Metal bioaccumulation in plant leaves from an industrious area and the Botanical Garden in Beijing

The concentrations of Fe, Mn, AI, Zn, Pb, Ni, Cr, and As were measured in soils and leaves from 21 plant species growing on hills near the Beijing Steel Factory(BSF) and 17 plant species in the Beijing Botanical Garden(BBG). The results showed that soils from BSF were Zn contaminated according to the threshold of natural background of China. There was a metal contamination of the soils by Ni,and Cr in BSF comparing with those in BBG. The comparison between concentrations of metals in leaves from both sites indicated that, in general, accumulation of metals in the leaves of the same species was significantly different between the two sites. Even within the same locality each species accumulation of metals was significantly variable. The study aimed to screen landscape plants for the capacity to clean-up toxic metals in soils, and developed an overall metal accumulation index(MAI) for leaves and then categorized the MAI that can be applied broadly in the selection of species in polluted areas. To do this, the spectrum of MAI values were divided into four classes: strongly accumulated(SA or grade I), moderately accumulated(MA or grade II), intermediately accumulated( IA or grade III), and weakly accumulated(WA or grade IV). The results showed that elemental association between Fe, AI, Ni, and As was generally highly correlated with each other in the sampling sites. This may suggest their common biochemical characteristics. Generally, those species containing strong and moderate accumulation in both sites are considered including Vitex negundo, Broussonetia papyrifera, Ulmus pumila, and Rubia cordifolia. At BSF and other industrial sites with a similar ecosystem, strong and moderate accumulation species include Sophora japonica, Ampelopsis aconitifolia var. glabra, Platycladus orientalis, Wikstroemia chamaedaphne, Cleistogenes squarrosa, Grewia biloba, and in BBG, in addition Setaria viddis, Cotinus coggygria, Lespedeza flodbunda, Rhamnus parvifolia, Lespedeza tomentosa.     

窗外有绿

清晨．拉开窗帘．我开始拥有敞亮、绿和风景。天湛蓝着、清新着、倾斜着．很适合飞翔．比如心情、小鸟抑或飞行器。此时．小鸟从几个方向衔来曲线,在常青树的枝头啁啾着、嬉戏着,露珠点缀着湿润,绿便更加养眼。我的目光炯炯地去了．在绿意上跳荡。树,有意把绿集中到树叶。树叶是风的尾巴,摇曳着和谐的声音。阳光从绿的空隙中跳出来,亮了眼界。有绿,真好。     

上海市公园绿地树叶对大气重金属污染的磁学响应

为探究城市公园绿地树叶对大气重金属污染的磁学响应,按照上海市年均主导风设置纵横两个采样断面,采集城郊区公园绿地中广泛分布的香樟树叶,进行岩石磁学和重金属元素分析.结果表明,样品磁性矿物以亚铁磁性矿物为主导,磁性颗粒物的含量和粒径由典型工业区沿冬季风方向逐级递减.对叶片进行超声清洗后磁化率下降63%~90%,即样品的磁性特征主要取决于叶表附尘.树叶重金属元素Fe、Mn、Zn、Cu、Cr、V、Pb含量与磁参数显著相关(0.442≤R≤0.799,P0.05),说明城市公园绿地树叶磁参数可以作为大气重金属污染的替代指标.运用多元统计分析方法表明,研究区树叶磁性矿物及重金属含量主要受工业活动和交通道路污染的复合影响.     

榕树叶对铀吸附的研究

为探讨榕树叶对铀的吸附特性 ,考察 pH、吸附时间、含重金属溶液浓度对吸附能力的影响 ,绘制出吸附等温线 ,并求出Langmuir曲线和Freundlich曲线相应方程 .结果表明 :榕树叶在pH =3 ,吸附时间t=2 0min时吸附铀的能力最高 .重金属离子浓度越高 ,榕树叶的吸附量越高。     

上海市吴泾工业区周边土壤和树叶中汞污染调查

对上海市吴泾工业区热电厂、氯碱厂、焦化厂周边土壤和树叶中汞及甲基汞的含量作了调查.结果显示,三个厂区周边土壤中总汞含量在几十到几百ng·g-1,而甲基汞的含量则很低.树叶中总汞浓度约为十几到几十ng·g-1.三个厂中以热电厂周边土壤和树叶中的总汞含量最高,氯碱厂甲基汞含量比较大.三个厂区周边土壤和植物部分受到了汞污染.     

希望是不幸者的第二灵魂

小时候曾经听过一个广播剧:一个生命垂危的小女孩,望着窗外渐渐枯落的树叶,也同时数着自己的生命,如果树上的叶子落尽,自己的生命也就走到了尽头。隔壁邻居是一位画家,他为了     

生物对铀的吸附研究

研究榕树叶、啤酒酵母菌、大肠杆菌在不同pH值、吸附时间t和不同初始浓度的铀下吸附的规律,进行了实验室吸附模拟实验,绘制出吸附等温线,并由吸附等温线Freundlich曲线求出相应参数。初步对榕树叶、啤酒酵母菌、大肠杆菌对铀的吸附能力进行评价:大肠杆菌对铀酰离子吸附强度强于啤酒酵母菌和榕树叶的吸附强度;而榕树叶的吸附强度优于啤酒酵母菌铀酰离子的吸附强度。