DOI: 10.5061/dryad.866t1g1vj
title: Polymer characterization of submerged plastic litter from Lake Tahoe, United States

description: Monitoring plastic litter in the environment is critical to understanding
 the amount, sources, transport, fate, and environmental impact of this
 pollutant. However, few studies have monitored plastic litter on lakebeds
 which are potentially important environments for determining the fate and
 transport of plastic litter in freshwater basins. In this study,
 self-contained underwater breathing apparatus (SCUBA) was used for litter
 collection at the lakebed along transects at five locations in Lake Tahoe,
 United States. Litter was brought to the surface and characterized by
 litter type. Plastic litter was subsampled for polymer determination using
 Attenuated Total Reflectance-Fourier Transform InfraRed (ATR-FTIR)
 spectroscopy. The average plastic litter recovered from the lakebed for
 the five dive sites was 83 ±49 items per kilometer. The top plastic litter
 categories were other plastic litter (i.e. plastic litter that did not
 fall in another category), followed by food containers, plastic bags,
 toys, and bottles &lt;2 L. These results are in line with prior
 studies on submerged litter, supporting that intervention approaches or
 ongoing education is needed. The six polymers most frequently detected in
 the subsamples were polyvinyl chloride, polystyrene/expanded polystyrene,
 polyethylene terephthalate/polyester, polyethylene, polypropylene, and
 polyamide. These observations generally reflect the global plastic
 production trend and global compilations of microplastic studies from lake
 surface water and sediments. We found that some litter subcategories were
 primarily comprised of a single polymer type, therefore, in studies where
 the polymer type cannot be measured but litter is categorized, these
 results could provide an estimate of the total polymer composition for
 select subcategories.
description: The polymer of each subsample (n=516) was determined through
 Attenuated Total Reflectance-Fourier Transform InfraRed (ATR-FTIR)
 spectroscopy using a Thermo Nicolet 6700 FTIR (ThermoFisher, United
 States) at the University of Nevada, Reno. Spectra were collected using 32
 scans with a spectral resolution of 4 cm<sup>-1</sup> within
 the range of 3950 and 650 cm<sup>-1</sup>. The Norton-Beer
 strong apodization function was applied by the instrument software (OMNIC
 software, ThermoFisher, United States) and the background was subtracted
 from each spectrum automatically by the software. The subtracted
 background was measured every six spectra (approximately every 10
 minutes). The diamond ATR crystal was cleaned with isopropanol/methanol
 before every background collection. Each sample spectrum was compared to
 known spectra in the Hummel Polymer Library Database and a database
 created from the spectra of plastics in the Center for Marine Debris
 Research Polymer Kit 1.0 (Hawaii Pacific University, United States)
 collected using the same settings as described above.
 In the OMNIC software, we used the correlation approach for
 comparing the spectra to the libraries. The match value ranges from 0 to
 100, with a match of 100 indicating a perfect match. The library match
 best fitted to the unknown sample spectrum was considered to be the
 identity of that sample. The polymer match was categorized as “unknown
 polymer” when the best match was less than a 70% similarity. All matches
 were additionally verified by the instrument user. For each subsample
 analyzed, we noted the polymer type and match.
description: Excel file can be opened with most data viewing programs.
description: # Title of Dataset: Polymer characterization of submerged plastic litter
 from Lake Tahoe, United States Monitoring plastic litter in the
 environment is critical to understanding the amount, sources, transport,
 fate, and environmental impact of this pollutant. However, few studies
 have monitored plastic litter on lakebeds which is potentially important
 for determining the fate and transport of plastic litter in freshwaters
 basins. In this study, self-contained underwater breathing apparatus
 (SCUBA) was used for litter collection at the lakebed along transects at
 five locations in Lake Tahoe, Nevada. Litter was brought to the surface
 and characterized by litter type. Plastic litter was subsampled for
 polymer determination using Attenuated Total Reflectance-Fourier Transform
 InfraRed (ATR-FTIR) spectroscopy. Dataset contents include Plastic litter
 type (code), ATR-FTIR spectral results, and identified plastic type. ##
 Description of the data and file structure We analyzed 516 plastic litter
 subsamples using ATR-FTIR. Data are presented by site. For each site,
 information on the plastic category, identified plastics, and spectral
 results. The polymer of each subsample was determined through Attenuated
 Total Reflectance-Fourier Transform InfraRed (ATR-FTIR) spectroscopy using
 a Thermo Nicolet 6700 FTIR at the University of Nevada, Reno. Spectra were
 collected using 32 scans with a spectral resolution of 4 cm-1 within the
 range of 3950 and 650 cm-1. The background was subtracted from each
 spectrum automatically by the instrument software. The subtracted
 background was measured every six spectra (approximately every 10
 minutes). The diamond eyepiece was cleaned with acetone before every
 background collection. Each sample spectrum was compared to known spectra
 in the Hummel Polymer Library Database and a database created from the
 spectra of plastics in the Center for Marine Debris Research Polymer Kit
 1.0 collected using the same settings as described above. The database
 spectrum best fitted to the spectrum of the unknown sample was considered
 to be the identity of that sample. The polymer match was categorized as
 “unknown polymer” when the best match was less than a 70% similarity. For
 each subsample analyzed, we noted the polymer type and match percent.
 Litter code - Found in Column 1 Litter type Litter type sub category *
 PL01 Plastic Bottle caps & lids * PL02 Plastic Bottles &lt; 2
 L * PL03 Plastic Bottles, drums, jerrycans & buckets &gt; 2 L
 * PL04 Plastic Knives, forks, spoons, straws, stirrers, (cutlery) * PL05
 Plastic Drink package rings, six-pack rings, ring carriers * PL06 Plastic
 Food containers (fast food, cups, lunch boxes & similar) * PL07
 Plastic Plastic bags (opaque & clear) * PL08 Plastic Toys
 & party poppers * PL09 Plastic Gloves * PL10 Plastic Cigarette
 lighters * PL11 Plastic Cigarettes, butts & filters * PL12 Plastic
 Syringes * PL13 Plastic Baskets, crates & trays * PL14 Plastic
 Plastic buoys * PL15 Plastic Mesh bags * PL16 Plastic Sheeting (tarpaulin
 or other woven plastic bags, palette wrap) * PL17 Plastic Fishing gear
 (lures, traps & pots) * PL18 Plastic Monofilament line * PL19
 Plastic Rope * PL20 Plastic Fishing net * PL21 Plastic Strapping * PL22
 Plastic Fibreglass fragments * PL23 Plastic Resin pellets * PL24 Plastic
 Other Abbreviation - Found in Row 2 Polymer * PVC Polyvinyl Chloride *
 PET/PEST Polyethylene terephthalate/Polyester * PS/EPS
 Polystyrene/Expanded polystyrene * PE Polyethylene * PP Polypropylene *
 PA6/PA66 Polyamide 6/Polyamide 6,6 * ABS Acrylonitirile-Butadiene-Styrene
 * PC Polycarbonate * ABS Acrylonitirile-Butadiene-Styrene * EVA Ethylene
 Vinyl Acetate Location Name Start transect Stop transect * Nevada Beach
 38.97663789, -119.9540862 38.98852004, -119.95471108 * Zephyr Cove
 39.00575679, -119.95310787 39.01787844, -119.95392789 * South Sand Harbor
 39.19329585, -119.92800956  39.17897252, -119.92699464 * East Incline
 39.22302604, -119.93251783 39.23640226, -119.94604386 * Hidden Beach
 39.22308327, -119.93215629 39.2164737, -119.92872056 ## Sharing/Access
 information Nothing to report ## Code/Software Nothing to report.