Heavy Metal Contamination Analysis of Montanic Soil and Crops of Tin Mine in Gejiu of Yunnan

Through field investigation and sampling of Yunnan old tin mine montanic soil and crops,the contents of soil organic matter,available nitrogen,available phosphorus and available potassium and other basic nutrients and heavy metals in soil and crops such as lead,cadmium,chromium,copper and zinc were analyzed and evaluated. The results showed that the alkali-hydrolysable nitrogen content of Yunnan Gejiu stannary mountain sampling area soil was 49. 38 mg/kg,belonging to the medium fertility. The average soil organic matter,available phosphorus and available potassium content were 34. 56 g/kg,17. 25 mg/kg and 159. 72 mg/kg,rich in content. Pb content of sampling area soil was 142. 88- 580. 88 mg/kg. Cr content was 4. 18- 74. 85 mg/kg. Cd content was 17. 25- 86. 18 mg/kg. Cu content was 25. 44-256. 24 mg/kg. Zinc content was 19. 95- 1041. 24 mg/kg. Cd pollution was the most serious,which belonged to the severe pollution. According to the comprehensive pollution index,the heavy metals of sampling soil were serious pollution. The contents of lead,cadmium,chromium,copper,and zinc were more than the national food safety standard 9. 7- 89. 7,1. 15- 9. 1,9. 1- 5. 4,0. 08- 2. 66 and 2. 66- 1.27 times,respectively. Lead,cadmium and chromium in crops belonged to the severe pollution.