Cu(II) removal from aqueous solution using Dogantepe (Amasya) zeolites

This paper investigates the effects of zeolite particle size, zeolite/ solution ratio and stirring time on the performance of zeolites from Dogantepe in removing Cu(II) from aqueous solution to establish optimum operating conditions. The results indicated that the size of the zeolite samples, the concentration of Cu(II) and the zeolite/solution ratio affected the removal efficiencies, whilst the stirring time was found to have no significant effect on the removal efficiencies. The equivalent numbers of sodium, magnesium, calcium and potassium ions passed into the Cu(II) solution were found to be 1.196, 0.208, 0.117 and 0.009 meq/l, respectively, and the passing percentages of these ions were calculated to be 11.27, 2.45, 1.57 and 0.37%, respectively. The removal mechanism of Cu(II) with zeolite samples was mainly ion exchange with a fraction of approximately 65%. The maximum exchange capacities obtained by using Dogantepe zeolites, Yavu zeolites, and synthetic resin were found to be 9.2, 7.0 and 72.7 mg/g, respectively. However, in relatively low concentrations of Cu(II), the differences in the removal efficiencies or exchange capacities obtained for above different three materials were significantly decreased.     

碱熔融法合成NaA和NaX型粉煤灰沸石的品质表征

以粉煤灰为原料采用碱熔融法合成了2种单一沸石矿物种的NaA和NaX型沸石,并对产物的结构、性能和应用指标进行了详细表征.经x射线衍射和IR光谱分析,表明合成产物是无杂晶生成的NaA和NaX型沸石相;在扫描电镜观察下,产物分别具有NaA和NaX型沸石的立方体和八面体晶体骨架结构.DTA分析表明了合成产物中沸石水的存在,且产物热稳定性较好.通过对比,粉煤灰合成的NaA和NaX型沸石的比表面积达到了相应商品沸石的66.9%和83.6%;孔容为41.1%和70.2%;阳离子交换容量(CEC,cation exchange capacity)为82.93%和84.31%.通过比较化学组成表明,大规模应用合成产物不会对环境造成危害.     

The influence of humic acids on the phytoextraction of cadmium from soil

Cadmium poses a major environmental and human health threat because of its constant release through anthropogenic activities. A need, therefore, exists for cost-effective remediation procedures. Phytoremediation, the use of plants to extract contaminants from soils and groundwater, has revealed great potential. However, it is limited by the fact that plants need time, nutrient supply and, moreover, have a limited metal uptake capacity. Synthetic chelators have shown positive effects in enhancing heavy metal extraction through phytoremediation, but they have also revealed a vast number of negative side-effects. The objective of this research was to investigate the use of humic acids as an alternative to synthetic chelators. Humic acids were applied to a cadmium-contaminated soil at various dosages, and the uptake of cadmium into Nicotiana tabacum SR-1 was determined in relation to the amounts of total and bioavailable cadmium in the soil. It was found that the theoretical bioavailability of cadmium, as determined by diethylenetriaminepentaacetic acid (DTPA) extraction, did not change, but its plant uptake was enhanced significantly, in some cases up to 65%. Humic acids added at a rate of 2 g kg(-1) soil increased the cadmium concentration in the shoots from 30.9 to 39.9 mg kg(-1). A possible reason for this enhancement is the decrease in pH, resulting in higher cadmium availability. Another possibility taken into account is that plants may take up cadmium complexes with humic acid fragments, which result from microbiological degradation or, self-dissociation.     

Willow ptarmigan (Lagopus lagopus) as a biomonitor of environmental metal levels in Norway

The purpose of this study was to examine the potential of a native wild bird, Lagopus lagopus, as a monitor of environmental metal levels, in particular with respect to the influence of atmospheric deposition of metals from long-range transport. Specimens of willow ptarmigan were collected from ten different locations in Norway. The concentrations of cadmium, zinc and copper were determined in kidneys of birds from all sites. Mean cadmium levels in adult ptarmigan kidney ranged from 6.6 to 48.5 microg g(-1) (wet weight), with individual concentrations up to 71.0 microg g(-1). These are among the highest cadmium levels reported in wild birds. The kidneys of adult birds contained 3-10 times higher cadmium levels than kidneys from juvenile birds in the same collection area, and most of the high cadmium levels probably reflect natural exposure, rather than atmospheric pollution. Concentrations of elements in kidney tissues were highly correlated with each other.     

镉胁迫对向日葵幼苗生长和生理特性的影响

采用溶液培养方法,研究了不同浓度镉(0、0.05、0.1、0.5和1 mg/L)处理7 d对向日葵幼苗生长和生理特性的影响。结果表明：随着镉处理浓度的增加，向日葵幼苗对镉的吸收显著增加。1 mg/L镉浓度处理时，叶、茎和根中镉浓度分别为0.05 mg/L镉处理时的16.3、19.2和581倍；根中积累的镉含量明显高于叶和茎, 各浓度根部积累的镉分别为叶和茎的37.8～63倍和29.4～41倍。镉胁迫显著抑制向日葵幼苗生长和叶绿素合成，当镉浓度达1 mg/L时，整株植物生物量和总叶绿素含量分别为对照的55.9%和52.6%。镉胁迫下向日葵幼苗游离脯氨酸和丙二醛（MDA）含量显著增加，1 mg/L镉浓度时，根中含量分别为对照的4和5.8倍。向日葵幼苗可溶性蛋白含量和过氧化物酶(POD)活性变化与镉胁迫浓度呈明显的倒U字型关系，可溶性蛋白含量在0.05 mg/L镉浓度时达到最大值，叶、茎、根中的POD活性分别在0.1、0.1和0.05 mg/L镉浓度时达到最大值。     

Changes of emissions and atmospheric deposition of mercury,lead, and cadmium

This paper reviews the information on trends of past emissions of mercury, lead, and cadmium in Europe, as well as examines current levels and future scenarios of these emissions. The impact of various factors on emission changes is discussed including the implementation of various strategies of emission controls in Europe. Future emissions are forecasted on the basis of various scenarios of economy growth in Europe, implementation of European and global legislation (e.g. the Kyoto agreement), population changes, etc.Changes of emissions of mercury, lead, and cadmium are then related to the changes of concentrations of these contaminants in air and precipitation samples at selected stations in Europe. It can be concluded that the reduction trends of anthropogenic emissions of cadmium and lead in Europe are similar to the reduction trends of air concentrations of these metals during the last 2 decades. Somewhat different relationship has been noted for changes in emissions and precipitation. In general for Europe, 60% reduction of Cd emissions was met by about 45% reductions of Cd concentrations in precipitation at the studied stations during the last 2 decades.There is a potential for further reduction of these emissions until the year 2010 up to about 37% for Cd, 51% for Pb, and 49% for Hg as estimated within various emission scenarios presented in the paper.     

碱熔预处理对粉煤灰溶解规律的影响及其动力学

在用粉煤灰合成沸石分子筛的过程中，粉煤灰在碱液中的溶解影响到合成反应的速率以及合成分子筛的性能。采用碱熔的方法处理粉煤灰，研究了粉煤灰在碱液中的溶解机理以及碱熔预处理对粉煤灰溶解规律的影响，并采用Noyes-Whitney方程分析其溶解动力学。结果表明，经过碱熔预处理的粉煤灰有36．11％的SiO2和16．33％的Al2O3转化为水溶性成分，剩余的非水溶性部分在碱液中的溶解速率也有大幅提高，硅铝离子达到平衡浓度的时间缩短，铝离子的平衡浓度有较大提升。Noyes-Whitney方程对粉煤灰在碱液中的溶解规律适用，相关系数都达到0．979以上。     

Distribution of heavy metals in muscle, liver and kidney of northern fur seal (Callorhinus ursinus) caught off Sanriku, Japan and from the Pribilof Islands, Alaska

The concentrations of iron, manganese, zinc, copper, cadmium, and mercury were determined in muscle, liver and kidney of 67 northern fur seals (Callorhinus ursinus) collected off Sanriku, Japan, and from the Pribilof Islands, Alaska. Almost all the elements except cadmium were highest in liver. Cadmium levels in kidney were higher than those in liver and muscle for all animals analyzed. Concentrations of mercury increased significantly with age in muscle, liver and kidney, as did iron levels in muscle and liver and cadmium levels in muscle, while manganese concentrations decreased with age in muscle and kidney. The kidney also showed decreased copper concentration with age. Cadmium concentrations of the northern fur seals in this study were higher than the other otariids, reflecting a predominantly squid diet. Concentrations of manganese and mercury were found to be higher in the fur seals caught off Sanriku than in animals from the Pribilof Islands, while those of zinc and cadmium were found to be lower. Variable concentrations of cadmium might have been attributed to those in seawaters. Discriminant analysis of heavy metal concentrations was used to identify habitat. Sixty-three of 67 animals (94%) were correctly classified using this technique. Heavy-metal concentrations in tissues may provide a useful method to elucidate the primary feeding grounds of fur seals.     

Multi-generation cadmium acclimation and tolerance in Daphnia magna Straus

The cladoceran Daphnia magna was acclimated for seven generations to cadmium concentrations ranging from 0 (control) to 250 microg/l Cd (corresponding to a free ion activity of 4.60 nM Cd2+). Acute and chronic cadmium tolerance as well as cadmium accumulation were monitored as a function of acclimation time. After two to three generations of acclimation to concentrations ranging from 0.23 to 1.11 nM Cd2+ increases in acute tolerance were maximal (factor 7.2) and significant. Acclimation for seven generations to the same acclimation concentrations did result in an increased chronic cadmium tolerance (21 days EC50 values increased). Organisms acclimated to 1.93 nM Cd2+ were equally or more sensitive than non-acclimated daphnids in acute and chronic toxicity tests. Cadmium contents in D. magna increased significantly as a function of the acclimation concentration. Maximum body burdens of 236+/-30 microg Cd/g dry weight were measured in organisms exposed to 4.60 nM Cd2+, but detoxification mechanisms were only successful up to 82+/-20 microg Cd/g dry weight as this concentration did not cause major decreases in survival and reproduction in chronic toxicity tests. As the potential positive effect of acclimation on cadmium tolerance disappeared with successive acclimation generations and increasing acclimation concentrations, it is concluded that multi-generation acclimation studies are important for the evaluation of the long-term effects of environmental toxicants.     

Phytoremediation potential of Spirulina (Arthrospira) platensis: biosorption and toxicity studies of cadmium

This study examines the possibility of using Spirulina (Arthrospira) platensis TISTR 8217 to remove low concentrations of cadmium (less than 100 mg/l) from wastewater. The cyanobacteria were exposed to six different cadmium concentrations for 96 h, and the growth rate was determined using an optical density at 560 nm. The inhibiting concentration (IC50) was estimated using probit analysis. The IC50 at 24, 48, 72, and 96 h were 13.15, 16.68, 17.28, and 18.35 mg/l Cd, respectively. Cellular damage was studied under a light microscope and a transmission electron microscope. Swollen cells and fragmented filaments were observed. Cell injury increased with increasing concentrations of cadmium. Ultrastructural changes were observed in the algae exposed to cadmium concentrations both close to IC50 (14.68 mg/l) and at IC50 (18.35 mg/l). The alterations induced by cadmium were disintegration and disorganization of thylakoid membranes, presence of large intrathylakoidal space, increase of polyphosphate bodies, and cell lysis. In addition, the cadmium adsorption by algal cells was studied. Environmental factors were found to have an effect on biosorption. The uptake of cadmium was not affected by the temperature of the solution, but the sorption was pH dependent. The optimum pH for biosorption of algal cells was 7. The cadmium uptake process was rapid, with 78% of metal sorption completed within 5 min. The sorption data fit well to the Langmuir isotherm. The maximum adsorption capacity for S. platensis was 98.04 mg Cd per g biomass.     

Influence of clay on the adsorption of heavy metals like copper and cadmium on chitosan

The influence of clay on the adsorption of heavy metals like copper and cadmium on chitosan from simulated industrial wastewater is evaluated. Chitosan–clay blend with ratio of (1:1), (1:2), and (2:1) have been prepared, and these were used as membranes to remove copper and cadmium ions from synthetic industrial wastewater. The chemical parameters for quantities of adsorption of heavy metal contamination have been done, and the kinetics of adsorption has also been carried out. Clay provides enough absorbable sites to overcome mass transfer limitations. The number of absorbable sites for cadmium is more compared to copper, and thus the rate of recovery of cadmium is faster than copper, and the percentage removal of cadmium is more than copper at all times on clay over nylon 6. This difference indicates the influence of clay in the adsorption of heavy metals in comparison to synthetic polymer nylon 6. Rate constant for first-order kinetics of adsorption, k ₁, for copper and cadmium is less than that of clay, which clearly indicates that clay, which is a natural polymer, is more kinetically favored compared to synthetic polymer. The difference in the intraparticle diffusion in both the natural and synthetic polymer is not much, and it suggests that the particle diffusion mechanism is the same in both cases. Copper and cadmium recovery is parallel at all times. The percentage of removal of copper increased with an increase in pH from 3 to 5. In the case of cadmium containing wastewater, the maximum removal of metal occurred at pH 5. The uptake amount of Cu²⁺ ions on chitosan increased rapidly with increasing the contact time from 0 to 360 min and then reaches equilibrium after 360 min, and the equilibrium constant for copper and cadmium ions are more or less the same for the adsorption reaction. There are more adsorption sites for cadmium in the presence of clay and mass transfer limitation is avoided without resorting to rotation, which is the highlight of the present work. And more so, this is pronounced in the case of natural polymer compared to synthetic polymer.     

Palygorskite as a feasible amendment to stabilize heavy metal polluted soils

The sorption behaviour of palygorskite has been studied with respect to lead, copper, zinc and cadmium in order to consider its application to remediate soils polluted with these metals. The Langmuir model was found to describe well the sorption processes offering maximum sorption values of 37.2 mg/g for lead, 17.4 mg/g for copper, 7.11 mg/g for zinc and 5.83 mg/g for cadmium at pH 5-6. In addition the effect of palygorskite amendment in a highly polluted mining soil has been studied by means batch extractions and leaching column studies. The soluble metal concentrations as well as the readily-extractable metal concentrations were substantially decreased at any concentration of palygorskite applied to soil (1, 2, 4%), although the highest decrease is obtained at the 4% dose. The column studies also showed a high reduction in the metal leaching (50% for lead, 59% for copper, 52% for zinc and 66% for cadmium) when a palygorskite dose of 4% was applied.     

Dioxin and furan residues in wood mice (Apodemus sylvaticus) following a large scale polyvinyl chloride (PVC) fire

A forest ecosystem was contaminated as a result of a fire involving 600 t of PVC. A wide range of 2,3,7,8-substituted dioxin and furan congeners were elevated (by up to 4-fold) on soil adjacent to the factory compared to a site 200 m from the factory perimeter. Livers of wood mice (Apodemus sylvaticus) caught on these areas were also analysed for dioxins and furans. Toxic equivalents (TEQs) were 9-fold higher in wood mice caught on the site 10 m from the factory perimeter compared with the site 200 m from the perimeter, with individual 2,3,7,8-substituted congeners being elevated by up to 30-fold. Wood mouse liver TEQs were found to be highly correlated with cadmium kidney concentrations, cadmium also being found at elevated concentrations at the accident site. There was also a significant positive correlation between wood mouse liver TEQs and relative liver weights (wet weights expressed as a percentage of total body weight). The results of this study are discussed in the wider context of dioxin contamination in the environment.     

Physiological responses of Alternanthera philoxeroides (Mart.) Griseb leaves to cadmium stress

Aquatic macrophytes were found to be the potential scavengers of heavy metals from aquatic environment. In this study, several physiological responses of Alternanthera philoxeroides (Mart.) Griseb leaves to elevated concentrations of cadmium (up to 10mM) were investigated. It was found that A. philoxeroides was able to accumulate cadmium in its leaves. The pigment contents decreased with the increase of the Cd concentrations. The Cd could induce rise of the activity of peroxidase (POD) at lower concentration (<5mM), however, when the concentration of Cd rose up to 10mM, the POD activity declined. The changes of superoxide dismutase (SOD) and Catalase (CAT) activities were exactly opposite to that of POD. In the leaves of Cd-treated fronds, the amounts of three polypeptides with apparent molecular weights 80, 39 and 28kDa, respectively, were became visible in SDS-PAGE. The nature of these polypeptides remains to be determined.     

Metal concentrations in seabirds of the New Zealand region

Concentrations of the heavy metals cadmium, copper, lead, zinc, mercury and, in some individuals, methyl mercury were determined in a range of tissues of 64 tropical, subtropical, subantarctic and antarctic seabird taxa mostly from the New Zealand region. Although apparently natural, levels of cadmium and mercury in some species greatly exceed those known to have toxic effects in some terrestrial birds. Copper and zinc levels exhibited less inter-species variation than the non-essential metals cadmium and mercury. Cadmium concentrations were highest in kidney tissues but uniformly low in feathers. Total mercury concentrations showed most inter-species variation. Mean methyl mercury levels in liver tissues of several large procellariiforms represented less than 5% of the corresponding mean total mercury level. Lead concentrations were generally low or below the limits of detection, but elevated levels were measured in some coastal or scavenging species. In a significant number of species, mean concentrations of liver cadmium and mercury and kidney cadmium were greater in adults than in young birds. The reverse was true for copper. Mean zinc levels in liver did not differ between adults and young. High levels of cadmium in some species seem likely to be due to diet, whereas high levels of mercury probably reflect more closely the moult intervals which constrain the ability of birds to eliminate methyl mercury.     

Biological nitrification/denitrification of high sodium nitrite (navy shipyard) wastewater

In the hydroblasting of ships' boiler tubes, a wastewater high in nitrite (as high as 1200 mg litre(-1)) is produced by the US Navy. This research has evaluated the use of a suspended-growth biological system to treat this wastewater by denitrification. Two biological treatment configurations were evaluated (direct denitrification versus nitrification/denitrification) with nitrification/denitrification producing better nitrite removal efficiencies (54 to 62% versus 40%, respectively). The introduction of metals (cadmium, chromium, lead, copper and iron) in concentrations typical for this wastewater did not inhibit the nitrite removal efficiencies. The influent metal concentrations ranged from 0.02 mg litre(-1) for cadmium to 22 mg litre(-1) for iron and the metal removal efficiencies ranged from 4.8% for cadmium to 50% for copper. Increasing sludge age resulted in improved nitrite removal efficiencies (52%, 57% and 74% for sludge ages of 4, 6 and 8 days, respectively). The resulting biokinetic constants were similar to those reported by others for lower influent concentrations of nitrite or nitrate (Ygs=0.02 mg/mg; Ygn=0.16 mg/mg; Yb=0.8 mg/mg; and b=0.006 h(-1)).     

Haematological and biochemical effects of polyphenolics in animal models

Polyphenols of natural and synthetic origin are exploited in tanning sector to convert putrescible skin/hide to non-putrescible leather. However, only 30-40% of the inputs have been taken up for processing, the remaining is released as unspent. The existing conventional wastewater treatment systems are inefficient in removing or degrading these unspent polyphenols and thus detrimental to ecosystem. The present study demonstrates the evaluation of impact of both synthetic and natural polyphenols on biochemical and haematological properties of blood and serum in animal models. The results reveal that concentrations of polyphenols play a major role. At higher concentrations, irrespective of their nature, there was a marked change in the lipid profile (81% reduction), followed by insignificant change in glucose levels, RBC and WBC counts and other haematological parameters. At lower concentrations, no significant changes in the above said properties were observed.     

Long-range air pollution and its impact on heavy metal accumulation in dippers Cinclus cinclus in Norway

Heavy metals such as cadmium, lead and zinc are deposited in Norway as long-range transported air pollution, while copper deposition is of mainly local origin. This study examined whether the deposition influences the metal concentrations in dippers Cinclus cinclus. The lead concentration in dippers reflected the deposition pattern of long-range air pollution, with higher concentrations in Southern Norway than Central Norway and a significant decrease (>/=40%) between 1987 and 1994. For cadmium, copper and zinc there were no geographical or temporal variations in metal concentrations. For zinc, this lack of geographic and temporal variation probably reflects the fact that it is a homeostatically regulated metal. For both cadmium and copper, local sources are probably more important than long-range sources. Zinc and copper was at higher level in livers of females than in males during the egg laying period. The concentrations of zinc and copper in livers were positively correlated.     

两株镉抗性奇异变形杆菌对龙葵修复镉污染土壤的强化作用

以广东省大宝山尾矿区植物根际土壤为分离样品，人工制备镉污染LB培养基，从中分离筛选出2株具有较强镉耐受能力的细菌，分别为TL3和DBS2，最高镉耐受浓度达300mg／L。结合其形态学特征、生理生化特性及16SrDNA序列分析，初步确定2株菌均为奇异变形杆菌（Proteusmirabilis）。随后以龙葵为实验植株，分别接种TL3、DBS2及TL3与DBS2混菌的培养液，通过盆栽实验检验2株菌对龙葵吸收土壤中镉的强化作用。结果显示，2株菌对龙葵吸收镉具有显著的提升作用，且能够促进植株的生长，3个实验组龙葵根部镉含量分别比对照组（122．7mg／kg）增加了17．2％、85．6％和130．1％。