Comparison of phytotoxic effects of bio-synthesised copper oxide nanoparticle and ionic copper on Elodea canadensis

This study aims to investigate the phytotoxic effects of both Punica granatum peel extract directed copper oxide nanoparticles (CuONPs) and copper nitrate on Elodea canadensis. The CuONPs were characterised by UV–visible spectroscopy (UV-Vis), Dynamic Light Scattering (DLS), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Fourier Transform Infrared (FT-IR) Spectroscopy. The ratio of photosynthetic pigments, total soluble protein, malondialdehyde (MDA), catalase (CAT), ascorbate peroxidase (APX), and copper accumulation in the E. canadensis was determined to evaluate the phytotoxicity of the CuONPs and copper nitrate on E. canadensis. The significant improvements were observed in the growth rate of E. canadensis, chlorophyll a and b, carotenoid contents, and total soluble protein in the E. canadensis when it was exposed to the CuONPs. Additionally, CAT and APX activities and MDA contents were enhanced by accumulation of the CuONPs into the E. canadensis. These results suggested that oxidative stress was alleviated, owing to the result of an increase in the antioxidants such as CAT and APX, with an increase in the concentration of the CuONPs. Finally, the findings of this study show that copper nitrate has many negative effects on E. canadensis compared bio-synthesised CuONPs.     

氧化铜活化过硫酸盐的界面反应机理

本文以苯酚为降解对象,系统性研究了氧化铜(CuO)活化过二硫酸盐(PDS)与过一硫酸盐(PMS)降解苯酚的界面反应机理.结果表明,CuO可高效活化PDS和PMS降解苯酚,电子顺磁共振(EPR)结果表明CuO/PDS体系中的活性物种有SO_4~(·-)、·OH和O_2~(·-),而CuO/PMS体系中主要存在O_~(·-)和~1O_2,猝灭实验结果表明CuO/PMS体系中O_2~(·-)起到了关键作用. CuO/PDS和CuO/PMS体系均可选择性降解具有给电子官能团的有机物.在CuO/PDS体系中,主要活化机理为富电子有机物通过取代表面羟基吸附于CuO表面,与CuO发生电子传递产生苯氧自由基,进一步可活化PDS和O_2产生SO_4~(·-)、·OH、O_2~(·-)等活性物种实现对有机物的降解.而在CuO/PMS体系中,PMS通过取代CuO表面羟基产生亚稳态中间体,与PMS及O_2~(·-)反应生成~1O_2实现对苯酚的降解,虽然体系中也存在与CuO/PDS体系中类似的苯氧自由基活化过程,但其对有机物降解的贡献较小.     

Acute toxicity of copper oxide nanoparticles to Daphnia magna under different test conditions

The acute toxicity of monodispersed 6 nm and <100 nm poly-dispersed copper oxide nanoparticles toward Daphnia magna was assessed using 48 h immobilization tests. CuSO₄ was used as a reference. Four different exposure conditions were tested, to study whether the toxicity of the nanoparticle suspensions changed in a way similar to what is known for dissolved Cu: first in ISO standard test conditions (pH 7.8), second with slight acidity (pH 6.5), third in the presence of citric acid, and fourth in the presence of humic acid. For all four exposure conditions, the toxicity of Cu employed in the three forms followed the same sequence, i.e., CuSO₄ > monodispersed 6 nm CuO ? poly-dispersed CuO. The toxicity of all Cu forms decreased from pH 6.5, ? pH 7.8, > pH 7.8 + citric acid, to ? pH 7.8 + humic acid. This pattern is in agreement with concentrations of Cu²⁺ calculated using the equilibrium model MINTEQ. These findings show that the acute toxicity of copper oxide nanoparticles is governed by test water composition and the chemical species Cu²⁺.     

Effects of copper (I) oxide on growth and biochemical compositions of two marine microalgae

In copper based antifouling (AF) paints Cu (I) oxide was largely used as booster biocide. In this study effect of Cu (I) oxide on two marine microalgae, Tetraselmis suecica and Dunaliella tertiolecta was demonstrated. EC50 (96 hr) concentrations estimated for T. suecica and D. tertiolecta were 1.3 mg l(-1) and 1.34 mg l(-1), respectively. Copper (I) oxide induced changes in growth, chlorophyll, carbohydrate and protein contents were observed in T. suecica and D. tertiolecta. At low concentration of 0.0625 mg l(-1), 3-26% and 1-16% growth stimulation was observed in T. suecica and T. tertiolecta respectively. Increasing Cu (I) oxide concentrations proportionately decreased the carbohydrate and protein contents. This study clearly indicates the toxicity of excessive Cu (I) oxide on growth and biochemical compositions of T. suecica and D. tertiolecta.     

Susceptibility of the freshwater pulmonate snail Lymnea luteola L. to copper oxide nanoparticle

Copper oxide nanoparticles (CuONP) are among the most widely used engineered nanoparticles and thus likely to permate the environment predominantly in sediments. The present study was designed to examine the adverse effects of CuONP in freshwater snail Lymnea luteola L. (L. luteola) exposed for 5 days. Induction of oxidative stress in digestive gland was evidenced by a decrease in reduced glutathione (GSH) levels, and activities of glutathione peroxidase (GPx) and glutathione-S-transferase (GST) whereas lipid peroxidation levels were increased at CuONP 7 or 21 µg/L. Superoxide dismutase activity was numerically higher at lower concentration of CuONP at 1 day but significantly decreased at 5 days. Catalase activity was reduced at 2 days but elevated at lower concentration of CuONP at 5 days. DNA impairment was noted in L. luteola based upon comet assay findings and expressed in terms of % tail DNA and olive tail moment. Results indicate that interaction of CuONP with snail produces toxicity, which is mediated by oxidative stress.     

Mechanism of toxicity of ionic copper and copper complexes to algae

The mechanism of toxicity of ionic copper and copper complexes to growth, photosynthesis, respiration, ATP levels and mitochondrial electron-transport chain-activity in two marine diatoms, Nitzschia closterium (Ehrenberg) W. Smith (Hasle, 1964) and Asterionella glacialis Castracane, and one freshwater green alga, Chlorella pyrenoidosa Chick was investigated. Copper ions depressed both cell division and photosynthesis in A. glacialis and C. pyrenoidosa, whereas ionic copper concentrations which were inhibitory to cell division in N. closterium had no effect on photosynthesis, respiration, ATP production, electron transport or membrane ultrastructure. This suggests that in N. closterium, copper does not act on the chloroplast, the mitochondrion, or the cell membrane, since if it did, the above parameters should be affected. Copper-ethylxanthogenate was exceptional amongst the copper complexes in that it stimulated respiration, mitochondrial electrontransport and ATP formation in N. closterium under conditions of strongly inhibited cell division and slightly stimulated photosynthesis. Ionic copper toxicity may result from an intracellular reaction between copper and reduced glutathione (GSH), leading to a lowering of the GSH:GSSG ratio and suppression of mitosis. In addition, copper inhibits the enzyme catalase and reduces cell defence mechanisms against H₂O₂ and oxygen-free radicals. Lipid-soluble copper complexes are more toxic than ionic copper because both the metal and the ligand are introduced into the cell. Toxicity of ionic copper is ameliorated by trivalent metal ions in the growth medium, including those of Mn, Co, Al, Fe and Cr which form a layer of metal (III) hydroxide around the algal cell, adsorb copper and reduce its penetration into the cell. The degree of insolubility of the metal (III) hydroxide is related to its ability to protect against copper toxicity. In addition, manganese and cobalt catalytically scavenge damaging H₂O₂ and superoxide radicals, respectively, produced by the cell.     

Sequential extraction of copper from soils and relationships with copper in maize

We studied copper uptake by maize grown on soils that have been contaminated with CuSO₄. In soil the total copper level ranged from 24 to 135 mg kg^–1. The copper distribution in soil fractions was assessed by sequential extraction, showing that anthropogenic copper is mainly concentrated in oxides fractions. The copper concentration of maize at the maturity stage reached values from 36.3 to 65.9 mg kg^–1 compared to copper levels usually found in non-contaminated crops (5–30 mg kg^–1). Here we demonstrate that copper can be accumulated by maize and that copper concentration in maize can be predicted by equations including copper concentration of soil fractions.     

Histopathological effects of copper oxide nanoparticles on the gill and intestine of common carp (Cyprinus carpio) in the presence of titanium dioxide nanoparticles

In current research, the combined effects of copper oxide nanoparticles (CuO NPs) and titanium dioxide nanoparticles (TiO₂ NPs) on the histopathological anomalies of gill and intestine tissues in common carp (Cyprinus carpio) were studied. Common carp were exposed to TiO₂ NPs (10.0?mg L^?1), CuO NPs (2.5 and 5.0?mg L^?1), and mixture of TiO₂ NPs (10.0?mg L^?1)?+?CuO NPs (2.5 and 5.0 mg?L^?1) for two periods of exposure (10 and 20 days) and recovery (30 and 40 days). The most common histopathological anomalies in the gill of common carp such as hyperplasia, oedema, curvature, fusion, aneurism, and necrosis were observed. The synergistic effect of co-existing TiO₂ NPs and CuO NPs reduced the length of secondary lamella and increased the diameters of the gill filaments and secondary lamellae. Moreover, the presence of TiO₂ NPs increased the CuO NPs effects on the histopathological anomalies of intestine tissue and the synergistic effect of TiO₂ NPs and CuO mixture leads to an increase in the severity of histopathological lesions such as degeneration, swelling of goblet cells, and necrosis - erosion in the intestine tissue. In conclusion, the presence of TiO₂ NPs increased the toxicity of CuO NPs.     

植物铜素毒害及其抗性机制研究进展

Cu是植物生命活动必需的微量矿质元素，广泛参与各种生命活动；但过量Cu胁迫将诱导植物细胞产生大量活性氧，引起膜脂过氧化，膜透性增大，细胞内容物大量外渗，甚至发生细胞死亡。Cu^2 扩散到细胞核内会诱发DNA之间、蛋白质之间以及DNA和蛋白质之间发生分子内和分子间交联，DNA链的断裂、重排和脱嘌呤作用等前诱变损伤以及DNA期外合成、DNA甲基化异常等遗传毒害。植物细胞在长期进化过程中形成了各种抗Cu素毒害机制，如细胞壁的固着作用、质膜的限制作用、有机小分子(有机酸、植物螯合肽、金属硫蛋白)螯合作用等。文章综述了有关研究的最新进展。     

Biosynthesis and effects of copper nanoparticles on plants

Copper nanoparticles have improved properties compared to the bulk copper material. Copper nanoparticles indeed find applications in gas sensors, heat transfer fluids, catalysis, solar energy and batteries. Antibacterial and antifungal activities of copper nanoparticles find applications in the agriculture and healthcare sectors. Nonetheless, careless use of copper nanoparticles may cause environmental pollution and health effects. Here we review the biosynthesis of copper nanoparticles using plant materials, named phytosynthesis, and micro-organisms. We also discuss the effect of copper nanoparticles on crops and pathogenic micro-organisms. Copper nanoparticles varying in sizes from 5 to 295 nm have been synthesized using leaf extracts and latex from plants, and using bacteria and fungi. Biosynthesized copper nanoparticles show good antimicrobial activity inhibiting the growth of pathogenic bacteria and pathogenic fungi. Copper nanoparticles enhance the germination and growth of some plants at lower concentrations, whereas high concentrations result in retarded growth.     

Nickel and copper accumulation strategies in Odontarrhena obovata growing on copper smelter-influenced and non-influenced serpentine soils: a comparative field study

The present investigation is the first in situ comparative study for the identification of Ni and Cu accumulation strategies involved in Odontarrhena obovata (syn. Alyssum obovatum (C.A. Mey.) Turcz.) growing in Cu-rich smelter-influenced (CSI) and non-Cu-influenced (NCI) sites. The total and Na₂EDTA (disodium ethylenediaminetetraacetic acid)-extractable metal concentration in soils and plant tissues (roots, stem, leaves and flowers) were determined for CSI and NCI sites. High concentrations of total Ni, Cr, Co and Mg in the soil suggest serpentine nature of both the sites. In spite of high total and extractable Cu concentrations in CSI soil, majority of its accumulation was restricted to O. obovata roots showing its excluder response. Since the translocation and bioconcentration factors of Ni?>?1 and the foliar Ni concentration?>?1000 μg g^?1, it can be assumed that O. obovata has Ni hyperaccumulation potential for both the sites. No significant differences in chlorophyll content in O. obovata leaves were observed between studied sites, suggesting higher tolerance of this species under prolonged heavy metal stress. Furthermore, this species from CSI site demonstrated rather high viability under extreme technogenic conditions due to active formation of antioxidants such as ascorbate, free proline and protein thiols. The presence of Cu in higher concentration in serpentine soil does not exert detrimental effect on O. obovata and its Ni hyperaccumulation ability. Thus, O. obovata could act as a putative plant species for the remediation of Cu-rich/influenced serpentine soils without compromising its Ni content and vitality.

     

Amelioration of free copper by hydrothermal vent microbes as a response to high copper concentrations

We examined the effect of increased copper concentrations (0–10 μM) on hydrothermal vent micro- organisms and the production of copper (Cu)-binding ligands as a response. Hydrothermal vent microbes originated from diffuse fluids at the Lilliput mussel field and the Irina II site in the Logatchev hydrothermal vent field, both on the Mid-Atlantic Ridge. Parallel studies were also conducted with amino acids supplemented to the incubations in order to verify whether dissolved amino acids, present in hydrothermal fluids, can buffer the bioavailable copper and reduce the active production of Cu-binding ligands. In all incubations, ligand concentrations increased with rising copper concentrations, but microbial cell numbers remained constant. This study shows that microbes were able to cope with as much as 10 μM dissolved copper by buffering the free copper concentration. The presence of amino acids had no significant influence on the active ligand production. Our results imply that mediation of chemical speciation by vent microbes may have an important impact on hydrothermal trace metal fluxes into the ocean.     

Effects of copper and zinc on two planktonic ciliates

The interactive effects of copper and zinc on two estuarine planktonic ciliates, Favella sp. and Balanion sp., were determined in seawater media in which the free metal ion activities were controlled by nitrilotriacetic acid (NTA) trace metal ion buffer systems. Cupric ion activities of 10^-10 M caused abnormal motility in both ciliates in shortterm (5 h) tests, and cupric ion activities as low as 10^-12.8 M decreased the growth rates of both species in longer-term experiments. In the short-term tests, zinc ion activity by itself did not affect the motility of the ciliates, but there were significant interactions between copper and zinc. In the longer-term experiments, the growth of Favella sp. was optimal at the lowest cupric ion activity (10^-13 M) and the two lowest zinc ion activities (10^-12 and 10^-13 M) and the two lowest zinc ion activities (10^-12 and 10^-11 M), and copper and zinc inhibited growth at activities above these values. By contrast, optimal growth rate of Balanion sp. occurred at the highest zinc ion activity (10^-10 M) and the lowest cupric ion activities (10^-13 to 10^-12 M) and growth rate was reduced at zinc ion activities 10^-11 M. There was an antagonism between copper and zinc which was particularly pronounced in Balanion sp.Contribution No. 5871 from the Woods Hole Oceanographic Institution     

Acclimation and tolerance of Artemia salina to copper salts

The brine shrimp Artemia salina L. was acclimated in sea water with cupric chloride, acetate, carbonate, and sulphate, each at concentrations of 0.1, 0.05 and 0.025 ppm Cu⁺⁺, together with sea water controls. Growth inhibition was observed in all four compounds, generally in direct relationship to the concentration. It was least in sulphate, and increased progressively in chloride, acetate and carbonate in that order. No inhibition however was observed in carbonate at 0.025 ppm Cu⁺⁺. In toxicity tests, 2-week old larvae from each solution were exposed to concentrations of 10, 7.5, 5, 2.5 and 1 ppm Cu⁺⁺ of the same compounds, together with unacclimated larvae of the same age. Similar tests were held with 6-week old adults acclimated (a) in 0.1 ppm Cu⁺⁺ (chloride, acetate and sulphate) using the same concentrations and (b) in 0.5 ppm Cu⁺⁺ (carbonate), using 150, 125, 100, 75, and 50 ppm Cu⁺⁺. Toxicity to unacclimated larvae and adults differed with the compounds, carbonate being the least toxic, followed by sulphate, chloride and acetate in increasing order. Larvae acclimated in chloride (0.025 ppm Cu⁺⁺) and sulphate (0.1 and 0.5 ppm Cu⁺⁺) showed an increased tolerance to 1 and 2.5 ppm Cu⁺⁺ compared to untreated controls. Tolerance was not enhanced from 5 ppm Cu⁺⁺ upwards. In both compounds, adults acclimated in 0.1 ppm Cu⁺⁺ showed an increased tolerance to concentrations between 1 and 7.5 ppm Cu⁺⁺ compared to controls. Larval mortality in carbonate was below 50% in all test solutions. Adults acclimated at 0.5 ppm Cu⁺⁺ showed an increased tolerance to 50 ppm Cu⁺⁺ compared to controls. Considerable precipitation occurred with the high levels of this compound, thus effecting the final concentrations. No acclimation effect was observed in acetate for either larvae or adults. It is suggested that in A. salina, copper toxicity depends on the particular form of the metal, and that this difference is also evident in growth inhibition and in the potential acquisition of increased tolerance through exposure to low concentrations.     

表面涂层影响铜纳米材料和溶解性铜对大型溞的蓄积动力学和急性毒性

本研究评价了未涂覆或有三种不同表面涂层（即羧基化，聚乙二醇化和氨基团）的氧化铜纳米材料（CuO-NMS）对大型溞（Daphnia magna）的急性毒性和累积动力学。首先利用生物动力学模型确定了溶解铜和CuO-NMS水溶液对大型溞的吸附和消除速率常数。然后评估模型参数与急性毒性终点之间的关系，以考察累积动力学参数是否可作为急性毒性的预测指标。采用朗格缪尔方程表征铜纳米材料和氯化铜（溶解铜对照）的生物吸附动力学。得到的吸收速率依次为：CuO-NMs>NH3-CuO-NMs>Cu水溶液>PEG-CuO-NMs>COOH-CuO-NMs。采用单室模型测定大型溞对铜的去除率。估算了每种被测化学物质的不同消除速率常数。结果显示，容易被生物吸收的物质也更容易从生物体中去除。纳米材料在悬浮液中的吸附和净化性能与Zeta电位值和纳米材料团聚体直径有关。而生物吸附和毒性之间没有联系。水性暴露于较难生物吸附的CuO-NMs比易被生物吸附的CuO-NMs更易诱发不良反应。本文提出了纳米材料在介质中的某些物理化学性质，包括Zeta电位和团聚体直径，可以导致较高的生物吸附，但不一定影响毒性。总而言之，纳米材料与生物体的相互作用模式似乎很复杂，取决于生物体内纳米材料的化学形态和物理化学性质。     

Removal of copper and cyanide from solution using activated carbon

The removal of copper and cyanide from aqueous solution by activated carbon has been investigated. Using a coal-based activated carbon, initial concentrations of 244 to 2441 mg/litre total cyanide combined with 61 to 610 mg/litre copper were reduced to a minimum of 3.6 mg/litre total cyanide and 0.6 mg/litre copper in the presence of a fixed initial quantity of air.Cyanide removal was, found to be augmented by the presence of copper in solution, and by the supply of additional air.It is suggested that cyanide removal is accomplished by catalytic oxidation on the carbon surfaces, and that additional cyanide is removed in the presence of copper by adsorption of cyano-cuprate complexes onto the activated carbon.     

Mechanisms for copper tolerance in Amphora coffeaeformis-internal and external binding

Growth of the ship-fouling diatom Amphora coffeaeformis and accumulation of copper in the cells were evaluated for cultures exposed to copper. Comparisons with literature reports for other species revealed that A. coffeaeformis shows no ability to maintain normal growth rates in the presence of high cellular copper levels. This suggests that internal binding is not the principal copper tolerance mechanism for this species. In addition, the copper complexing capacity of A. coffeaeformis exudates was evaluated. Significant complexing by these exudates was demonstrated by DPASV analysis. When added to the culture medium of another species (Thalassiosira profunda), A. coffeaeformis exudates were also able to reduce copper toxicity and accumulation in the cells of that species. However, the copper tolerance of A. coffeaeformis was greater than that acquired by T. profunda grown with A. coffeaeformis exudates; thus exudate production was deemed not to be a primary tolerance mechanism. Comparison of copper accumulations inside and outside cells of A. coeffeaeformis suggests that binding at the cell surface or to mucilage may be an important factor in the tolerance of this species to copper.     

Cadmium,copper, and zinc in carrots in Japan

Cadmium (Cd), copper (Cu), and zinc (Zn) in carrots obtained from different regions throughout Japan were assessed in a baseline study on the contents of trace metals in foods. These three metals were measured by flameless atomic absorption spectrophotometry. The geometric mean contents (with one geometric standard deviation indicated in parentheses) of Cd, Cu, and Zn were 0.02 (2.2), 0.7 (2.1), and 2.4 (1.6) mg?kg^?1 wet weight in carrots obtained in Japan. While there was a close relationship among the contents of the three metals in the carrots grown in Cambisols and Gleysols, a significant relationship was recognized only between the contents of Cd and Zn in those grown in Andosols and Fluvic Gleysols. Cd and Zn are classified as 2B metals in the periodic table of elements, and the authors speculate that the similarity of the metal characteristics between Cd and Zn may be responsible for the close relationship in the contents of the two metals, with no relation to the soil type.     

Phytotoxicity of copper fungicides to guava fruits

The copper fungicides viz., Bordeaux mixture, stabilized Bordeaux mixture and copper oxychloride were found phytotoxic to guava fruits, while carbendazim, benomyl and mancozeb were non-phytotoxic. Bordeaux mixture was highly phytotoxic and caused heavy russetting, followed by stabilized Bordeaux mixture and then copper oxychloride. The higher concentrations of these fungicides were more toxic than their lower doses. Russetted fruits failed to attain normal size and thus reduced the quality of fruits to a greater extent.