Characteristic Analysis Of Heavy Metal Contents In Soil And Bamboo Shoots In Phyllostachys Praecox Stands Associated With Various Mulching Times

Total of 18 mixed soil samples from Phyllostachys praecox stands in a various mulching times were collected and analyzed by ICP-MS to investigate the present of 8 kinds of heavy metals in bamboo soils,bamboo shoots, mulching materials and fertilizer. The influence of mulching time on heavy metal contents was calculated by correlation analysis. Also enrichment factors, pollution index, target hazard quotient, and risk assessment were conducted to evaluate the risk of uptake bamboo shoots and being exposed to the environment, basing on which the safety guide could be made by government. Research findings are:1. Conditions of microwave digestion process of soil, bamboo shoots were confirmed, so were the analyze conditions of ICP-MS. The results were stable and reliable.2. Results showed that the concentration of total Cd in soil on 10 yr site was beyond the range of China Environmental Quality Standard values, and the concentration of Cd in bamboo shoots was very close to the limited value. The concentrations of Zn, Cu and Cd were out of the standard range in organic fertilizer. The concentrations of available heavy metals of Zn, Hg, and Cd climbed the fastest.3. Correlation analysis showed that total Zn, total Cu, total Hg, total Cd in soil,and all heavy metals except Ni and As were positively related to mulching year and content of OM, and were negative related to p H. Concentrations of all heavy metals in bamboo shoots were positively related to available concentrations of heavy metals in soil. Cluster analysis suggested that the growth of concentrations of Zn, Cu, Hg and Cd were mainly resulted from the cultivation management.4. Risk assessment showed that after 10 years of mulching, enrichment factors of Zn, Cu, Cd were up to lever â…¡. The risk of uptake bamboo shoots and being exposed to the environment was minimal.However the risk was increasing by time. Soil acidification of Phyllostachys praecox stands with time stimulated the activity of heavy metals that should be paid more attentions as well.