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Microplastic abundance in marine sediments off the coasts of Maine and New Hampshire, USA
Citation:
Langknecht, T., K. Ho, AND R. Burgess. Microplastic abundance in marine sediments off the coasts of Maine and New Hampshire, USA. Society of Environmental Toxicology and Chemistry North America, 42nd Annual Meeting, NA, Virtual, November 14 - 18, 2021.
Impact/Purpose:
Microplastics, which are plastic pieces less than 5 mm, vary in their size and polymer composition, making it difficult to understand how they may affect marine ecosystems and organisms. Quantification and identification of microplastics are increasingly important to understanding their impact on marine ecosystems. Marine sediments are often a sink for these types of plastic pieces; therefore, microplastic abundance in marine sediments may have serious implications for many marine species. This study aims to measure the abundance of microplastics along the coasts of Maine and New Hampshire and understand how microplastic abundance interacts with other sediment measurements. Microplastics were extracted from sediments and then identified for polymer type using Raman spectroscopy. We will then compare this data to other sediment measurements taken at the same sites, such as sediment toxicity and diversity, to understand potential relationships. This research will give us a better understanding of microplastic abundance in the region, as well as if microplastic abundance is related to other marine sediment measures. The intended audience of this research includes state, local, and federal agencies interested in conducting microplastic research, as well as academic and private research institutions.
Description:
Microplastics (MP) (< 5 mm) are ubiquitous in the environment and pose unique toxicological challenges because of their small size, measurement difficulties, and polymeric diversity, leading to uncertainties in our understanding of their fate and potential for adverse impacts. Quantification and identification of MP are crucial to better understanding their impacts. Studies suggest marine MP settle into sediments due to weathering, biofouling, aggregation, ingestion, and other biotic and abiotic processes; therefore, MP abundance may have serious implications for many marine species. The objective of this study is to quantify and identify MP particles between 45 – 1000 µm in coastal sediments using a novel extraction method and Raman spectroscopy, to compare MP abundance among sites with varying degrees of human disturbance, and to correlate MP abundances with other sediment measures. Marine sediment samples were collected off the coasts of Maine and New Hampshire by the U.S. EPA’s National Coastal Condition Assessment (NCCA) program during the 2020 field season and a subset (n=10) was chosen for MP abundance. NCCA samples were also examined for a wide variety of con-commitment measures, such as sediment toxicity, benthic diversity, and chemical contamination, which are valuable supplementary data for this type of study. MP sampling sites were selected based on proximity to areas of high human development (i.e. Portsmouth, NH; Portland, ME), as they are possible land-based sources of plastics, and then chosen to represent varying levels of human disturbance. A novel hybrid method was utilized to extract MPs from the sediments, followed by polymer identification using Raman spectroscopy. This research attempts to broaden our understanding of MP abundance and polymer composition in marine sediments to identify potential sources and to better understand the relationship between MP abundance and other sediment measures.
