Beneath the water column: Uncovering microplastic pollution in the sublittoral coastal sediments of the Canary Islands, Spain
Cristina Villanova-Solano, Francisco J. Díaz-Peña, Cintia Hernández-Sánchez, Javier González‐Sálamo, Carlos Edo, Daura Vega-Moreno, Sonia Fernández-Martín, E. Fraile‐Nuez, Francisco Machín, Javier Hernández‐Borges
Abstract
Marine ecosystems pollution by microplastics (MPs) is a global problem of special concern. The present study examines the prevalence and distribution of MPs and cellulosic particles in sublittoral coastal sediments of the Canary Islands archipelago (Spain). At twenty-six different locations alongside seven islands, three samples were taken parallel to the shoreline between 1-10 m depth (n=78). Sediment samples were primarily digested with a H2O2 solution followed by four flotations in a saturated NaCl solution. The mean concentration obtained was 3.9 ± 1.6 items/g of dry weight. A similar distribution pattern was observed across all islands concerning particles morphology, color, size and composition: mainly colorless/translucent and blue fibers (60.0%). Additionally, fragments were also found, and to a much lesser extents microbeads, films and tangled messes. MicroFourier Transform Infrared spectroscopy analysis of 12.5% of the fibers, showed that they were mainly cellulosic (54.5%) -either natural or semisynthetic- followed by polyester (22.7%) and acrylic (4.5%). The potential correlation between particle distribution in nearshore sediments and wave intensity was also explored. This work provides the first comprehensive report on the current MPs content of the seabed of the region. Microplastics constitute nowadays an important group of emerging and ubiquitous contaminants since they are present in all environmental compartments and cause important environmental problems also to biota. In the particular case of humans, there are still important issues that are not yet fully known. This work provides a better overview of the current state of sublittoral coastal sediments from oceanic islands concerning plastic pollution, establishing also a correlation between the distribution of anthropogenic particles in sublittoral coastal sediments and wave intensity, providing valuable insights into the relationship between these factors.