The Effects Of Zinc-lead Pollution On The Diversity Of Soil Microorganisms

Zinc-lead mine resources are very rich in the southwest of china, although the development of mineral resources for economic development in our country has made tremendous contributions, however, mining was a large number of soil damage or degradation of heavy metals pollution, causing soil ecosystem damage seriously, the resulting soil heavy metals pollution has now become the most serious environmental problems. In the environment, few contamination of heavy metals is solitary, which are combined in most cases.This research collected soil polluted by heavy metals, studied the influence of combined pollution of heavy metals to biomass, structure, and activities of soil microorganisms in natural state. This research was focused on effects of soil microbial diversity by combined heavy metals contamination, which was supposed to support the ecological remediation of contaminated by heavy metals. The conclusions are as following:1. Zn, Pb, Cd, Cu content of zinc-lead mine in the soil was significantly higher than that of non-mining, and their basic physical and chemical properties were corresponding varied.2. From the test result, we can find that combined pollution of heavy metals influence on the growth quantity of the chiefly kind of soil microorganisms is main restrictive. The microbial diversity index of eight sampling areas was inconsistent, non-mining diversity index of soil was greatest, the higher heavy metals in regions, the smaller the diversity index. Available dose of heavy metals in soils and the number of microorganisms were to some extent the trend of negative correlation. 3. Most polluted and less polluted regions of zinc-lead mine in their respective species composition of bacteria is quite similar. Bacillus, micrococcaceae and corynebacterium are the highest frequency of occurrence of mine soil, that they have good patience with zinc-lead mine. Between mine soil and non-mining soil, and between different pollution levels of mining, the composition of actinomyce is different larger than that bacteria and fungi, so they are more sensitive to zinc-lead mine. Between mine soil and non-mining soil, the composition of advantages fungi species is different, and the advantages fungi species mine soil have a similar composition. Trichoderma, aspergillus, fusarium are the highest frequency of occurrence of mine soil, that they have good patience with zinc-lead mine.4. The accumulation of the heavy metals has caused biological activity abnormal in the soil, life activation suppressed, and microbial carbon and cellulose decomposition reduced. Thus it causes of soil fertility subsided. In order to maintain its normal life activity in adverse circumstance, the microorganisms can strengthen metabolizing intensity. Available Zn, Pb and microbial biomass carbon, cellulose decomposition was negatively correlated with soil respiration based on a significant positive correlation.5. Zn, Pb, Cd, Cu stress on different soil enzyme activities there are certain differences, soil urease, alkaline phosphatase, polyphenol oxidase on the zinc-lead mine were more sensitive, and invertase, catalase were not obvious by inhibition. Activities of urease, alkaline phosphatase, polyphenol oxidase can be effective biochemical evaluation indexes to indicate pollution degree of heavy metals.