Population Nintate And Nitrite Exposure And Health Risks In A High Cancer Incidence Area In Huai River Basin

Nitrate intaked through diet can be reduced and tansformed into nireite in the digestive processes of human stomach, and the nitrite can present in human bloodstream quickly after the transformation, cause the hemoglobin oxidation of the low iron into high iron, and the lose of oxygen in blood. Excessive dose of nitrite can induce the infant disease methemoglobinemia. While nitrate combined with subprime amine, forming nitrosamines strong carcinogen, induce digestive system cancer in human body.Through field sampling and indoor testing of the nitrate and nitrite in human body in Shicao Village of Shenqiu County, Huaihe river basin, compared with the control poplution from Henan University in Kaifeng City, this paper conducts pilot study on the exposure pathway and exposure dose of nitrate and nitrite in human body.This paper is divided into seven parts:Partâ… : The introduce of current situation and problems of the nitrate and nitrite in soil,water,vegetable and human at home and aboard,along with the content and the significance of this study.Partâ…¡: Overview of study area,including the general situation of physical geography and the society economy.Partâ…¢: The research methods of this study were introduced.Partâ…£: The nitrate and nitrite exposure ways and exposure dosage of body in the study area.Partâ…´: The content and analysis of nitrate and nitrite of human saliva and urine.Partâ…¥: The risk and evaluation of nitrates and nitrites for human health.Partâ…¦: Main conclusions were drawn.The main conclusions of this study can be summed up as follows:(1)Vegetable is the main nitrate and nitrite exposure pathway for the population in study area.(2)Saliva nitrate and nitrite contents are related to the age but present discrepancy, nitrate and nitrite average contents of the saliva in youth groups all hit the maximum level. Saliva Nitrite fractional conversions of every age group are different in the study zone, the old groups >the youth groups > the juniors groups > the middle-aged groups. Nitrite and nitrite content of the youth groups are higher than that of the controls youth groups, which have statistics significance. Nitrite conversion rate in each groups in the study zone are all higher than that of the controls youth groups. There were no gender differences with the nitrate and nitrite content in study area.(3)Urine nitrate and nitrite level had shown significant differences with different groups and individuals in study area. An obvious positive correlation has also been demonstrated between nitrate as well as nitrite metabolism and dietary intake, in concern with the youth groups, average daily intake doses of nitrate and nitrite are much higher than that of control groups, urine nitrate and nitrite level are also higher than that of control groups with statistical significance. Urine nitrate and nitrite content showed no gender differences in all groups.(4)Nitrate and nitrite content in saliva and urine of the youth groups were significantly higher than that of the controls groups, which suggested that there is close relationship between the high cancer incidences and nitrate as well as nitrite exposure in the study area. Long-term excessive fertilizer application had lead to high nitrate and nitrite level in soil, drinking water as well as vegetables, which may bring obvious health risks such as digestive cancer to the local people.(5)Health risk index of nitrate exposure are all much higher in different groups in study area than that of control groups, and obviously higher in rainy season than that of dry season. Health risk index in juniors groups is higher than other groups, and the index declined with age in different groups.