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Estimation of external dose by car-borne survey in Kerala, India.

Hosoda M, Tokonami S, Omori Y, Sahoo SK, Akiba S, Sorimachi A, Ishikawa T, Nair RR, Jayalekshmi PA, Sebastian P, Iwaoka K, Akata N, Kudo H - PLoS ONE (2015)

Bottom Line: The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h.The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y.More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.

View Article: PubMed Central - PubMed

Affiliation: Hirosaki University Graduate School of Health Sciences, Aomori, Japan.

ABSTRACT
A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass surfaces, and the range of activity concentration was estimated to be 0.7-2.3 kBq/kg. The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.

No MeSH data available.


Related in: MedlinePlus

Correlation between air kerma rate which was calculated by software using the response matrix method and total count rate outside the car.This regression formula was used as the dose rate conversion factor.
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pone.0124433.g003: Correlation between air kerma rate which was calculated by software using the response matrix method and total count rate outside the car.This regression formula was used as the dose rate conversion factor.

Mentions: Fig 2 shows the relationship between the outside and inside count rates, yielding a shielding factor of 1.47. This value was similar to the previously reported value [11]. Fig 3 shows the relationship between air kerma rate (nGy/h) evaluated using the 22 × 22 response matrix method and total count rate (cpm). The conversion factor was evaluated as 0.00244 (nGy/h/cpm). Thus, Kout the air kerma rate 1 m above the ground surface at each measurement point can be estimated using Eq (1).


Estimation of external dose by car-borne survey in Kerala, India.

Hosoda M, Tokonami S, Omori Y, Sahoo SK, Akiba S, Sorimachi A, Ishikawa T, Nair RR, Jayalekshmi PA, Sebastian P, Iwaoka K, Akata N, Kudo H - PLoS ONE (2015)

Correlation between air kerma rate which was calculated by software using the response matrix method and total count rate outside the car.This regression formula was used as the dose rate conversion factor.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401755&req=5

pone.0124433.g003: Correlation between air kerma rate which was calculated by software using the response matrix method and total count rate outside the car.This regression formula was used as the dose rate conversion factor.
Mentions: Fig 2 shows the relationship between the outside and inside count rates, yielding a shielding factor of 1.47. This value was similar to the previously reported value [11]. Fig 3 shows the relationship between air kerma rate (nGy/h) evaluated using the 22 × 22 response matrix method and total count rate (cpm). The conversion factor was evaluated as 0.00244 (nGy/h/cpm). Thus, Kout the air kerma rate 1 m above the ground surface at each measurement point can be estimated using Eq (1).

Bottom Line: The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h.The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y.More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.

View Article: PubMed Central - PubMed

Affiliation: Hirosaki University Graduate School of Health Sciences, Aomori, Japan.

ABSTRACT
A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass surfaces, and the range of activity concentration was estimated to be 0.7-2.3 kBq/kg. The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.

No MeSH data available.


Related in: MedlinePlus