SARS-CoV-2 RNA in Wastewater Was Highly Correlated With the Number of COVID-19 Cases During the Fourth and Fifth Pandemic Wave in Kobe City, Japan.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the current coronavirus disease 2019 (COVID-19) pandemic and associated respiratory infections, has been detected in the feces of patients. Therefore, determining SARS-CoV-2 RNA levels in sewage may help to predict the number of infected people within the area. In this study, we quantified SARS-CoV-2 RNA copy number using reverse transcription quantitative real-time PCR with primers and probes targeting the N gene, which allows the detection of both wild-type and variant strain of SARS-CoV-2 in sewage samples from two wastewater treatment plants (WWTPs) in Kobe City, Japan, during the fourth and fifth pandemic waves of COVID-19 between February 2021 and October 2021. The wastewater samples were concentrated via centrifugation, yielding a pelleted solid fraction and a supernatant, which was subjected to polyethylene glycol (PEG) precipitation. The SARS-CoV-2 RNA was significantly and frequently detected in the solid fraction than in the PEG-precipitated fraction. In addition, the copy number in the solid fraction was highly correlated with the number of COVID-19 cases in the WWTP basin (WWTP-A: r = 0.8205, p < 0.001; WWTP-B: r = 0.8482, p < 0.001). The limit of capturing COVID-19 cases per 100,000 people was 0.75 cases in WWTP-A and 1.20 cases in WWTP-B, respectively. Quantitative studies of RNA in sewage can be useful for administrative purposes related to public health, including issuing warnings and implementing preventive measures within sewage basins.

Radiation measurements in the Chiba Metropolitan Area and radiological aspects of fallout from the Fukushima Dai-ichi Nuclear Power Plants accident.

Large amounts of radioactive substances were released into the environment from the Fukushima Dai-ichi Nuclear Power Plants in eastern Japan as a consequence of the great earthquake (M 9.0) and tsunami of 11 March 2011. Radioactive substances discharged into the atmosphere first reached the Chiba Metropolitan Area on 15 March. We collected daily samples of air, fallout deposition, and tap water starting directly after the incident and measured their radioactivity. During the first two months maximum daily concentrations of airborne radionuclides observed at the Japan Chemical Analysis Center in the Chiba Metropolitan Area were as follows: 4.7 × 10(1) Bq m(-3) of (131)I, 7.5 Bq m(-3) of (137)Cs, and 6.1 Bq m(-3) of (134)Cs. The ratio of gaseous iodine to total iodine ranged from 5.2 × 10(-1) to 7.1 × 10(-1). Observed deposition rate maxima were as follows: 1.7 × 10(4) Bq m(-2) d(-1) of (131)I, 2.9 × 10(3) Bq m(-2) d(-1) of (137)Cs, and 2.9 × 10(3) Bq m(-2) d(-1) of (134)Cs. The deposition velocities (ratio of deposition rate to concentration) of cesium radionuclides and (131)I were detectably different. Radioactivity in tap water caused by the accident was detected several days after detection of radioactivity in fallout in the area. Radiation doses were estimated from external radiation and internal radiation by inhalation and ingestion of tap water for people living outdoor in the Chiba Metropolitan Area following the Fukushima accident.