A new sampling method for airbone hygroscopic particulate matter such as alkali metal chlorides (NaCl, KCl, RbCl, and CsCl: called as AX) using water-rinsed and cooled glass coiled tube was developed. Sample gas involving gaseous or fine particulate AX was cooled and moisturized in the glass coiled tube, resulting in water soluble coarse coagulated matter, which are collected on the inside wall of the tubes; afterwards, rinsing with injected water, analytical water sample was obtained. As a preliminary step, AX was vaporized at 1000 ℃ , condensed through 200 ℃, and collected at the cooled tubes. Arrival rate defined as the ratio of collection to vaporization was around 50% for NaCl and KCl, 85% for RbCl, and 96% for CsCl. The order of the arrival rate of AX agrees to the volatility estimated from thermochemical estimation of saturated vapor pressure. Fine particulate matter of AX less than 0.3 µm generated by passing a PTFE thimble filter at 200 ℃ was introduced to the serial glass coiled tubes; sufficient collection was evidenced by the ratio of 80:20 at the 1st and 2nd tubes. Theoretical calculation of two physical processes in the glass coiled tube: diffusive displacement and centrifugal motion proved that only centrifugal mechanism for particulate matter larger than 1 µm is effective but diffusion scarcely function. However, the experimental results gave perfect collection even for fine particulate matter less than 0.3 µm. Comparing the theoretical and experimental discussions, hygroscopic growth enabled all particulate matter to be collected by centrifugal mechanism. This method is suitable for hygroscopic particulate matter as total amount determination.

From FY2013 to FY2015, hexabromocyclododecane (HBCD) and benzotriazole UV stabilizers (BUVSs) concentrations in water environments of several cities were investigated by the joint environmental research project, "The survey of the emission sources and destiny of chemicals under Chemical Substances Control Law, in Japan". Though the maximum levels of HBCD in effluent and sediment samples were 160 ng/L and 465 ng/g-dry, respectively, in terms of ΣHBCD, both were lower than the predicted no-effect concentration (PNEC: 0.31 μg/L for water and 860 ng/g for sediment). BUVSs levels in the road dust samples were higher than those in the sediment samples. There were correlations between the BUVSs concentrations and the organic component in the road dust samples.

We investigated the dynamics of air dose rate and radiocesium (¹³⁴Cs and ¹³⁷Cs) in pond sediments at urban environment, Hikarigaoka Park, Tokyo, where drained the water from the pond on Dec. 2017 for the first time after the Fukushima accident (Mar. 2011). The average of the air dose rates at the height of 1 m outside/inside the pond was 0.069±0.024 μSv/h (n=1926, Ave ±1σ), which did not conflict with the decontamination criteria. The distribution of radiocesium in sediment was totally uniform. The maximum radioactivity of pond sediments was 58.3 Bq/kg-wet, and that of average was 30.6±11.4 Bq/kg-wet (n=80, Ave ±1σ). The maximum inventory was 4.10 kBq/m², which was clearly less than the inventory (6.94 kBq/m²) when assuming the pond as Japanese paddy field. This fact showed that the pond had the small accumulation effect of radiocesium at the time of our survey. It is estimated that this effect is caused by a mechanism that constantly circulates the pond water.