SEM/EDS and optical microscopy analyses of microplastics in ocean trawl and fish guts Zhong-Min Wang ⁎, Jeff Wagner, Sutapa Ghosal, Gagandeep Bedi, Stephen Wall California Department of Public Health, Environmental Health Laboratory Branch, 850 Marina Bay Parkway, Richmond, CA 94804, United States HIGHLIGHTS • Optical microscopy and SEM/EDS were used to screen for potential microplastics. • PVC particles have distinctive SEM/EDS elemental signatures. • SEM images of microplastic surfaces re- vealed characteristic cracks and pig- ments. • Microplastic surfaces were covered with biofilms, radiolarians, and crustaceans. GRAPHICAL ABSTRACT abstract article info Article history: Received 30 March 2017 Received in revised form 5 June 2017 Accepted 6 June 2017 Available online xxxx Editor: D. Barcelo Microplastic particles from Atlantic and Pacific Ocean trawls, lab-fed fish guts and ocean fish guts have been char- acterized using optical microscopy and SEM/EDS in terms of size, morphology, and chemistry. We assessed whether these measurements could serve as a rapid screening process for subsequent identification of the likely microplastic candidates by micro-spectroscopy. Optical microscopy enabled morphological classification of the types of particles or fibers present in the sample, as well as the quantification of particle size ranges and fiber lengths. SEM/EDS analysis was used to rule out non-plastic particles and screen the prepared samples for poten- tial microplastic, based on their element signatures and surface characteristics. Chlorinated plastics such as poly- vinyl chloride (PVC) could be easily identified with SEM/EDS due to their unique elemental signatures including chlorine, as could mineral species that are falsely identified as plastics by optical microscopy. Particle morphology determined by optical microscopy and SEM suggests the fish ingested particles contained both degradation frag- ments from larger plastic pieces and also manufactured microplastics. SEM images of microplastic particle sur- faces revealed characteristic cracks consistent with environmental exposure, as well as pigment particles consistent with manufactured materials. Most of the microplastic surfaces in the fish guts and ocean trawls were covered with biofilms, radiolarians, and crustaceans. Many of the fish stomachs contained micro-shell pieces which visually resembled microplastics. © 2017 Elsevier B.V. All rights reserved. Keywords: Microplastic Plastic SEM EDS Optical microscopy Fish gut 1. Introduction Plastic debris has been identified within marine environments for many decades, but has become an area of growing concern in recent years. Production rates of plastics have seen nearly a hundred fold in- crease since the beginning of their mass production around 1950. Esti- mates from 2010 have shown that nearly 5–13 million tons of those manufactured plastics have entered marine ecosystems (Herzke et al., 2016). Especially alarming are the accumulation of plastics within ocean gyres, and the widespread movement of plastics through ocean currents Science of the Total Environment 603–604 (2017) 616–626 ⁎ Corresponding author. E-mail address: zwang@cdph.ca.gov (Z.-M. Wang). http://dx.doi.org/10.1016/j.scitotenv.2017.06.047 0048-9697/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv