Comparison of Absorption Capacity of Different Flue-cured Tobacco Cultivars for Six Kinds of Heavy Metals

[Objective] This study aimed to analyze the differences in absorption capacity of different flue-cured tobacco cultivars for chromium （Cr）, arsenic （As）, cadmium （Cd）, lead （Pb）, mercury （Hg） and copper （Cu）. [Method] With 4 flue-cured tobacco cultivars as the experimental materials, their absorption capacity for 6 kinds of heavy metals was compared by pot experiment. [Result] There were great differences in absorption capacity of different flue-cured tobacco cultivars for the six kinds of heavy metals. According to the absorption capacity of different flue-cured tobacco cultivars for the heavy metals, the six heavy metals could be classified into three categories. The first category included only Cd with average enrichment coefficient of 8.564; the second category included Hg with average enrichment coefficient of 0.753; and the third category included Cr, As, Pb and Cu with average enrichment coefficients below or equivalent to 0.114. [Conclusion] The absorption capacity of different flue-cured tobacco cultivars for heavy metals was grasped by this study, thereby providing reference data for screening of high-yielding and high-quality flue-cured tobacco cultivars.

Study on Pollution Sources and Degree of Sediments in Northwestern Rivers Flowing into Taihu Lake

[ Objective] The study aimed to analyze the pollution sources and degree of sediments in seven northwestern rivers flowing into Taihu Lake. [ Method] Based on a survey for the sediments in seven rivers flowing into the northwestern Taihu Lake from 2005 to 2007, the molar ratio of major elements was used to determine the main pollution sources of each channel, and the heavy metal pollution of sediments in the seven rivers was assessed by enrichment coefficient. [ Result] Mashan River, Liangxi River and Xiwan River mainly suffered municipal pollution; Zhihu Port and Caoqiao River were chiefly subjected to industrial pollution; Dapu River and Wujin River were mainly affected by agricultural pollution. In addition, the rivers mainly suffering industrial pollution had the most serious heavy metal pollution, followed by the rivers mainly undergoing agricultural pollu- tion, while the rivers chiefly affected by municipal pollution had the minimum pollution. [ Conclusion] The research could provide scientific references for the control of river pollution by heavy metals along Taihu Lake basin.

Soil Heavy Metal Pollution and Bioavailability in Baoshantao Mining Area, China

In areas with a high geological background of heavy metals,some edible plants could pose a serious threat to human health.In order to find effective methods to remove heavy metals or reduce their harm,this study investigated the enrichment conditions of five soil heavy metals,Cd,Pb,Cu,Zn and Cr,in four edible plants in a mining area,Baoshantao,in eastern China that has a high geological background of metals,and two groups of experiments were designed to investigate the effects of passivators on their enrichment.The results showed that the soil heavy metal content in the study area has a certain degree of spatial variability.The five heavy metal element contaminants in the soil are in the order of Cd>Cu>Zn>Pb>Cr.The enrichment coefficients and the transfer coefficients of different edible plants were different for the different heavy metals.The two groups of passivators showed better passivating effects with an increase in passivating agent dosage.The smaller the enrichment coefficient of water spinach,the lower the bioavailability.The results of this study can provide a scientific basis for the restoration of soil heavy metal pollution and the safe use of land in areas with a high geological background of heavy metals.

Relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan,China

This paper studied the relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan,China.50 herbaceous plant samples of 9 plant species from 4 families and 50 soil samples were collected and then ana1yzed for the tota1 concentrations of Pb,Cd,and Zn.The results showed that the average concentrations of Pb,Cd,and Zn in soil samples were 3772.83,168.81,and 5385.65 mg/kg,respectively.The average concentrations of Pb,Cd,and Zn were 395.68,28.14,and 1664.20 mg/kg in the shoots,and 924.12,57.25,and 1778.75 mg/kg in the roots,respectively.Heterospecific plants at the same site and conspecific plants at various sites had different average levels of Pb,Cd,and Zn,both in the shoots and the roots.Enrichment coefficients of Pb,Cd,and Zn were greater than 1 in 2,3,and 9 herbaceous plant samples,respectively.Translocation factors of Pb,Cd,and Zn were greater than 1 in 10,17,and 25 herbaceous plant samples,respectively.In all 50 samples,the concentrations of Pb,Cd,and Zn between the shoots and the roots,the shoots,and the soils,and the roots and the soils had significant positive relationships.