Saitama Sinkhole Remains Open 1 Year after Forming

Saitama, Jan. 28 (Jiji Press)–A sinkhole up to about 30 meters wide remains open in the city of Yashio in Saitama Prefecture, north of Tokyo, on Wednesday, which marked one year after the hole formed and a truck fell into it. Restoration work to fix the hole, caused by a sewer pipe rupture underneath an intersection, is expected to take at least five to seven years to complete. Sewage odors and hydrogen sulfide generated in the pipes spread around the hole, tormenting residents. Business owner Fumie Kinoshita, 56, said odors began to seep into her house, located about 70 meters from the sinkhole, after the incident. “It smelled bad during the year-end and New Year holidays, and many visitors were surprised,” Kinoshita said. She moved to Yashio from Tokyo about 20 years ago to live in a house with a garden, and moving again is crossing her mind. “But who would buy this land?” she said. “I can’t realistically do anything.” Kinoshita and her family evacuated to the city office building after the sinkhole formed. After returning home about two weeks later, she experienced vibrations and noise from restoration work, and “suffered sore throat and watery eyes outdoors.” A year later, the discomfort in her throat and eyes has subsided, but odors from the hole remain and are absorbed into laundry even when hung indoors. Since last June, metallic accessories and the emblem on her car have started to corrode and turn black. This is believed to be related to hydrogen sulfide generated when microorganisms decompose sewage in sewer pipes. “It’s not ordinary rust,” Kinoshita said. “The surface is being worn out and turning black, and it seems as though the metal is melting away.” The Saitama prefectural government hosted a lecture by a doctor last November, after receiving complaints from residents about foul odors and corrosion damage. Yoshito Kamijo, head of the Clinical Toxicology Center at Saitama Medical University Hospital, who gave the lecture, explained that the hydrogen sulfide concentration near the sinkhole was around the same level as in hot spring areas. “It’s detoxified in the body and doesn’t cause any health damage,” he said. Meanwhile, he said that hydrogen sulfide causes corrosion even at low concentrations, and that discomfort and stress caused by the odor can cause psychological problems. The prefectural government is currently installing a new pipe inside the damaged sewer pipe. “If the sewage bypassing the site flows straight through, the odor may disappear,” a senior prefectural official said. “But we won’t know (if the odor will disappear completely) until we proceed with the construction.” END [Copyright The Jiji Press, Ltd.]