11:55 〜 12:10
[MIS19-10] Comparative investigation of Carbonyl Index of Microplastics around Japan coasts by using Specified Area Under Band method
キーワード：MPs, ATR-FTIR, CI, Polyethylene, Polypropylene
Microplastics (MPs) are known to be a global threat due to their adverse effects on biotic and abiotic environments. Although there are many studies on the effects and formation processes of MPs, sufficient information and valid methods have not been evaluated yet. As MPs are considered to be finer plastics in which the plastic that is flowed into the sea has degraded by the time. To accurately understand the behavior of marine MPs, it is necessary to know the process of their formation in detail.
In this study, Carbonyl Index (CI) analysis with Specified Area Under Band (SAUB) method was conducted for Polyethylene (PE) and Polypropylene (PP) samples collected from Tsushima Strait (Station-1; 35-34.478 N, 132-00.780 E) in Jul. 2017, the Sea of Japan (Station-2; 33-56.342 N, 129-10.156 E) in Aug. 2017, Off Okinawa (Station-3; 28-25.447 N, 131-25.177 E) in Aug. 2018, Off Boso Peninsula (Station-4; 36-31.993 N, 140-58.770 E) in Jul. 2017, the Sea of Japan (Station-5; 37-03.785 N, 137-58.666 E) and Off Iwate (Station-6; 38-41.800 N, 141-43.590 E) in Aug. 2017.
Within the context of this study; samples were obtained from all the stations (Station-1,2,3,4,5,6) by using Neuston net (350µm mesh opening), and then, the extraction of the MPs samples were carried out by simple floating methods, lastly, the polymer types were determined by using Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR; a total of 784 MPs particles from Station-1, 516 MPs particles from Station-2, 178 MPs particles from Station-3, 393 MPs particles from Station-4, 248 MPs particles from Station-5, 410 MPs particles from Station-6). After then, The CI was calculated from the ratio between the integrated specified area under band absorbance of the carbonyl (CO) peak from 1,850 to 1,650 cm−1 and that of the methylene (CH2) scissoring peak from 1,500 to 1,420 cm−1.According to the results obtained:A total number of 2589 MPs were identified as 508 particles of PE and 276 particles of PP from Station-1 and 187 particles of PE and 329 particles of PP from the Station-2, 104 particles of PE and 74 particles of PP from the Station-3, 225 particles of PE and 168 particles of PP from the Station-4, 161 particles of PE and 87 particles of PP from the Station-5, 294 particles of PE and 116 particles of PP from the Station-6.Fragment shaped particles were dominant in all the stations, followed by fibers.The mean CI values were calculated for PE as 0.79 ± 0.67 and for PP as 0.77 ± 0.95 in the Station-1, 0.55 ± 0.30 for PE and 0.56 ± 0.22 for PP in the Station-2, 0.69 ± 0.31 for PE and 0.75 ± 0.24 for PP in the Station-3, 0.75 ± 0.32 for PE and 0.80 ± 0.30 for PP in the Station-4, 0.74 ± 0.24 for PE and 0.73 ± 0.27 for PP in the Station-5, 0.69 ± 0.31 for PE and 0.64 ± 0.21 for PP in the Station-6.The mean length values were measured for PE as 5.26± 7.34 and for PP as 3.11 ± 3.22 in the Station-1, 6.66 ± 5.15 for PE and 5.56 ± 4.58 for PP in the Station-2, 4.91 ± 3.19 for PE and 3.41 ± 2.69 for PP in the Station-3, 2.38 ± 2.37 for PE and 2.10 ± 3.04 for PP in the Station-4, 1.63 ± 1.06 for PE and 1.30 ± 0.67 for PP in the Station-5, 3.91 ± 4.90 for PE and 2.90 ± 2.54 for PP in the Station-6.Statistically significant negative correlations between MPs major length and CI were found in Station-1 (R: -0.20, p < 0.05) and Station-5 (R: -0.390, p < 0.05) for PE. Furthermore, statistically significant positive correlations between the length and CI were found in Station-2 (R:0.15, p < 0.05), Station-3 (R:0.26, p < 0.05) and Station-6 (R:0.24, p < 0.05) for PP.For both PE and PP samples, it was determined that while the size of MPs was higher in Station-1,2,3,4 and Station-6, CI was lower.Consequently, according to the evaluation regardless of the colors and shapes of the samples obtained, there is a negative relationship between the major length and CI at all stations except for Station-5.
In this study, Carbonyl Index (CI) analysis with Specified Area Under Band (SAUB) method was conducted for Polyethylene (PE) and Polypropylene (PP) samples collected from Tsushima Strait (Station-1; 35-34.478 N, 132-00.780 E) in Jul. 2017, the Sea of Japan (Station-2; 33-56.342 N, 129-10.156 E) in Aug. 2017, Off Okinawa (Station-3; 28-25.447 N, 131-25.177 E) in Aug. 2018, Off Boso Peninsula (Station-4; 36-31.993 N, 140-58.770 E) in Jul. 2017, the Sea of Japan (Station-5; 37-03.785 N, 137-58.666 E) and Off Iwate (Station-6; 38-41.800 N, 141-43.590 E) in Aug. 2017.
Within the context of this study; samples were obtained from all the stations (Station-1,2,3,4,5,6) by using Neuston net (350µm mesh opening), and then, the extraction of the MPs samples were carried out by simple floating methods, lastly, the polymer types were determined by using Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR; a total of 784 MPs particles from Station-1, 516 MPs particles from Station-2, 178 MPs particles from Station-3, 393 MPs particles from Station-4, 248 MPs particles from Station-5, 410 MPs particles from Station-6). After then, The CI was calculated from the ratio between the integrated specified area under band absorbance of the carbonyl (CO) peak from 1,850 to 1,650 cm−1 and that of the methylene (CH2) scissoring peak from 1,500 to 1,420 cm−1.According to the results obtained:A total number of 2589 MPs were identified as 508 particles of PE and 276 particles of PP from Station-1 and 187 particles of PE and 329 particles of PP from the Station-2, 104 particles of PE and 74 particles of PP from the Station-3, 225 particles of PE and 168 particles of PP from the Station-4, 161 particles of PE and 87 particles of PP from the Station-5, 294 particles of PE and 116 particles of PP from the Station-6.Fragment shaped particles were dominant in all the stations, followed by fibers.The mean CI values were calculated for PE as 0.79 ± 0.67 and for PP as 0.77 ± 0.95 in the Station-1, 0.55 ± 0.30 for PE and 0.56 ± 0.22 for PP in the Station-2, 0.69 ± 0.31 for PE and 0.75 ± 0.24 for PP in the Station-3, 0.75 ± 0.32 for PE and 0.80 ± 0.30 for PP in the Station-4, 0.74 ± 0.24 for PE and 0.73 ± 0.27 for PP in the Station-5, 0.69 ± 0.31 for PE and 0.64 ± 0.21 for PP in the Station-6.The mean length values were measured for PE as 5.26± 7.34 and for PP as 3.11 ± 3.22 in the Station-1, 6.66 ± 5.15 for PE and 5.56 ± 4.58 for PP in the Station-2, 4.91 ± 3.19 for PE and 3.41 ± 2.69 for PP in the Station-3, 2.38 ± 2.37 for PE and 2.10 ± 3.04 for PP in the Station-4, 1.63 ± 1.06 for PE and 1.30 ± 0.67 for PP in the Station-5, 3.91 ± 4.90 for PE and 2.90 ± 2.54 for PP in the Station-6.Statistically significant negative correlations between MPs major length and CI were found in Station-1 (R: -0.20, p < 0.05) and Station-5 (R: -0.390, p < 0.05) for PE. Furthermore, statistically significant positive correlations between the length and CI were found in Station-2 (R:0.15, p < 0.05), Station-3 (R:0.26, p < 0.05) and Station-6 (R:0.24, p < 0.05) for PP.For both PE and PP samples, it was determined that while the size of MPs was higher in Station-1,2,3,4 and Station-6, CI was lower.Consequently, according to the evaluation regardless of the colors and shapes of the samples obtained, there is a negative relationship between the major length and CI at all stations except for Station-5.