阳江天然放射性高本底地区剂量调查的新进展

作者报告了阳江天然放射性高本底地区环境辐射水平的测量和居民吸收剂量估算方面近几年的调查结果，根据辐射流行病学调查的需要，将高本底地区因外照射所致居民的年吸收剂量，按村庄平均分成高、中、低３个组。对照地区将根据分组人数的配对要求，仅在以前调查过的对照地区选部分村庄。

Recent advances of dosimetry investigation in the high background radiation area in Yangjiang, China

This paper reports on the results of measurements of natural radiation level in environment and the estimation of absorbed doses for inhabitants living in the high background radiation area in Yangjiang (HBRA)and the neighboring control area in Enping (CA) in recent four years. For using these data in radiation epidemiology, the inhabitants in HBRA were divided into three groups based on their annual absorbed doses to external radiation, namely the high, moderate and low annual absorbed dose groups. Only part of villages in CA which had been investigated previously were selected according to pairing requirements. Thus, there are 384 villages in HBRA and 142 in CA. The present purpose of the investigation for annual absorbed dose to inhabitants is to obtain every individual cumulative dose in HBRA and CA. Thus, since 1991, we have consecutively carried out four investigations of individual and environmental cumulative dose. The total numbers of persons subjected to cumulative individual dose measurement in HBRA and CA up to now are 3900 and 1304, respectively. The average annual individual cumulative doses are 2.11 mGy/a and 0.7mGy/a in HBRA and CA, respectively. The results indicate that females in HBRA had slightly higer dose than males,but the difference was not significant statistically (P=0.18) . However, the annual dose received by the 0-7 year age group in HBRA was the highest among all age groups (P<0.05), while the annual dose for the age group of 41-60 years was lower than these for other four age groups(P<0.05). But there are no significant differences between 8-16, 17-40, and over 60 year groups(P>0.05) .In CA, there was no significant difference between both sexes,nor between various age groups. The people living in brick houses in HBRA received the highest dose among the whole subjects(P<0.O1).The individual cumulative dose to inhabitants living in houses built over 30 years ago was the lowest, compared with those living in houses built not so long ago (P<0.o1) However,this difference was not revealed in CA.