Microplastic pollution on Cape Cod beaches 1 Plastic Beach (The Arrival) Spatial heterogeneity of microplastic pollution on Cape Cod beaches and the impacts of different hydrographic sources Hector Ricardo Salazar Connecticut College Project Mentors: Rut Pedrosa Pamies*, JC Weber, Maureen Conte Ecosystems Center Marine Biological Laboratory Semester in Environmental Science Class of 2018 *Corresponding author: Rut Pedrosa Pamies [email protected] Microplastic pollution on Cape Cod beaches 2 ABSTRACT Plastic has become a large source of global pollution; it has entered our marine ecosystems and we are only beginning to see the effects on ecosystem health, animals, and humans. Plastic is a great threat to the environment due to its non-biodegradable properties and long resonance time once in the environment. Plastic debris now contaminate sandy, estuarine, and subtidal habitats in the Europe, Asia, and the Americas, with the global extent of microplastic contamination remaining unknown. This study aimed to assess the distribution of microplastics on Cape Cod beaches, and understand how microplastic contamination is influenced by various hydrodynamic sources as well as local and regional contamination sources. Microplastics are the result of these degraded discarded plastics that become ubiquitous in the marine environment; they are defined as plastic particles less than 5 mm in size. The results of this study suggest that microplastics are ubiquitous in coastal systems of Cape Cod, with a highly variable distribution. Total abundance was about an order of magnitude higher in Nantucket Sound (60g/m3) and Buzzards Bay (120g/m3) than Cape Cod Bay and Atlantic Ocean beaches (~15g/m3), possibly reflecting seasonal and year-round population trends. The most abundant microplastics found on Cape Cod beaches in this study were between 63-500 μm, suggesting the greatest contamination is a result of regional pollution sources. The smallest size fraction of plastics had the highest abundance on Buzzards Bay beaches (80g/m3) compared to all other beaches on Cape Cod (~10-20g/m3), suggesting sourcing from increased runoff from populated watersheds and the tidal characteristics of the Buzzards Bay basin. Furthermore, the variability of microplastics in this study is consistent with variability in microplastic abundance in the northeast Atlantic Ocean. The implications of microplastic contamination is one of global concern; microplastics are an increasing threat to marine and coastal environments. Plastic contamination is a result of anthropogenic consumerism and waste discard, there is nothing else in the environment that resembles this synthetic parasite. Key words: microplastics, plastic, pollution, coastal ecology, marine ecology, anthropogenic contamination, Cape Cod, New England, plastic distribution, environmental contamination, debris Microplastic pollution on Cape Cod beaches 3 INTRODUCTION “There are, in short, a multitude of ways for trash to escape and plastic to go missing. But there is only one ultimate end point for this wild trash: the greatest future, the biggest surface, the deepest chasm, the broadest desert and the largest burial ground on the planet. It's the ocean...No matter where you are, there’s no getting over it, no getting away from it,”... “It’s a plastic ocean now … We’re putting everything in the ocean on a plastic diet.” ― Edward Humes, Garbology: Our Dirty Love Affair with Trash The implications of microplastic contamination is one of global concern. Contamination of the marine environment is an increasing problem, threatening the health of marine and coastal ecosystems, organismal health, as well as human health (Law et al., 2010; Andrady 2011). The first reports of plastic litter in the world’s oceans were as early as the 1970s. Understanding the sources (both local and regional) as well as the current magnitude of microplastic contamination is extremely critical in the first steps to mitigating this chronic, global environmental issue. Plastic has become a large source of global pollution. It has entered our marine ecosystems and we are only beginning to see the effects on the ecosystem health, animals, and humans. In 2016, global plastic production totaled 336 million metric tons. Plastics are used in a wide variety of products used every day, displacing other materials previously used such as wood, metal and glass (Statista 2018). We live in a high consumption society that thrives on a capitalist market; based upon use and discard principles of consumption. Therefore, the average person in the United States will have produced 102 tons of trash in their lifetime (Humes 2013). The average person does not consider the impacts of waste disposal, or specifically, where their discarded waste will end up. Current estimates show that at least 8 million pieces of plastic are entering the world’s oceans daily, and there is an estimated 5.25 trillion plastic particles floating in the ocean; plastics currently account for 60-80% of marine litter (Xanthos et al 2017). Much of these discarded single use plastics have settled into coastal marine habitats, as a result of ocean current redistribution. In order to understand the impacts of microplastic pollution, how much is concentrated in certain areas, what its possible sources are, and how it is distributed are critical pieces of information. Plastic debris now contaminates sandy, estuarine, and subtidal habitats in the United Kingdom, Singapore and India, with the global extent of microplastic contamination remaining unknown. However, anyone who has visited a beach in recent years has definitely encountered discarded cigarette butts, broken beach toys left behind, or pieces of fishing gear or buoys that have washed ashore (Law 2017). Microplastics are the result of these degraded discarded plastics that become ubiquitous in the marine environment; they are defined as plastic particles less than 5 mm in size (Coppock et. Al 2017). Microplastic contamination can span from coastlines to the Microplastic pollution on Cape Cod beaches 4 deep-sea and is accumulating within these habitats, outnumbering larger debris (Browne et. al 2006). In the last 50 years, there has been an increase in plastic particles in surface waters of the northeast Atlantic Ocean. Major pathways for microplastics to enter the environment include: sewage waste and wastewater systems, fragmentation of larger plastics, small particles used as abrasives in cleaning products, and spillage of plastic powders and pellets; another major source is direct contamination of habitats through human refuse and litter. Spatial patterns may influence sources of microplastics, with more material along shorelines adjacent to densely populated areas, which generate a greater abundance of large debris and produce millions of tons of sewage every year. Few studies have addressed plastic pollution in New England coastal systems, even though there have been studies confirming the presence of plastics on the outer coast of Cape Cod, Massachusetts (Schneiderman 2016). To assess the impact of microplastics on coastal ecosystems, it is critical to understand how much plastic is present and whether it is concentrated in certain areas. This research project assessed the abundance and distribution of microplastic pollution on Cape Cod Beaches. For the purpose of this study, Cape Cod was divided into four “zones” referring to the coastal systems along the four sides of the cape; to the north is Cape Cod Bay, the Atlantic Ocean to the east, Nantucket Sound in the south, and Buzzards Bay to the west. These four bodies of water have their own unique hydrodynamic sources and circulation patterns (see background section). Circulation patterns can control the transport and deposition of pollutants throughout coastal ecosystems. Factors that influence the direction of currents include water temperature, weather/ storm activity, and wind patterns. Understanding the movement of ocean water, specifically near coastal systems, can provide critical information in understanding deposition of oceanic debris and pollutants. Additionally, understanding land uses can also provide insight into pollution sources in coastal ecosystems. Land use information can provide possible local sources of plastic pollution that directly enter coastal systems. I hypothesized that microplastics would be ubiquitous on Cape Cod beaches, as a result of local plastic pollution as well as regionally sourced and carried by the ocean currents surrounding the cape. In order to quantify the abundance and distribution of microplastics on Cape Cod beaches, sediment samples were collected from twelve beaches all around Cape Cod. In the laboratory, microplastics were separated from sediment via microplastic flotation. I found that the smallest microplastic size fraction (63 -500 μm) was the most abundant on Cape Cod beaches. Additionally, beach characteristics as well as land usage in coastal regions is correlated with the abundance of plastic on beaches, which has implications for microplastics resonance time on coastal systems as well as local and regional sources for plastic pollution. Overall there was high variability and no consistent difference in the abundance of microplastics across the four zone regions. Microplastic pollution on Cape Cod beaches 5 BACKGROUND Cape Cod is located at the juncture of two major ocean biogeographic regions; waters north of Cape Cod are influenced by Gulf of Maine and Labrador currents, while the waters south and east of Cape Cod are