Occurrence of plastics and their association with radiocesium in the coastal rivers in Fukushima, Japan

Battulga, B. ; Nakanishi, Takahiro   ; Atarashi-Andoh, Mariko  ; Koarashi, Jun   

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.