| Hair is an important way of the human metabolism. The contents of trace elements can indicate the environmental conditions and the load conditions in human body. Under certain conditions, the trace elements levels in human hair can be used to evaluate the human exposure in surrounding environment as well as the environmental impact on human health. As a biopsy material, hair is an ideal biological indicator of the environment. Many diseases and certain physiological phenomena can be diagnosed according to the changes of the trace elements in the hair. Especially the hair mercury content has a greater influence on physiological phenomena. Therefore, it is of great significance to determine the human total mercury contents accurately in order to understand human health status.Here, we choose some districts of the important economic center—Shanghai as the study area, mainly including urban district (Luwan District) and suburbs (Baoshan District, Pudong District, Fengxian District, Jinshan District).On the basis of the human mercury content among the local residents, we furtherly study on the factors that influence human hair mercury levels aiming to investigate the primary route of human exposure to mercury in Shanghai. The human exposure levels in urban district and suburbs of Shanghai are revealed by health risk assessment.We conclude under firsthand datas as follow:1) The mercury content among 492 hair samples collected from urban area (Luwan District) and rural area (Baoshan District, Pudong District, Fengxian District, Jinshan District) ranges from 0.035 to 9.727mg/kg with an average of 0.528mg/kg, a median value of 0.419mg/kg。Only the mercury content in one sample approaching to the national diagnostic criteria of 10mg/kg.2) For the total hair mercury concentration, there is no significant difference between males and females. The significant correlation was found slightly between hair mercury content and age of residents from urban and rural area. The median value of the hair mercury in 46～55 years old age group is highest and the maximum is in this group which shows that the mercury exposure level of people in this group is highest.3) Compare the median hair mercury value of samples in the same sex as well as in the same group between urban area and rural area, the median hair mercury value of samples in urban area is higher.4) Comparing the mercury level in the environment between urban area (Luwan District) and rural area (Baoshan District), the results are as follows. Firstly, the mercury concentration in the plant leaves and the vegetables is very low, most of which nonpulluted .Secondly, the mercury concentration in precipitation and in surface soil in urban area is higher than that in rural area. In contrast, the mercury concentration in the total suspended particles (TSP) and in the particulate matter PM2.5 in urban area is lower than that in rural area. Because of gaseous mercury oxidated and particulate mercury in composition of the mercury in the precipitation, the inference that the gaseous mercury concentration in the air of the urban area is higher than that of rural area can be drawn. Mercury vapor inhalation is the primary route of mercury into human body.5) In 9.35% of the population in the urban area and the rural area, the hair mercury content exceeded the reference dose of lmg/kg set by US EPA. The result of health risk assessment indicated the greater risk to local residents in the urban area than in the rural area.
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