SANTA CRUZ DE TENERIFE, September 8 (EUROPA PRESS) –
A study recently published in the journal ‘Science of the Total Environment’, developed jointly by the Applied Analytical Chemistry research group (AChem) of the University of La Laguna, and the Azores Marine Litter research group of the University of the Azores , has revealed that the beaches of Macaronesia are acting as sinks for microplastics by accumulating them in depth.
The study, carried out on the beaches of Porto Pim on the island of Faial, Milicias on the island of San Miguel and in Playa Grande, in Tenerife, quantified the microplastics of 1 to 5 millimeters in size that were buried up to 1 meter deep from the line of maximum high tide, towards the supralittoral zone.
In each of the three beaches, a total of 16 samples were taken and analyzed in the laboratories of both universities.
The results obtained showed that the concentration of microplastics increases as you move towards the outside of the beaches and that the vast majority of these are not found on the surface.
In fact, 84% of the microplastics found were found in deep layers (below 10 centimeters deep).
Despite this, the type of microplastics found in both Playa Grande and Porto Pim (considered as black spots of mass arrival of this matter) was the same and that usually found on the surface of the beaches of Macaronesia.
Specifically, they are mostly fragments (87%) (pieces of rigid plastic and irregular edges) of white color and of polyethylene (the vast majority) and polypropylene.
Both types of plastic are the most produced worldwide and, as they have a low density, they float in the sea and can be transported long distances, according to a note from the ULL.
The great similarity between the morphology and composition of the microplastics from both beaches (generally from the beaches of Macaronesia, as studied by the Interreg-MAC IMPLAMAC project, led by the University of La Laguna) is fundamentally due to the fact that the The Macaronesian archipelagos are affected by the subtropical gyre of the North Atlantic, which sends significant quantities of marine litter of similar composition to the islands.
MILITIA BEACH
For its part, in the case of Milicias beach, both fragments and foams were found in similar quantities, although in lower concentrations than the other two beaches.
In addition to the above, pre-production pellets or pellets of around 6% were also found on the three beaches.
These microplastics constitute the raw material used to manufacture larger plastics and end up in the sea due to the fall of containers that contain them.
Of the three beaches studied, the one with the highest concentration of microplastics at depth was Playa Grande. In all cases, microplastics with a size between 3 and 4 millimeters predominated.
To date, the vast majority of studies trying to determine the presence of microplastics on beaches have focused on microplastics found on the surface (first 5 centimeters) and that reach the beach with the last tide.
However, this type of work highlights the need to also study its presence in areas that are not flooded by the tide, as well as in the deepest layers of the beach, since everything seems to indicate that these are acting as sinks by accumulating them. in deeper areas.
