Study On Heavy Metal Concentration Of Hair And Exposure Risk In Ordinary Residents In The Three Gorges Reservoir Area

In recent years,heavy metal pollution and the health of residents in the country have occurred frequently.Heavy metal pollution has become an environmental issue that is of great concern to all countries in the world.Exploring the exposure risk of heavy metals in the population is the basis for understanding the impact of heavy metals in the region on the health of residents and establishing strategies for preventing heavy metal pollution.After the completion of the Three Gorges Reservoir,the environment in the reservoir area has undergone major changes.As an ecologically sensitive area,the exposure risk of heavy metals in the population is also worth studying.Therefore,this paper selects Fuling and Zhongxian,both of which are located in the abdominal area of the Three Gorges reservoir area,as the survey area.On the basis of surveys of the local residents'dietary consumption and daily life habits,different sexes and different age groups are surveyed.A total of 238 hair samples were analyzed.The contents of four heavy metal elements including mercury?including total mercury and methylmercury?,Pb,As,and Cr were analyzed.At the same time,according to the results of the questionnaire survey,a total of 62 food samples including cereals,potatoes,fish,meat,and vegetables were collected from the residents of the two places for analysis of heavy metal content.Based on the measured levels of Hg,Pb,As,and Cr in food samples and hair samples,and the exposure risk assessment model for heavy metals in the population,the exposure risk of heavy metals in residents of the two places was evaluated.The result is as follows:The average total mercury content,the methylmercury content,the lead content,the arsenic content and the chromium content in the hair of residents in the two districts were?0.50±0.54??g·g^-1,?0.35±0.25??g·g^-1,?3.82±5.26??g·g^-1,?0.44±0.34??g·g^-1and?1.11±2.47??g·g^-1.The over-standard rate of total mercury in the hair samples of the two places was 5.04%,the over-standard rates were 4.20%in Fuling County and 5.88%in Zhongxian County.The over-standard rate of Pb in hair samples was 3.78%in both hair samples,the over-standard rates were and 3.63%in Fuling County and 4.20%in Zhongxian County.The over-standard rate of As in hair samples was 4.20%in the two places,among which the over-standard rate was 5.04%in Fuling County and 3.36%in Zhongxian County.The contents of Hg,Pb,As and Cr in the hair of residents of the two cities showed that the exposure risk of the four heavy metals is at a lower level.Through the analysis of the contents of heavy metals such as Hg,Pb,As and Cr in the hair samples of ordinary residents in the two places,it was found that there are significant differences in the heavy metals of Hg and Pb at different ages.But the heavy metals As and Cr are different,there was no significant difference among the age groups.The trends of the content of the four heavy metals varied with the age:the THg and MeHg contents of the residents in the two places decreased slightly with age,then rise and then drop again.The content of total mercury and methylmercury in the hair of residents aged at 40⁵0 years is the highest.The content of Pb in hair shows a trend of decreasing first and then increasing with age.The content of As in hair shows a downward trend with age.The content of Cr in hair increases with age.There was no significant difference in the three heavy metals of Hg,Pb and As contents between different genders;The content of Cr was significantly different among different sexes,and males were higher than females.The content of four heavy metals in hair was significantly different between smoking and non-smoking residents.The content of four heavy metals in hair of smokers was higher than that of non-smokers.The contents of THg and MeHg in cereals consumed by residents of the Three Gorges reservoir area in Fuling and Zhongxian were 0.016 mg/kg and 0.003 mg/kg,respectively;the contents of Pb,As and Cr were respectively 0.032 mg/kg,0.021mg/kg and 0.017 mg/kg.The contents of THg and MeHg in potato were 0.022 mg/kg and 0.002 mg/kg,respectively.The contents of Pb,As and Cr were 0.324 mg/kg,0.026mg/kg and 0.082 mg/kg,respectively.The contents of THg and MeHg were 0.030mg/kg and 0.019 mg/kg,respectively.The content of Pb and As were 0.891 mg/kg and0.001 mg/kg,the content of Cr in fish was lower than the detection limit.The content of THg in meat was 0.004 mg/kg,and the content of MeHg was lower than the detection limit of the instrument.The contents of Pb and As were 0.031 mg/kg and0.001 mg/Kg,and the content of Cr was lower than the detection limit.The content of THg in vegetables was 0.002 mg/kg,and the content of MeHg was lower than the detection limit.The contents of Pb,As and Cr were 0.071 mg/kg,0.036 mg/kg and0.033 mg/kg,respectively.Of the five foods,only the content of THg and Pb in the potato exceeded the standard limit,and the remaining heavy metal content in all kinds of dietary samples was within the standard limits.Although the content of THg and Pb in the potato meal sample exceeded the standard,the daily dietary intake of the residents was small and there was no significant exposure risk.The dietary intake of four heavy metals of the residents was not exceed the ADI value and PTWI value.Therefore,the risk of exposure to four heavy metals through the dietary route is relatively low.The study found that the contents of heavy metals in the hair of the residents of the two reservoirs in the Three Gorges Reservoir area were low,and the amount of heavy metals that passed through the diet was small.Therefore,the risk of heavy metal exposure in residents of the Three Gorges reservoir area is at a lower level.