Cu In Combination Research Articles

Supplementation of a corn-soybean meal diet with manganese, copper, and zinc from organic or inorganic sources improves eggshell quality in aged laying hens

An experiment was conducted to evaluate the effects on eggshell quality of supplementing the diet of laying hens with a combination of Zn, Mn, and Cu from organic or inorganic sources. Three groups of hens, aged 32, 60, and 69 wk were fed a corn-soybean basal diet containing 32.6 mg/kg Zn, 24.7 mg/kg Mn, and 4.95 mg/kg Cu or a basal diet supplemented with 30-30-5 and 60-60-10 mg/kg of Zn, Mn, and Cu, respectively. Addition of Zn, Mn, and Cu in combination increased their concentrations in egg yolk and slightly decreased egg weight during some sampling from aged hens. The Zn, Cu, and Mn dietary supplementation did not affect the following measures of eggshell quality: percentage eggshell, eggshell index (shell weight per unit surface area), and eggshell stiffness. However, there was a small increase in elastic modulus of the eggs from one group of the older hens due to supplementation with Zn, Mn, and Cu. More consistently we observed improved breaking strength and fracture toughness (resistance to fracture) in the two oldest groups of hens at 1, 5, and 9 wk after introduction of the experimental diets. The effect was observed regardless of the source of trace elements.

Removal and speciation of heavy metals along the treatment path of wastewater in subsurface-flow constructed wetlands

This study was conducted to: (1) evaluate the performance of constructed wetlands in removing Zn, Pb and Cd, respectively, and Zn, Pb, Cd and Cu in combination and (2) investigate the speciation patterns of the dissolved metals differentiated according to their detectability by anodic stripping voltammetry (ASV) and their lability towards Chelex resin along the treatment path of metal-containing wastewater in horizontal subsurface-flow constructed wetlands. Four laboratory scale wetland units planted with cattails (Typha latifolia) were operated outdoors for six months. Three of the units were, respectively, fed with primary-treated domestic wastewater spiked with Zn(II), Pb(II) and Cd(II) whilst the fourth was spiked with a combination of Zn(II), Pb(II), Cd(II) and Cu(II). The results demonstrate that a metal removal efficiency of over 99% was achievable for wetland units treating the metals singly or in combination provided the sorption capacity of the media was not exceeded. When treating the metals in combination, an antagonistic effect, more significantly for Pb and Cd, on the sorptive metal uptake by media was observed. Based on the metal speciation patterns, the wetland system seemed to be capable of maintaining the ASV-labile metal species at relatively low level (< 10%) before media exhaustion.

Microbial activity in grassland soil amended with sewage sludge containing varying rates and combinations of Cu, Ni and Zn

Cu, Ni and Zn were added at different rates (low and±25% of current limits) and combinations to sewage sludges and the effects on soil microorganisms were monitored in laboratory incubations. Respiration was measured frequently during weeks 1–7, whilst extractable metals (with EDTA and CaCl2), microbial biomass C and metabolic quotient were recorded at 3 and 7 weeks. Inputs of one metal affected extractable concentrations of that metal and of the second metal tested in each experiment. Cu behaved differently from Ni and Zn, with little extractable by CaCl2. Whereas CaCl2-Ni and -Zn increased markedly between weeks 3 and 7, Cu concentrations did not change. Respiration was reduced at 1 week by Ni inputs and by Cu in combination with Ni. Zinc inputs at 1 week, and all metal inputs after 3 weeks, increased respiration. Biomass C was lower at higher metal inputs and with Zn the exception occurred at 3 weeks when biomass C was higher. Metal inputs generally increased metabolic quotient, although responses to Zn were often non-significant. Not all metal responses were additive, with effects of one metal frequently more pronounced with high levels of another. For Cu, the organic bound fraction was a better predictor of microbial response than the exchangeable fraction. For Ni the reverse was the case in one experiment, whilst extractable Zn was not closely correlated with microbial indices. Metal inputs close to permitted levels, in particular Cu, affected microbial processes but responses varied with time after sludge application.

Effects of zinc and copper on growth and metal accumulation in duckweed, Lemna minor

Heavy metal pollutants are known to be quite toxic to a wide variety of aquatic plants. Lemna (duckweed), due to its special feature, is sought as a test organism for aquatic pollutant studies and for wastewater treatment. Lemna grows rapidly and reproduces vegetatively; its biomass is measured easily. It is adaptable to various aquatic conditions; it extacts and also accumulates metals in its frond bodies. Among the metals, Cu is classified as extremely toxic and Zn is classified as moderately toxic to Lemna. It is reported that both Cu and Zn concentrations in the medium have a great impact on the growth responses and the physiological processes in Lemna. Deficiencies in Cu and Zn resulted in chlorosis of L.minor fronds and low concentrations of CU interfered with the floral induction in L.minor and L.gibba. Excess Cu inhibited both frond growth and frond multiplication of L. paucicostata and it decreased the content of chlorophyll [alpha] and photosynthetic CO[sub 2] uptake in L.minor. In water bodies, metals always are present in combination. Consequently, metal pair interaction is a factor to be considered. However, there are few studies on the effects of metal pair interactions on duckweed growth and metal accumulation. The purposemore » of this study was to investigate the effects of increased concentrations of Zn and Cu in combination on growth and metal accumulation by Lemna minor L. under controlled laboratory conditions. Zn and Cu were chosen since they are known as essential trace elements for duckweed up to a certain concentration; above that growth inhibition might occur. 16 refs., 3 figs., 6 tabs.« less

Influence of adding copper on the properties of the 01970 alloy

Increasing the corrosion resistance of weldable Al−Zn−Mg alloys requires the addition of up to 0.5% Cu in combination with strong modifiers. This sharply refines the cast grains in the welded seam and thus reduces the tendency to cracking during welding.