The amount of microplastics found in beaches increases whenever there is heavy rainfall, a University Of Malta study has found, with the particles coming both from land and sea.

Samples from four different beaches -  Għajn Tuffieħa, Golden Bay, Għadira Bay and Pretty Bay - were taken on a monthly basis between November 2018 and August 2019 as part of a Masters study by Department of Geosciences student John Montebello. 

Through coring and sieving at different distances from the shoreline down to a depth of half a metre, the student collected over 6,200 microplastic particles.

Besides sampling on a regular basis, the student also took samples immediately after the aftermath of heavy rainfall, confirming that the greatest amount of the plastics on the four beaches were recorded following the stormiest and wettest weather.

Microplastic numbers could be lower during summer months due to beach management by cleansing entities as well as due to particles being blown away with dry sand. 

Which beach has the biggest problem?

The study showed that the highest microplastic abundances were recorded at Għajn Tuffieha, while the lowest numbers were at Għadira.  Most of the particles were recorded in the upper 20cm of sand sediment.

The microplastic size category most commonly encountered during the sampling was that of the 4 to 5mm, while the three most popular microplastic colours were grey, white and brown, suggesting that the majority of the particles were so-called primary microplastics. 

What are microplastics?

The term microplastics was introduced in the last decade to describe small pieces of plastic found in the ocean, commonly defined as smaller than 5mm in diameter.

One distinct category of microplastics are plastic pellets. These represent one of the main ways of transporting plastics between plastics producers and companies converting plastics into products.

Accidental spillages and poor handling mean that plastic pellets are common on beaches, especially near ports and industrialised regions.

Plastic pellets and plastic particles manufactured for particular applications, such as cosmetic products and abrasives, are often called ‘primary’ microplastics.

Microplastics produced as a result of fragmentation from larger items are called ‘secondary’ microplastics. The distinction is crucial in pin-pointing sources and target reduction measures.

The student was supervised by resident academics Alan Deidun and Adam Gauci throughout the study.