Digestible Fluorescent Coatings for Cumulative Quantification of

Dec 26, 2017 - The DFC microplastics' fluorescence intensities were characterized via fluorescence microscopy and image analysis software (ZenLite, Fi...
1 downloads 16 Views 842KB Size
Subscriber access provided by AUBURN UNIV AUBURN

Letter

Digestible Fluorescent Coatings for Cumulative Quantification of Microplastic Ingestion Evan G. Karakolis, Brian Nguyen, Jae Bem You, Percival J. Graham, Chelsea M. Rochman, and David Sinton Environ. Sci. Technol. Lett., Just Accepted Manuscript • DOI: 10.1021/acs.estlett.7b00545 • Publication Date (Web): 26 Dec 2017 Downloaded from http://pubs.acs.org on December 27, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Environmental Science & Technology Letters is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 12

Environmental Science & Technology Letters

2

Digestible Fluorescent Coatings for Cumulative Quantification of Microplastic Ingestion

3

Evan G Karakolisa#, Brian Nguyena#, Jae Bem You a, Percival J Grahama, Chelsea M Rochmanb and David

4

Sintona*

5 6 7

a

8

#

Equally contributing author

9

*

Corresponding author

1

10

Department of Mechanical and Industrial Engineering and Institute for Sustainable Energy, University of Toronto, 5 King’s College Road, Toronto, ON, Canada, M5S 3G8. b Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St, Toronto, ON, Canada, M5S 3B2

*E-mail: [email protected]. Tel: +1 (416) 978-1623 (David Sinton).

11 12

ABSTRACT: The ubiquitous presence of microplastics in the environment makes it imperative to understand

13

their effects. In particular, we must understand exposure – i.e., how many microplastics are ingested by

14

organisms. This has proved difficult because counting microplastics in an organism’s gut content provides only a

15

snapshot in time. Here, we show a method that uses a digestible fluorescent coating (DFC) to quantify cumulative

16

microplastic ingestion. Our method enables precise and automated enumeration of cumulative microplastic

17

ingestion with the flexibility to track different microplastic types and sizes with distinct fluorescent tracers. We

18

confirm the coating is not acutely toxic and is not preferentially ingested by several invertebrate species. This

19

method provides a unique and reliable approach to quantify cumulative microplastic ingestion in laboratory

20

exposure studies, and can be used to advance our understanding of the impact of microplastics to wildlife.

21 22

INTRODUCTION

23

Emissions of plastic waste to aquatic1,2 and terrestrial3 ecosystems is a growing concern. In particular,

24

microplastics (particles < 5 mm in size) are recognized as a global concern4,5, and have been extensively studied

25

in recent years. Microplastics interact with a wide range of organisms6,7 either directly, via dermal contact or

26

ingestion8, or indirectly, via trophic transfer9 (where microplastics outside of an organism’s typical prey size are

27

consumed because they have been previously ingested by or attached to their typical prey). Their impact on

28

ecosystems can be twofold. Microplastics can adhere to, and be ingested by, organisms, and have the potential to

29

cause harmful physical effects including internal abrasions and blockages, translocation throughout the body and

30

inflammation2. Microplastics can also be a source of hazardous chemicals from their production10 or via sorption

31

of priority pollutants11,12, and a source of microorganisms13. To fully assess the impact that microplastics will have

32

on biota, it is critical to be able to measure exposure, including the amount of microplastics that are ingested.

33 34

While existing enumeration techniques, counting microplastics in the gut and/or feces or subsampling the exposure water

6,14–18

, determine the amount of plastics ingested at a given time point, they are not easily 1 ACS Paragon Plus Environment

Environmental Science & Technology Letters

Page 2 of 12

35

adaptable to accurately quantify cumulative ingestion. Furthermore, current methods that use visual sorting of the

36

entire contents of an exposure vessel to identify plastics in fecal pellets for a cumulative measure suffers from key

37

limitations: (1) microplastics that pass through the digestive tract without being encased in a fecal pellet are not

38

counted; (2) microplastics on the surface of animals or fecal pellets can be misidentified as ingested; and (3)

39

manually identifying and counting is labor intensive, operator-dependent and susceptible to error, particularly for

40

studies with smaller organisms (