Proportion Of Cadmium Research Articles

Growth temperature-dependent properties of electrodeposited CdSe thin films for optoelectronic application

Cadmium selenide (CdSe) thin films were synthesized using a two-electrode electrodeposition technique in potentiostatic mode. The solution matrix contains 0.3 M Cd(NO3)2.4H2O and 0.03 M SeO2 on conductive glass substrates/fluorine-doped tin oxide (FTO). The electrodeposited CdSe thin films were examined at various growth temperatures of 55, 65, and 85 °C, both as-deposited (AD) and annealed (HT) samples. A polycrystalline cubic structure of the prepared CdSe thin films was identified using x-ray powder diffraction. The energy bandgap of films was found to vary with deposition temperature and was recorded as 1.85, 2.00, and 2.13 eV for AD and 1.86, 2.16 and 2.70 eV for HT samples deposited at 55, 65, and 85 °C, respectively. Surface morphology images show that the form and grain size varied with growth temperature. The average surface roughness varied with deposition temperature. The elemental analysis confirmed that the proportion of cadmium (Cd) increased while that of Se decreased as the deposition temperature increased for both AD and HT films. The film that was deposited at low temperature (55 °C) can be as a layer for absorption. Conversely, however the film deposited at a high growth temperature (85 °C) is capable of serving as a buffer layer in thin-film solar cell technology.

Toxic and carcinogenic constituents of jewelry in the Indian retail market determined using x‐ray fluorescence

The elemental composition of about 60 items of precious and non‐precious jewelry in the Indian retail market has been explored through x‐ray fluorescence (XRF) measurements using silicon drift and high‐purity germanium detectors. The proportions of various elements have been established through the use of Gaussian fitting and background subtraction routines, along with corrections for photopeak detection efficiencies at different energies. Tabulated XRF yields were accounted for in the determination of proportions however matrix correction and absorption enhancement effects, if present, could not be included. The non‐destructive characterization and quantification allowed by x‐ray spectrometric methods indicate the presence of significant amounts of toxic bromine and antimony in fashion jewelry. A disturbing trend observed in many items of non‐precious, metal imitation jewelry is that carcinogenic cadmium is the predominant constituent (around 80% w/w) which poses a significant health hazard for a large section of the population. The proportion of cadmium is found to be far greater than the minor fractions reported earlier. It has been determined that cadmium continues to be added to precious jewelry, albeit in smaller amounts, though its use is restricted by existing regulations. This pan‐Indian study underscores the urgent necessity to inspect and regulate, particularly the metal imitation and fashion jewelry business, in order to mitigate the harmful effects of some of the constituent elements on human health and the environment.

Toxicological approaches for the quantitative inhalation risk assessment of toxic metals from tobacco smoke: application on the deterministic and probabilistic inhalation risk assessment of cadmium for Austrian smokers

Objective The objective of this study was the assessment of risks from inhalation exposure of Austrian smokers to cadmium through established toxicological approaches with emphasis on the exposure assessment component, which is challenging regarding the actual amount of metal that is inhaled and the simulation of the smoking pattern. Materials and methods Exposure assessment comprised an estimation of the proportion of cadmium inhaled through smoking and actual occurrence data in tobacco products and survey smoking habits, which were integrated in alternative scenarios through a deterministic and a probabilistic Monte Carlo simulation method. Risks were characterized through the comparison of the exposure with health-based guidance values, as well as through the assessment of the excess lifetime cancer risk (ELCR), the non-cancer hazard quotient (NCHQ), and the margin of exposure (MOE). The strengths, the uncertainties, and the limitations of the different methodologies were discussed. Results and discussion Upper exposures are close or exceed the Permitted Daily Exposure. Respiratory ELCRs are unacceptable compared to the benchmark range of 1.0E–06 to 1.0E–04. Renal and respiratory NCHQs exceed the target value of 1.0 by 3- to 17-fold. MOEs are not protective enough for cancer and non-cancer effects. The amount of cadmium that reaches the lung is a key source of uncertainty. Conclusion Probabilistic estimates provide a refined capture of the actual inhalation exposure. Risk estimates and gender and age profiles are alarming, especially for young smokers. Application of toxicological approaches, combined with realistic assessment of the inhalation exposure levels, can support risk communication and management.

Effects of zinc on the accumulation and subcellular distribution of cadmium in the bay scallop, Argopecten irradias

PDF HTML阅读 XML下载 导出引用 引用提醒 锌对海湾扇贝中镉累积和亚细胞分布的影响 DOI: 作者: 作者单位: 1. 南京农业大学 无锡渔业学院, 江苏 无锡 214081;2. 中国水产科学研究院 黄海水产研究所, 农业部水产品质量安全检测与评价重点实验室, 山东 青岛 266071 作者简介: 翟明丽(1991-),女,硕士研究生,研究方向为水产品安全与质量控制.E-mail:1548152661@qq.com 通讯作者: 中图分类号: S968 基金项目: 国家自然科学基金项目（41206101）. Effects of zinc on the accumulation and subcellular distribution of cadmium in the bay scallop, Argopecten irradias Author: Affiliation: 1. Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China;2. Key Laboratory of Testing and Evaluation for Aquatic Product Safety and Quality, Ministry of Agriculture;Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用室内模拟混合暴露方式，研究了在镉（Cd）质量浓度一定（0.05 mg/L）的条件下，添加不同质量浓度（0 mg/L、0.1 mg/L、0.5 mg/L、1 mg/L）的锌（Zn）对海湾扇贝整体、组织及亚细胞水平Cd累积和分布的影响。结果表明，Zn能显著抑制扇贝全贝对Cd的富集，并且这种抑制作用随暴露时间的延长和Zn浓度的升高而增强。在扇贝不同组织中Zn对Cd的富集均具有抑制作用，其中以鳃最为明显。在亚细胞水平，扇贝各组织累积的Cd主要分布在类金属硫蛋白（MTLP）和细胞碎片（CD）组分。在内脏各亚细胞组分中，Zn对Cd的抑制作用显著，且Zn的加入使CD中的Cd百分比从32%下降到21%~27%，而MTLP中的Cd百分比从57%增加到59%~67%。鳃组织中Zn对Cd百分比的影响更加明显，CD中Cd百分比从36%下降到14%~17%，MTLP中Cd百分比从59%增加到76%~79%；而性腺中MTLP和细胞器（ORG）组分中Cd百分比受Zn浓度影响较为明显，随着Zn浓度的升高，MTLP中Cd百分比下降，而ORG中Cd百分比升高；肌肉组织中Cd含量及百分比分布在亚细胞水平没有明显规律。 Abstract:Cadmium is among the most toxic metals in the aquatic environment. Cadmium has unknown biological role and exhibits high toxicity if allowed to accumulate in metabolically-active sites. Many bivalves accumulate high concentrations of cadmium in tissues and organs, particularly scallops, which have a high tolerance to cadmium and accumulate large quantities from the water. Zinc and cadmium often coexist in the aquatic environment and often demonstrate the substitution effect because of their similar chemical properties. Most previous studies have focused on absorption, accumulation, transport, distribution, and detoxification mechanisms in scallops under a single cadmium exposure, but results from mixed-exposure experiments are relatively rare, particularly the effects of zinc exposure on the accumulation and distribution of cadmium in scallop tissues. Because of the potential interaction between essential and non-essential metals, the present study was conducted to investigate the effects of accumulation and distribution of cadmium in bay scallops during short-term exposure to cadmium and zinc. The accumulation and distribution characteristics of cadmium at the whole body, tissue, and subcellular levels of bay scallops, , exposed to mixed metals of Zn and Cd were investigated under laboratory conditions. The results showed that exposure to different zinc concentrations inhibited bioaccumulation and distribution of cadmium in bay scallops and was time-and concentration-dependent. Bay scallops concentrated cadmium in all soft tissues, and cadmium content increased over the 7-day exposure. The inhibitory effect of zinc was enhanced as zinc concentration was increased. Cadmium concentrations in different tissues after exposure to the two metals were in the order of:viscera > gill > gonad > muscle, and inhibtory effect by zinc occurred in all tissues, particularly in the gill. Subcellular metal partitioning in bivalves has received increasing attention as it provides valuable information on metal toxicity and bioavailability. Here, subcellular cadmium content was examined following differential centrifugation, which divided the tissues into five subcellular fractions, including metallothionein-like proteins (MTLP), cellular debris (CD), metal-rich granules (MRG), organelles (ORG), and heat-sensitive proteins (HSP). The MTLP fraction was the predominant cadmium-binding compartment, suggesting that MTLP plays a key role detoxifying metals in bay scallops. The CD fraction contained the second largest cadmium fraction, whereas the CD fraction mainly contained tissue fragments and cell membranes. We speculate that the inhibitory effect by zinc on cadmium demonstrates competition between Zn2+ and Cd2+ to bind cell membrane sites. MRG and HSP only played a minor role in cadmium binding. Cadmium content in the metal-sensitive HSP fraction was lower than that in the other subcellular fractions, which may be the reason why scallops have high tolerance to cadmium. Inhibition occurred in all subcellular fractions of the viscera, and the proportion of cadmium in the CD fraction decreased, whereas that in the MTLP fraction increased as zinc was added. Zinc had an antagonistic and protective action on the uptake and toxic effects of cadmium, probably because zinc induces synthesis of MT, which detoxifies cadmium by binding. A similar effect was observed in the gill. However, the percentages of cadmium in the MTLP and ORG fractions of the gonad were affected by zinc concentration. The proportion of cadmium in the MTLP fraction decreased as zinc concentration was increased, whereas the proportion of cadmium in the ORG fraction increased. Cadmium content in the subcellular muscle distribution was relatively low. These results provide insight into the toxic effects of cadmium on bay scallops under mixed-metal exposure, but the mechanisms require further study. 参考文献 相似文献 引证文献

A novel quinternary alloy (Cu2Zn1−xCdxSnS4) nanostructured sensor for biomedical diagnosis

A new quinternary alloy (Cu2Zn1−xCdxSnS4) nanostructure with different proportions of cadmium (Cd) was synthesised using spin coating technique on oxidized silicon (100) substrate and analysed by x-ray diffraction (XRD) and photoluminescence (PL). The XRD peaks were shifted towards the lower angle side with increasing Cd concentrations. A shift of PL band gap from 1.79 eV (x = 0) to 1.69 eV (x = 1) was observed. We attributed this phenomenon to the phase transition from kesterite to stannite phase in the series of Cu2Zn1−xCdxSnS4 (0 ≤ x ≤ 1) quinternary alloy nanostructures. Further, the generated novel structure was found to be more suitable for biomedical diagnosis, as evidenced by dengue serotype-2 detection with higher specificity. The biosensor shown with quinternary alloy nanostructure could attain the sensitivity to 100 fM and able to discriminate specific DNA from dengue against single and triple mis-match sequences. The biosensor demonstrated here with a novel Cu2Zn1−xCdxSnS4 quinternary alloy nanostructure opens the way for developing high-performance biosensors.

Interaction and fractionation of added cadmium in some typical soils of the Danubian Lowland

This study was conducted to investigate the effect of time on cadmium (109Cd) availability in four typical soils of the Danubian Lowland through the modified Tessier’s sequential extraction procedure as well as its short-term sorption in the bulk soils and their two grain-size fractions. Results of the fractionation study showed that there were significant changes in the proportional distribution of cadmium in all studied soils during 180 days of incubation with spiked cadmium. Generally, the proportions of cadmium associated with the most weakly bound fractions (water soluble and exchangeable) tended to decrease with corresponding increases in the residual fraction during the incubation. The extent of cadmium sorption in all studied soils was high, exceeding 95% of the spiked amount after 60 min of incubation, likely due to slightly alkaline character of the soils. The finding that soil particles less than 10 μm sorbed up to 51% of the spiked cadmium in soils is of great importance since they could play a role in colloid-facilitated transport of cadmium through preferential pathways, as previously observed in the region. Addition of 1 M ammonium nitrate into the soil solution generally decreased cadmium sorption in all four soils. The lowest extractabilities of Cd were obtained using 1 M ammonium nitrate as a single extractant, whereas 0.025 M ammonium ethylenediaminetetraacetate solution extracted the highest proportions of cadmium from the studied soils.

Cd, Cu, Pb and Zn content of the riparian zone of the Tisza River (Hungary) after heavy metal pollution

At the beginning of the year 2000 two considerable waves of pollution occurred on the river Tisza. With the second wave, in a simultaneous flood, a huge amount of mud contaminated with heavy metals settled on the floodplains. As most of the contaminated areas are under agricultural use, the study of the heavy metal charge of soils and herbaceous plants of the floodplain has great importance. Along the Tisza four sampling sites were established and 300 cm deep drill cores were taken. The results of analytical examinations show that the heavy metal content of the topsoil is higher than that of the earlier formed lower layers, although contamination is also present there. This suggests that pollutions like this are not unknown in the Tisza Valley. It is greatly important to take cadmium pollution into consideration, as this element is extremely toxic and easily taken up by plants, and is likely to be a serious problem in the floodplain. The risk of contamination in the topsoil of the floodplain soils were examined in detail. The soils’ heavy metal content was the highest where the two pollution waves can be measured first at the same site. For determining the amount of heavy metals bound to other compounds sequential extractions were carried out. The proportion of the water soluble and exchangeable fraction – that is bioavailable to plants – is negligible in respect of Cu, Pb, and Zn, while it is considerable in the case of Cd, showing the risk of contamination. The gained data show that the high proportion of cadmium results in a remarkable environmental risk, while other heavy metals turn into a bioavailable form only after intensive acidification. The proportion of the heavy metal fraction bound to humus materials was expected to be low due to the exogenous origin and freshness of the topsoil.

Effects of Irrigation Regimes during Grain Filling on Grain Quality and the Concentration and Distribution of Cadmium in Different Organs of Rice

The objective of this study was to investigate whether the grain quality could be improved and the proportion of cad-mium(Cd)be reduced in grains through a proper irrigation regime when rice was planted in Cd-contaminated soil.Two rice cul-tivars of Yangjing 9538(japonica)and Yangdao 6(indica)were pot-grown.150 mg kg-1 Cd was added into pots before seedling transplanting(Cd treatment),and no Cd addition was taken as control(CK).Three irrigation regimes,well-watered(WW),mod-erate dry-wet alternate irrigation(MD,soil was re-watered when soil water potential reached at-20 kPa),and severe dry-wet al-ternate irrigation(SD,soil was re-watered when soil water potential reached at-40 kPa),were imposed from 7 d after heading to maturity.The results showed that under the same Cd concentration in soil and when compared to WW,MD significantly increased,whereas SD significantly reduced,seed-setting rate,1 000-grain weight,grain yield,brown rice rate,milled rice rate,and head rice rate.MD markedly reduced,while SD increased,chalkiness.There were no significant differences in the seed-setting rate,1 000-grain weight,and each index of rice quality between the Cd treatment and the control.Under the Cd treatment and com-pared to WW,MD,and SD significantly increased the concentration and proportion of Cd in roots,while significantly reduced Cd concentration in stems and leaves and reduced Cd proportion in grains.Cd concentrations in grains and milled rice were signifi-cantly higher under SD than under WW,and exhibited no significant difference between MD and WW.SD showed lower propor-tion of Cd in milled rice,when compared to MD or WW.The two cultivars behaved the same.The results indicate that a moderate dry-wet alternate irrigation during grain filling could increase grain yield,improve milling and appearance quality and not in-crease Cd concentration or even reduce Cd proportion in grains.Reasons for variations in grain yield,quality,and the concentra-tion and proportion of Cd under different irrigation regimes were analyzed from the aspects of root activity,photosynthetic cha-racters,and Cd translocation.

Effects of Irrigation Patterns during Grain Filling on Grain Quality and Concentration and Distribution of Cadmium in Different Organs of Rice

The objective of this study was to investigate whether grain quality could be improved and the proportion of cadmium (Cd) be reduced in grains through a proper irrigation management when rice ( Oryza sativa L.) was planted in Cd-contaminated soil. Two rice cultivars, Yangjing 9538 ( japonica) and Yangdao 6 ( indica), were pot-grown. A total of 150 mg kg −1 Cd was added into pots before seedling transplantation (Cd treatment), and Cd-free treatment was used as the control. Three irrigation patterns, well-watered (WW), moderate dry-wet alternate irrigation (MD, soil was re-watered when soil water potential reached −20 kPa), and severe dry-wet alternate irrigation (SD, soil was re-watered when soil water potential reached at −40 kPa), were carried out from 7 d after heading to maturity. Under the same Cd concentration in soil and compared to WW, MD significantly increased, but SD significantly reduced seed-setting rate, 1000-grain weight, grain yield, brown rice rate, milled rice rate, and head rice rate. Moderate dry-wet alternate irrigation markedly reduced, whereas SD increased chalkiness. There were no significant differences in seed-setting rate, 1000-grain weight, and quality traits of rice between the Cd treatment and the control. Under the Cd treatment and compared to WW, MD and SD significantly increased the concentration and proportion of Cd in roots, but significantly reduced Cd concentration in stems and leaves and reduced Cd proportion in grains. Cadmium concentrations in grains and milled rice were significantly higher under SD than under WW, and exhibited no significant difference between MD and WW. Severe dry-wet alternate irrigation resulted in lower proportion of Cd in milled rice compared to MD or WW. The results from this study indicate that moderate dry-wet alternate irrigation during grain filling increases grain yield and improves milling and appearance quality, but does not increase Cd concentration or even reduce Cd proportion in grains. The reasons for variations in grain yield, quality, and the concentration and proportion of Cd under different irrigation patterns were analyzed in terms of root activity, photosynthetic characters, and Cd translocation.

Assessment of Cadmium Distribution in Some Australian Krasnozems by Sequential Extraction

A sequential extraction procedure was used to investigate the influence of long-term phosphate fertilization on the distribution of cadmium throughout the major components of krasnozemic soils in the potato growing district located to the East of Ballarat, Victoria, Australia. The soil fractions investigated consisted of the water soluble, exchangeable, weakly bound to metal oxides, strongly bound to metal oxides, bound to organic material and residual. Other soil parameters, such as pHH2O, pHCaCl2, electrolytical conductivity and total organic material were investigated. The concentrations of Ca, Mg, Fe, Mn and Zn in each soil fraction were also measured. The total concentration of cadmium in the farmed soils had increased from the background level of 100.5 μg/kg to an average of 210 μg/kg. The proportion of cadmium available or potentially available for plant uptake was very low. On average, 89% of the cadmium in the farmed soils had been adsorbed by amorphous metal oxides and organic material, or was associated with silicates, and is therefore unavailable for plant uptake. The metal oxides adsorbed the highest proportion of cadmium.

Distribution of cadmium in an octanol/water system in the presence of xanthates and diethyldithiocarbamate

The octanol/water partition coefficient of cadmium was measured in the presence of ethyl-, isopropyl-, isobutyl-, and amylxanthates and diethyldithiocarbamate. For each complexing agent, the threshold concentration at which hydrophobic cadmium complexes started to appear was established. Cadmium was shown to form hydrophobic complexes with xanthates and diethyldithiocarbamate (maximal log POW = 1.73–2.64) at total ligand concentrations of 10−6 to 10−1 M. The proportion of cadmium in the octanol phase began to increase within the range of approximately 10−6.5 to 10−6 M for xanthate and approximately 10−5.0 M for diethyldithiocarbamate.

Low-Concentration Cadmium Diffusion into GaAs

Experimental results to obtain low p-type surface concentration into GaAs at high temperature using Ga-Cd alloy as a diffusion source, for the fabrication of a bipolar transistor optical switch, have been presented for the first time. The values of the diffusion coefficient of different proportions of cadmium into the alloy source are measured. The diffusion constant, D0, and the activation energy, ε, for pure cadmium and 1% cadmium into the Ga-Cd alloy as a source have also been measured. The modified values of these parameters for pure cadmium seem to be different as compared to the data reported earlier due to the SiO2 thin film deposited on the surface of the substrate to prevent arsenic loss at high temperature. The experimental results show a continuous reduction in surface concentration and diffusion coefficient by reducing the percentage quantity of cadmium into the Ga-Cd alloy diffusion source.

DISTRIBUTION OF CADMIUM IN AN OCTANOL/WATER SYSTEM IN THE PRESENCE OF XANTHATES AND DIETHYLDITHIOCARBAMATE

The octanol/water partition coefficient of cadmium was measured in the presence of ethyl-, isopropyl-, isobutyl-, and amylxanthates and diethyldithiocarbamate. For each complexing agent, the threshold concentration at which hydrophobic cadmium complexes started to appear was established. Cadmium was shown to form hydrophobic complexes with xanthates and diethyldithiocarbamate (maximal log POW = 1.73–2.64) at total ligand concentrations of 10−6 to 10−1 M. The proportion of cadmium in the octanol phase began to increase within the range of approximately 10−6.5 to 10−6 M for xanthate and approximately 10−5.0 M for diethyldithiocarbamate.

The effects of dietary selenium on cadmium binding in rat kidney and liver.

In acute studies, approximately 70-90% of cytosolic cadmium in liver and kidney has been shown to be bound to metallothionein, a low-molecular weight protein. In this study, we report on the influence of dietary selenium on the distribution of cadmium in rat kidney and liver. Contrary to the findings of most acute studies, our results indicate that only a relatively small proportion of cadmium (approximately 14% in the kidney and 44% in the liver) is bound to metallothionein when cadmium is administered for 7 weeks in the diet and via osmotic minipumps to selenium-deficient rats. Feeding rats the same diet supplemented with 1.0 ppm selenium results in no detectable cadmium-metallothionein peak in the kidney, and only about 10% of the cytosolic cadmium elutes as cadmium bound to metallothionein in the liver. In animals fed the selenium-supplemented diet, the bulk of the cadmium is recovered in the low-molecular weight fraction. Dietary selenium did not significantly affect the distribution of zinc and copper in the kidney or liver.

Fate of Heavy Metals and Potential for Clinker Formation during Pilot Scale Incineration of Municipal Sludge

This study describes multiple-hearth incineration investigations conducted at the Water Pollution Control Plant (WPCP) in Hamilton, Ontario. The objectives of the study were to determine, under controlled conditions, the fate of selected heavy metals present in the sludge and to determine optimal operating conditions to minimize clinker formation and residual organic content of the ash. A factorial experimental design which included four levels of temperature, three levels of throughput rate and three levels of centre shaft speed was conducted. Within the constraints of the experiment, zinc, iron, magnesium, aluminum, nickel, copper, calcium, chromium, lead, silica and phosphorus proved to be conservative and remained in the ash. Varying proportions of cadmium, mercury and arsenic were classified to the gas stream. The destruction of total carbon was essentially complete under all test conditions, with the minimum level being 98.7%. Clinker formation was observed only under conditions of high temperature combined with a long furnace residence time.

Influence of cadmium on zinc distribution in the mouse liver and kidney: Role of metallothionein

Male mice of the ICR strain were given 2.5 mg of Cd/kg by a sc injection of CdCl2 and were sacrificed by bleeding at 0.5, 4, and 10 hr and 1, 6, and 20 days. Cadmium was detected in the liver and kidney at 0.5 hr after the cadmium injection and the metal concentration increased progressively. In the kidney, zinc concentration at 20 days increased significantly in comparison with that of the control group. In the liver, the zinc concentration was not different from that in control mice up to 10 hr, but after 1 day, the concentration increased significantly. The proportion of cadmium in the liver and kidney supernatant increased with time up to 6 days after cadmium injection. The fact that cadmium content in the supernatant fraction increased with time to be more than 90% of the cadmium in the liver and kidney may suggest that the capacity of this fraction for cadmium accumulation increased with time. In the control group, about 78 and 68% of the total zinc content in the liver and kidney were present in the supernatant. After the injection, these values increased with time up to 6 days. At 20 days after the injection, the decrease of the proportion of zinc was synchronous with the decrease of cadmium. The increased zinc in the liver supernatant may be due mainly to the appearance of metallothionein which was induced de novo by cadmium. At 4 hr after the injection, about 63 and 55% of the cadmium in the supernatant of the kidney and liver, respectively, were detected at the region corresponding to the metallothionein fraction as separated on Sephadex G-75. However, at 4 hr, only about 4.6 and 9.3% of the soluble zinc was detected in this fraction of the kidney and liver, respectively. At later stages, the uptake of cadmium into the metallothionein fraction increased to more than 90%. However, this uptake of zinc was about 47 and 31% at 6 days in the liver and kidney. By further purification of the metallothionein using a DEAE cellulose column, two distinct proteins (Peak II and Peak III), metallothioneins, were obtained. These proteins contained Cd and Zn and were homogeneous as judged by the appearance of a single stainable band on polyacrylamide gel disc electrophoresis. However, the ratio of Cd/n was dependent on the length of time after the cadmium injection. At all times, the protein in Peak II occupied much more cadmium and zinc than that in Peak III.