Differences In Cu Concentrations Research Articles

Environmental efficacy of polyethylene microplastics: Enhancing the solidification of CuO nanoparticles and reducing the physiological toxicity to peanuts

Microplastics and metal-based nanoparticles (NPs) are environmental pollutants that have attracted significant attention. However, there have been relatively few studies on the combined pollution of these substances in the soil-plant system. To investigate the environmental impact and interaction mechanisms of these two pollutants, a pot experiment was conducted to examine the effects of soil exposure on peanut growth. The experiment results revealed that polyethylene (PE) had a minimal effect on peanut growth, while CuO NPs significantly inhibited peanut growth. Peanut biomass decreased by over 50 % in all Cu treatments. The presence of PE significantly impacted the dissolution and absorption of CuO NPs. When 0.5 % PE was present, the dissolution and transformation of CuO NPs were limited, resulting in a total Cu concentration of 458 mg/kg. Conversely, when 5 % PE was present, the dissolution and transformation of CuO NPs were promoted, leading to a DTPA-Cu concentration of 141 mg/kg, the highest level observed. The distribution of trace elements in peanut stems also responded to the differences in Cu concentration. Both pollutants significantly disrupted soil bacteria, with CuO NPs having a more pronounced effect than PE. Throughout the entire growth cycle of peanuts, no chemical adsorption occurred between PE and CuO NPs, and CuO NPs had no significant impact on the aging rate of PE. In summary, this study provides insights into the environmental impact and transport mechanisms of composite pollution involving microplastics and metal-based nanoparticles in the soil-peanut system.

105 Awardee Talk: Timing of Dietary Zinc Supplementation During Gestation did not Affect Trace Element Concentrations in Sows and Their Piglets

Abstract Gestating sows (n = 267) were used to determine if timing of high dietary zinc supplementation in a commercial setting would reduce pre-weaning mortality of pigs and influence maternal and piglet copper (Cu), iron (Fe), and zinc (Zn) concentrations. Sows from three consecutive weekly farrowing groups were assigned randomly within parity to one of three dietary treatments consisting of: 1) Control: a corn-soybean meal diet containing 125 ppm supplemental Zn supplied by zinc hydroxychloride; 2) Breed-to-Farrow (B-to-F): as Control + 141 ppm supplemental Zn as ZnSO4 (266 ppm total supplemental Zn) fed from 5 days after breeding to farrowing; and 3) Day 110-to-Farrow (D110-to-F): as the Control diet fed from breeding to farrowing + 2,715 ppm supplemental Zn as ZnSO4 (2,840 ppm total supplemental Zn) starting on day 110 of gestation until farrowing. A subset of ten sows per treatment (n = 30; average parity = 3) were selected to assess Cu, Fe, and Zn concentrations of serum, colostrum, and milk. Sera were isolated from blood collections at allotment and the day before respective farrowing date of each sow. Colostrum was collected the day of farrowing and milk on day 2 of lactation. At farrowing, two average and two low birth weight pigs from each sow (n = 122) were selected for collections of serum and tail samples at days 1 and 2 of age, respectively. The statistical model included fixed effects of treatment, farrowing group, and the random effect of their interaction. The piglet model was similar but included the random term of pig nested within sow. There were no differences in concentrations of Cu, Fe, and Zn in sow serum, milk, or colostrum attributable to dietary treatment. Piglet serum concentrations of Cu, Fe, and Zn were unaffected by feeding gestating sows high levels of supplemental zinc at any time (Table). Low birth weight pigs born to sows fed the Control diet tended (P = 0.082) to have increased concentrations of Cu in tails compared with pigs born to sows fed high zinc. In conclusion, timing of dietary zinc supplementation to gestating sows had minimal influence on concentrations of important trace elements in sows and their offspring.

Structure and magnetic properties of alnico alloy doped SmCo5–xCux ribbons

Multicomponent doping may be a promising way to optimize the composition of SmCo5-based alloys. Moreover, the magnetic properties of Sm-Co alloys are particularly sensitive to Cu. In this paper, the effect of Cu content and annealing process on the structure and magnetic properties of Alnico alloy doped SmCo5–xCux ribbons was studied. It was found that Cu addition refines the grains, expands the difference in Cu concentration of Sm- and M-rich (M = Al, Ni, Fe, Cu) Sm(Co, M)5 grains, promotes the solute and phase separation, and increases both coercivity and magnetization of the x ≤ 3 as-spun ribbons. The x = 0.3 as-spun ribbons exhibit excellent magnetic properties of Hc = 24.6 kOe, Mr = 55.9 emu/g, and M9T = 69.1 emu/g. Annealing at 600 °C for 30 min further improves the Hc to 30.1 kOe but decreases the Mr and M9T to Mr = 41.6 emu/g and M9T = 54.2 emu/g, respectively. The formation of the lamellar or granular Sm2(Co, M)7 grain boundary phase and ordered Sm(Co, M)5 grains may play important roles in improving the coercivity of the annealed ribbons.

Copper concentration in erythrocytes, platelets, plasma, serum and urine: influence of physical training

BackgroundPhysical training produces changes in the extracellular and intracellular concentrations of trace minerals elements. To our knowledge, only three compartments have been studied simultaneously. The aim of the present study was to analyze the influence of physical training on extracellular (serum, plasma and urine) and intracellular (erythrocytes and platelets) concentrations of Copper (Cu).MethodsForty young men participated in this study. The participants were divided into a training group (TG; n = 20; 18.15 ± 0.27 years; 68.59 ± 4.18 kg; 1.76 ± 0.04 m) and a control group (CG; n = 20; 19.25 ± 0.39 years; 73.45 ± 9.04 kg; 1.79 ± 0.06 m). The TG was formed by semi-professional soccer players from a youth category with a regular training plan of 10 h/week. All of them had been participating in high level competitions and had trained for at least 5 years. Plasma, serum, urine, erythrocyte and platelet samples of Cu were obtained and analyzed by inductively coupled plasma mass spectrometry (ICP-MS).ResultsThe TG showed lower concentrations of Cu in erythrocytes (p < 0.05) despite similar intakes. There were no significant differences in Cu concentrations in plasma, serum, urine and platelets although the trend was similar to that observed in erythrocytes.ConclusionsThe assessment of trace element concentrations should be carried out in both extracellular and intracellular compartments to obtain a proper evaluation and to identify possible deficiencies of the element. We believe that additional Cu supplementation is needed in athletes who perform physical training regularly.

Procjena koncentracije Cu u tlu i vrijednost pozadinskog praga u Crvenici iz Dalmacije

The aims of this study were (i) to assess the soil Cu concentration in the mineral A horizon and cambic Bw horizon, (ii) to determine the background threshold value (BTV), and (iii) to quantify the differences between the horizons in terra rossa soil from Dalmatia. A total of 128 samples from 64 soil profiles located on terrains used for non-agricultural purposes were analysed for aqua regia soluble Cu concentration. The soils were classified according to the Croatian Soil Classification System and World Reference Base for Soil Resources as terra rossa soil and Chromic and Rhodic Cambisols. The median value of Cu concentration in A horizon (CuA) and cambic Bw horizon (CuB) were 34.9 and 36.1 mg/kg, respectively, and ranged between 16.2 and 69.5 mg/kg in the CuA and from 17.0 to 73.0 mg/kg in the CuB horizon. The estimated BTV for CuA varied between 43.6 and 58.4 mg/kg depending on the calculation method applied. The median ratio CuA/CuB of 0.96 was close to identical. The Wilcoxon matched pairs signed rank test and the Hodges-Lehmann estimator showed that the median difference in Cu concentration between the CuA and CuB was very small (-1.78 mg/kg). Mentioned statistical evidence on the small differences in Cu concentration between the horizons suggests that Cu concentrations measured in the Bw horizon can be considered a “local background” for the samples collected in A horizon and its utilization in screening terra rossa soil contamination can be suggested.

The importance of H2O in arc magmas for the formation of porphyry Cu deposits

Porphyry copper deposits (PCDs) hosted in subvolcanic intrusions at convergent margins are the primary world’s copper resources. However, the set of magmatic processes that lead to the generation of ore-bearing magmatic provinces remains unclear. In this paper we review the systematic of Cu evolution during arc magma differentiation using new and existing global compilations of whole rock geochemistry data. We trace the Cu evolution from primitive arc magmas through lower crustal plutonic to volcanic rocks. We focus on the well-known tholeiitic and calc-alkaline fractionation sequences, where arc tholeiitic series represents damp primitive melts (<2 wt% H2O) evolving with iron enrichment, and calc-alkaline series are wet primitive melts (>2 wt% H2O) that differentiate with iron depletion.Our study shows that the Cu concentration in primitive arc basalts (~80 ppm) is indistinguishable from that of primitive melts formed at mid-ocean ridges (MORBs) implying that Cu is mainly sourced from the mantle wedge in arcs with a limited contribution from the subducted oceanic lithosphere. A global compilation of plutonic rocks whole rock geochemistry (lower crustal cumulates and derivative melts) indicate no systematic difference in Cu concentrations between cumulates associated with tholeiitic or calc-alkaline series. Yet a complementary global compilation of arc volcanic whole rock geochemistry highlights the contrasting behavior of Cu in tholeiitic and calc-alkaline series during magmatic differentiation. In tholeiitic arc series, Cu shows an incompatible or compatible behavior during magma differentiation influenced by the crustal thickness. In calk-alkaline arc series, Cu is compatible during magma differentiation independently to the crustal thickness. This relates to the timing of sulfide saturation, which is controlled by the liquid lines of descent (LLD) and/or crustal thickness at redox conditions relevant for arc magmas.We demonstrate that the initial melt H2O content in primitive arc melts controls the LLD and the volume of remaining melt mass at fluid saturation. We show that the remaining H2O-saturated melt mass positively correlates with the total mass of Cu transferred into degassing fluids. The mass of extractable Cu ranges from ~3 to ~10 Mt (i.e., large PCD) for calc-alkaline series, and ranges from ~0.3 to ~2.5 Mt for tholeiitic series. The ore-forming potential of calc-alkaline arc magmas is at least ~4 to ~10 times higher relative to tholeiitic arc magmas. Despite the compatible behavior of Cu during magmatic differentiation, we propose that a single stage model for the formation of large economic PCDs (as opposed to multi-stage model for Cu-sulfides storage and remobilization) is most applicable for the calc-alkaline melts. The importance of the initial melt H2O content ultimately reflects the key role of flux melting associated with wet calc-alkaline series and high ore-forming potential, in opposition to decompression melting associated with damp tholeiitic series in arc.

Comparative metal analysis in a species assemblage of mammals from the Southeastern United States.

Metal pollution commonly occurs in many terrestrial environments and may pose a threat for the animals inhabiting such areas. Here, we present concentrations of six metals (cadmium [Cd], copper [Cu], nickel [Ni], lead [Pb], selenium [Se], and zinc [Zn]) in the liver tissues of seven species of mammals obtained from a study that examined the impact of mesopredator removal on northern bobwhite (Colinus virginianus) populations. A total of 1326 samples were collected from 2003 to 2006 at four sites in southwest Georgia and north Florida from nine-banded armadillos (Dasypus novemcinctus), bobcats (Lynx rufus), feral cats (Felis catus), coyotes (Canis latrans), grey foxes (Urocyon cinereoargenteus), opossums (Didelphis virginiana), and raccoons (Procyon lotor). Data from armadillos, bobcats, opossums, and raccoons were published previously to examine age, sex, spatial (between sites), and temporal (between years) variation. In this paper, we present similar comparisons for the remaining three species as well as comparisons of metal concentrations among all seven species. Concentrations of Cu and Pb exhibited strong negative relationships with body weight in coyotes, while Ni was positively correlated with weight in feral cats. Concentrations of these metals, as well as the other two tested (Cd and Zn), were not significantly correlated with one another in any of the three species. The only sex difference in liver metal concentrations was observed in female feral cats, which had higher levels of Pb than did males. Coyotes exhibited significant differences in Cu concentrations between sites and between years (2005 versus 2006). We also found significant differences between sites in Pb concentrations for both feral cats and grey foxes. There were significant differences in metal concentrations among all seven species for all metals except Cd. With the exception of Cd and Se (tested only in bobcats and opossums), a three-way ANOVA with species, year, and site as the three factors revealed significant differences among species for every metal but only a single main effect of year for Cu, and no main effects of site. In sum, our results provide an extensive survey of metal concentrations in a diverse assemblage of mammals and suggest that metal accumulation may be heavily influenced by species identity, which in turn may reflect ecological lifestyle.

The effects of a mixture of copper, nickel, and zinc on the structure and function of a freshwater planktonic community.

It is generally assumed that as long as the majority of species experiences no direct adverse effects attributable to a single substance (i.e., potentially affected fraction [PAF] <5%), no significant structural or functional effects at the community level are expected to occur. Whether this assumption holds for mixed metal contamination is not known. In the present study, we tested this by performing a microcosm experiment in which a naturally occurring freshwater planktonic community was exposed to a copper-nickel-zinc (Cu-Ni-Zn) mixture for 8 wk and various structural and functional community-level traits were assessed. In the low mixture concentration treatments (i.e., Ni-Zn mixtures, because there was no difference in Cu concentrations in these treatments with the control), community-level effects were relatively simple, only involving phytoplankton species groups. In the high mixture concentration treatments (Cu-Ni-Zn mixtures), community-level effects were more complex, involving several phytoplankton and zooplankton species groups. Multisubstance PAF (msPAF) values for all mixture treatments were calculated by applying the concentration addition model to bioavailability-normalized single-metal species sensitivity distributions (SSDs). Consistent effects on the structural traits community composition, abundance of zooplankton species groups, species diversity, and species richness and on the functional trait dissolved organic carbon (DOC) concentration (as a proxy for the microbial loop and pelagic food web interactions) were only observed at msPAF values >0.05 (i.e., in the Cu-Ni-Zn mixture). However, consistent effects on the abundance of various phytoplankton species groups (structural traits) and on 2 measures of community respiration, overnight Δ dissolved oxygen (ΔDO) and ΔpH (functional traits), were already observed at msPAF values of ≤0.05 (i.e., in the Ni-Zn mixture). This indicates that the threshold msPAF value of 0.05 was not protective against metal mixture exposure for all community-level structural and functional endpoints in the present study. A possible explanation for this result is the mismatch between the species in the SSD and those in our microcosm community. Indeed, our data suggest that the presence of one single dominant and very Zn- and/or Ni-sensitive species in the investigated community (i.e., a cyanobacteria of the genus Oscillatoria), which is not represented in the SSD of these metals, was probably the driver of all observed effects at or below an msPAF of 0.05. Overall, the present results show that SSDs are not necessarily a good predictor of community-level effects for all types of communities and that the presence of dominant sensitive species may result in significant, consistent effects on certain structural and functional community-level endpoints at msPAF values ≤0.05, which is generally considered protective in many regulatory frameworks. Environ Toxicol Chem 2018;37:2380-2400. © 2018 SETAC.

Investigation of chlorotic foliage on European aspen (Populus tremula L.)

Leaf analyses showed significant differences in dry matter content (DMC), chlorophyll (a+b), and carotenoids between two landscape-grown genotypes of P. tremula L. 'Erecta'. The Zn concentration was significantly higher in PtG than in PtY with a significant difference between the two genotypes at different growing stages in a season. The Cu concentration reached its peak at the middle growing stage and no significant differences in Cu concentration were found between PtG and PtY at all three growing stages. Under iron deficiency, a significant decrease of the ferric reductase activity (FRA) was detected in the root of PtY at pH 5.5. At pH 5.5, the leaf FRA was enhanced by iron deficiency. At pH 8.0, the leaf FRA of PtY was significantly higher than that of PtG regardless of Fe status. A leaf analysis of hydroponic plants confirmed the differences in chlorophyll, carotenoids, and Chl a/b ratio between PtG and PtY under the iron deficient condition; however, no significant difference in DMC was found between the two genotypes. These results indicate different responses of PtG and PtY to iron deficiency. PtG showed the potential for development of iron deficiency tolerant poplar trees.

Effects of joint size and isothermal aging on interfacial IMC growth in Sn-3.0Ag-0.5Cu-0.1TiO2 solder joints

The influence of the joint size on the growth of intermetallic compound (IMC) between Sn-3.0Ag-0.5Cu-0.1TiO2 composite solder and Cu pad during isothermal aging at temperatures of 100 °C, 120 °C, and 150 °C has been investigated in this study. Scanning electron microscopy was used to observe the microstructural evolution of the solder joints and to measure the thickness of IMC layer. Results for micro-joints show that the size of the solder joints has a significant effect on the interfacial reaction. The IMC thickness and the growth rate increase, whereas the activation energy decreases with the increase in joint size for all aging temperatures. The size effect might be due to the difference in Cu concentration near the IMC interface. Finite-element model was applied to examine the thermo-mechanical stresses at the interface of the solder joint as thermo-mechanical stress can cause the formation of crystal defects in solder matrix and interfacial IMC layer. We assume that these crystal defects serve as fast diffusion paths for atomic diffusion and affect Cu distribution.

Preliminary Assessment of Heavy Metal Contamination in Water and Wastewater from Asaluyeh Port (Persian Gulf)

The impacts of pollutants on the marine environment of the Persian Gulf may be significant due to its shallow depth, limited circulation, high salinity, and temperature. Discharge of industrial and urban effluents, shipping, oil spills, and recent wars in the Persian Gulf are of the major causes of its pollution. In this study, the total concentration of As, Cd, Co, Cu, Mn, Mo, Ni, Pb, Sb, Se, V, and Zn in water and wastewater samples of the Asaluyeh port, located on the northern edge of the Persian Gulf, are investigated. The results demonstrated that the concentration of As, Cu, Mo, Cd, Co, Ni, Pb, Se, and Zn in water samples exceeds the world sea water average. In addition, the maximum-observed concentrations of heavy metals occur in water and wastewater samples in the Basatin coast, Nakhle Taghi dock, Shirino industrial complex, and fifth refinery reject water. Significant differences in concentrations of Cu and Zn could be found among the sampling sites. The mean concentration of Ni, Pb, and Cd in the water samples was relatively higher than those in some other regions of the Persian Gulf. The statistical results obtained from Mann–Whitney along with factor analysis support the results.

The use of chemical markers for the identification of farm escapees in feral mink populations

Variations in the contaminant burden in feral and ranch mink, resulting from differences in their diet, may permit the identification of farm escapees. However, this is only possible in the case of contaminants that accumulate to significantly different levels in the two groups of animals. The main objective of this study was to identify chemical markers whose concentrations differ between feral and ranch mink, by analyzing the accumulation of 13 chemical elements in liver and kidney samples. Total mercury levels were up to 15-fold higher in kidney, and up to 7-fold higher in liver of feral mink compared with ranch mink. The majority of feral mink samples analyzed for mercury, contained concentrations that ranged from 1 to 5 μg/g in kidney (68 %) and from 1 to 5 μg/g in liver (70 %). In comparison, the organs of ranch mink had significantly lower levels of mercury: 95 % of kidney samples had concentrations below 1 μg/g and 82 % of liver samples had concentrations below 1 μg/g. Small geographical variations in Hg levels were observed in mink from the four studied feral populations. Significant differences in Cu concentrations between ranch and feral mink were also detected, with low variation within the two groups. Less pronounced differences were recorded for other chemical elements. These data suggest that Hg and Cu may be used as chemical markers for the identification of first generation mink farm escapees.

Trace metals and micronutrients in bone tissues of the red fox Vulpes vulpes (L., 1758).

In this study we determined the levels of trace elements (zinc, copper, lead, cadmium and mercury) in three layers of bones of the hip joint (cartilage, compact bone and spongy bone) of 30 red foxes (Vulpes vulpes) from north-western Poland. Concentrations of Cu, Zn, Pb and Cd were determined by atomic absorption spectrophotometry (ICP-AES) in inductively coupled argon plasma using a Perkin-Elmer Optima 2000 DV. Determination of Hg concentration was performed by atomic absorption spectroscopy. In cartilage, compact bone and spongy bone samples from the red fox, median concentrations of the metals studied could be arranged in the following descending series: Zn > Cu > Pb > Cd > Hg, the values ranging from 142 to 0.002 mg/kg dw. There was a significant difference in Cu concentrations, among all the materials analyzed, with much more Cu found in spongy bone than in compact bone. Significant differences were also noted in the case of Hg concentrations in cartilage with compact bone and the spongy bone, and between concentrations of this metal in compact bone and spongy bone. In males, the concentration of Hg in spongy bone was greater than in females. Younger foxes had a higher concentration of this metal in cartilage than adults. The strongest synergistic relationships were observed in spongy bone between the Zn and Cu, Zn and Cd, as well as between Cu and Cd. Statistically significant antagonistic relationships were detected between zinc and lead in compact bone. In addition to monitoring studies conducted on the abiotic environment, an urgent need exists for long-term monitoring of concentrations of heavy metals with long-term effects on living organisms. An important addition is provided by biomonitoring studies on domesticated and free-living mammals, including Canidae.

Copper Pellets Simulating Oral Exposure to Copper Ammunition: Absence of Toxicity in American Kestrels (Falco sparverius)

To evaluate the potential toxicity of copper (Cu) in raptors that may consume Cu bullets, shotgun pellets containing Cu, or Cu fragments as they feed on wildlife carcasses, we studied the effects of metallic Cu exposure in a surrogate, the American kestrel (Falco sparverius). Sixteen kestrels were orally administered 5mg Cu/g body mass in the form of Cu pellets (1.18-2.00mm in diameter) nine times during 38days and 10 controls were sham gavaged on the same schedule. With one exception, all birds retained the pellets for at least 1h, but most (69%) regurgitated pellets during a 12-h monitoring period. Hepatic Cu concentrations were greater in kestrels administered Cu than in controls, but there was no difference in Cu concentrations in the blood between treated and control birds. Concentration of the metal-binding protein metallothionein was greater in male birds that received Cu than in controls, whereas concentrations in female birds that received Cu were similar to control female birds. Hepatic Cu and metallothionein concentrations in kestrels were significantly correlated. Histopathologic alterations were noted in the pancreas of four treated kestrels and two controls, but these changes were not associated with hepatic or renal Cu concentrations, and no lesions were seen in other tissues. No clinical signs were observed, and there was no treatment effect on body mass; concentrations of Cu, hemoglobin, or methemoglobin in the blood; or Cu concentrations in kidney, plasma biochemistries, or hematocrit. Based on the parameters we measured, ingested Cu pellets pose little threat to American kestrels (and presumably phylogenetically related species), although the retention time of pellets in the stomach was of relatively short duration. Birds expected to regurgitate Cu fragments with a frequency similar to kestrels are not likely to be adversely affected by Cu ingestion, but the results of our study do not completely rule out the potential for toxicity in species that might retain Cu fragments for a longer time.

A comparative study of element concentrations and binding in transgenic and non-transgenic soybean seeds

Transgenic and non-transgenic soybean seeds were compared in terms of total element concentrations, behavior of elements during sequential extraction fractionation and element bioaccessibility using an in vitro simulated gastrointestinal digestion. The analysis were carried out by ICP-sector field-MS or size-exclusion ICP-MS (25 elements in concentrations varying from ng g⁻¹ to the % level). It seems that transgenic and non-transgenic soybean seeds exhibit statistically significant differences in concentrations of Cu, Fe and Sr, which are also reflected by element contents in water extracts and residues. Additionally, contributions of bioaccessible fractions of Cu, Fe and other elements (Mn, S, Zn) for transgenic soybean seeds appear to be larger than those found in non-transgenic soybean seeds.

Biodynamics To Explain the Difference of Copper Body Concentrations in Five Marine Bivalve Species

Copper is an essential metal for organisms but can be toxic when high intake occurs. The interspecific and intraspecific differences in concentrations of Cu in the tissues of different bivalve species have been recognized but the underlying mechanisms leading to these differences remain speculative. In this study, the biokinetics of Cu, using 67Cu as a radioactive tracer, was investigated in five species of marine bivalves, including scallops Chlamys nobilis, clams Ruditapes philippinarum, green mussels Perna viridis, black mussels Septifer virgatus, and oysters Saccostrea cucullata. All species have contrasting Cu concentrations in their bodies. Our results demonstrated the clear importance of biokinetics in controlling Cu concentrations in the bodies of bivalves. Assimilation efficiency (AE), feeding activity (filtration rate), and efflux rate all contributed to the observed interspecies differences. The AE and efflux rate were positively correlated with the respective Cu body burden, indicating their important roles in Cu concentrations in the body. The efflux rate also explained the intraspecies difference in Cu bioaccumulation. The subcellular distribution of Cu varied among different species of bivalves. There was a positive relationship between the newly accumulated Cu in the metallothionein-like protein (MTLP) fraction and the efflux rate, suggesting that MTLP may be responsible for Cu elimination and may control Cu regulation in bivalves. Calculations showed that the Cu partitioning coefficient and ingestion are important in determining the relative contribution of waterborne and dietborne exposure pathways to overall Cu accumulation. However, the dietary pathway was the most important source of Cu in bivalves under most circumstances.

Long-Term Changes in Trace Elements in Patients Undergoing Chronic Hemodialysis

Although the connection between aluminum intoxication and dialysis dementia was identified in the 1980s, understanding of trace element imbalances in hemodialysis patients is as yet incomplete. Recent application of newer inductively coupled plasma-mass spectrometry (ICP/MS) techniques has resulted in renewed study of this population. We used ICP/MS to evaluate serum concentrations of Cu, Se, Zn, Mn, and Ni in a relatively large population of hemodialysis patients compared with healthy age-matched controls. Comparisons were also done by duration of hemodialysis treatment to see whether length of treatment correlates with severity of imbalance. Patients had significantly lower concentrations of the three elements Se, Zn, and Mn. Patients had significantly higher concentrations of Ni, and there was a positive correlation between duration and severity of imbalance for this one element. There was no difference in Cu concentrations between patients and controls. Our findings confirm relative Ni excess and deficiencies of Se, Zn, and Mn in hemodialysis patients, documenting the value of ICP/MS in research work on trace element imbalances as well as clinical monitoring of individual patients.

Cu diffusion behavior of Ni-B diffusion barrier fabricated by electroless deposition

Thin Ni-B layer, <TEX>$1{\mu}m$</TEX> thick, was electrolessly deposited on Cu electrode fabricated by electro-deposition. The purpose of the layer is to encapsulate Cu electrodes for preventing Cu oxidation and to serve as a diffusion barrier. The layers were annealed at <TEX>$580^{\circ}C$</TEX> with and without pre-annealing at <TEX>$300^{\circ}C$</TEX> for . 30minutes. In the layer with pre-annealing, the amount of Cu diffusion was lower about 5 times than the layer without pre-annealing. The difference in Cu concentration may be attributed to <TEX>$Ni_3B$</TEX> formation prior to Cu diffusion. However, the difference in Cu concentration decreased during the annealing time of 5 h due to the grain growth of Ni.

Oxidase activity of ceruloplasmin and concentrations of copper and zinc in serum of cancer patients

A balance between oxidant carcinogens and endogenous antioxidant defence is of particular relevance to the carcinogenesis. Ceruloplasmin (Cp) carries up to 90% of Cu in plasma and performs ferroxidase, antioxidant and amine oxidase activity. Cu and Zn, as trace elements, have been recognized to play an important role as cofactors of SOD. The study presents the relationship of the Cp oxidase activity and concentrations of Cu and Zn in serum of 62 patients with breast (BCA), lung (LCA), gastrointestinal (GICA) and gynecological (GYNCA) cancer. The Cp oxidase activity was determined in serum with o-dianisidine as a substrate. Cu and Zn concentrations in serum were measured by using atomic absorption spectrometry. The results of the study have shown significant increase in the mean serum Cp oxidase activity and total Cu concentrations in all patient groups compared with the control one. The total mean serum Zn concentration was found to be decreased only in LCA group as compared with the control. The effect of the cancer progress on the Cp oxidase activity and concentrations of Cu and Zn was observed within the group of all cancer patients (ALLCA) and within the GICA group. The only significant difference in Cu concentrations among various stages of the disease was observed in GICA between local and distant one. Significant positive correlation coefficients were calculated for the Cp activity and Cu concentrations in the control group and all patients groups, also according to the cancer progress. Future research is needed to evaluate the consequences of the elevation of the serum Cp oxidase activity and concentration of Cp, Cu and Zn for the host antioxidant-oxidant balance.

Processes influencing distributions and concentrations of Cd, Cu, Mn and Ni at the North West European shelf break

Concentrations of total dissolved Cd, Cu, Mn and Ni were measured at the shelf edge in the Celtic and Hebridean Seas during the Ocean Margin Exchange (OMEX) and the Land Ocean Interaction Study (LOIS) programmes, respectively, in order to assess the relative importance of the processes which control the distributions of these elements. These processes include those related to hydrographic features specific to the shelf edge such as fronts, slope currents and cascading, as well as the more ubiquitous processes such as particle exchange, atmospheric and benthic inputs, remineralisation and mixing between water masses. In near-surface waters at both study sites, mixing between shelf and oceanic waters was the predominant process influencing the distributions of Cu, Ni and Mn. The concentrations of Mn decreased from shelf to oceanic waters, but a chemical front could not be characterised at the study sites. Comparison between atmospheric inputs and concentrations in surface waters of the Celtic Sea suggests that the atmosphere may be a source of Mn near the shelf edge. The distributions of Cd were little affected by lateral mixing. Cd concentrations were controlled by inputs from deep water masses, biological uptake and regeneration. The influence of biological activity and possibly of wet atmospheric inputs may explain the differences in concentrations of Cu and Cd observed at different seasons. At depth, off the shelf, the effect of mixing with shelf water decreased and processes, such as mixing between deep water masses and remineralisation, were dominant.