MICROPLASTIC: A CONSISTENT COMPARISON OF GLOBAL SAND AND SOIL SAMPLES

The mass production of plastics which began in the 1950's with 2 million tonnes per year, has increased nearly 200-fold to 381 million tonnes in 2015. Because of their durability, persistence, increasing production, and low rates of recovery, most of the 8.3 billion tonnes of plastics produced globally over the past 65 years, still exist today. The resulting accumulation of plastic debris has been of global concern for decades. More recently, concern over the harmful impacts of contamination by small plastic fragment has emerged as a global environmental issue. A growing body of work from researchers around the globe have shown that small plastic fragments, known as microplastics (< 5mm), are ubiquitous in the biosphere. Our understanding of differences in the type, abundance, and composition of microplastics around the globe come from a variety of studies often employing different methods, making it difficult to compare results. No single study, that we are aware of, has collected and described microplastics in coastal sand and soil samples from around the world. Here we present results from our ongoing work describing microplastics in nearly 600 sand and soil samples from every continent, except for Antarctica. Samples were collected worldwide over a more than 20 year period. Samples were collected in 5 ml glass jars and sealed until opened for analysis in this study. Following the methods of Besley et al. 2016, microplastics were separated and extracted from sand/soil samples using density separation with a NaCl and deionized water solution followed by vacuum microfiltration. Filters were visually inspected using a stereoscope and all microplastics were photographed and their area measured using NIH ImageJ software. The composition of microplastics will be identified using Raman laser spectroscopy. By consistently employing the same methodology to describe microplastics in sand and soil samples from around the world, it is our hope that this study will provide a more reliable means to compare microplastics at a global scale.