Natural radiation levels in Tamil Nadu and Kerala, India

Tokonami, Shinji; Yonehara, Hidenori; Akiba, Suminori; Thampi, Madhavi; Zhuo, Weihai; Narazaki, Yukinori; Yamada, Yuji

doi:10.1016/s1569-4860(04)07066-4

Cited by 11 publications

(9 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As stated in Section 2.4, this yields a sensitivity factor of 0.94 Tr cm −2 d −1 /EETC (Bq m −3 ) for use in indoor thoron progeny dosimetry using DTPS system. It is interesting to note that this is similar to the sensitivity factor of 1.15 Tr cm −2 d −1 /EETC (reciprocal of their calibration factor, 0.87 EETC/Tr cm −2 d −1 ) reported by Tokonami et al (2002) for CR-39 detectors.…”

Section: Deposition Velocity and Sensitivity Factorsupporting

confidence: 79%

“…Direct progeny measurement by passive energy discrimination techniques using suitable absorbers, which was initiated by Fleischer (1984), has established (Nikezic and Baixeras, 1996;Da Silva and Yoshimura, 2005) the feasibility of detecting individual radon progeny species using barriers placed in front of nuclear track detectors. Their application to environmental thoron progeny dosimetry has been initiated by Zhuo et al (2000) and Tokonami et al (2002), using CR-39 detectors covered with aluminium-evaporated plastic and a polypropylene film so as to detect alpha particles emitted from 212 Pb only. Tokonami et al (2002) have carried out sample studies of progeny concentrations in HBRAS areas in Manavalakurichi, India.…”

Section: Introductionmentioning

confidence: 99%

“…Their application to environmental thoron progeny dosimetry has been initiated by Zhuo et al (2000) and Tokonami et al (2002), using CR-39 detectors covered with aluminium-evaporated plastic and a polypropylene film so as to detect alpha particles emitted from 212 Pb only. Tokonami et al (2002) have carried out sample studies of progeny concentrations in HBRAS areas in Manavalakurichi, India. This development is a novel and promising approach for thoron progeny dosimetry and requires to be systematically investigated for establishing the individual factors contributing to the response of the detector system.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Study of a deposition-based direct thoron progeny sensor (DTPS) technique for estimating equilibrium equivalent thoron concentration (EETC) in indoor environment

Mishra

Mayya

2008

Radiation Measurements

131

View full text Add to dashboard Cite

Section: Deposition Velocity and Sensitivity Factorsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Study of a deposition-based direct thoron progeny sensor (DTPS) technique for estimating equilibrium equivalent thoron concentration (EETC) in indoor environment

Mishra

Mayya

2008

Radiation Measurements

131

View full text Add to dashboard Cite

“…A study by Tokonami et al (2002) in Karunagappally and Manavalakurichy, another HBR area near Kerala state, showed that the radon concentration, thoron concentration and equilibrium equivalent thoron concentration ranged from 2-70, 6 -690 and 0.1-1.6 Bq m Ϫ3 , respectively. The effect of internal exposure from environmental radionuclides on cancer risk, however, is not established.…”

Section: Discussionmentioning

confidence: 99%

Background Radiation and Cancer Incidence in Kerala, India—karanagappally Cohort Study

Nair¹,

Rajan²,

et al. 2009

View full text Add to dashboard Cite

The coastal belt of Karunagappally, Kerala, India, is known for high background radiation (HBR) from thorium-containing monazite sand. In coastal panchayats, median outdoor radiation levels are more than 4 mGy y-1 and, in certain locations on the coast, it is as high as 70 mGy y-1. Although HBR has been repeatedly shown to increase the frequency of chromosome aberrations in the circulating lymphocytes of exposed persons, its carcinogenic effect is still unproven. A cohort of all 385,103 residents in Karunagappally was established in the 1990's to evaluate health effects of HBR. Based on radiation level measurements, a radiation subcohort consisting of 173,067 residents was chosen. Cancer incidence in this subcohort aged 30-84 y (N = 69,958) was analyzed. Cumulative radiation dose for each individual was estimated based on outdoor and indoor dosimetry of each household, taking into account sex- and age-specific house occupancy factors. Following 69,958 residents for 10.5 years on average, 736,586 person-years of observation were accumulated and 1,379 cancer cases including 30 cases of leukemia were identified by the end of 2005. Poisson regression analysis of cohort data, stratified by sex, attained age, follow-up interval, socio-demographic factors and bidi smoking, showed no excess cancer risk from exposure to terrestrial gamma radiation. The excess relative risk of cancer excluding leukemia was estimated to be -0.13 Gy-1 (95% CI: -0.58, 0.46). In site-specific analysis, no cancer site was significantly related to cumulative radiation dose. Leukemia was not significantly related to HBR, either. Although the statistical power of the study might not be adequate due to the low dose, our cancer incidence study, together with previously reported cancer mortality studies in the HBR area of Yangjiang, China, suggests it is unlikely that estimates of risk at low doses are substantially greater than currently believed.

show abstract

“…There was no correlation between background radiation and chromosomal aberrations in lymphocytes or constitutional anomalies (Th02, Thampi et al, 2005).…”

Section: Indiamentioning

confidence: 92%

Documented optimum and threshold for ionising radiation

Luckey

2007

IJNUCL

View full text Add to dashboard Cite

A concept of the complete dose-response curve of ionising radiation will allow us to live in harmony with this ubiquitous agent. Convincing data show ionising radiation is essential for life. Ambient levels of ionising radiation (about 2 mSv/y without medical and cosmic radiation) are adequate for life but insufficient for abundant health. We live with a partial deficiency of ionising radiation. Thousands of people have lived for generations with 2-20 times the ambient levels of radiation without showing ill health. A conservative threshold, the maximum safe level of radiation, was estimated from abundant rodent data to be about 8000 mSv/y. When human and rodent data were collated, a conservative optimum of 60 mSv/y was obtained. Radiation levels greater than the threshold are harmful. The facts suggest that radiobiologists and governments should abandon the 'linear no threshold' (LNT) paradigm and accept natural and industrial low level sources of ionising radiation in order to promote abundant health.

show abstract

Natural radiation levels in Tamil Nadu and Kerala, India

Cited by 11 publications

References 5 publications

Study of a deposition-based direct thoron progeny sensor (DTPS) technique for estimating equilibrium equivalent thoron concentration (EETC) in indoor environment

Study of a deposition-based direct thoron progeny sensor (DTPS) technique for estimating equilibrium equivalent thoron concentration (EETC) in indoor environment

Background Radiation and Cancer Incidence in Kerala, India—karanagappally Cohort Study

Documented optimum and threshold for ionising radiation

Contact Info

Product

Resources

About