Biosorption Kinetics and Isotherm Studies of Cd(II) by Dried Enteromorpha compressa Macroalgae Cells from Aqueous Solutions     

Aida Sahmurova  Harun Türkmenler  Emine Elmaslar Özbaş 《洁净——土壤、空气、水》2010,38(10):936-941

For the first time ever, Enteromorpha compressa macroalgae (ECM), which is commonly found in Turkey, has been used as biosorbent by us. This study aims to investigate the biosorption of Cd²⁺ from aqueous solutions in a batch system by using an alga of ECM in different concentrations, pH levels, agitation rates (90–150 rpm), and contact periods. The maximum biosorption capacity of the ECM was found to be 9.50 mg/g at pH 6, Cd²⁺ initial concentration of 10 mg/L and agitation rate 150 rpm. Cadmium removal efficiency was about 95%. The experimental isotherm data were analyzed using the Langmuir and Freundlich equations. Isotherm parameters for both equations were determined and discussed. The stated biosorption mechanism is explained by the Freundlich isotherm (r² = 0.998) theory. Two simplified kinetic models including a pseudo‐first‐ and second‐order equation were selected to follow the biosorption process. Kinetic parameters; rate constants, equilibrium adsorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was shown that the biosorption of cadmium onto ECM could be described by the pseudo‐second‐order equation (r² > 0.99).  相似文献   

The barnacle Balanus amphitrite as a bioindicator for Cd: Development and application of a simulation model     

Eduardo Teixeira da Silva  David Klumpp  Michael Ridd 《Estuarine, Coastal and Shelf Science》2009

The efficacy of the barnacle Balanus amphitrite as a bioindicator for Cd in the environment was investigated through simulation exercises in an ecotoxicological simulation model based on field data. The study showed in general that B. amphitrite is a good bioindicator to record mean trends of the Cd bioavailability in the environment. The model correct reflected differences between high and low patterns of Cd concentrations in the barnacle in the field, but it did not accurately reflect short-term temporal variations. A model investigation pointed out three issues that must be taken into account when using B. amphitrite as bioindicator for Cd bioavailability in the environment: (1) variations in the mean weight of the sampled population may affect the barnacle's Cd concentration determination, specially if a size effect for the metal concentration in the organism is not detected; (2) a sampling effort approximately 5 times greater than that of usually applied in such studies would be required to detect an environmental change that caused a realistic increase in the main source of Cd to the barnacle; and (3) barnacle tissue better responds to long-term changes in the Cd level of its sources.  相似文献   

Effects of iron limitation on intracellular cadmium of cultured phytoplankton: Implications for surface dissolved cadmium to phosphate ratios     

Erin S. Lane  David M. Semeniuk  Robert F. Strzepek  Jay T. Cullen  Maria T. Maldonado   《Marine Chemistry》2009,115(3-4):155-162

This study compares intracellular Cd content (Cd:C) of cultured marine phytoplankton grown under various Fe levels, with estimated particulate Cd:P ratios derived from regression slopes of Cd versus PO₄³⁻ relationships from a global dataset. A 66-fold difference in Cd:C ratios was observed among the seven species grown under identical Fe concentrations, with oceanic diatoms having the highest Cd quotas and prymesiophytes the lowest. Interestingly, all species significantly increased their Cd:C ratios under Fe-limitation (on average 2-fold). The global data set also showed that the mean estimated Cd:P ratio of surface water particulates in HNLC (high nutrient low chlorophyll) regions were approximately 2-fold higher than non-HNLC regions. A sequence of events are proposed to explain high Cd:P ratios in HNLC waters. First, the seasonal relief from Fe-limitation in HNLC regions leads to blooms of large chain forming diatoms with high intrinsic Cd:P ratios. These large blooms may, in theory, deplete surface water CO₂ and Zn concentrations, which ultimately, would result in increased Cd uptake. Eventually these blooms will run out of Fe, which has been shown to further increase intercellular Cd via growth biodilution and increased Cd uptake through non-specific Fe(II) transporters. Ultimately, Fe-limited diatoms with enhanced Cd quotas will sink out of surface waters leading to pronounced regional differences in Cd:P ratios between HNLC and non-HNLC waters in the global ocean.  相似文献   

Metallothioneins and cytosolic metals in Neomysis integer exposed to cadmium at different salinities     

Erk M  Muyssen BT  Ghekiere A  Janssen CR 《Marine environmental research》2008,65(5):437-444

In the present study the induction of metallothioneins (MTs) and its relation to cytosolic metal concentrations (Zn, Cu and Cd) in the euryhaline crustacean Neomysis integer exposed to Cd at different salinities was studied. N. integer was exposed to the same free cadmium ion activity of 5.74 x 10(-9) mol l(-1) (i.e. 1/5 of the 96 h LC(50) value expressed as cadmium activity) in hypo-osmotic (5 psu), isosmotic (16 psu) and hyper-osmotic media (25 psu) for 7 days. In this way, the effect of salinity on cadmium speciation was eliminated and therefore the physiological effect of salinity on Cd accumulation and MT induction could be studied. The accumulation of cytosolic Cd in N. integer changed with salinity from 1.11+/-0.05 micromol l(-1) at 5 psu up to 1.43+/-0.17 micromol l(-1) at 25 psu. This could indicate that the physiological response of euryhaline estuarine invertebrates like N. integer to salinity changes can influence the rate of trace metal uptake from solution. While the salinity changes did not cause significant differences in cytosolic Zn concentrations (mean value of all tested salinities: 34.4+/-2.8 micromol l(-1)), an inverse relationship between salinity and cytosolic Cu concentration was observed. The highest concentration of 15.7+/-2.3 micromol Cul(-1) was determined at 5 psu and the lowest 10.9+/-1.4 micromol Cul(-1) at 25 psu. This could point to a possible relationship between the copper concentration and the hemocyanin metabolism in N. integer. This is the first time that differential pulse voltammetry method was applied to MT assays with N. integer. Although the exposure to Cd resulted in a higher Cd cytosolic concentration, no subsequent MT increase was detected. The significant positive correlation between MT levels and cytosolic Cu concentrations (Spearman correlation coefficient r(s)=0.356, p=0.009) implies a strong relationship between MT and Cu in N. integer.  相似文献   

Quantitative immunochemical evaluation of fish metallothionein upon exposure to cadmium   总被引：1，自引：0，他引：1  

Yudkovski Y  Rogowska-Wrzesinska A  Yankelevich I  Shefer E  Herut B  Tom M 《Marine environmental research》2008,65(5):427-436

  相似文献   

原子荧光法测试地质样品中的镉     

况云所 《贵州地质》2010,27(1):73-78

实验研究了以试样前处理掩蔽干扰物质,使用原子荧光光谱法测试地质样品中痕量重金属镉的分析,原子荧光测试镉的仪器条件,地质样品中对镉造成严重干扰物质的定性及掩蔽,测试方法的检出限和精密度试验、使用国家标准物质测试方法的准确度实验,结果令人满意。  相似文献   

重金属Pb和Cu对Cd在泥鳅（Misgurnus anguillicaudatus）组织器官蓄积的影响          下载免费PDF全文

唐建勋  程樟顺  张婕  徐玉花  邢承华 《海洋与湖沼》2011,42(2):262-265

采用静水生物测试方法,研究了Pb（0.5mg/L）和Cu（0.1mg/L）的相互作用对Cd（0.05mg/L）在泥鳅组织器官中蓄积的影响。结果表明,重金属离子相互作用对Cd在泥鳅组织器官中蓄积的影响与重金属的种类、数量、染毒时间及组织器官性质有关,Cd在泥鳅组织器官中的蓄积顺序为肝〉肾〉肌肉。研究发现,Cd在组织器官中...  相似文献   

Biosorption of Cadmium(II) Ions by Citrus Peels in a Packed Bed Column: Effect of Process Parameters and Comparison of Different Breakthrough Curve Models     

Abhijit Chatterjee  Silke Schiewer 《洁净——土壤、空气、水》2011,39(9):874-881

The efficiency of low cost citrus peels as biosorbents for removal of cadmium ions from aqueous solution was investigated in a fixed bed column, a process that could be applied to treat industrial wastewaters similar to commonly used ion exchange columns. Effluent concentration versus time profiles (i.e., breakthrough curves) were experimentally determined in a laboratory‐scale packed bed column for varying operational parameters such as flow rate (2, 9, and 15.5 mL/min), influent cadmium concentration (5, 10, and 15 mg/L), and bed height (24, 48, and 72 cm) at pH 5.5. Column operation was most efficient for empty bed contact times of at least 10 min, which were apparently necessary for mass transfer. While the sorption capacity was largely unaffected by operational variables, the Thomas (Th) rate constant increased with the flow rate, and slightly decreased with increasing column length. Three widely used semi‐mechanistic models (Th, Bohart–Adams, and Yoon–Nelson) were shown to be equivalent and the generalized model was compared with a two‐parameter empirical model (dose‐response). The latter was found to be able to better simulate the breakthrough curve in the region of breakthrough and saturation.  相似文献   

Baseline heavy metals and metalloid values in blood of loggerhead turtles (Caretta caretta) from Baja California Sur, Mexico     

Ley-Quiñónez C  Zavala-Norzagaray AA  Espinosa-Carreón TL  Peckham H  Marquez-Herrera C  Campos-Villegas L  Aguirre AA 《Marine pollution bulletin》2011,62(9):1979-1983

Environmental pollution due to heavy metals is having an increased impact on marine wildlife accentuated by anthropogenic changes in the planet including overfishing, agricultural runoff and marine emerging infectious diseases. Sea turtles are considered sentinels of ecological health in marine ecosystems. The objective of this study was to determine baseline concentrations of zinc, cadmium, copper, nickel, selenium, manganese, mercury and lead in blood of 22 clinically healthy, loggerhead turtles (Caretta caretta), captured for several reasons in Puerto López Mateos, Baja California Sur, Mexico. Zinc was the most prevalent metal in blood (41.89 μg g⁻¹), followed by Selenium (10.92 μg g⁻¹). The mean concentration of toxic metal Cadmium was 6.12 μg g⁻¹ and 1.01 μg g⁻¹ respectively. Mean concentrations of metals followed this pattern: Zn > Se > Ni > Cu > Mn > Cd > Pb and Hg. We can conclude that blood is an excellent tissue to measure in relatively non-invasive way baseline values of heavy metals in Caretta caretta.  相似文献   

镉诱导长江华溪蟹(Sinopotamon yangtsekiense)心肌细胞凋亡的研究   总被引：1，自引：0，他引：1  

雷雯雯  徐团  王兰 《海洋与湖沼》2012,43(2):299-305

采用急性毒性实验方法,研究了不同浓度氯化镉(0、7.25、14.50、29.00、58.00和116.00mg/L)处理不同时间(1d、3d、5d和7d)对长江华溪蟹心肌细胞凋亡的影响。结果表明,低浓度组及染毒时间较短时镉对心肌的影响不明显,但随着染毒浓度的增加和时间的延长,心肌出现空泡变性、玻璃样变性、炎细胞浸润等病理现象,在染毒7d虽然观察到疑似的凋亡细胞,但凋亡率较低;荧光显微镜未观察到心肌细胞典型的凋亡细胞核形态学变化;琼脂糖凝胶电泳图谱未出现凋亡细胞所特有的梯状条带;流式细胞术检测结果显示镉处理组细胞凋亡率增加,但与对照组相比,无统计学意义(P>0.05);Caspase-3活性也没有显著性变化(P>0.05)。因此,在本实验所选取的浓度和时间范围内,镉未诱导长江华溪蟹心肌细胞发生细胞凋亡,这与本课题组前期研究中观察到的肝胰腺、精巢组织在染毒2d、7d发生细胞凋亡的情况明显不同,这可能与心脏组织的特殊性、不同组织对镉的积累量不同有关。  相似文献