Abstract
Aim: To investigate the baseline abundance of microplastics on two sandy beaches along an exposed coastline in an understudied region of the Northwest Atlantic.
Methods: Sandy sediments were sampled from two beaches along the eastern shore of Nova Scotia, Canada from High, Mid, and Low intertidal positions. Density floatation using a sodium iodide (NaI) solution was used to separate particles from 100 g of sediments in each sample. Particles were characterized by size, shape, and colour, and Fourier transform infrared (FTIR) spectroscopy was conducted for polymer identification.
Results: At both beaches, the majority of particles found were small (< 1.4 mm), transparent microfibers. Microplastics were polymers of polyethylene terephthalate (PET), nylon, or alkyds (paints). The mean concentrations at both beaches were similar, at 5.08 ± 3.20 and 5.58 ± 4.52 microplastics per 100 g of sediment. Non-plastic (i.e., natural and semi-synthetic cellulosic) microfibers were up to 19 times more abundant than microplastics, with mean concentrations of 75.9 ± 60.1 and 97.7 ± 87.9 per 100 g sediment. Mean particle counts did not differ significantly across tidal ranges due to their high variability over small spatial scales (10 s of m).
Conclusion: Using new investigative tools yielded estimates of microplastic pollution 1-2 orders of magnitude lower than earlier research conducted at these sites, and was generally lower than values reported from other beaches globally. Sources of microfibers were potentially from high recreational use at these sites. Future monitoring could target these sites for time series analysis of microplastic change on exposed sandy beaches.