Carbon Isotope Characteristic Of Food Chain In Aba Kaschin-Beck Disease Areas

Aba in Sichuan is one of the most serious Kashin-Beck Disease wards in China. The etiology of KBD has close relationship with local ecological environment. The investigation of local ecological environment characteristic and the residents’diet structure can provides scientific basis for further resettlement and wells engineering. This thesis relies on the "sub-topic" Aba Eco-geochemical Survey (No.1212010913022) of China Geological Survey Project Sichuan Province Kashin-Beck Disease Ward Groundwater Investigation and Security of Water Supply Demonstration. In this paper, KBD wards in Aba is selected as the research object. On the base of investigation of the geochemical characteristics of the food chain elements, the migration and transformation of the food chain elements are discussed by carbon isotope study, and the food structure of local residents is estimated.The results as followed:1. The heavy metals content in the soil of the research area is low, within the normal range. Other trace elements such as Calcium are abundant, while Manganese, Molybdenum and Selenium in KBD are comparatively lack.2. Water and atmospheric environment in research area are both well. Various heavy metal elements in plants is normal. Arsenic, Cadmium, Chromium, Mercury and Lead content in human hair are all in normal range of the upper limit. Selenium content is lower than that in human hair from normal areas. The contents of Calcium and Strontium are significantly influenced by the geological environment.3. The stable carton isotope valves in plants are in the range of-11.5‰--32.5‰, the average valve is-25.9%o. Among those, the valve of C4plants is-11.5%o; the valve of C3plant is between-21.1‰to-32.5‰, and the average valve is-26.9‰. The carton isotope fractionation in plants of the research area is influenced by the altitude, soil, water, terrain, light intensity and plants growth cycle, showing different characteristics.4. The stable carbon isotope813C of human hair is between-18.6%o and-22.4%o, the average valve is-21.3‰. In a certain district, the higher degree of the Kashin-Beck Disease, the richer of the light isotope relatively; The older of the person, the more obvious of the carton isotope fractionation; Carbon isotope valve of human has close relationship with residential environment. The older of the person, the closer of the carbon isotope valve of resident environment.5. Carbon isotope in pork and beef is close to in the plants they eat; the carbon isotope valve is related to the animal growth cycle. The longer of the growth cycle, the richer of the light isotope.6. According to the isotope inheritance and biochemical process, human with most heavy isotope, is of the top nutrition grade of food chain. Estimating from the food, grain(such as barley and wheat)is the main food, and it takes account of68.3%.7. In the aspect of element migration and enrichment, the order of the heavy mental elements enrichment of the human hair is Zn>Cd> Hg>Pb>Cr>As, while that of wheat is Zn> Hg> Cd> Cr> As> Pb, for the barley, the order is Zn> Hg> Cr> Cd> As> Pb, for rice, the order is Zn> Cd> Cr> Hg> As> Pb. The resource of Zinc and Selenium in human body is meat and fish etc, therefore, The content of Zn and Se in human hair is higher than that in environment, while the enrichment valve of Selenium and Strontium in human hair are both higher than in plants, and the Molybdenum enrichment valve is far lower than in plants.