Relationship between the ^134+137Cs activity and the grain size of surface sediments in the Tokyo Bay water system.

<p>So: Soil in the Sakagawa catchment area, S: Sakagawa river, E: Edogawa and Old-Edogawa rivers, X: Old-Edogawa estuary, Y: Off the Old-Edogawa estuary, Z: Center of Tokyo Bay, V: Tamagawa estuary, W: Sumidagawa estuary. If the radiocesium is adsorbed on the suspended materials in water owing to the grain size effect [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0193414#pone.0193414.ref056" target="_blank">56</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0193414#pone.0193414.ref058" target="_blank">58</a>], the relationship should obey the inverse square law. The vertical arrow in the Fig 8A indicates the range of the radiocesium background referred from the JCG report [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0193414#pone.0193414.ref023" target="_blank">23</a>].