Ambient dose equivalent rate and soil contamination density with 137Cs in kitchen gardens in settlements of the Bryansk region, Russia in 2020–2021

Abstract

The article provides results of application of the field (in situ) gamma spectrometry method for carrying out mass monitoring measurements of ambient dose equivalent rate and soil contamination density with 137Cs in kitchen garden plots located in the zone of radioactive contamination after the Chernobyl accident. In 2020 and 2021, 115 private farmsteads in 46 settlements of the Bryansk region were surveyed. At the time of the survey, the officially established average density of soil contamination with 137Cs in the settlements ranged from 27 to 533 kBq/m2 . The field spectra were measured using a portable scintillation gamma-spectrometer-dosimeter. Results of the field measurements and subsequent calculations of soil contamination density with 137Cs in the kitchen gardens were in good agreement with official data on the average soil contamination density with 137Cs in the surveyed settlements. The mean value of the ratio of the experimental data to the official data was 1.04. Individual values of experimental data deviated from corresponding official values by no more than two times. The use of the gamma spectrometry method in situ made it possible: 1) to determine separately values of the ambient dose equivalent rate from 137Cs and from natural radionuclides in the soil, and 2) to estimate the effective external doses to a person who worked in the kitchen gardens. The measured values of ambient dose equivalent rate varied from 17 to 53 nSv/h (mean ± standard deviation = 35 ± 9 nSv/h) for natural radionuclides and from 8 to 432 nSv/h (mean ± standard deviation = 125 ± 91 nSv/h) for 137Cs. The ambient dose equivalent rate from 137Cs normalized to the soil contamination density with 137Cs in the same kitchen garden was in the range of 0.41–0.84 (nSv/h)/(kBq/m2 ) with a mean value of 0.55 (nSv/h)/(kBq/m2 ). If a person stayed in kitchen garden for 840 hours per year, the estimated effective external doses from natural radionuclides and 137Cs were respectively in the range of 0.008–0.025 mSv/year and 0.004–0.20 mSv/year.

Estimation of Ambient Dose Equivalent Rate Distribution Map Using Walking Survey Technique in Hirosaki City, Aomori, Japan

“…A similar value (1.63 Sv Gy −1 , with a standard error: 0.02 Sv Gy −1 ) was reported by Omori et al [15] for outdoor sites in Fukushima City, Japan. Ramzaev and Barkovsky [16] reported an average ratio of 1.47 Sv Gy −1 for wooden houses and asphalt streets.…”

“…A similar value (1.63 Sv Gy −1 , with a standard error: 0.02 Sv Gy −1 ) was reported by Omori et al [15] for outdoor sites in Fukushima City, Japan. Ramzaev and Barkovsky [16] reported an average ratio of 1.47 Sv Gy −1 for wooden houses and asphalt streets. According to UNSCEAR (2000) [17], the world's absorbed dose rates in air are in the range 0.024-0.160 µGy h −1 , with an average of 0.057 µGy h −1 , which is higher than the average value obtained in the current study.…”

Current status of reference location in the basic model for assessment of external radiation doses to the population living in radioactively contaminated areas after the Chernobyl accident

“…Мы провели сравнение вариабельности (изменчивости) МД т-норм для целинных участков почвы и огородов в Брянской области. Источниками информации являлись публикации в реферируемых журналах, посвященные изучению радиационной обстановки в Брянской области после Чернобыльской аварии [1,[6][7][8][9][10]. Определение КВ проводили либо используя уже приведенные в публикациях значения средней величины и СКО, либо на основании вычислений этих параметров по индивидуальным значениям результатов измерений МД т и A т в выборках.…”

“…2). Измеренные значения МД т на огородах весьма жестко связано с плотностью их поверхностного радиоактивного загрязнения [9], и данный вид радиационного контроля может использоваться для экспрессной оценки плотности радиоактивного загрязнения НП.…”

Dynamics of decrease of the gamma dose rate in air in rural settlements of the Bryansk region (Russia) in the remote period after the Chernobyl accident

“…Для измерения мощности поглощенной дозы в воздухе (нГр/ч) использовали переносной спектрометр-дозиметр гамма-излучения МКС-СК1 «СКИФ» фирмы «Синко» (Санкт-Петербург, Россия) [11]. Спектрометр-дозиметр «СКИФ» имел сцинтилляционный детектор с цилиндрическим кристаллом NaI(Tl) размером 63 мм × 63 мм и 480-канальный анализатор импульсов.…”