| Objective:Survey the content of 5 kinds of heavy metals, lead, zinc, cadmium, copper and manganese in water, soil and agricultural products in Lanping mining area, in order to understand the environmental pollution condition and influence on safety of agricultural products result from the exploitation of mineral resources.Methods1. Field survey:Take the eight mines of six townships in Lanping County for the sampling point, collecting samples within the mining area 3 Km according to the corresponding sampling requirements. Collecting the representative water, soil and various crops (grain, vegetables and fruit) samples, Separated by category bagging. A total of 119 samples collected in the mining area, of which 43 water samples, soil 39, and crop 37. Take two no minerals towns in Lanping county as the control point, Collect the control samples in residential areas.39 control samples were collected, of which 11 water samples, soil 9, copies 19.2. Sample survey:Using acid digestion method to digest the sample, then determination of lead, zinc, cadmium, copper and manganese five elements content in sample by atomic absorption spectrometry.3. Data Analysis:With element maximum limit of national environmental quality standards as a comparison scale to analysis the exceeded condition of heavy metals in water, soil and crops. With spss16.0 for windows software analysis the pollution condition of three samples.Results: 1. Exceeding standard rates of lead, zinc, cadmium, copper and manganese five kinds of heavy metal elements in water respectively were 97.67%,3.33%,65.12%, 0% and 4.56%; The average pollution index respectively were 21.94,0.30,35.74,0.05 and 1.53,.2. Exceeding standard rates of lead, zinc, cadmium, copper and manganese in soil respectively were 23.08%,14.81%,89.74%,0% and 43.59%; The average pollution index respectively were 1.07,0.82,18.51,0.03 and 0.84。3. Exceeding standard rates of lead, zinc, cadmium, copper and manganese in crop respectively were 61.11%,51.72%,88.89%,0 and 8.11%; The average pollution index respectively were11.42,1.1,20.12,0.19 and 0.28.4. The copper content of all samples were in the normal range in this survey.5. Most of the contents of lead, zinc, cadmium and manganese in the samples in mining area were higher than normal and to varying degrees higher than the control area (non-mining). In water, the lead and manganese content was statistics significant difference between the mining area and non-mining (P<0.01). However, cadmium was no statistics significant difference (P>0.05).In soil, cadmium content was statistically significant difference (P<0.01) between the mining and control areas. The lead and manganese contents of the two places was no statistics significant difference (P>0.05).In crop, the lead content was no statistics significant difference (P>0.05) between the mining and control areas. The cadmium and manganese contents of the two places was statistics significant difference (P<0.01,0.01<P<0.05).6. The pollution index and exceeding standard percentage of heavy metals in crops increased with the quantity in soil and (or) water.Conclusions:1. There were widespread and serious pollution of lead and cadmium in water in Lanping mining area. There were heavy pollution of zinc and manganese in individual mine.2. There were widespread and serious pollution of cadmium in soil. There were slight pollution of lead,zinc and manganese in Part of the mine.3. There were widespread and serious pollution of lead and cadmium in crop in Lanping mining area. There were widespread but minor contamination of zinc in crop and slight contamination of manganese in some of the mines.4. It was not detected copper content exceeded samples in Lanping mining area.5. The phenomenon that heavy metals exceed the standard in mining significantly higher than the control area.6. The heavy metal contents are positive correlation between crops and water or soil.7. Many years of mining activities have resulted in different degrees pollution of lead, zinc, cadmium and manganese in water, soil and crops. It affected the production safety of crops in mine and is also give the crowd a lot of health risks. The economic value caused by the exploitation of heavy metals can not to a huge environmental damage and pollution cost. It is need to raise the mining sector and mining management's attention. They should pay attention to protecting the environment while develop economic and make every effort to reduce the harm to the environment. |
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