Distribution Characteristics and Ecological Risk Assessment of Total Mercury in Phyllostachys Pubescens in Zhejiang Province
As an important and excellent bamboo species in Zhejiang,Phyllostachys pubescens accounts for 87.75％of the total bamboo forest area.Studying the total mercury distribution characteristics of bamboo forests is of great significance to further understand its im-pact on the biogeochemical cycle process.In this paper,fresh and fallen bamboo leaves,as well as soil samples from 9 control forests less affected by anthropogenic mercury emission sources and 12 phyllostachys pubescens forests close to coal-fired power plants in Zhe-jiang Province were sampled and analyzed for total mercury concentrations to explore the effects of anthropogenic mercury emission sources and altitude on the distribution of total mercury in phyllostachys pubescens forests.In addition,the mercury risk of bamboo for-ests soil was evaluated using potential ecological risk factors.The results show that Phyllostachys pubescens forest can absorb atmospher-ic mercury through leave assimilation,and finally accumulate mercury in soil through decomposition of fallen leaves.The order of mean total mercury concentration in Phyllostachys pubescens forest system is fresh leaves(88.6±49.0 ng/g)＜fallen leaves(139.9±71.6 ng/g)＜soil(216.4±130.3 ng/g),and there is a positive correlation between mercury concentrations in fresh leaves and deciduous leaves(R2=0.57),deciduous leaves and soil(R2=0.81).Atmospheric mercury emitted by coal-fired power plants will not only di-rectly lead to large mercury deposition to the surrounding phyllobamboo forests,but also will promote the absorption of atmospheric mer-cury to fresh leaves.The total mercury concentration of all samples in the bamboo forest closed to power plant is correspondingly higher than that in the control forest,and the leaves and soil samples in the former forest are significantly higher than that in the control forest(P＜0.05).The total mercury concentration in fresh leaves increased with the altitude,but there was no significant correlation between the total mercury concentration in fallen leaf and soil.There are strong potential ecological risks of soil mercury in phyllobamboo forests around thermal power plants.
atmospheric mercuryphyllobamboo forestcoal-fired power plantpotential ecological risk
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