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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 count rates outside and inside the car.This regression formula was used as the shielding factor of the car body.
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pone.0124433.g002: Correlation between count rates outside and inside the car.This regression formula was used as the shielding factor of the car body.

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 count rates outside and inside the car.This regression formula was used as the shielding factor of the car body.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0124433.g002: Correlation between count rates outside and inside the car.This regression formula was used as the shielding factor of the car body.
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