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Battulga, B.; Nakanishi, Takahiro; Atarashi-Andoh, Mariko; Otosaka, Shigeyoshi*; Koarashi, Jun
Environmental Science and Pollution Research, 31, p.60080 - 60092, 2024/10
A ubiquitous distribution of plastic debris has been reported in aquatic and terrestrial environments; however, the interactions between plastics and radionuclides and the radioactivity of environmental plastics remain largely unknown. Here, we characterize biofilms developing on the surface of plastic debris to explore the role of plastic-associated biofilms as an interaction medium between plastics and radiocesium (
Cs) in the environment. Biofilm samples were extracted from plastics (1-50 mm in size) collected from two contrasting coastal areas in Japan. The radioactivity of plastics was estimated based on the Cs activity concentration of the biofilms and compared seasonally with surrounding environmental samples (i.e., sediment and sand). Cs traces were detected in biofilms with activity concentrations of 21-1300 Bq kg
biofilm (dry weight), corresponding to 0.04-4.5 Bq kg plastic (dry weight). Our results reveal the interaction between Cs and plastics and provide evidence that organic and mineral components in biofilms are essential in Cs retention in environmental plastics.
Battulga, B.; Munkhbat, D.*; Matsueda, Makoto; Atarashi-Andoh, Mariko; Oyuntsetseg, B.*; Koarashi, Jun; Kawahigashi, Masayuki*
Environmental Pollution, 357, p.124427_1 - 124427_10, 2024/09
Times Cited Count：1 Percentile：0.00(Environmental Sciences)The occurrence and characteristics of plastic debris in aquatic and terrestrial environments have been extensively studied. However, there is still limited information on the properties and dynamic behavior of plastic-associated biofilms in the environment. In this study, we collected plastic samples from an inland river system in Mongolia and extracted biofilms from the plastics to uncover the characteristics of the biofilms using analytical, isotopic, and thermogravimetric techniques. Mixtures of organic and mineral particles were detected from extracted biofilms, revealing the plastic as a carrier for exogenous substances including contaminants in the river ecosystem. The present study provides insights into the characteristics and environmental behavior of biofilms which are useful to elucidate the impact of plastic-associated biofilms on organic matter and material cycling in the aquatic ecosystems.
I in riverbank sediment after the Fukushima accidentNakanishi, Takahiro; Sakuma, Kazuyuki; Oyama, Takuya; Hagiwara, Hiroki; Suzuki, Takashi
Environmental Pollution, 355, p.124213_1 - 124213_7, 2024/08
Times Cited Count：3 Percentile：59.12(Environmental Sciences)This study investigated the transport behavior of I by riverbank surveys conducted from 2013 to 2015 in a watershed where the I/Cs activity ratio is low in the mountainous area and high in the plain as of 2011. Until 2015, the I/Cs activity ratio of the levee crown in the studied watershed was similar to that of the surrounding area in 2011. However, the I/Cs ratios of the surface riverbank sediments were all low, indicating that radionuclides transported from the mountainous area were deposited on the riverbank in the plain. The vertical distribution of the I/Cs ratio in the riverbank sediments indicated that some I and Cs deposited during the accident remained in the lower layers, but most were eroded immediately after the accident. Based on the I/Cs ratios of sediments deposited on the riverbank, which remained constant until 2015 after the accident, the amount of I discharged to the ocean was determined from the previously evaluated Cs discharge. It was calculated that 1.8
10
Bq and 1.210
Bq of I were discharged with sediment from the studied watershed and the contaminated river watersheds (Abukuma River and Fukushima coastal rivers, including the study river), respectively. The results of this study indicate that the continuous I discharge from the river contribute little to their amount in the seafloor sediments along the Fukushima coast.
Battulga, B.; Atarashi-Andoh, Mariko; Matsueda, Makoto; Koarashi, Jun
Environmental Science and Pollution Research, 30(31), p.77226 - 77237, 2023/05
Times Cited Count：2 Percentile：10.09(Environmental Sciences)The global survey for the presence of microplastics (MPs) in aquatic environments has attracted widespread scientific attention over the past decade. This study demonstrates a multidimensional analytical approach, including isotopic and thermogravimetric analyses to evaluate characteristics and behavior of MPs in the environment. The MP samples were collected in two contrasting coastal areas of Japan. The 
C values of field-collected polyethylene (PE), polypropylene (PP), and polystyrene (PS) MPs were ranged from -25.6 to -31.4, -23.4 to -30.9, and -27.3 to -28.6 per mil, respectively. The differences in C signature between MPs with the same polymer types (i.e., PE and PP) but different colors. Through thermal analysis, the single-step endothermic process was observed for environmental PE and PS-MPs. The results reveal that degradation may play a significant role in the behavior and characteristics of MP debris in the aquatic environment.
Kato, Takuma*; Nagaoka, Mika; Guo, H.*; Fujita, Hiroki; Aida, Taku*; Smith, R. L. Jr.*
Environmental Science and Pollution Research, 28(39), p.55725 - 55735, 2021/10
Times Cited Count：0 Percentile：0.00(Environmental Sciences)In this work, hydrothermal leaching was applied to simulated soils (clay minerals vermiculite, montmorillonite, kaolinite) and actual soils (Terunuma, Japan) to generate organic acids with the objective to develop an additive-free screening method for determination of Sr in soil. Stable strontium (SrCl
) was adsorbed onto soils for study and ten organic acids were evaluated for leaching Sr from simulated soils under hydrothermal conditions (120 to 200
C) at concentrations up to 0.3 M. For strontium-adsorbed vermiculite (Sr-V), 0.1 M citric acid was found to be effective for leaching Sr at 150C and 1 h treatment time. Based on these results, the formation of organic acids from organic matter in Terunuma soil was studied. Hydrothermal treatment of Terunuma soil produced a maximum amount of organic acids at 200C and 0.5 h reaction time. To confirm the possibility for leaching of Sr from Terunuma soil, strontium-adsorbed Terunuma soil (Sr-S) was studied. For Sr-S, hydrothermal treatment at 200C for 0.5 h reaction time allowed 40% of the Sr to be leached at room temperature, thus demonstrating an additive-free method for screening of Sr in soil. The additive-free hydrothermal leaching method avoids calcination of solids in the first step of chemical analysis and has application to both routine monitoring of metals in soils and to emergency situations.
Yang, B.*; Onda, Yuichi*; Wakiyama, Yoshifumi*; Yoshimura, Kazuya; Sekimoto, Hitoshi*; Ha, Y.*
Environmental Pollution, 208(Part B), p.562 - 570, 2016/01
Times Cited Count：18 Percentile：45.97(Environmental Sciences)
Hu, P.*; Yin, Y.-G.; Ishikawa, Satoru*; Suzui, Nobuo; Kawachi, Naoki; Fujimaki, Shu; Igura, Masato*; Yuan, C.*; Huang, J.*; Li, Z.*; et al.
Environmental Science and Pollution Research, 20(9), p.6306 - 6316, 2013/09
Times Cited Count：57 Percentile：80.16(Environmental Sciences)Awual, M. R.; Hossain, M. A.*; Shenashen, M. A.*; Yaita, Tsuyoshi; Suzuki, Shinichi; Jo, Akinori*
Environmental Science and Pollution Research, 20(1), p.421 - 430, 2013/01
Times Cited Count：184 Percentile：97.09(Environmental Sciences); ;
Nuclear Techniques in Environmental Pollution, p.169 - 181, 1970/00
no abstracts in English
