A field survey concerning lead and cadmium pollution in environment mediums and hair samples around the Chatian mercury mining deposit in western Hunan Province,China,was conducted to preliminarily evaluate their heal...A field survey concerning lead and cadmium pollution in environment mediums and hair samples around the Chatian mercury mining deposit in western Hunan Province,China,was conducted to preliminarily evaluate their health hazard to local inhabitants.The results show that mining wastes,especially tailing,contain high cadmium level with the maximum of 79.92μg/g. High levels of lead and cadmium are accumulated in surface water and paddy soil,respectively,and both metals pollution occurs in brown rice.The average daily intake dose(ADD)of lead for local adults via three routes reaches up to 7.7μg/(kg·d),exceeding the provision tolerable daily intake by JECFA of 3.5μg/(kg·d),and drinking water exposure route contributes the highest daily intake.As an indicator for heavy metal exposure,the hair of local population contains Pb(5.06±3.02)μg/g.The average daily intake dose of cadmium for adults is 0.119μg/(kg·d).More attention must be paid on health risk from lead pollution compared with cadmium.展开更多
Sources,components and calibration of paleodose were studied for proper evalua-tion of the paleodose of porcelain in thermoluminescence(TL)dating.In the TL dating of porcelain using the pre-dose technique,theβdose fr...Sources,components and calibration of paleodose were studied for proper evalua-tion of the paleodose of porcelain in thermoluminescence(TL)dating.In the TL dating of porcelain using the pre-dose technique,theβdose from the internal natural radiation in the body of porcelain is the first,the environmental dose the second,and theαdose negligible.Sample thickness of 0.2―0.5 mm was used in the paleodose calibration.For a porcelain sample of such thickness,the distribu-tion ofβdose inside the sample was nonlinear when the sample(aluminium re-places porcelain in this experiment)was irradiated by a laboratory 90Sr-90Yβsource.Therefore,theβdose used was only an average value.A distribution curve ofβdose and the calculation of averageβdose in the sample were obtained,according to the build-up and attenuation effects ofβdose in the sample.The results showed that a sample thickness of 200μm resulted in an average dose increment of about 4%compared to the surface whereas for a sample with a thickness of 400μm,the average dose reduced by the same percentage,and that for a sample of 300μm in thickness the average dose is equal to surface dose approximately.The averageβdose in samples with various thickness can be obtained by the provided equations.展开更多
基金Project(40571008)supported by the National Natural Science Foundation of ChinaProject(KZCX3-SW-437)supported by Knowledge Innovation Programs of the Chinese Academy of Sciences
文摘A field survey concerning lead and cadmium pollution in environment mediums and hair samples around the Chatian mercury mining deposit in western Hunan Province,China,was conducted to preliminarily evaluate their health hazard to local inhabitants.The results show that mining wastes,especially tailing,contain high cadmium level with the maximum of 79.92μg/g. High levels of lead and cadmium are accumulated in surface water and paddy soil,respectively,and both metals pollution occurs in brown rice.The average daily intake dose(ADD)of lead for local adults via three routes reaches up to 7.7μg/(kg·d),exceeding the provision tolerable daily intake by JECFA of 3.5μg/(kg·d),and drinking water exposure route contributes the highest daily intake.As an indicator for heavy metal exposure,the hair of local population contains Pb(5.06±3.02)μg/g.The average daily intake dose of cadmium for adults is 0.119μg/(kg·d).More attention must be paid on health risk from lead pollution compared with cadmium.
文摘Sources,components and calibration of paleodose were studied for proper evalua-tion of the paleodose of porcelain in thermoluminescence(TL)dating.In the TL dating of porcelain using the pre-dose technique,theβdose from the internal natural radiation in the body of porcelain is the first,the environmental dose the second,and theαdose negligible.Sample thickness of 0.2―0.5 mm was used in the paleodose calibration.For a porcelain sample of such thickness,the distribu-tion ofβdose inside the sample was nonlinear when the sample(aluminium re-places porcelain in this experiment)was irradiated by a laboratory 90Sr-90Yβsource.Therefore,theβdose used was only an average value.A distribution curve ofβdose and the calculation of averageβdose in the sample were obtained,according to the build-up and attenuation effects ofβdose in the sample.The results showed that a sample thickness of 200μm resulted in an average dose increment of about 4%compared to the surface whereas for a sample with a thickness of 400μm,the average dose reduced by the same percentage,and that for a sample of 300μm in thickness the average dose is equal to surface dose approximately.The averageβdose in samples with various thickness can be obtained by the provided equations.
