溫泉附近吸入毒氣死亡

Recently Yomiuri News reported the following:

青森市の酸ヶ湯温泉近くの山中をタケノコ採りに訪れた中学２年の伊藤実姫さん（１３）が死亡した事故は、２７日で１週間を迎える。 県警のこれまでの調べで、実姫さんは小川沿いの岩場で休憩した直後に突然意識を失っていたことが判明。わずか十数秒の間に、高濃度の硫化水素を吸い込み、死亡した可能性が浮上している。このため県警は、休憩前後のガスの発生状況を詳しく調べることにしている。
　
　捜査関係者らによると、実姫さんは母親ら３人と２０日早朝、登山道から獣道に入り、たどり着いた小川沿いで岩に座って５分ほど休憩した。川を見下ろす斜面の高い場所だった。再び歩き始めた母親らが実姫さんが付いてこないのに気づき振り返ると、あおむけに倒れて意識を失っていた。気づくまで十数秒だった。駆け戻った母親や親類も、岩の付近で一時気を失った。 しかし、県警が事故後に実施した実況見分では、岩付近の大気で検出された硫化水素は微量だった。県の要請で現場周辺を調べた弘前大学大学院の鶴見実教授（地球化学・環境化学）も、「硫化水素の発生地帯である」としながらも、「現場の小川は、周囲の岩場も含めると幅数十メートルはある広い場所。硫化水素が普段たまるような場所ではない」と分析する。

　　一方で、捜査関係者によると、実姫さんは休憩時、「疲れた」と母親らに話しており、この時すでに硫化水素を吸い込んでいたとの見方もある。 このため県警は、岩場で高濃度の硫化水素を吸引してほぼ即死した可能性のほか、それ以前から周囲の硫化水素を徐々に吸い込んで死に至った線も含め、専門家の知見などを参考にガスの発生状況を解明する。

On the 27th, one week had passed since the accident that Ito (13) a second grade of junior high-school had died while looking for bamboo shoot when visiting hills in the vicinity of the acidic hot spring in Aomori City. Based on the examination of prefecture police, it was apparent that Ito lost consciousness suddenly immediately after taking a rest at the rock field near the stream. When high density hydrogen sulfide was inhaled merely in tens of seconds, the possibility of death could occur. Therefore, prefecture police examined in detail the environmental situation on the emission of the gas before and after the rest was taken.

In the early morning of the 20th, three people include Ito and his mother entered the animal trail from the mountain climbing trail, Ito sat on the rock along the stream that they had reached at last and took a rest for about five minutes, according to the people related to the investigation. It was a high slope location in which it looked down at the river. When the mother began to walk again she soon noticed Ito had not turn up and she returned back to find Ito had fallen on the ground unconscious. Many seconds had passed before such happening was noticed. Mother and the relative who ran and returned back also experienced temporarily lost consciousness near the rock. However, after the accident the prefecture police carried out a check to detect hydrogen sulfide in the atmosphere and only found small amount in the vicinity of the rock. Tsurumi the professor (geochemistry and environmental chemistry) of Hirosaki University graduate school who investigated the surrounding of the site at the request of the prefecture also believed that "It is a generation zone of the hydrogen sulfide", he also analysed that ｢When the stream at the site includes a surrounding rock field, width up to tens of meter is certainly a wide place. It is not a place where hydrogen sulfide usually collects. ｣

On the other hand according to people related to the investigation, Ito had said to his mother when taking a rest, "I had become tired", and there was also a view that Ito had already inhaled the hydrogen sulfide. Therefore, prefecture police investigated along the line that besides the possibility of the inhaling a high density hydrogen sulfide at the rock and caused death almost immediately, there was a possibility of gradually inhaling the surrounding hydrogen sulfide until a point that caused death, and the police clarified the situation of the occurrence of the gas based on specialist's finding etc.

The sudden death of this young student looks like a myth. I think it is a good topic for writers of detective stories.