The Micro Ecology Effect Of Protein Peptide On Copper Mine Tailings

This paper studied the micro ecology effect of protein peptide to copper mine tailings. The total and available copper (Cu) contents of the copper mine tailings in which microorganisms and plants are difficult to grow are1450.10mg/kg and249.24mg/kg respectively. A separate application of protein peptide (total Cu contents is3.03mg/L) and a combined application of laccase bacteria and protein peptide are used to control the micro ecological and the forms of Cu of the copper mine tailings. It’s aimed at reducing the toxicity of the Cu on plant and establishing foundation for the research that the concentration of copper ions of plants. The experiments that the protein peptide medium is used to cultivate laccase bacteria show that, the best culture medium for cultivating Ochrobactrum sp.575and Ochrobactrum sp.531is the medium which content2ml protein peptide and0.5g glucose in100ml, and its pH is adjusted to6.5～7.0by citric acid. The germ solution will be applied to the copper mine tailings. The results by studying the influence of different amount protein peptide (Oml/kg,2ml/kg,5ml/kg,10ml/kg,20ml/kg,30ml/kg,40ml/kg,50ml/kg,60ml/kg,80ml/kg, the ordinal numbers are A, B1, B2, B3,C1, C2, C3, D1, D2and D3) to the available Cu content of the copper mine tailings show that the available Cu contents are different. The average available Cu content from A to D3is between38.69and102.73mg/kg, which reduced2～6times as much as the average available copper content of the original sample of copper mine tailings. After4months the Ochrobactrum sp.575bacteria liquid was applied to the processed copper mine tailings (50ml every pot except the matched group), the minimum available Cu contents of A～D3groups reached10.52mg/kg, which reduced43times as much as the original sample.By studying the micro ecological control effect as well as the plant growth regulating effect of the protein peptide on copper mine tailings, we found that the protein peptide affected significantly to how many microorganisms (bacteria, fungi and actinomycetes) the copper mine tailings contented, and it has increasing trend with the volume of protein peptide processed increase. After3month the protein peptide processed alone, the total microbial quantity of the group B1-D3is4.23×108～45.36×108per gram, which is1～11times as much as group A (4.12×108per gram). Moreover, the total microbial quantity of group B1-B3, C1～C3, D1～D3are respectively4.23×108～19.08×108per gram,14.30×108～45.36×108per gram and21.93×10～31.41×10per gram. The total microbial quantity of every group are respectively3.42×109～1.22×1010per gram,1.63×109～9.57×109per gram,1.26×108～8.01×108per gram and1.79×105～1.49×106per gram after the protein peptide processed7,8,13and17month. It shows that the total quantity of microorganisms is decreased with the extension of the time protein peptide processed. After12months the copper mine tailings processed by the protein peptide alone, the canola was planted in it. The canolas which have flower and seed and grow best are that planted in the copper mine tailings processed by the protein peptide (10ml/kg) adjusted to neutral by phosphoric acid, and the maximum height can reach66cm. But their seeds are not full. The other canolas are small and their heights are below10cm. It indicates that the copper mine tailings treated by the protein peptide (10ml/kg) adjusted to neutral by phosphoric acid is more suitable for canola to grow. After canola matured, the highest Cu ions contents of the aboveground and underground part canola were320.14mg/kg and1689.45mg/kg, and it proves that canola can obviously absorb Cu ions from the copper tailings. However, the tatol adsorption amount of Cu ions is few because the biomass of canola is little.We also studied how the five forms of copper (water soluble state, weak acid combination state, reduction state, oxidation state and residue state) contents of different processed copper mine tailings change with the extension of time. The results indicate, among group B1～D3, the change trend of the water soluble state copper content is increased first and then reduced, and the content are19.66～176.94mg/kg,27.57～79.78mg/kg and10.77～19.58mg/kg with3,9,15month. The minimum of the water soluble state copper content is10.77mg/kg, which is lower than the value of original sample11.62mg/kg. After processed15months, the weak acid combination state copper contents (59.73～105.51mg/kg) of groups B1-D3are reduced compared with the content of original sample (106.50mg/kg), which is about2times as much as the minimum value of groups B1～D3. The change trend of the reduction state copper content is increased with the protein peptide content of copper tail increase, and the minimum value is about0.3times to the original sample value (466.67mg/kg). The oxidation state copper content of groups B1-D3(124.32-195.31mg/kg) is1-2times as much as the original sample value (103.68mg/kg) after15months of treatment by protein peptide. The residue state copper contents of groups B1-D3(121.21-313.55mg/kg) are decreased compared with the original sample value (765.64mg/kg), which is about6times as much as the minimum value of the groups B1-D3. As a whole, the available Cu content of the copper mine tailings have significantly reduced with the synergy of protein peptide and microorganism.At last, we did the exploratory experiment that we used untreated copper mine tailings to plant the woody plants-----sumac. The results show that sumac grew well, and their stems height can grow5.2cm after planted six months. The Cu adsorption quantity of sumac roots is large and its Cu content can reach1004.19mg/kg. If the sumac continue grow, it may become a hyperaccumulator of copper.