Project Tocoen. the fate of selected pollutants in the environment. Part XIX. the phytotoxicity of organic and inorganic pollutants‐cadmium. The effect of cadmium on the growth of germinating maize plants

The effect of increasing cadmium concentration (10, 100 and 1000 μmol dm^‐3) on the growth, leaf area, content of assimilation pigments, cadmium content and the regulatory ability of the tissue of maize plants was investigated.

The results obtained document, already after 6 days, a significant decrease of dry weight, reduction of leaf area, chlorophyll a and b as well as carotenoids in plants grown in the nutrient solution containing 1000 μmol dm ^‐3 of cadmium. A highly significant inhibition of growth, leaf area and assimilation pigments in plants growing in the nutrient solutions with 100 and 10 μmol dm^‐3 of cadmium was registered after 17 days of cultivation. In plants growing in the nutrient solution containing 100 μmol dm^‐3 of cadmium a demonstrable reduction of the content of assimilation pigments was registered after 11 days of culture.

With increasing cadmium concentration in the nutrient solution as well as in the plant tissue after 6 and 17 days of culture both the range of the regulatory zone and the extent of optimum pH increased into the acid region. The pH values of the isoelectric point decreased with increasing cadmium content in the solution.     

Mutagenic and carcinogenic effects of cadmium†

There is limited evidence to suggest that certain compounds of cadmium may be mildly mutagenic. Some compounds of cadmium have given rise to fibrosarcoma and rhabdomyosarcoma following subcutaneous or intramuscular injection in the rat and also to interstitial cell tumours of the testis as a sequel to cellular damage and testicular atrophy. Cadmium chloride aerosol inhalation has induced a high incidence of dose‐related lung cancer in the rat. Epidemiological observations suggest that mortality from prostatic and possibly from lung cancer has been increased in cadmium workers who had experienced the very high levels of cadmium, mainly as oxide dust or fume, which existed in the past. The more recent epidemiological studies have not added further evidence in support of the carcinogenic role of cadmium.     

Choice of chelating antidotes for acute cadmium intoxication∗

During acute oral intoxication by cadmium compounds, gastrointestinal epithelial damage contributes to immediate toxicity. However, secondary systemic toxicity may develop due to intestinal uptake of cadmium. This review presents an evaluation of the effects of chelators on the acute toxicity of cadmium after parenteral or oral exposure and on the intestinal uptake of cadmium. This review shows:

1. Chelating agents may affect the acute toxicity of cadmium in a variety of ways depending on the exposure route for cadmium and administration route for the chelator.

2. With regard to survival, systemic toxicity of absorbed cadmium is of major importance, as intraperitoneal administration of chelators could eliminate or reduce mortality due to orally administered cadmium chloride.

3. Lipophilicity of chelators and their cadmium complexes may result in extensively augmented intestinal uptake. However, hydrophilic chelators may efficiently reduce the intestinal cadmium uptake.

4. For hydrophilic chelators, the stability of the cadmium complex is an important determining factor of efficacy.

5. The optimal oral antidote towards orally administered cadmium are the BAL analogs, especially DMSA, while the optimal intraperitoneal antidotes towards orally or intraperitoneally administered cadmium are the higher members of the polyaminopolycarboxylate family, especially TTHA.

6. When administered simultaneously (DMSA orally and TTHA intraperitoneally), these chelators synergistically reduce the whole‐body retention of cadmium.

In conclusion, chelation treatment in acute oral cadmium intoxication should first prevent/reduce intestinal damage and uptake by rapid oral administration of a chelating antidote and then alleviate systemic toxicity due to absorbed cadmium and enhance renal/biliary cadmium excretion by parenteral administration of a chelating antidote.     

Comparisons in subcellular and biochemical behaviors of cadmium between Iow-Cd and high-Cd accumulation cultivars of pakchoi （Brassica chinensis L.）

Subcellular distributions and chemical forms of cadmium （Cd） in the leaves, stems and roots were investigated in low-Cd accumulation cultivars and high-Cd accumulation cultivars ofpakchoi （Brassica chinensis L.）. Root cell wall played a key role in limiting soil Cd from entering the protoplast, especially in the low-Cd cultivars. The high-Cd cultivars had significantly higher leaf and stem Cd concentrations than the low-Cd cultivars in cell wall fraction, chloroplast/trophoplast fraction, organelle fraction and soluble fraction. In low-Cd cultivars, which were more sensitive and thus had greater physiological needs of Cd detoxification than high-Cd cultivars, leaf vacuole sequestrated higher proportions of Cd. Cd in the form of pectate/protein complexes （extracted by 1 tool. L~ NaC1） played a decisive role in Cd translocation from root to shoot, which might be one of the mechanisms that led to the differences in shoot Cd accumulation between the two types of cultivars. Furthermore, the formation of Cd- phosphate complexes （extracted by 2% HAc） was also involved in Cd detoxification within the roots of pakchoi under high Cd stress, suggesting that the mechanisms of Cd detoxification might be different between low- and high-Cd cultivars.     

Detection of metallothionein in the intestinal mucosa and brain with 109cadmium∗

Metallothionein (MT) has a great capacity of binding metal ions showing an interesting connection with metal toxicology, as a biochemical marker for environmental metal pollution.

To normal male Wistar rats (200±10 g) and other groups with ferropenic anemia, are administered 1 mg Cd/Kg/day, during 6 days, and MT labelled with the administration 2 h before sacrifice of 3 μCi ¹⁰⁹CdCl₂, also through intragastric catheter. The MT concentration in the intestinal mucosa is expressed in μg MT/g fresh tissue, being for control rats 1.4 ± 0.5; for rats administered with 6 doses of Cd 2.5 ± 0.6 (P<0.05); with ferropenic anemia 4.3±0.7 (P<0.001), and for anemic rats treated with 6 doses Cd 12 + 0,3 (P<0.001) μg MT/g fresh tissue respectively. PAGE 15% T, 2% C_Bis show for intestinal mucosa 2 MT peaks and for brain 3 MT peaks. Anemia induce MT accumulation and increases cadmium incorporation, being anemic subjects eligibles to be submitted first to control and detoxication than the rest of the population, and also MT should be studied as biochemical marker of the pollution.     

The physiological response and iron and potassium contents in the hairy roots of Brassica rape L. Under cadmium stress北大核心CSCD

The experiments were conducted to investigate the tolerance and enrichment capabilities by elucidating the physiological response and cadmium impact on iron and potassium accumulation amounts of brassica rape hairy roots under different cadmium concentrations by using liquid suspension culture method. The results showed the following. (1) The growth of hairy roots was not significantly different under low cadmium concentrations (below 100 μmol/L), whereas it was obviously inhibited under high cadmium concentrations (more than 100 μmol/L). Further, the maximum fresh weight of brassica rape hairy roots reached 4.34 g under 25 μmol/L cadmium stress after 7 days. (2) The content of ROS in brassica rape hairy roots increased with increasing concentrations of cadmium; the antioxidant enzyme activities of brassica rape hairy roots (SOD, POD, and CAT) decreased first and then increased with increasing cadmium concentrations under 1-day stress, whereas showed an opposite trend under 7-day stress. (3) PI staining and MDA content indicated that cellular damage was more serious with increasing cadmium concentrations. (4) With the increase of cadmium concentrations, cadmium content of hairy roots increased and reached maximum of 2.97 mg/g under 400 μmol/L cadmium stress after 7 days. The iron content also increased significantly with the maximal weight of 14.52 mg/g after 1-day cadmium stress, whereas no significant difference was noted under 7-day cadmium stress. The potassium content under 7-day cadmium stress was 1.6 times of that after 1-day stress (15.73 mg/g). The study showed that the physiological response of Brassica rape hairy roots was correlated with the concentration and time of cadmium stress. Moreover, cadmium stress caused metabolic disorders of iron and potassium in the hairy roots, but the hairy roots of Brassica rape had better enrichment effect on cadmium. © 2018 Science Press. All rights reserved.     

Biological Decolorization of C.I. Basic Green 4 Solution by Chlorella sp.： Effect of Operational Parameters

In recent years, the ability of microorganisms to decolorize textile wastewater has received great attention due to the environmental persistence and toxicity of these pollutants. In this paper biological decolorization of triphenylmethane dye, C.I. Basic Green 4 (BG 4), by Chlorella species was investigated. The effect of operational parameters (temperature, pH, initial dye concentration and algal concentration) on decolorization efficiency was examined. Results indicated that the desired initial pH was 9. The stability and efficiency of the algae in long-term repetitive operations were also examined. Michaelis-Menten kinetics was employed to describe the apparent correlation between the decolorization rate and dye concentration. The optimal kinetic parameters, Vmax (specific decolorization rate) and Km (maximum specific decolorization rate) were 4.6 mg dye g cell-1 h-1and 151.0 mg L-1, respectively. Fig 10, Tab 2, Ref24     

Inhibitory kinetics of β-N-acetyl-D-glucosaminidase from Nile tilapia (Oreochromis niloticus) by cadmium北大核心CSCD

Cadmium (Cd2+) pollution in an aquatic environment can negatively affect certain reproductive parameters of aquatic animals. β-N-acetyl-D-glucosaminidase (NAGase) is considered to play an important role in the fertilization process. The aim of the present study was to investigate the effect of Cd2+ on the activity of NAGase purified f rom the testis of Nile tilapia, toward contributing new knowledge on the breadth of negative effects of Cd2+ for Nile tilapia production. The kinetic method of substrate reaction was used for this assessment, and an inhibitory model was established to study the kinetics of NAGase under inhibition by Cd2+. The results showed that Cd2+ could reversibly inhibit the enzymatic activity of NAGase, and the half-maximal inhibitory concentration was estimated to be 40.95 mmol/L. Cd2+ was found to be a competitive inhibitor of NAGase, and the inhibitory constant was determined to be 17.13 mmol/L. The microscopic rate constants of inactivation were also determined. Together, these findings demonstrate that Cd2+ is a reversible inhibitor that can competitively inhibit NAGase. These results may provide a theoretical foundation for further studies on the reproduction of tilapia. © 2018 Science Press. All rights reserved.     

Trace analysis. Determination of the “breakthrough volume”; (B.T.V.) of atmospheric isoprene

This paper presents the first results of a study of B.T.V. on Tenax TA, at various flow rates of sampling, with standard isoprene gaseous mixtures whose concentration ranging from 0.7 ppbV to 4 ppbV was very similar to the concentrations found in natural atmosphere. The method used is based on the exploitation of chromatographic signals obtained from a preconcentration—thermodesorption —analysis cycle carried out on a standard isoprene mixture. The B.T.V. of isoprene on Tenax TA does not show a significant change at very low concentrations of isoprene.     

Preconcentration of cadmium and copper ions on magnetic core–shell nanoparticles for determination by flame atomic absorption

Magnetic core–shell nanoparticles modified by (3-aminopropyl) trimethoxy silane were prepared and used as adsorbent for the extraction and preconcentration of cadmium and copper ions. The ions were desorbed with nitric acid followed by determination with flame atomic absorption spectrometry. The extraction conditions were investigated systematically. The method was applied for the determination of Cd(II) and Cu(II) ions in different water samples. The accuracy was also evaluated through analysis of certified reference material.     

Presence of Cd‐binding proteins in pre‐exposed and not pre‐exposed cadmium brine shrimp Artemia

The presence of metal binding proteins has been variously suggested as indicating involvement in uptake, storage, transport and elimination of toxic metals and in the routine metabolism of metals in mammals and a variety of marine invertebrates. This report describes results on the characterization of Cd‐BPs obtained from cadmium pre‐exposed and not pre‐exposed Anemia. The effect of pre‐exposure in the Cd‐binding protein induction in Artemia is discussed.     

Analysis,accumulation and central effects of trihalomethanes. I. bromoform†

The paper presents the results obtained in a study on the effects of organic micropollutants on the central nervous system of the rat, used herein as a suitable model for neurotoxicologic work. Bromoform, a member of the trihalomethane (THM) family, was the pollutant selected since it becomes a characteristic marker in the Barcelona potable water supply.

Analytical data on the GC‐ECD separation of THMs from other volatile halocarbons is presented. A mixed packed column 10% SE‐30/PEG 20M (94:6) at 70°C provides an adequate separation. The distribution of bromoform in rat plasma and tissues showed an accumulation in brain, kidney and fat, increasing in this order and a rapid elimination after 30 min. The effect on the central aminergic metabolism is studied by HPLC. The increased metabolic activity detected could be attributed either to an increased nervous activity, stimulating the metabolism of serotonin, or to its greater degradation.     

Photodegradation of pesticides .1. Photolysis rates and half‐life of acylanilides and their major metabolites in water

The photolysis in water solution of three fungicides (Metalaxyl, Benalaxyl, and Furalaxyl) was studied under artificial light. At λ = 254 Benalaxyl and Furalaxyl underwent fast degradation with rearrangement reactions less complex than those of Metalaxyl. Under A = 254–290 the photolysis was very fast and Benalaxyl and Furalaxyl show a common behaviour. This was found to be a kinetic consecutive process leading, at first, to N‐2,6‐xylyl‐D,L‐alaninate (II), which was degraded to 2,6‐dimethylaniline (IV). This amine gives unknown products. Metalaxyl underwent a parallel/consecutive photodegradtion to give (II) and N‐(methoxyacetyl)‐2,6‐dimethylaniline (VI). While (II) was easily converted to (IV) as earlier, (VI) was more stable to photolysis. Under λ > 290 all the fungicides shown very slow degradation with pseudo first order rate constants. The photoproducts were degraded faster than the parent compounds by factors from 13 to 1800. The presence of photosensitizer in water (humic acids or acetone) resulted in total decomposition of fungicides and of their photoproducts.     

Total Contents of Chinese Journal of Appliedand Enviromental Biologyin 2002 Vol.8

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Protective properties of filamentous blue–green alga Spirulina against the oxidative stress induced by cadmium in freshwater mussel Unio ravoisieri

ABSTRACT

Cadmium (Cd) is a toxic-heavy metal that induces a wide range of behavioural, biochemical and physiological effects in aquatic organisms. Oxidative damage has been proposed as a possible mechanism involved in cadmium toxicity. The current study was carried out to evaluate the antioxidant activity of Spirulina as feed additive (1?mg/L) against the toxicity of cadmium (Cd) 0.5?mg/L in freshwater mussel Unio ravoisieri. At the end of the exposed period of 4 days, digestive gland antioxidant status Superoxide dismutase, Catalase, Glutathione-S-transferase and damage markers such as Malondialdehyde and Protein carbonyl were determined. Associations between biomarkers were assessed by a multivariate analysis technique, principal component analysis (PCA). The results of this study revealed that digestive gland antioxidant status showed a significant decrease when mussels were exposed to Cd. Superoxide dismutase, Catalase and Glutathione-S-transferase activities in the Cd?+?SP group were significantly higher than the Cd group (p P?相似文献   

Dispersive liquid–liquid microextraction of cadmium(II) for preconcentration prior to flame atomic absorption spectrometric detection in water

A dispersive liquid–liquid microextraction procedure for cadmium(II) as its 2-(5-bromo-2-pyridylazo)-5-diethylamino-phenol chelate is presented. Carbon tetrachloride and methanol were used as extraction and dispersive solvents, respectively. After phase separation, the preconcentrated-separated cadmium(II) is determined by flame atomic absorption spectrometry with a microinjection technique. The factors which affected the extraction efficiency, i.e. the pH of the sample solution and the volumes of reagent and sample were investigated. The effects of some alkali, alkali earth, and transition metal ions, and of some anions on the recovery of cadmium were also studied. A preconcentration factor of 250 was obtained for a sample volume of 50?mL under optimum conditions. The method was validated by analysis of certified reference materials and applied to some water samples from Turkey.     

Active protection of unrelated offspring against parasitoids. A byproduct of self defense?

Natural enemies exert selection pressure on their prey. Predators and parasitoids drive their prey into the evolution of novel traits to cope with this stress. When eggs and juveniles are the target of enemies, defense strategies may rely on adults. However, it is not easy to predict whether adults should actively protect unrelated offspring. Females of the golden egg bug (Phyllomorpha laciniata) mainly oviposit on conspecifics of either sex. Females can also lay eggs on their food plant. Eggs placed on plants suffer from a higher mortality caused by natural enemies than eggs carried by bugs. Females never carry their own eggs and males are seldom related to the eggs they carry. We experimentally explored if conspecifics protect the eggs by studying the behavioral interaction between P. laciniata individuals and the specialist egg parasitoid Gryon bolivari. All bugs exhibited active responses against parasitoids regardless of the sex of the bug, the egg load, and their mating status. Most of the responses prevented parasitoids from reaching the eggs, and thus they reduced the risk of egg parasitization. Although responses of bugs were effective to overcome parasitoid attacks, we suggest that egg protection against parasitoids has evolved as a co-opted trait from a general defense of adult bugs against enemies. In this system, egg defense is not an individual's strategy to protect the offspring, but rather a consequence of the eggs being attached to one's body. It may also explain the low parasitization carried eggs suffer in the wild. The results further highlight the idea of conspecifics as an enemy-free space in P. laciniata.     

Low level inhalation experiments with four different cadmium compounds in rats†

This long‐term inhalation study was designed to describe the toxicity and the carcinogenic risk from Cd compounds because it had been shown from former long‐term inhalation studies that cadmium choloride induced primary lung tumors in Wistar rats. It was therefore logical to examine whether other cadmium compounds to which human beings are more frequently exposed have also carcinogenic potency. In a long‐term inhalation study cadmium aerosols consisting of cadmium chloride (CdCl₂), cadmium oxide (CdO) as dusts and fumes, cadmium sulfate (CdSO₄), cadmium sulfide (CdS) and a combination of cadmium oxide/zinc oxide were used. Wistar rats were continuously exposed in inhalation chambers for 18 months 22 hrs a day or for 40 hrs a week. The studies will be terminated at the mean survival life time of the species. The aerosols were generated by several different systems. The particles of the cadmium aerosols have the average mass medium diameters in the range from 0.2 to 0.5 μm.     

Growth promotion and disease prevention effects of streptomyces on Amorphophallus konjac K. Koch ex N.E.Br北大核心CSCD

This study aimed to evaluate the disease antagonism and seed growth promotion effects of streptomyces on Amorphophallus konjac by agar block and axenic fermentation extract experiments. Pot experiments were taken to assess relative biocontrol effiency and effect of streptomyce preparation M (mixture of S. carnosus and S. pactum in solid-state fermentation with 1:1 ratio) on biomass, photosynthetic rate, yield and corm quality of A. konjac K. Koch ex N.E.Br. Results showed that: 1 Streptomyces Act12 had obvious antagonistic activity against six soft rot pathogens, and the diameter of growth inhibition zones ranged from 19.4 to 31.6 mm. Fermentation filtrate of streptomyces exhibited growth-promoting activity on melon seed germination and seedling growth. 2 Streptomyce-derived viable preparations had biocontrol effect on A. konjac regarding soft rot-disease prevention. In the pot experiment, individual inoculation of preparations achieved 65.0% relative biocontrol effect on A. konjac during the harvest stage. After 10 and 20 days of inoculation combined with Pectobacterium chrysanthemi (a bacterial pathogen), the relative biocontrol effiency of streptomyces were 100.0% and 58.4%, respectively. 3 Streptomyces showed obvious growth-promoting effect on growth and yield of A. konjac. In the pot experiment, combined inoculation of streptomyces and Pectobacterium chrysanthemi significantly increased the petiole diameter by 11.1%, net photosynthetic rate by 111.7%, fresh weight of corm by 54.8%, fresh weight of rhizome by 304.2%, and the number of rhizomes by 200.0%, compared with individual inoculation of Pectobacterium chrysanthemi. 4 Individual inoculation with streptomyces improved corm quality of A. konjac. The contents of glucomannan, starch and cellulose significantly increased by 14.0%, 8.1% and 27.7%, respectively compared with control (P < 0.05) . This study indicates that streptomyces promotes the growth of A. konjac, enhances the yield and the content of glucomannan, and at the same time helps disease prevention of A. konjac.