The majority of the area contaminated by the Fukushima Daiichi Nuclear Power Plant accident is covered with forests. We developed a dataset for radiocaesium (137Cs) in trees, soil, and mushrooms measured at numerous forest sites. The 137Cs activity concentration and inventory data reported in scientific journal papers written in English and Japanese, governmental reports, and governmental monitoring data on the web were collated. The ancillary information describing the forest stands were also collated, and further environmental information (e.g. climate) was derived from the other databases using longitude and latitude coordinates of the sampling locations. The database contains 8593, 4105, and 3189 entries of activity concentration data for trees, soil, and mushrooms, and 471 and 3521 entries of inventory data for trees and soil, respectively, which were collected from 2011 to 2017, and covers the entire Fukushima prefecture. The data can be used to document and understand the spatio-temporal dynamics of radiocaesium in the affected region and to aid the development and validation of models of radiocaesium dynamics in contaminated forests.

A series of laboratory-based soil column studies has been carried out to determine the comparative behaviour of the radioactive halogens ^Cl and 12S I (as a surrogate for i29 I) in the soil-plant system. Physical migration of ^Cl in the soil appears to be unretarded due lo its presence predominantly in the chloride form. This lead to substantial accumulation of № CI at the sot) surface in a column experiment in which the net flux of water was upwards. Physical migration of l "l in soils appears to be relatively rapid at low oxidaUon-reduction potentials, but is substantially retarded under more oxic soil conditions. This lead to accumulation of 1Z, I in the zone of transition between anoxic and oxic zones in the soil. Gel filtration chromatography confirmed that the predominant chemical form of ^Cl in the soil is the chloride anion. Conversely, 12S I showed a strong tendency to associate with both high and low molecular weight fractions of soil humic substances, though its attachment to the low molecular weight fraction appears to be more specific than to the high molecular weight fraction. Soil-plant transfer was measured for both ^Cl and ,2S I in rye grass swards in undisturbed soil columns. Biological assimilation of 36 C1 was particularly significant, with more than 50% of the total W CJ activity in the soil being taken up by the grass sward after three weeks' growth Uptake of l25 l by grass swards was less spectacular, though still resulted in approximately 1% or the total soil 12i I activity being assimilated even though the standing biomass of the grass sward was low.

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A former bulk fuel terminal in North Carolina is a groundwater phytoremediation demonstrationsite where 3,250 hybrid poplars, willows, and pine trees were planted from 2006 to 2008 over approximately 579,000 L of residual gasoline, diesel, and jet fuel. Since 2011, the groundwater altitude is lower in the area with trees than outside the planted area. Soil-gas analyses showed a 95 percent mass loss for total petroleum hydrocarbons (TPH) and a 99 percent mass loss for benzene, toluene, ethylbenzene, and xylenes (BTEX). BTEX and methyl tert-butyl ether concentrations have decreased in groundwater. Interpolations of free-phase, fuel product gauging data show reduced thicknesses across the site and pooling of fuel product where poplar biomass is greatest. Isolated clusters of tree mortalities have persisted in areas with high TPH and BTEX mass. Toxicity assays showed impaired water use for willows and poplars exposed to the site's fuel product, but Populus survival was higher than the willows or pines on-site, even in a noncontaminated control area. All four Populus clones survived well at the site. c⃝ 2014 Wiley Periodicals, Inc.

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