Addition/Correction Cite This: Environ. Sci. Technol. XXXX, XXX, XXX−XXX
pubs.acs.org/est
Corrections to “Combined Effects of UV Exposure Duration and Mechanical Abrasion on Microplastic Fragmentation by Polymer Type” Young Kyoung Song, Sang Hee Hong, Mi Jang, Gi Myung Han, Seung Won Jung, and Won Joon Shim* Environ. Sci. Technol. 2017, 51, 4368−4376; DOI: 10.1021/acs.est.6b06155. S Supporting Information *
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In our paper, the total volume of the fragmented particles according to UV exposure was miscalculated in Figure 5 and Supporting Information Figure S7. The volume of the fragmented particles was described as 10 pellets; the remaining volume of the parent pellet was correct. In addition, the void volume of EPS pellet and the laminar shape of fragmented EPS particles were considered in recalculation of EPS volume. The corrected Figure 5 is given below. The corrected Figure S7 is provided in the Supporting Information, and the y-axis has been corrected in Figure S7. In addition, the following corrections should be made in the main text. Page 4372. The second paragraph should read, “The volume of the remaining parent pellets was calculated from the measured mean diameters, and the volume of produced particles was calculated on the assumption that all particles were spherical with a diameter at the midpoint of each size category (e.g., 150 μm for 100−200 μm). In case of EPS pellet, it consists of 98% gas and 2% polystyrene on a volume basis. The remaining EPS pellet contained void volume of gas while the fragments in very laminar shape did not have any void gas volume, which was confirmed by scanning electron microscope (data not shown). Thus, in EPS volume calculation, the volume of remaining EPS pellet included 98% of gas, but the volume of EPS fragments was calculated as laminar-shaped polystyrene itself without the void gas volume. While the volume of parent PE pellets remained almost intact (>90%) in all exposure groups, the missing portion of PE volume after weathering increased from 0% to 9.9% according to the UV exposure duration (Figure 5a). In addition, 98% and 96% of PP parent pellets remained after exposure to UV for 0 and 2 months, respectively, with corresponding proportions of 1.6% and 4.2% unaccounted for. After 6 and 12 months, the parent PP pellet volume decreased to 81% and 81%, respectively, while fragmented particles accounted for 1.2% and 2.1%, respectively (Figure 5b). After exposure to UV for 0 and 2 months, parent EPS pellets accounted for 78% and 35% of the original volume, respectively, while 5.4% and 12% of the pellets were fragmented. After 6 and 12 months, no visible parent pellets were apparent, but the volume of fragmented particles accounted for only 21% and 12% of the original parent pellet volume, respectively. The proportion of EPS pellets unaccounted for increased gradually with UV exposure duration, accounting for 17, 53, 79, and 88% in the UV0, UV2, UV6, and UV12 groups, respectively (Figure 5C).” © XXXX American Chemical Society
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.est.8b00172. Corrected Figure S7 (PDF)
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DOI: 10.1021/acs.est.8b00172 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
Environmental Science & Technology
Addition/Correction
Figure 5. Change in the total volume of plastics calculated from the sum of the parent pellets remaining (solid bar) and the fragmented particles (open bar) according to UV exposure duration for (a) polyethylene (LDPE), (b) polypropylene (PP), and (c) expanded polystyrene (EPS).
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DOI: 10.1021/acs.est.8b00172 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
