Study On The Heavy Metal Pollution Of Tailing Reclamational Crops In Feng Xian, Shanaxi

In recent years, with the fast development of the mine tailing reclamation, heavy metal pollution of the reclamation crops has been paid new attention to. The heavy metal can cause cancer, intragenic mutation and have an outstanding cumulating effect to human being, which causes the acute poisoning or chronic poisoning. In 1955 the itai-itai disease has already astonished the world. A group of villagers and their children from Shui Yang county in China's northern Gansu province, showed excessive amounts of lead in their blood and a number of them are suffering from severe lead poisoning, confirmed officials from the province in northwest China 2006. So to study the heavy metal pollution on reclamational crops,prevent and control the pollution has become one of the environmental problems that should be resolved urgently.This paper makes a spot inspection of reclamation area of lead-zinc mine gangue in Feng Xian, and gathers tailing ore, soil and farm crops samples. Test the heavy metal element contents such as lead, zinc, copper, cadmium with the Flame Atomic Absorption Spectrophotometric.The distribution and chemical forms of heavy metals are studied based on mineralogical and chemical analyses as well as sequential extraction.Based on the contents of heavy metal, this paper makes an assessment on heavy metal of the soil through pollution index and comprehensive pollution index. The pollution index of two tailing soil was more than 3, which heavy metal pollution was serious. The sequential extraction by Dold shows that for all metals in mine tailings and soil the concentration of slag is the highest, the concentration of exchangeable is lower. If the condition changes, the lead and cadmium may be released and absorbed by the crop.Based on the data of the pH value, moisture content and nutrition element N, P, K, it gathers the typical farm crops samples (such as wheat, soybean, corn, spinach, garlic, onion, bupleurum chinensis and green bristlegrass).Accurately mensurates the content of heavy metal such as zinc, lead, copper, and cadmium in crops samples with the Flame Atomic Absorption Spectrophotometric Method. The conclusion is as follows: The content of lead, cadmium of all the reclamational crops is beyond the NY/T744-2003 and NY 5200-2004.The content of copper, zinc in most reclamational crops is high too, which is bad for our health. So the reclamational crops can not be eaten. The absorption and transfer of different parts in same crop is varies. For example, the order of content on copper, zinc, lead, cadmium in core is as follow:"root>caudal>fructification". The absorption and transfer of the heavy metal in ore-soil-farmcrops is a complicated homeostasis, which varies with different character of soil , farmcrop and heavy metal.