Microplastics in coastal sediments from Southern Portuguese shelf waters

• Microplastic fibres and fragments were found in nearly 56% of sediment samples.
• 31 microplastics were recovered.
• 25 were fibres identified as rayon through FTIR.
• 6 were fragments identified as polypropylenw.
• Microplastics were more common at depth below 20 m.

Microplastics are well-documented pollutants in the marine environment that result from fragmentation of larger plastic items. Due to their long chemical chains, they can remain in the environment for long periods of time. It is estimated that the vast majority (80%) of marine litter derives from land sources and that 70% will sink and remain at the bottom of the ocean. Microplastics that result from fragmentation of larger pieces of plastic are common to be found in beaches and in the water surface. The most common microplastics are pellets, fragments and fibres.This work provides original data of the presence of microplastics in coastal sediments from Southern Portuguese shelf waters, reporting on microplastic concentration and polymer types.Microplastic particles were found in nearly 56% of sediment samples, accounting a total of 31 particles in 27 samples. The vast majority were microfibers (25), identified as rayon fibres, and fragments (6) identified as polypropylene, through infrared spectroscopy (μ-FTIR). The concentration and polymer type data is consistent with other relevant studies and reports worldwide.