USGS Grant Number: G19AC00004
Year Established: 2018 Start Date: 2018-10-18 End Date: 2021-10-17
Total Federal Funds: $220,173 Total Non-Federal Funds: $220,882
Principal Investigators: James Cizdziel
Abstract: It is well known that small plastic pieces, or microplastics (MPs), are harming aquatic organisms and are entering the human diet. The majority of seafood comes from coastal areas where MPs congregate. Given their small size and ubiquitous nature, ingestion of MPs by aquatic life is concerning because they can block digestive tracts and interfere with mobility, reproduction, and offspring performance, and because they are known to absorb contaminants including hormone disruptors and heavy metals. Bivalve mollusks, such as oysters, a vital part of the Gulf Coast economy, are especially vulnerable because they filter water to feed and thus are exposed to relatively high numbers of MPs. Abundances of MPs in the northern Gulf of Mexico (nGoM) are among the highest levels reported globally. To better understand the chemical properties and behavior of MPs in the environment and the threat they pose to water quality and aquatic organisms, it is imperative to assess the sizes, shapes and composition of the particles - not just the numbers of particles present. This is especially true for smaller MPs (~1- 500 u cm) that are most biologically relevant because they can move around more freely within organisms. However, there is 1) a shortage of empirical data on their presence and distribution in major rivers and productive estuaries; 2) limited understanding of the transport pathways and factors that affect their distributions in the riverine systems and estuaries; 3) a lack of widely accepted methods for their accurate detection and quantification, particularly the small sizes; and 4) a number of questions on the extent and relevance of their impacts on aquatic life. In addition, plastics are known to adsorb mercury (Hg), a US EPA priority hazardous substance and the primary reason for fish consumption advisories. However, we know nothing about the interaction of MPs and Hg, two major pollutants that impact water quality and ecosystem health worldwide.