A Japanese person measured highly contaminated substance on the roof of her house. The house is located in Kashiwa city Chiba, where is known to be a hotspot. (cf. 192.5 Bq/Kg of cesium from citron in Kashiwa city Chiba)
On 8/9/2012, she blogged like this below, [Link]
先月末、家では屋根の掃除が行われました。
屋根にはこのように黄色の苔のようなものがビッシリと生えていました。表面の線量は0.7μSv/h。
キッチンナイフを使い、20gほどこそげ取ってきました。
線量計を当てるとレットゾーンでした。
20gの重量で1.2μを出す土なんて、この辺でも見たことがありません。
作業が終了したので再び屋根の上に上ると、屋根は見違えるように
きれいになっていました。表面の線量も少し下がり、0.4μSv/h。しかし、雨樋に
黄色い粒々（先ほどの苔みたいな物）が目立つプルプルとした汚泥が溜まっていました。
ドス黒い土3.6kg。回収してきました。
私はフルアーマー（タイベック、防毒マスク、眼鏡、ゴム手袋+ビニール手袋）でその作業に臨み、
作業後は汚染された防護服などを屋外で脱いで密閉し、すぐにシャワーを浴びて目や耳の穴、鼻の穴
などくまなく身体を洗いました。これでも大変に危険な作業ですので真似しないでください。
真似して何かあった時の責任は私は取りません。
14μSv/hでした。2桁を見たのは初めてです。2階の線量が高いのも頷けます。
今までこんなブツを上に乗せて生活していたのですね、私たちは。
屋根の上に登った時、他の家の屋根が見えましたが、ほとんどが同じような黄色の苔で覆われていました。
恐らく、汚染の度合いも似たようなものでしょう。
<Translate>
Around the end of July, I had the professional cleaners wash the roof of our house.
The roof was covered with something like this yellow moss. It was 0.7 μSv/h on its surface.
I took 20g of it by a kitchen knife. Radiation meter indicated it was red zone, 1.2 μSv/h.
I haven’t measured 1.2μSv/h from merely 20g of sample even around here known to be hotspot.
It was totally washed off after cleaning, radiation level was decreased a little bit, 0.4 μSv/h on the surface, but the yellow substance was still with mud in the rain gutter.
I took 3.6 kg of it with the perfect protective clothing (tyvek, gas mask, goggles, plastic gloves).
I packed the clothing soon after taking off the sample, had shower to clean eyes, ears, nostrils carefully.
This is very dangerous, please don’t do it. I can’t take a responsibility if something happened to you.
The radiation level was 14 μSv/h. I haven’t measured higher than 10 μSv/h before. It makes sense why the radiation level is high on the second floor.
We were living with such a thing on our roof..
When I stepped on the roof, I saw the roofs of other houses, most of them were covered with the same yellow substance. Probably the radiation level is high as well.
<End>
As reference, in March. 2011, yellow power remained on the street or rain gutters after rain and they measured quite high level of radiation as well. (cf. 2.16 μSv/h from yellow powder)
It is not known what the yellow powder was.
The connection between the yellow powder and this yellow substance is not known either.
Iori Mochizuki