), are accumulated in the continental platform, from where they are swept and taken by several oceanographic processes to marine hollows through the natural conducts -marine canyons," she said.

The findings also confirm previous studies which detected microfibres that were ingested by deep water organisms in a natural environment.

"Recent results show ingests of microplastics by different organisms and in different ecosystems, but the specific impact on the organisms is unknown," said Sanchez Vidal.

"It can depend on a wide range of factors, such as features of the microfibres, or chemical substances these absorbed as well as the physiology and ecology of marine organisms," she said.

The main type of microfibre they found in marine floors is the natural cellulose (cotton, linen) and regenerated cellulose (rayon of viscose), coming from clothes and industrial textiles mainly.

Regarding synthetic fibres, polyester is the most common one, followed by acrylic, polyamide, polythene and polypropylene.

"Some of these synthetic microfibres are made of plastic, which does not degrade shortly, it can contain chemical additives, which can be easily incorporated to the trophic network," researchers said.