Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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.
Tanaka, Tadao; Nagao, Seiya; Sakamoto, Yoshiaki; Ogawa, Hiromichi
Journal of Nuclear Science and Technology, 39(Suppl.3), p.524 - 527, 2002/11
Influence of humic acid on the sorption of Pu onto a coastal sand, which does not sorb humic acid, and an ando soil, which sorbs humic acid very well, was examined with respect to molecular sizes of humic acid. Sorption affinity of Pu for the coastal sand decreased with increasing humic acid concentration. As to the ando soil, the sorption affinity of Pu in the presence of humic acid was larger than that in the absence of humic acid, in low humic acid concentration range. These results suggest that apparent sorption affinity of Pu on the soils is dependent on the complexation ability with humic acid and the sorption affinity of the resulting humic complexes. Concentration profiles of Pu in each size fraction of solution before and after the sorption experiment were obtained by ultrafiltration technique. It was found that the complexation and sorption properties of humic acid are dependent on its molecular size and the important molecular size relating to the complexation and sorption properties tends to shift into smaller size ranges with increasing humic acid concentration.
