Extractable Concentrations Of Cu Research Articles

Effective remediation of electronic waste contaminated soil by the combination of metal immobilization and phytoremediation

In this study, laboratorial tests were conducted to evaluate the efficiency of metal immobilization and phytoremediation for remediating an actual electronic waste (e-waste) contaminated soil. Carbon black (CB) and its modified product (MCB) were used as the metal passivators to reduce the mobility and biotoxicity of soil heavy metals, while tall fescue was employed as the plant material to enhance soil microbial activity. The results show that the extractable concentrations of Cu, Pb and Zn could be reduced by 85.3%, 86.1% and 82.4%, respectively, at a MCB dosage of 5% (w/w). The removal of persistent organic pollutants [POPs, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs)] was highest (83.5%) in the case of 5% MCB+plant (M5-planting treatment) compared to 22.3% for the treatment without both passivator and planting. Specifically, in M5-planting treatment, the removal ratios of PAHs, PCBs and PBDEs were 82.8%, 89.3% and 75.6%, respectively. In M5-planting treatment, naphthalene, PCB-28 and BDE-28 were the most easily removed PAH, PCB and PBDE congeners, respectively, with a removal ratio of 98.5%, 98.6% and 97.5%, respectively. Contrastly, benzo[g,h,i]perylene, PCB-206 and BDE-209 were the most recalcitrant PAH, PCB and PBDE congeners, respectively, with the removal efficiency of 60.6%, 57.1% and 58.3%, respectively. Adding the passivators to the contaminated soil increased plant biomass, reduced metal bioavailability, raised soil dehydrogenase activity and bacterial density. MCB demonstrated better performance than CB on accelerating POPs removal and reducing the availability of heavy metals in soil.

Combined effect of nano-CuO and nano-ZnO in plant-related system: From bioavailability in soil to transcriptional regulation of metal homeostasis in barley

The co-existence of engineered nanoparticles (ENPs) in the environment is an emerging issue remaining poorly investigated. The present study aimed at analyzing the fate of binary mixtures of CuO and ZnO ENPs in a soil-plant system. The ENPs were singly or jointly dosed into soil at 300 mg kg−1 and aged for 7 and 30 days. To evaluate nano-specific effects, individual and combined treatments of metal salts were also applied. Interactions between ENPs and soil-grown barley Hordeum vulgare were determined in terms of biomass, plant mineral composition as well as expression of genes regulating metal homeostasis (ZIP1,3,6,8,10,14, RAN1, PAA1,2, MTP1, COPT5) and detoxification (MT1–3). The bioavailability of Zn and Cu in bulk soil and in the rooting zone was determined using the 0.01 mol L−1 CaCl2 extraction. After combined treatment of ENPs, the extractable concentrations of Cu and Zn were lower than upon individual exposure in bulk soil. The opposite tendency was noted for metal salts. Genes related to metal uptake (ZIP) and cellular compartment (PAA2, RAN1) were mostly up-regulated by single rather than combined application of ENPs. The single and joint exposure to metals salts induced the down-regulation of these genes.

Riparian plants on mine runoff in Zimapan, Hidalgo, Mexico: Useful for phytoremediation?

ABSTRACTDispersion and runoff of mine tailings have serious implications for human and ecosystem health in the surroundings of mines. Water, soils and plants were sampled in transects perpendicular to the Santiago stream in Zimapan, Hidalgo, which receives runoff sediments from two acidic and one alkaline mine tailing. Concentrations of potentially toxic elements (PTE) were measured in water, soils (rhizosphere and non-rhizosphere) and plants. Using diethylenetriaminepentaacetic acid (DTPA) extractable concentrations of Cu, Zn, Ni, Cd and Pb in rhizosphere soil, the bioconcentration and translocation factors were calculated. Ruderal annuals formed the principal element of the herbaceous vegetation. Accumulation was the most frequent strategy to deal with high concentrations of Zn, Cu, Ni, Cd and Pb. The order of concentration in plant tissue was Zn>Pb>Cu>Ni>Cd. Most plants contained concentrations of PTE considered as phytotoxic and behaved as metal tolerant species. Rorippa nasturtium-aquaticum accumulated particularly high concentrations of Cu. Parietaria pensylvanica and Commelina diffusa, common tropical weeds, behaved as Zn hyperaccumulators and should be studied further.

Suitability of Different Soil Extractants for Determination of Available Cu and Mn Contents in Polish Soils

The aim of this study was to compare four micronutrient soil-test extractants currently in common use in Poland, Rinkis, Mehlich 3, modified Lindsay and Norvell, and Yanai, for ability to determine the plant-available concentration of copper (Cu) and manganese (Mn) in two acidic soils (pH 4.8–4.9) that had been amended with different doses of Cu and Mn fertilizers. The comparison was based on two pot experiments (each with a different soil) with corn (Zea mays), barley (Hordeum vulgare), spring wheat (Triticum aestivum), rape (Brassica napus), red clover (Trifolium pratense), and English ryegrass (Lolium perenne). The extractants were evaluated based on a correlation analysis of the microelement concentrations in plants at the end of the vegetative phase and micronutrient concentration in the fertilized soil determined by each extractant at the end of the experimental period. The largest extractable concentrations of Cu and Mn in soils were obtained with Rinkis. The modified Lindsay and Norvell soil test extracted the lowest amount of both microelements. For soil Cu, the results with the Mehlich 3 and Yanai extractants were highly correlated with the Rinkis procedure results (r = 0.98). The modified Lindsay and Norvell results were not as well correlated with Rinkis (r = 0.84). For soil Mn, the correlation of results of Yanai, Mehlich 3, and modified Lindsay and Norvell to Rinkis ranged from r = 0.80 to r = 0.86. Levels of Mn and Cu measured with each of the extractants were highly correlated with plant tissue concentrations of Mn and Cu in most of the six plant species. The exceptions to this were the following: The modified Lindsay and Norvell soil Cu levels were not correlated with ryegrass and wheat plant Cu levels; Mehlich 3 Cu was not correlated with red clover Cu; and the Rinkis-extractable Mn was not correlated with the wheat Mn. It is concluded that the Yanai and Mehlich 3 procedures are suitable alternatives to the Rinkis for Cu but not for Mn.

A comparative study of metal pollution and potential eco-risk in the sediment of Chaohu Lake (China) based on total concentration and chemical speciation

Total and extractable concentrations of Cu, Pb, and Zn were determined in surface sediments of west Chaohu Lake (China) by HCl-HNO3-HF-HClO4 digestion and an optimized BCR sequential extraction procedure, respectively. The metal pollution was evaluated by the enrichment factor approach, and the potential eco-risk was evaluated by the sediment quality guideline (SQG) and risk assessment code (RAC) assessments. The results indicated that both total and extractable metal concentrations were highly variable and were affected by sediment properties, even though the sediments were predominantly composed of <63-μm particles (>89%). Enrichment factors of the metals based on the total and extractable concentrations all showed higher values in the northern lake area and decreasing values towards the south. This distribution indicated an input of anthropogenic metals via the Nanfei River. Anthropogenic Cu, Pb, and Zn in surface sediments showed comparable values for each metal based on the total and extractable concentrations, suggesting that anthropogenic Cu, Pb, and Zn resided predominantly in the extractable fractions. Sediment Cu had low eco-risk, and Pb and Zn had medium eco-risk by the SQG assessment, whereas the eco-risk rankings of Cu, Pb, and Zn were medium, low, and low-high, respectively, by the RAC assessment. Referencing to the labile (dilute acid soluble) metal concentrations, we deduced that the eco-risk of Cu may be largely overestimated by the RAC assessment, and the eco-risk of Pb may be largely overestimated by the SQG assessment. Overall, sediments Cu and Pb may pose low eco-risk, and Zn may pose low-high eco-risk.

DTPA AND MEHLICH-3 MICRONUTRIENT EXTRACTABILITY IN NATURAL SOILS

Most soils of the humid area in the Iberian Peninsula are characterized by acid, desaturated, organic rich surface horizons. In this study micronutrients (Cu, Fe, Mn and Zn) were extracted using DTPA and Mehlich-3. Total contents were also determined by digestion with nitric acid. Seven natural soil profiles, representing major acid soil types developed over a wide variety of parent materials were collected. In addition, three soil profiles containing carbonates and/or a high base saturation were sampled. The organic matter content when all samples were included in the data set ranged between 0.37 and 26.51%. For the acid set of samples, Mehlich-3 extractable concentrations of Cu, Fe, Mn and Zn were higher than contents extracted by DTPA. However, DTPA extracted higher concentrations of Cu, Fe and Mn than Mehlich-3 in near neutral or calcareous soils. Correlation coefficients between DTPA and Mehlich-3 extractable amounts were in the range from 0.49 to 0.96 for the set of acid soil samples and in the range from 0.71 to 0.92 for non-acid horizons. However, for acid and non-acid samples combined, correlations between micronutrient contents extracted by both solutions were much weaker and not significant. Results illustrate difficulties for selecting a single multielement extractant for different soils of the studied region. Interactions between micronutrient extractability, pH and organic matter content were evaluated. In all of the studied soil profiles, there was a decrease in the extractable Cu, Fe, Mn and Zn contents with increasing soil depth.

Chemical fractions of copper and zinc in organic‐rich particles from aqueous extracts of a metal‐contaminated granite soil

Abstract Chemical fractions of copper (Cu) and zinc (Zn) in the organic‐rich particles collected from filtered aqueous extracts (<20 μm) of an acid soil were determined. A sequential extraction procedure was used to partition the particulate Cu and Zn into four operationally defined chemical fractions: adsorbed (ADS), iron (Fe) and manganese (Mn) oxides bound (FeMnOX), organic matter bound (OM) and residual (RESD). Total extractable concentrations of Cu and Zn in the fine particles were higher than their total concentrations in the original bulk soil. The concentration of particulate Cu was usually much higher than that of particulate Zn. Addition of lime stabilized sewage sludge cake and/or inorganic metal salts markedly increased the concentrations of particulate Cu and Zn in aqueous extracts, especially from limed soil. The proportional distributions of particulate Cu and Zn were quite similar. The two particulate metals were present predominantly in the ADS and FeMnOX fractions, with less (about 20%) ...

Growth of tulips treated with sludge containing dewatering chemicals

Tulips were grown for 56 days in pots with a greenhouse medium containing a ferric chloride-lime treated, dewatered sludge called chemical sludge. Growth was compared with that of tulips receiving dried organic sludge, liquid organic sludge, primary effluent or tap water, to make a total of five treatments. The organic sludge, dried and liquid, had no chemicals added. It was either incorporated in a dried form into the medium or added in a liquid form to the surface. Average height of plants, in millimetres, at the end of the experiment for the five treatments was chemical sludge, 120; dried organic sludge, 192; liquid organic sludge, 466; effluent, 463 and water, 460. Extractable concentrations of Fe and Cl were no higher in the medium treated with the chemical sludge than in that treated with dried or liquid organic sludge. Electrical conductivities and extractable concentrations of Ca were 1·4 and 1·6 times higher, respectively, and extractable concentrations of Cu, Fe, K, P and Zn, 5·9, 2·6, 3·3, 2·8 and 1·8 times lower, respectively, in the medium treated with the chemical sludge than in that treated with the dried organic sludge. The results showed that the lime added to condition sludge at the sewage treatment plant reduced trace element, K and P availability.