Microplastics in Oysters from the Mississippi Sound

Analyzing Microplastics in the Environment: Striving to Better Assess Occurrence, Fate and Effects
Oral Presentation

Prepared by K. Wontor1, D. Gochfeld2, A. Barnett3, J. Cizdziel1, A. Scircle1
1 - University of Mississippi, 380 Coulter Hall, University, MS, 38677, United States
2 - University of Mississippi, 2014 Thad Cochran Research Center, University, MS, 38677, United States
3 - University of Mississippi, 414 Faser Hall, University, MS, 38677, United States


Contact Information: kwontor@go.olemiss.edu; 662-915-1814


ABSTRACT

The occurrence of microplastics (MPs) in the aquatic environment has been well documented so their presence in consumer seafood, while worrisome, is not surprising. Bivalve mollusks, such as oysters, may be especially vulnerable because they filter water to feed and thus are exposed to relatively high numbers of MPs. Whereas oysters provide a variety of valuable ecosystem services and are a vital part of the Gulf Coast economy, they may also represent a larger risk in terms of a potential route of exposure to MPs for humans because, unlike fish, they are consumed whole. Our previous work on MPs in the Mississippi River suggested that the waters of the northern Gulf of Mexico (nGoM) likely act as a sink for plastic pollution that is continually funneled through the Mississippi River. Herein, we report our preliminary findings for the concentration and types of MPs in oysters (Crassostrea virginica), both whole and dissected tissues (digestive gland, mantle, gills), sourced from a variety of sites in the nGoM over the past year. The MP analysis was performed using previously developed sample preparation methods along with optical microscopy and micro-spectroscopy including ยต-FTIR and Laser Direct Infrared Imaging (LDIR). Anthropogenic particles in the oysters were primarily identified as polyethylene, polystyrene, and rubber, with the latter possibly from tire wear particles. MPs were found in greater numbers in the gills and digestive system tissues than in the mantle and other tissues. MP fibers were also found in whole tissues but in low numbers (range 0-11 per oyster). Data analysis on the compartmentalization of MPs retained in oysters is ongoing and will provide additional insight into the characteristics of MPs in oysters along the Mississippi Coast.