An annual study on plastic accumulation in surface water and sediment cores from the coastline of Tenerife (Canary Island, Spain).

Sediment core samples from high tide lines and in submerged zones as well as surface water samples from eight beaches of Tenerife were analysed. Sampling was conducted over a period of one year in intervals of 5 weeks. The majority of particles were found in the high tide sediment (66%), followed by water samples (23%) and finally in sediment from submerged zones (11%). Regarding the particle amount per volume (items/L), accumulation in sediment samples was statistically higher compared to water samples. Mean values of items/L were higher in high tide sediments. In high tide and water samples, mostly white and transparent particles >1 mm were found. More than 70% were represented by fragments. In sediments from submerged zones, yellow and blue microparticles (<1 mm) were predominant and 61.9% consisted of fibres. Larger particles were mainly identified as PP, PE, PS, PTFE and PVC, while polymer types of smaller particles were more variable.

Extraction of microplastic from marine sediments: A comparison between pressurized solvent extraction and density separation.

Due to the ecotoxicological effects, microplastics are considered a threat for the marine environment. Recent reports indicate their presence not only in subsurface water and in coastal beach sediments, but also in the deep-sea. Notwithstanding, there is still not a scientific consensus about the analytical procedure to be applied for their determination. In this work we compared the performance of two extraction methods: pressurized solvent extraction (PSE) and density separation. Sea sand and seafloor sediments were spiked with known amounts of polystyrene (PS), polyethylene (PE) and polypropylene (PP) microplastics and submitted to both the extraction procedures. Results showed that the PSE ensured higher recoveries for the smaller size particle fractions (89,2 ± 1.1% in the 50-150 µm range) whereas the density separation enabled precise recoveries for the larger size particles (SD = 1,5%). No significant differences in terms of blanks control were highlighted.