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313.
分别用混合酸湿法消解和微波消解两种方法处理鱼虾样品,用原子吸收法测定样品中铜、锌、铅、镉、铬的含量.结果表明微波消解相对标准偏差均在4.0%以下,加标回收率在95.6%~112%之间.湿法消解相对标准偏差在0.3%~5.6%之间,加标回收率在88.9%~115%之间.微波消解比湿法消解的精密度、准确度高,且微波消解操作安全简便,耗时短,适用于样品数量多的情况.混合酸湿法消解操作复杂,耗时长,由于使用了在高温下易爆的高氯酸,又容易发生"炭化"现象,安全性差,在样品数量少的情况下可用此法. 相似文献
314.
渤海湾及其邻近河口区重金属环境背景值和污染历史 总被引:3,自引:1,他引:3
用长箱式静压取样器和挖探槽采集了渤海湾及毗邻河口区11个沉积物岩芯样.结合~(210)Pb测年、沉积物重金属分析,测定了沉积速率、重金属环境背景值及渤海湾4个时期(1983,1974,1964,1933年)Cu、Pb、Zn、Cd的人为增量部分.研究表明,测区沉积速率范围为1.8—44.2mm/a.高速沉积区位于蓟运河口、海河口及废黄河口;低速率区位于湾中部.Cu、Pb、Zn、Cd环境背景值分别为24.80—25.63mg/L、15.96—16.55mg/L、72.58—74.61mg/L和0.10—0.12mg/L.经重金属沉积通量计算,人为排放最大负荷量分别为:Cu,73.75t(1964年);Pb,64.57t(1974年);Zn,249.32t(1983年);Cd,5.77t(1983年). 相似文献
315.
苎麻(B.nivea(L).Gaud)对土壤Cd的吸收及其生物净化效应 总被引:7,自引:0,他引:7
通过4年微区定位试验,研究了苎麻对土壤Cd的吸收及其净化效应。结果发现,苎麻地上部分年生物产量(YB)与土壤Cd含量)(Sc)的关系可用对数函数模型LogYB=3.3874-0.0753(LogSc)^2描述; 相似文献
316.
The pollution is increasing in the environment by different kinds of human activities, which results in the accumulation of heavy metals including cadmium in the soil and water and it causes different types of problems to living beings. As the plants are utilized by human being as food and medicine, therefore, it is mandatory to see the effect of metals on plants. In this context, efforts have been made to observe the effect of different concentration of Cadmium (Cd) on Phyllanthus amarus Schum. and Thonn., because Cd is the widespread metal and the plants response to low and high level of exposure is a complex phenomenon. P. amarus is mostly grown as weed in agricultural and waste lands. It is a reputed plant used in Indian indigenous systems of medicine with hepatoprotective, diuretic, stomachic properties and is recently being used for the treatment of hepatitis B. The study revealed that Cd causes significant decrease in fresh and dry weight, length of root and shoot, protein, chlorophyll, carotenoids and sugar and increase in starch content. It is interesting to note that the therapeutically active compounds—phyllanthin and hypophyllanthin, enhanced at certain levels of Cd due to abiotic stress. Besides, the ultramorpholical changes were also observed in stomatal opening and wax deposition on both the surfaces of leaves. 相似文献
317.
Acute toxicity of cadmium to fish Labeo rohita and copepod Diaptomus forbesi pre-exposed to CaO and KMnO4 总被引:5,自引:0,他引:5
96-h LC50 values of cadmium (Cd) to fish Labeo rohita and the copepod Diaptomus forbesi, determined by static bioassays, were, respectively, 89.5 and 10.2 mg/l. LC50 values increased significantly when fish pre-exposed to 100–350 mg/l CaO or 0.5–1.5 mg/l KMnO4 for 4 d and the copepod to 20–70 mg/l CaO or 0.25–1.0 mg/l KMnO4 for same period. The LC50 values also increased when the pre-exposure period of CaO was increased to 12 d at concentration 100 mg/l for fish and 20 mg/l for copepod. All fish died when pre-exposed to 1.5 mg/l KMnO4 for 8 d. But LC50 values of Cd to copepod increased when pre-exposure period of 0.5 mg/l KMnO4 was increased from 4 to 8 d. 相似文献
318.
Clay and organic matter are considered as important parameters influencing bioavailability and ecotoxicity of metals in soils. As there exists a large variation in the type of clay and organic matter in field soils, the quantity of these variables alone may not be good indicators of metal bioavailability. To test this hypothesis, toxicity experiments with the potworm Enchytraeus albidus were conducted in artificial soils with three types of clay and seven types of organic matter, while the soil pH was kept constant. The 14d LC50 of zinc and cadmium varied from 83.0 to 1140 mg Zn/kg D.W. and from 55.2 to 704 mg Cd/kg D.W., respectively, depending on the type of clay and organic matter that were used. Simultaneous measurements of the cation exchange capacity showed that this soil parameter is a better indicator of the bioavailability as it takes into account the type of clay and organic matter as well as other adsorption phases such as metal oxyhydroxides. 相似文献
319.
Welt M Mielke HW Gonzales C Cooper KM Batiste CG Cresswell LH Mielke PW 《Environmental geochemistry and health》2003,25(4):387-396
This research examines the pattern of sediment contamination of an urban bayou of New Orleans (formerly a natural waterway) and the potential for human exposure from consumption of fish caught in the bayou. Sediments and soils of Bayou Saint John were evaluated for lead (Pb), zinc (Zn), and cadmium (Cd). Sediment cores were collected at bridges (n = 130) and sites between the bridges (n = 303) of the bayou. In addition, soil samples (n = 66) were collected along the banks of the bayou. Sediments below the bridges contain significantly more (p-value approximately 10(-7)) Pb and Zn (medians of 241 and 230 mg kg(-1), respectively) than bayou sediments located between bridges (medians of 64 and 77 mg kg(-1), respectively). Sediments below bridges of the upper reaches of the bayou contain significantly larger amounts of metals (p < 10(-14) for Pb and Zn and p approximately 10(-8) for Cd) (medians of 329, 383 and 1.5, respectively) than sediments below bridges in the lower reaches of the bayou (medians of 43, 31 and 0.5 for Pb, Zn and Cd, respectively). Likewise, medians for sediments located between bridges contain significantly (p < 10(-14)) higher quantities of Pb, Zn and Cd (170, 203 and 1.8 mg kg(-1), respectively) in the upper bayou than Pb, Zn, and Cd (48, 32, and 0.8 mg kg(-1), respectively) in the lower reaches of the bayou. The potential risk for human exposure may be magnified by the fact that fishing generally occurs from the numerous bridges that cross the bayou. Poor and minority people do most of the fishing. Most people (87%) indicated they ate fish they caught from the Bayou. 相似文献
320.
The effects of single Cd~(2+)and Pb~(2+),and combined Cd~(2+)and Pb~(2+)on dehydrogenase activity and polysaccharide content of the substrate biofilms in the integrated vertical-flow constructed wetland(IVCW)were studied.Dehydrogenase activities decreased linearly with the increasing concentrations of Cd~(2+)and Pb~(2+)at different times(6,24,72,and 120 h).The activities at both 6 and 24 h were significantly higher than that at 72 and 120 h in the case of single and combined treatments.The single Cd~(2+)... 相似文献