Influence of windward versus leeward settings on microplastic distribution in beach sediments of Kish Island, Gulf region

Abstract

Two beaches from Kish Island were compared with respect to their microplastics (MPs) load, by combining well established sedimentological methods with microplastic (MP) extraction by an oxidative procedure and subsequent density separation using ZnCl 2 solution. One beach (Site A) is located upwind experiencing low tourist pressure, while the other one (Site B) is a highly frequented tourist beach which is located downwind. Generally, the concentrations vary from 530.00 ± 14.14 to 580.00 ± 84.85 particles/kg, and thus are in the range of values reported from elsewhere, but on the higher side. The quantity of MPs was not substantially different between the two areas; particle sizes are larger upwind. Overall the extracted MPs are secondary particles (65.5%), dominated by fragments, followed in abundance by fibers (23.5%). Granules (6%) and films (5%) were less commonly observed. This distribution is in contrary to reports of beaches elsewhere where fibers are by far dominant. The present study points to dominant sources of MPs outside the island, being transported to Kish Island by marine pathways, where further wind-driven transport leads to an absence of small synthetic fibers in the windward setting (Site A). The present study provides an initial evaluation of MP pollution in beach sediments of Kish Island, and in the region of the eastern Gulf.