Microplastics in Sandy Beaches of Puerto Vallarta in the Pacific Coast of Mexico

Abstract

In this research, the abundance and physical and chemical characteristics of microplastics (MPs) in coastal sediments from three beaches of Puerto Vallarta in Mexico were investigated. The objective of characterizing and finding MPs in sand is to generate information that is useful to manage macroplastic waste, prevent its additional generation, and thus reduce environmental pollution and achieve sustainable development. The MPs were classified according to their physical characteristics such as color, size, and shape under a stereoscopic microscope, and their wear and surface were observed using a scanning electron microscope. The chemical composition of the most representative types of polymers were detected by Fourier-transform infrared spectroscopy. It can be observed that Los Muertos beach presents the highest number of MPs (97.5 particles/m2) followed by Boca de Tomates beach (69.75 particles/m2) and Oro beach (28.75 particles/m2). The differences found between the beaches are attributed to the tourist influx and proximity to the mouth of a river. In total, 37% of MPs were white, followed by 19% yellow, and 11% transparent. The shape distribution of microplastics of sizes < 5 mm and 1 mm was fragmented, the greatest abundance was microfibers, microfragments, and microfilms for MPs between <1 mm and 1 µm, and these corresponded to polyester, polyethylene, cellophane, and polystyrene, respectively.