Effect of high-level natural radiation on chromosomes of residents in southern China

Abstract

To study the effect of low-dose (rate) radiation on human health, we analyzed chromosomes of peripheral lymphocytes of residents in a high background radiation area (HBRA) and compared the results with those obtained from residents in a control area (CA) in Guangdong Province, China. Unstable types of chromosome aberrations (dicentrics and rings) were studied in 22 members of eight families in HBRA and 17 members of five families in CA. Each family consists of three generations. On average 2,600 cells per subject were analyzed. 27 adults and six children in HBRA and 25 adults and eight children in CA were studied with respect to translocations. On average 4,741 cells per subject were examined. We found an increase of the frequency of dicentrics and rings in HBRA, where the natural radiation level is three to five times higher than in the control area. But the increase of translocations in HBRA was within the range of individual variation in the controls.

The Linear No-Threshold Relationship Is Inconsistent with Radiation Biologic and Experimental Data

“…In China (Yangjiang and its surrounding area), people are exposed to two levels of radiation per year-6.4 and 2.4 mSv, respectively. There was no increase in cancer or mortality (142,143), although the higher level of background radiation was confirmed by a higher incidence of chromosomal aberration (144). The existence of these aberrations despite the absence of a cancer excess is an argument in favor of the absence of a causal relationship between a chromosomal aberration and cancers.…”

Human exposure to high natural background radiation: what can it teach us about radiation risks?

“…The difference in the frequencies of dicentrics in adults was statistically significant, but not for those in children. Stable-type chromosomal aberrations were analysed by chromosome painting in another group of subjects: 30 from HNBR and 27 from control areas [33, 34]. In subjects from both areas, the frequencies of translocations were much higher than those of dicentrics.…”

“…Also, the effects of nonradiation clastogens is an important factor, and data could be collected. As shown in the chromosome study in China [34], the large individual variations of confounding effects caused by non-radiation clastogens masked the effect of low dose radiation. That study indicates that in an epidemiologic study of cancer related to very low dose radiation, increasing the size of the cohort increases the individual variations and does not necessarily increase the statistical power.…”

La controverse sur les effets des faibles doses de rayonnements ionisants et la relation linéaire sans seuil

“…De même il n'est pas rapporté d'augmentation du nombre de translocations chromosomiques en Chine (Hayata et al, 2004). Il s'agit dans tous les cas de très faibles débits de dose.…”