Association between urinary indicators of renal dysfunction and metal concentrations in workers chronically co-exposed to cadmium,zinc and lead

The study was carried out in 31 workers co-exposed to cadmium, lead and zinc fumes and dusts in a zinc ore refinery. Urinary cadmium, lead, zinc, β₂-M levels and NAG activities were determined to evaluate the possible dose-effect relationship between these parameters. A correlation was found between urinary cadmium, lead and zinc concentrations, and urinary β₂-M levels and NAG activities of the exposed group. A statistically significant increase was also observed for urinary NAG activity in exposed workers who had urinary cadmium concentrations > 2 μg g^?1 creatinine. However, in the same exposed group, the increment of β₂-M was not statistically significant. In conclusion, the present study thus confirms the earlier observations and may suggest the notion that the urinary NAG seems to be a more sensitive indicator than urinary β₂-M level in early stages of renal injury of moderately cadmium co-exposure with lead and zinc even at urinary cadmium concentration as low as 2 μg g^?1 creatinine. When the earlier studies on the irreversibility of cadmium-induced tubular dysfunction and the present results were taken into consideration, the present health-based biological limit proposed by the WHO (5 μg g^?1 creatinine) seems to be high for the occupational exposure to cadmium.     

Effect of zinc on cadmium toxicity to the amphipod Gammarus pulex

The freshwater amphipod Gammarus pulex was sampled from several sites in Northumberland, England and analysed for total body zinc and cadmium concentrations.The toxicity of cadmium to animals from the different sites was determined and a positive relationship was found between the initial total body zinc concentration and the ability to survive in an artificial medium containing 0.5 mg 1^–1 cadmium as cadmium sulphate.Exposure in the laboratory to a low concentration of zinc (0.01 mg 1^–1) as zinc sulphate for two weeks resulted in a decreased susceptibility to cadmium poisoning.     

NTAGONISM BETWEEN CADMIUM AND IRON IN THE MARINE DIATOM THALASSIOSIRA WEISSFLOGII1

Cadmium inhibits iron uptake and assimilation in the coastal diatom Thalassiosira weissflogii Grun. The effect of cadmium on short term Fe uptake fits ft competitive binding model: where (Fe³+) and (Cd²++) tire the free ferric and cadmium ion concentrations, respectively. The apparent binding constant K_cds, is calculated to be ca. lO^8.2M^-1 compared to a K^fe of lO¹⁹ M^-1. At low free ferric ion concentrations. interference of cadmium with iron transport (at pCd = 8 and pFe* < 20) results in a simultaneous decrease in growth rate and Fe accumulation to a level known 1o limit growth. Upon decreasing the free cadmium ion concentration, cells accumulate a large amount oj iron prior to resumption of normal growth. At higher free ferric ion concentrations (pFe* < 20) normal or elevated Fe quotas are absented but “luxury consumption” of iron still occurs upon reversal of toxicity. Evidence that these algae with high cellular iron quotas are effectively Fe deficient is provided by a decrease in the cytochrome f/chlorophyll a ratio and a much greater decrease in NO₃- reductase activity than in aldolase activity or H¹⁴C0₃ assimilation. Under the conditions of this study, cadmium had little effect on Si accumulation. The transport of methylamine (an analog of NH⁺₄) is unaffected by short term exposure to high free cadmium ion concentration but is greatly inhibited upon long term (97 h) exposure.     

Cadmium,mercury, and lead effects on gill tissue of freshwater crayfishProcambarus clarkii (girard)

Intermolt adult crayfishP. clarkii were used for this work. After acclimatation to laboratory conditions crayfish were exposed to sublethal concentrations of cadmium, mercury, and lead for 96 h. Gills of control and exposed crayfish were removed and ATPase activity and oxygen uptake rate were determined. Structural damage of gill filaments was also observed. Gill tissue respiration rates were measured for individual crayfish using a Gilson differential respirometer. Lead causes a decrease of gill oxygen uptake, but neither cadmium nor mercury seems to affect it at the concentrations employed. Although all metals studied alter gill filament structure, lead damage is the most apparent. In the same way, significant differences in gill ATPase activity owing to metal exposure were only observed in lead treated crayfish.     

土壤镉胁迫对田七体内镉分布及富集特性影响

田七(Panax notoginseng)是我国的一种传统珍贵的草本药用植物,其重金属污染问题已经引起广泛关注。为了分析田七不同部位对镉毒害的响应,明确不同浓度镉污染对田七体内镉分布的基本特征以及不同部位的富集特性,以揭示镉胁迫对田七不同部位的影响机制及富集转移特性。该研究在"田七之乡"广西靖西市田七园以3年生田七为材料,土培条件下以不施镉处理为空白对照,设置6个镉浓度(5、10、20、30、40、50 mg·kg~(-1))梯度,研究了在不同浓度镉胁迫下田七不同部位镉积累特征以及转移特性。结果表明:在不同器官(叶、茎、剪口、须根、主根)随着镉浓度的增加各器官镉的积累量均显著(P0.05)增加,呈现出正相关关系。田七不同部位镉含量的分布特征表现:空白对照下田七各器官镉累积分布表现为须根剪口主根茎叶;当镉浓度为5、10、20、30、40、50 mg·kg~(-1)时,田七镉分布表现为剪口主根须根茎叶;地下部的镉含量显著高于地上部的镉含量;随着镉浓度的增加,无论地下部生物富集系数还是地上部生物富集系数均表现为逐渐降低的趋势。     

Effect of cadmium on glutathione reductase in potato tubers

Short-term treatment of potato tuber (Solanum tuberosum L.) discs with CdCl₂ changed glutathione reductase (GR) activity depending on cadmium ions concentrations, kind of tuber and time of incubation. The increase of GR activity at 10 and 100 μmol·dcm⁻³ of CdCl₂ solutions was marked in less resistant tissues of cv. Bintje after 24 hrs, and was slight in more resistant tissues of cv. Bzura after 72 hrs. At 1 mmol·dcm⁻³ concentration of CdCl₂ rapid and total inactivation in both kind of tissues was observed, which disappeared after a few days. However this elevation was faster in more resistant tissues. These inhibition effects come from the inactivation process of GR by cadmium. The values of K_I for cadmium and K_M for GSSG of GR from potato tuber tissues indicated that enzyme from more resistant tissues possessed lower affinity to toxic metal and higher affinity to substrate.     

Effects of declining calcium availability on the survival,growth and calcium content of a freshwater crayfish,Orconectes virilis

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Comparative study of effects of cadmium cations in free and chelated forms on activity of glutathione S-transferase, growth, and endocytosis in culture of the infusoriumTetrahymena pyriformis

Effects of cadmium cations in free (Cd²⁺) and chelated with EDTA (Cd²⁺-EDTA) forms were studied on growth, endocytosis, and activity of glutathione S-transferase (GT) in the free-living infusoriaTetrahymena pyriformis. It is shown that the cytotoxicity of Cd²⁺ in the free form at a concentration of 10 μM is much higher than of the Cd²⁺-EDTA complex at the equimolar concentration. Even at a low concentration (2 μM), Cd²⁺ produces an inhibition of the growth rate and endocytosis in theT. pyriformis culture, while the Cd²⁺-EDTA complex suppresses these functions insignificantly. Cd²⁺ in the free form at concentrations of 10 and 100 μM reduced activity of glutathione S-transferase by 39 and 61%. The chelated Cd²⁺-EDTA complex at these concentrations inhibited the GT activity by 5 and 55%, respectively.     

Effects of certain cadmium species on pure and litter populations of microorganisms

Cadmium inhibition of microorganisms was found to be bacterial and chemical species dependent. E. coli inhibition was a function of the cadmium-ion concentration irregardless of the presence of citrate, a chelator for cadmium that it could not metabolize. Whereas with a Pseudomonas sp. able to metabolize citrate, cadmium inhibition was a function of both the cadmium ion and the presence of citrate. With no citrate, inhibition of this organism occurred only at relatively high cadmium-ion concentrations (above 10^–4 m); when citrate was added to the same cadmium-containing growth medium, inhibition was observed at a 1000 times lower cadmium-ion concentration (i.e., 10^–7 m). This observation is contrary to the classical understanding where a chelate reduces the toxic form of a metal allowing increased growth of the organism.The species of cadmium also differentially inhibited the Douglas fir litter respiration and nitrogen-fixing community activities.     

Effects of Cadmium on Respiration Rate and Activities of Several Enzymes in Soybean Seedlings

Soybean (Glycine max L. ev. Columbus) seedlings grown in culture solution were treated with cadmium as CdSO₄. Final concentrations of cadmium (Cd²⁺) in the solution were 0, 0.45, 0.90, and 1.35 μM. Soybean leaves, analyzed 10 days after Cd²⁺ was added to the culture solution, showed increased respiration rate and activities of malate dehydrogenase, acid phosphatase, ribonuclease, deoxyribonuclease, and peroxidase but decreased activity of carbonic anhydrase. Increased activity of hydrolytic enzymes and peroxidase reflects a general senescence response while the carbonic anhydrase decrease is consistent with an antagonism between cadmium and endogenous zinc. Chlorosis, epinasty, abscission of leaves, and decreased growth rate occurred in seedlings treated with 1.35 μM Cd²⁺.     

镉胁迫下硒对罗汉果组培苗光合特性的影响

实验以罗汉果组培苗为材料,室内栽培在内装市售营养土的塑料盆中,以0、10、50、100、200mg·kg-1浓度镉离子和1mg·kg-1浓度硒处理,培养20d后分析罗汉果幼苗的相关光合生理指标。结果表明:低浓度Cd2+对叶片叶绿素含量、光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)影响不大或稍有上升,但高浓度镉离子处理植株叶片的叶绿素含量、光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)明显下降;随Cd2+处理浓度的增加,叶片胞间CO2浓度(Ci)呈现上升趋势;加硒则延缓叶绿素下降,促进光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)上升,降低叶片胞间CO2浓度(Ci)。表明高浓度镉离子的毒害导致罗汉果组培苗叶片光合性能受到伤害,从而影响罗汉果幼苗生长。镉硒混合处理反映出硒对镉的毒害有缓解作用。     

Mercury and cadmium concentrations in the tissues of three species of southern albatrosses

Cadmium and mercury concentrations were measured in the tissues of 64 individual albatrosses [23 wandering albatrosses (Diomedea exulans), 9 royal albatrosses (Diomedea epomophora) and 32 shy albatrosses (Thalassarche cauta)] which were killed as by-catch in longline fishing activities between 1991 and 1994. Mercury concentrations were also determined for 33 shy albatross eggs (excluding shells). The birds were all sexed and assigned to one of two age classes (immature and adult). The three species exhibited differences both in overall concentrations of cadmium and mercury, and also in the pattern of accumulation of metals with age and sex. Wandering albatrosses exhibited the highest mercury concentrations with a mean concentration in adult liver samples of 920.0 ± 794.1 μg g⁻¹ dry weight. Shy albatrosses had the lowest mercury concentrations with mean concentrations in adult livers of 36.3 ± 21.4 mg g⁻¹ dry weight. The highest mercury concentration was 1800 μg g⁻¹ for an adult female wandering albatross. Cadmium concentrations were less variable, with adult royal albatrosses having the highest average concentrations (180.0 ± 165.0 in adult kidneys) and adult shy albatrosses the lowest (40.1 ± 20.0 in adult kidney). The highest individual cadmium concentration was 287 μg g⁻¹ for a juvenile wandering albatross. There was no evidence of increased accumulation of cadmium with age in any of the species, but wandering albatrosses showed higher mercury concentrations in adults than juveniles. Female wandering albatrosses also had significantly higher mercury concentrations than males. The mercury contents of the shy albatross eggs were very low, with a maximum concentration of 5.4 μg g⁻¹. The results of this study are consistent with the findings of previous work on albatrosses and support the notion that the life-history strategy of these species (i.e. long-lived with low reproductive output) may be an important determinant in the concentrations of some metals found in their tissues. Accepted: 15 February 1999     

3种酰胺类稻田除草剂对克氏原螯虾的急性毒性

[目的] 研究稻虾共作模式条件下,稻田封闭除草剂对克氏原螯虾产生的急性毒性。[方法] 采用半静态试验方法,研究3种酰胺类除草剂（乙草胺、丙草胺和丁草胺）对克氏原螯虾的急性毒性,计算3种酰胺类除草剂对克氏原螯虾的安全浓度,并分析其LC₅₀衰减规律。[结果] 随着暴露时间和除草剂浓度的增加,虾体侧躺,步行足和游泳足活动频率降低,最终死亡。乙草胺对克氏原螯虾的96 h半致死浓度（LC₅₀）和安全浓度（SC）分别为0.0707和0.0146 mL·L^-1;丙草胺对克氏原螯虾的96 h LC₅₀和SC分别为0.0119和0.0021 mL·L^-1;丁草胺对克氏原螯虾的96h LC₅₀和SC分别为0.0073和0.0014 mL·L^-1。乙草胺、丙草胺及丁草胺除草剂LC₅₀随着暴露时间延长呈下降趋势,符合双曲线衰减模型,回归方程分别为：① y₁=2.0840x^-0.7380（R²=0.9973）;② y₂=0.1106x^-0.4930（R²=0.9872）;③ y₃=0.2236x^-0.7480（R²=0.9990）。克氏原螯虾对3种除草剂的敏感性由高到低依次为：丁草胺 > 丙草胺 > 乙草胺。[结论] 乙草胺和丙草胺可在稻田综合种养生产过程中按常规剂量使用,而丁草胺按常规剂量使用可能存在较大的风险。     

Genotoxic effect of cadmium is associated with apoptotic changes in tobacco cells

This work explores the influence of cadmium on a suspension cell culture of Nicotiana tabacum (TBY‐2) by examining cell morphology, viability and DNA integrity. Changes in these parameters were strikingly dependent on concentration of cadmium in the culture medium: a concentration of 50–100 mmol m ^{? 3} CdSO₄ induced apoptotic changes including DNA fragmentation into oligonucleosomal units, while 1 mol m ^{? 3} Cd^{2 +} showed strong cytotoxicity, but no fragmentation of DNA. Low cadmium concentrations (below 10 mmol m ^{? 3}) affected neither cell viability nor DNA integrity. A detailed kinetic study showed a significant delay in the onset of apoptosis after the application of high concentrations of cadmium. From days 0–3 after the application of 50 mmol m ^{? 3} CdSO₄, the morphology of the cells, their viability and growth were indistinguishable between control and treated cells, and ‘domain’ DNA fragmentation into 50–200 kb fragments was observed at the DNA level. After this (days 4–7), there was a characteristic and rapid decrease in cell viability, distinct changes in cell morphology and oligonucleosomal fragmentation. The results suggest that chronic exposure of plant cells to cadmium can trigger programmed cell death.     

Effect of Heavy Metal Ions on the Growth and Iron-oxidizing Activity of Thiobacillus ferrooxidans

Effect of heavy metal ions on the growth and the iron-oxidizing activity of Thiobacillus ferrooxidans were investigated.

Cupric, zinc, cadmium, and chromium ions had no effect on the growth and the iron-oxidizing activity of cell suspensions or cell-free extracts of the bacterium in high concentrations (10^?3~10^?2M). Lead ion delayed the start of the growth slightly in 10^?3 M, but it did not inhibit the iron-oxidizing activity of the cells in the concentration. Tin and molybdenum oxide ions inhibited both of them in the concentration above 10^?3 M.

Mercuric mercurous, and silver ions had the most harmful effect. In the concentration of 10^?3 .M, each of the cations inhibited almost completely both the growth and the iron-oxidizing activity of the cells.

In the experiments with cell-free extracts it was observed that the activity of cytochrome oxidase (cytochrome a₅₉₇) operating in the iron-oxidizing system of the bacterium was specifically inhibited with mercuric ion in the concentration above 5 × 10^?4 M.     

酵母菌促进铅和镉胁迫下麻疯树生长的研究

为了筛选对铅和镉具有抗性和吸附性的酵母菌,构建麻疯树根系-酵母菌联合修复体系,促进高浓度铅和镉胁迫下麻疯树的生长。该研究分别从麻疯树的根段、珙桐的茎段、珙桐的根段分离到3株具有铅、镉抗性的酵母菌,分别命名为Jc、Di1、Di2,测定了三者对铅、镉的抗性和吸附性,并将筛选出的2株能吸附铅、镉的酵母菌菌株接种到麻疯树幼苗,研究接种两种酵母菌的麻疯树植株对铅、镉胁迫的响应。结果表明:经形态学和生理生化特征观察,Jc初步鉴定红酵母属(Rhodotorula sp.),Di1为假丝酵母属(Candida sp.),Di2为德巴利酵母属(Debaryomyces sp.)。三种酵母菌对铅、镉都有一定的抗性,其抗性能力的大小为JcDi2Di1。Di1和Jc对铅和镉都具有一定的吸附性将其用于接种麻疯树幼苗。与不接种酵母菌(CK)的麻疯树植株相比,接种Di1和Jc的麻疯树植株在根、茎、叶、全株干重方面显著增加,叶绿素、全株氮、全株磷浓度显著增加,SOD、POD、CAT的活性提高,丙二醛(MDA)浓度显著下降。从综合接种效应来看,Jc、Di1作为铅、镉的钝化剂,是铅、镉胁迫下促进麻疯树生长的备选菌株,这对于提高麻疯树对铅、镉污染土壤修复效率具有重要的意义。     

The Tolerance and Accumulation of Miscanthus Sacchariflorus (maxim.) Benth., an Energy Plant Species,to Cadmium

Miscanthus sacchariflorus (Maxim.) Benth. is a metallophyte suitable for the phytoremediation of mine wastes. The tolerance and accumulation of M. sacchariflorus to cadmium was studied by pot experiments. The results showed that O₂·^? generation rate, plasma membrane permeability and MDA content of M. sacchariflorus leaves increased with increasing Cd concentrations in soil, but significant effect was only observed when Cd concentrations were ≥ 50 mg·kg^?1. SOD and POD activities increased initially but decreased later on, whereas CAT activity only increased significantly at higher Cd concentrations, 50–100 mg·kg^?1. The content of photosynthetic pigment and growth of M. sacchariflorus were both not significantly affected when Cd concentration was ≤ 25 mg·kg^?1. In contrast, both parameters were significantly affected when Cd concentration was ≥ 50 mg·kg^?1. M. sacchariflorus could accumulate much Cd, but most of the Cd assimilated was retained in the belowground part, suggesting that M. sacchariflorus has poor ability to translocate Cd to the aboveground part. Our results suggested that although M. sacchariflorus was not a hyper-accumulator, it has a strong capacity to tolerate and stabilize the Cd. Therefore, M. sacchariflorus has a certain potential in the phytostabilization of Cd-contaminated soils.     

In vitro biochemical evaluation of cadmium tolerance mechanism in callus and seedlings of Brassica juncea

In vitro grown callus and seedlings of Brassica juncea were treated with equimolar concentrations of cadmium and compared for their respective tolerance to cadmium. Calli cultures were grown on Murashige and Skoog medium supplemented with α 6-benzyl aminopurine (200 µg L^?1, naphthalene acetic acid 200 µg L^?1) and 2,4-dichloro-phenoxy acetic acid (65 µg L^?1) while the seedlings grown on Hoagland's nutrient solution have been carried out. Cellular homeostasis and detoxification to cadmium in B. juncea were studied by analyzing the growth in terms of fresh weight and dry weight, lipid peroxidation, proline accumulation, and antioxidative enzymes (superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT)). At 200 µM cadmium, callus and seedlings showed 73.61% and 74.76% reduction in tolerance, respectively. A significant increase in malondialdehyde (MDA) content was found in both calli and seedlings; however, the amount of MDA content was more in seedlings. Proline content increased on lower concentration of cadmium (up to 50 µM), and it further decreased (up to 200 µM). But the accumulation of proline was higher in callus cultures. The overall activity of antioxidative enzymes (SOD, CAT, and APX) was found to be higher in callus in comparison to seedlings of B. juncea. Callus and seedlings showed a significant (P?≤?0.5) increase in SOD activity in a concentration-dependent manner up to 50 µM cadmium concentration but decreased further. APX activity increased significantly at low cadmium levels but CAT activity decreased significantly throughout on increasing cadmium concentrations from 5 to 200 µM, respectively. Hence, it was observed that callus of B. juncea was more tolerant in comparison to seedlings exposed to equimolar concentrations of cadmium. Thus, from the present studies, it is concluded that calli were more tolerant toward cadmium-induced oxidative stress. Hence, it is suitable material for the study of cadmium tolerance mechanisms and for the manipulations within them for better understanding of cadmium detoxification strategies in B. juncea.     

Levels of toxic and essential elements in arctic fox in Svalbard

Concentrations of cadmium, mercury, lead, arsenic, selenium, copper, zinc, manganese and iron in liver, and cadmium in kidneys, were analysed in 95 carcasses of arctic fox (Alopex lagopus) caught in Svalbard during three winter seasons from 1984 through 1986. The hepatic concentration ranges of cadmium, mercury, lead and arsenic were 0.1–2.4, 0.01–2.2, < 0.5–2.9 and 0.01–1.3 g·g^–1 WW, respectively. The range of cadmium concentration in the kidneys was from 0.2 to 13 g·g^–1 WW. Cadmium and mercury concentrations were higher in adult animals than in juveniles. The average concentrations of cadmium and lead were similar to recently published levels in polar bear from Svalbard, but the mercury concentrations were lower. Significant geographical differences were observed between trapping areas. Foxes caught north of Isfjorden had lower levels of liver iron and higher levels of all other elements analysed than those caught south of Isfjorden. The recorded concentrations of heavy metals indicate a moderate degree of exposure, which most likely is of natural origin.Gunnar Norheim died January 9, 1991     

The influence of Procambarus clarkii (Cambaridae,Decapoda) on water quality and sediment characteristics in a Spanish floodplain wetland

This study describes the effects of the American red swamp crayfish, Procambarus clarkii Girard, on water quality and sediment characteristics in the Spanish floodplain wetland, Las Tablas de Daimiel National Park. Our short term enclosure study during a summer drawdown revealed that crayfish acted as a nutrient pump that transformed and translocated sediment bound nutrients to the water column. Water quality impoverishment was mainly due to the increase of dissolved inorganic nutrients (soluble reactive phosphorus and ammonia), and a significant increase of total suspended solids occurred likely as a result of crayfish associated bioturbation. At the same time, crayfish reduced the content of organic matter in the sediment and we observed a slight increase of total sediment phosphorus and nitrogen content as a result of crayfish benthic activity. P. clarkii effects, in terms of internal nutrient loading (229.91 mg TP m^–2 d^–1), were shown to be important on a local scale, indicating the significance of internal nutrient supply to water column primary producers particularly under low external supply (summer). Extrapolations to the whole ecosystem, however, revealed a negligible crayfish contribution (0.06%) to total internal nutrient loading (0.035 mg TP m^–2 d^–1). Hence, crayfish spatial heterogeneity patterns are important in global and local matter fluxes and nutrient cycles in wetlands.