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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.; Atarashi-Andoh, Mariko; Nakanishi, Takahiro; Koarashi, Jun
Science of the Total Environment, 849, p.157758_1 - 157758_11, 2022/11
Times Cited Count：4 Percentile：37.30(Environmental Sciences)Characterizing plastic-associated biofilms is key to the better understanding of organic material and mineral cycling in the "Plastisphere"-the thin layer of microbial life on plastics. In this study, we propose a new method to extract biofilms from environmental plastics, in order to evaluate the properties of biofilm-derived organic matter through stable carbon (
C) and nitrogen (
N) isotope signatures and their interactions with radionuclides especially radiocesium (Cs). After ultrasound-assisted separation from the plastics, biofilm samples were successfully collected via a sequence of syringe treatments. Biofilm-derived organic matter samples (14.5-65.4 mg) from four river mouths in Japan showed Cs activity concentrations of 
75 to 820 Bq kg biofilm (dw), providing evidence that environmental plastics, mediated by developed biofilms, serve as a carrier for Cs in the coastal environment. Significant differences in the (C and N signatures were also obtained for the biofilms, indicating the different sources, pathways, and development processes of biofilms on plastics.
Munkhbat, D.*; Battulga, B.; Oyuntsetseg, B.*; Kawahigashi, Masayuki*
no journal, ,
Battulga, B.; Nakanishi, Takahiro; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
Plastic debris in the aquatic environment receives special attention from scientific communities, whereas the radioactivity of environmental plastic and the dynamics of plastic-associated biofilm remain largely unknown. In this study, we addressed plastic-associated biofilms and bottom sediments from two contrasting coastal areas of Japan to elucidate their characteristics and interaction with radionuclides especially radiocesium (Cs) in the environment. We also explored stable isotope (C and N) signatures of the biofilm and sediment samples based on seasonal variations. Trace of Cs was observed in biofilm with an activity concentration of 292
19.4 Bq kg biofilm (dw) which correspond to 1.150.08 Bq kg plastic (dw).
Battulga, B.; Nakanishi, Takahiro; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
Plastic debris is pervasive and persistent which allows its interaction with a range of organisms and organic and inorganic materials in the environment. Considering that plastics are considered carriers and vectors for pollutants in the aquatic environment, it is of utmost importance to elucidate the interaction between plastic debris and radionuclides. Because the accident at the Fukushima Daiichi Nuclear Power Plant caused by the Great East Japan Earthquake in 2011 led to the release of fission products, in particular radiocesium (Cs), into the environment, we aimed to elucidate the interaction between plastic debris and Cs in the environment. We selected the Kuma, Ukedo, Odaka, and Ohta Rivers of the Fukushima prefecture to collect environmental plastic and sediment samples. In addition, we adopted a newly developed ultrasound-assisted extraction technique to extract biofilm (a thin but robust layer of microbial cells embedded in an extracellular matrix) from plastics. The Cs activity concentrations in plastic-associated biofilms and river bottom sediments were determined by gamma-ray spectrometry. Our results indicate the dominance of common polymer types (i.e., polyethylene, polypropylene, polystyrene) of plastic debris in the river environments. Preliminary results of Cs analysis revealed that plastics serve as carriers for radionuclides mediated by biofilms in the coastal rivers.
