carcinogenic 復習

お米の籾殻を燃やして灰にし、肥料にする取り組みが行われています。

Turning rice husk ash into fertilizer / Burning of waste product also generates energy

In Imizu, a rice-producing area in Toyama Prefecture, attempts are being made to generate heat from a large amount of rice husks burned in a special boiler after harvest and use the ashes as fertilizer.

Almost all of the approximately 2 million tons of rice husks generated annually in the nation are discarded. If it is used as an alternative energy source in place of petroleum, this could reduce carbon dioxide (CO2) emissions. The Imizu project is attracting attention from other rice-growing municipalities as well.

Kosugi Country Elevator is a facility in Imizu’s central district of Ogo to store and dry the reaped rice. In one part of the facility stands an experimental boiler. Through a small window in the boiler, rice husks could be seen burning red.

中略

Temperature control critical

Another challenge was how to put the ash to good use. About 20 percent of the content of rice husks is silicic acid, which is usable as a fertilizer. But if this acid is used on rice paddies as is, it does not dissolve well. Silicic acid first needs to be converted into something easily soluble in water for use as a fertilizer.

However, when rice husks combust at the conventional temperature of approximately 1,000 C, silicic acid crystallizes and does not dissolve well in water. In addition, this crystallized silicic acid was found to be carcinogenic on a level equivalent to asbestos.

以下省略

http://the-japan-news.com/news/article/0003183762

今回取り上げるのはcarcinogenicです。『ライトハウス英和辞典』（第5版　研究社）で調べますと、形容詞で「発癌性の」という意味が載っておりました。名詞形のcarcinogenは「発癌性物質」となります。carcinoとgenicを分解して調べると、carcinoは腫瘍やガンを表し、genicは「〜を生じる」という意味があることがわかりました。（スマートフォンに内蔵されているジーニアス英和辞典MX増補版for iOSより）これらの意味が合わさって上記の意味になります。

400度より低い温度で燃やすとダイオキシンが発生するため、この灰の肥料を作るのに適する温度は400度から600度の間だそうです。

この表現は過去にも取り上げられておりました。（aqua）
carcinogenic - 田邉祐司ゼミ 常時英心：言葉の森から