Trace Amounts Of Metals Research Articles

Can Supermassive Black Holes Form in Metal‐enriched High‐Redshift Protogalaxies?

Primordial gas in protogalactic dark matter (DM) halos with virial temperatures Tvir > 10^4 K begins to cool and condense via atomic hydrogen. Provided this gas is irradiated by a strong ultraviolet (UV) flux and remains free of H2 and other molecules, it has been proposed that the halo with Tvir ~10^4 K may avoid fragmentation, and lead to the rapid formation of a supermassive black hole (SMBH) as massive as M=10^5-10^6 Msun. This ``head--start'' would help explain the presence of SMBHs with inferred masses of several x 10^9 Msun, powering the bright quasars discovered in the Sloan Digital Sky Survey at redshift z>~6. However, high-redshift DM halos with Tvir~10^4K are likely already enriched with at least trace amounts of metals and dust produced by prior star-formation in their progenitors. Here we study the thermal and chemical evolution of low-metallicity gas exposed to extremely strong UV radiation fields. Our results, obtained in one-zone models, suggest that gas fragmentation is inevitable above a critical metallicity, whose value is between Zcr~3x10^{-4} Zsun (in the absence of dust) and as low as Zcr~ 5 x 10^{-6} Zsun (with a dust-to-gas mass ratio of about 0.01 Z/Zsun). We propose that when the metallicity exceeds these critical values, dense clusters of low--mass stars may form at the halo nucleus. Relatively massive stars in such a cluster can then rapidly coalesce into a single more massive object, which may produce an intermediate-mass BH remnant with a mass up to M <~10^2-10^3 Msun.

The 410,000 year terrestrial age of eucrite Río Cuarto 001

Abstract— We have measured a surprisingly long terrestrial age of 410,000 ±45,0020,000 yr (410 ±2045ka) for basaltic eucrite Río Cuarto 001 using accelerator mass spectrometry of 26Al, 36Cl, and 41Ca. Though many meteorites are known to have survived for tens or hundreds of ka in Antarctica or hot deserts, the mean annual precipitation of 815 mm in Río Cuarto, Cordoba Province, Argentina, makes the long survival of this meteorite remarkable. We propose two explanations for the exceptional preservation of Río Cuarto 001. First, the meteorite contains only trace amounts of metal, so the weathering and oxidation of metallic Fe, which commonly destroys chondrites, is ineffective in this case. Second, the meteorite was found in a relatively young deflation basin, and may have been exhumed only recently from beneath a protective layer of soil. Insofar as the survival on Earth of Río Cuarto 001 is due to environmental factors, there may be other meteorites with comparably long terrestrial ages still to be discovered in the vicinity.

Synergistic extraction and spectrophotometric determination of palladium(II), iron(III), and tellurium(IV) at trace level by newly synthesized p-[4-(3,5-dimethylisoxazolyl)azophenylazo]calix(4)arene

A spectrophotometric method for the determination of palladium, iron and tellurium from nitric acid media after extraction of their p-[4-(3,5-dimethylisoxazolyl)azophenylazo]calix(4)arene [DMIAPAC] complexes has been developed and possible synergistic effects have been investigated. Chloroform, carbon tetrachloride, cyclohexane, 1,2-dichloroethane, toluene and xylene were used as the diluents. The maximum enhancement was obtained in the presence of 30% 1,2-dichloroethane. The trace amounts of metals were determined spectrophotometrically. Beer’s law obeyed in the concentration range of 5.0–95.0 μg, 8.0–120.0 μg and 10.0–140.0 μg/10 mL of the final solution of palladium, iron and tellurium, respectively. The molar absorptivities (l mol−1cm−1) and Sandell’s sensitivities (μg cm −1) were calculated: Pd(II) = 1.73 × 104 and 0.0061; Fe(III) = 1.08 × 104 and 0.0052; Te(IV) = 1.67 × 104 and 0.0077. Ten replicate analyses containing 20 μg of Pd(II), 12.5 μg of Fe(III) and 32 μg of Te(IV) gave mean absorbance of 0.326, 0.242 and 0.418 with relative standard deviation of 0.36, 0.65 and 0.82% for Pd(II), Fe(III) and Te(IV), respectively. The interference of various ions was studied and optimum conditions were developed for the determination of these metals in certain alloys and synthetic mixtures.

Water Extractable Trace Elements in Poultry Litters and Granulated Products

Poultry litter contains many trace elements such as As, Cu, and Zn, and its land application may lead to the accumulation of these elements in soils, especially near the soil surface. The objectives of this study were to determine the total amount of trace elements and evaluate the effect of litter granulation and various litter to water extraction ratios on water extractable trace elements in 8 raw and granulated litter products. Granulated litters that contained urea, dicyandiamide, or hydrolyzed feathermeal had significantly lower contents of total As, B, Cu, Mn, and Zn than untreated litters because of the dilution of litters with additives. Trace element concentrations (mg/L) in the water extracts of the various poultry litters generally decreased when extraction ratios (litter to water) shifted from 1:10 to 1:250, or as the amount of poultry litter decreased with a constant water volume (200 mL). But, the water extractable content of trace metals (mg/kg) generally increased from an extraction ratio of 1:10 to 1:200, with values similar at 1:200 and 1:250 extraction ratios. Based on our results, we suggest using a 1:200 extraction ratio when evaluating water extractable As, Cu, and Zn in poultry litters. The estimated land application rates of trace metals, when poultry litter is applied on the basis of total P content, were considerably lower than the trace metal loadings allowable under the current environmental regulations governing biosolids and other materials with measurable amounts of trace metals. The laboratory water extractions of poultry litters and granulated products have increased our understanding of the potential risks to water quality posed by the land application of poultry litter and will contribute to the development of base knowledge needed to define land application practices that are protective of soil and water quality.

Mobility and bioavailability of Cr, Cu, Ni, Pb and Zn in a basaltic grassland: Comparison of selective extractions with quantitative approaches at different scales

Bulk Cr, Cu, Ni, Pb and Zn contents were analyzed in a Cr–Ni rich basalt, derived andic soil and in grass subaerial and aerial components to assess natural trace metal mobility in soil. Phytoavailability and relative mobility of elements were quantified by three different approaches: selective extractions, calculation at mineral scale after XRD, SEM-EDS and EMP analyses and measurement of pools at profile scale. Pool variations from rock to soil horizons give a view of the long-term mobility, while selective extractions and comparisons of pools measured in plants and top soil provide estimations of the current mobility and bioavailability. Major amounts of trace metals were held in the solid constituents of the soil. Examination of the solid residues following extractions clarified the potential mobility of these metal containing solids. Water soluble and exchangeable fractions never exceed 3% of the total trace metal amounts, which is of similar magnitude to pools found in grass roots and shoots. Zinc is the most easily extracted element followed by Cu, Ni and Cr. Over the short term, Zn also occurs in greater amounts in grass. Its involvement in organic matter turnover explains its greater accumulation in the soil profile over the long term. Chromium and Ni which are predominantly held in stable minerals (spinels) are less available for plants in the short term. They are both relatively depleted in soil, compared to initial pools in rock, over the long term. From a methodological point of view, the results demonstrate the necessity of comparing selective extraction data with other quantitative methods for assessing both short-term and long-term trace metal mobility and bioavailability.

The role of aluminum and copper on neuroinflammation and Alzheimer's disease

Metals such as aluminum (Al), copper (Cu), zinc and iron have been implicated in the pathogenesis of Alzheimer's disease (AD). Because trace amounts of metals are present in the drinking water, there is a possibility for low-dose chronic exposure. Since the presence of Al and Cu in drinking water has been shown to adversely affect the progression of AD, these two metals may aggravate some of the events associated with the disease process. The main focus of this review will be on the effects of Al and Cu in initiating or propagating an inflammatory response within the aging brain. Since inflammatory events are reported to be upregulated in the AD brain, this may be one of the mechanisms by which the metals potentiate neurodegeneration.

Bioaccumulation of heavy metals (Cu, Zn, Fe) in freshwater snail (&lt;i&gt;Pila ovata&lt;/i&gt;; Oliver 1804) from Ikpoba River of Southern Nigeria

In this study, the levels and bioaccumulation behaviors of copper, zinc and iron were determined in various body organs, viz: viscera and shell of freshwater snail, Pila ovata (Oliver 1804) collected from the upper and lower catchments of Ikpoba River, southern Nigeria. Heavy metal concentrations in snail and sediment samples were measured using an atomic absorption spectrophotometer. The mean concentrations (µgg -1 ) of Cu, Zn and Fe in the snail were estimated to be as follow, 4.56 – 6.71, 35.35 – 77.09 and 1257.21 – 1762.59, respectively. This study showed that under natural conditions, P. ovata is capable of bioaccumulating trace essential metals to elevated levels especially Fe and Zn up to 10 times higher than that found in the sediment. The accumulation pattern was strongly correlated with the amount of trace metals in the sediments. Bioaccumulation of Cu, Zn and Fe varied between the viscera and the shell. The viscera had the highest concentrations (µgg -1 ) of all metals than the shells; Cu, 2.03 – 5.8 (Viscera), 0.05 – 3.30 (Shell), Zn, 23.64 – 45.02 (Viscera), 1.87 – 15.15 (Shell) and Fe, 360.33 – 1526.59 (Viscera), 83.99 – 373.93 (Shell), which suggest that ingestion may be the main uptake route of these essential metals. A holistic biomonitoring approach is therefore proposed for these impacted areas to guide regulators in a direction of improvement. Keywords : heavy metals, bioaccumulation, freshwater snail, sediment, Ikpoba River Journal of Aquatic Sciences Vol. 21(1) 2006: 23-28

Colza (Brassica napus, v. Jaguar) Responses to Low Level of Metal Inputs Through Sewage Sludge Application: Induction of phytochelatin synthesis (10 pp)

Background, Aim and Scope Most studies of sewage sludge disposal effects on plants have focused on high metal loadings. Less attention has been paid to plant responses to trace metal loadings below the recommended limit values. Materials and Methods: Here, a lysimetric experiment was conducted to assess the uptake, distribution and binding of trace metals by metal-induced, sulfhydryl-rich peptides (phytochelatins) in colza (Brassica napus, v. Jaguar) grown on a clayey, silty soil amended with a sewage sludge compost containing trace metal contents far below the recommended limit values established by French legislation. Chemical fractionation of unamended and sludge-amended soils was performed using a sequential extraction technique. Results: Copper concentrations in plant tissues were not affected by compost disposal. Its application at a single rate equivalent to 30 t/ha stimulated the growth of plants. Lead was not detectable in the plant material (< 1 mg g-1 dry wt.). Plants grown on the amended soil accumulated significantly more zinc than control plants. These phytochelatin complexes detected in leaves had a lower molecular weight than those extracted from roots. Those extracted from roots were composed of one type of phytochelatins (PCs) such as in leaves or a mixture of glutathione, PC2 and PC4. In comparison with control plants, sewage sludge compost application caused the synthesis of longer chain PCs in roots and in leaves. Furthermore, in comparison with control roots, glutathione and phytochelatin mixtures of higher molecular weight were detected in roots produced on the amended soil, whereas no significant increase in \total\ Cu and Zn content was observed in these organs after sludge application. Discussion: Compost application induces a significant increase in the proportion of the most labile forms of zinc and especially its pH 4.7 acid-soluble forms and, as a consequence, a higher accumulation of zinc in plants. Effects of copper are limited due to its strong affinity for humic substances and lead does not seem to be transported in any organ of plants. The presence of phytochelatins, even in plants grown on the unamended soil, proved the ability of colza to synthesize them in the presence of zinc and copper. Conclusions: These primary results seem to prove, on one hand, ability of colza (Brassica napus, v. Jaguar) to synthesize phytochelatins as well as in roots, in leaves and, on the other hand, the sensitivity of the PC induction as suggested by their identification in plants grown on the control soil. Synthesis of longer chain PCs in roots and in leaves, and formation of glutathione and phytochelatin mixtures in roots, are plant responses to sewage sludge compost application. Recommendations and Perspectives: Phytochelatin analysis is thus supposedly able to be one of the bioindicators that may be used as an ecotoxicological risk assessment of wastes. Due to its ability to synthesize phytochelatins, colza could be chosen as a plant test. Phytochelatin analysis could also be limited to roots (more sensitive than leaves). However, further experiments are needed. Quantitative analysis of phytochelatins had not been carried out due to insufficient amounts of pure phytochelatin standards, that had allow us to better study relationships between trace metal amounts to vegetal response.

Water Extractability of Trace Metals from Soils: Some Pitfalls

Water soluble and/or dissolved metals represent the most ecotoxicologically relevant fraction of metals in the environment. However, water extractions may be prone to errors. This study aims to evaluate the performance of 5 filters as well as Rhizon soil moisture samplers, with respect to metal adsorption and/or release by the filter. In addition, the effect of equilibration time on water extractions of different types of soils was evaluated (silty loam, silty clay loam, loamy sand). Filtrations of synthetic solutions containing 40 μg 1−1 Zn, 20 μg 1−1 Cu, Ni and Pb, 10 μg 1−1 Cr and 2 μg 1−1 Cd were conducted using the different filters. The synthetic solutions either contained (i) no other competitive cations (Ca, Mg, Na, K, Fe, Mn, Al) (A1), (ii) competitive cations at concentrations similar to those observed in soil solutions (A2), (iii) competitive cations at 10 times lower concentrations than those in the synthetic soil solution (A3). Whiteband filters were observed to retain considerable amounts of trace metals (except Cr), both in the presence and absence of other competitive cations. Millipore filters did not exhibit metal retention. Rhizon soil moisture samplers did not retain trace metals from the synthetic soil solution (A2), whereas at lower concentrations of competitive cations (A1, A3) retention of Cu and Pb was observed. Whiteband filters without a predefined pore diameter allowed colloidal material of unknown particle size to pass into the filtrate, making interpretation of results very difficult and comparison between studies using different filters impossible. Millipore filters with a predefined pore diameter are to be recommended for this purpose. However, particular attention must be paid to potential constitutive Zn release by the sintered glass filter holders, the effect of which can be reduced by rigorous acid washing prior to and following every use. Rhizon samplers were also considered to be useful tools with well-defined and sufficiently small pore diameters to withhold colloidal material. However, in the absence or at reduced concentrations of competitive cations (A1, A3) retention of trace metals by the Rhizons, particularly Cu and Pb, was observed. Finally, short equilibration times may be insufficient for full assessment of the water extractable pool of trace metals in the soil.

The Impact of Acid Mine Drainage on the Water Quality of the Odiel River (Huelva, Spain): Evolution of Precipitate Mineralogy and Aqueous Geochemistry Along the Concepción-Tintillo Segment

The Odiel river emerges in Sierra de Aracena (N Huelva, Spain) as a clean, circumneutral river which shows abundant fish and fluvial microfauna. At 20km from the riverhead and along a 7km-long reach, this river receives four small discharges of acid mine water emanating from several abandoned mines of the Iberian Pyrite Belt (namely, Concepcion, San Platon, Esperanza and La Poderosa-El Soldado). During two field studies performed in October 2003 and May 2004, it has been observed that these acidic waters (with flow rate of 0.2–8.5L/s and pH 2.3–2.8) transfer to the Odiel river significant amounts of acidity and dissolved metals (specially Fe, Al, Mn, Cu, Zn, Cd, Co and Ni) and sulphate. Despite this mine-related pollution, the pH of the river remains near-neutral (pH = 7–8, flow rate = 220–1,000L/s), as the alkalinity of the river (108–155mg/L CaCO3 eq.) neutralizes the acidity and causes the precipitation of dissolved Fe and Al in the form of ochreous to whitish minerals (ferrihydrite, Al-oxyhydroxides). These poorly crystallized minerals retain, by sorption, large amounts of trace metals (specially Cu and Zn). Subsequently, the Odiel river converges with the acidic Tintillo river (pH = 2.5–2.8, flow rate = 48–240L/s), which drains a vast mining area occupied by large waste-rock piles and tailings impoundments around Corta Atalaya (Riotinto mines). At this confluence, all the alkalinity is totally consumed and the pH drastically decreases to around 3. The mineral paragenesis of the ochreous precipitates is then dominated by schwertmannite, which shows a very limited sorption capacity under such acidic conditions. Consequently, metal concentrations are sharply increased from near-zero to tens of mg/L (e.g., 18mg/L Fe, 76mg/L Al, 14mg/L Mn, 10mg/L Cu, and 20mg/L Zn in May 2004). The buffering capacity of the Fe(III) hydrolysis stabilizes the pH of the Odiel river around 3± 0.5 along the rest of its course to the Huelva estuary, and the water quality of the river is thus irreversibly damaged.

Measurement of concentrations of trace metals in arable soils with animal manure application using instrumental neutron activation analysis and the concentrated acid digestion method

An experiment was conducted to determine the accumulation of trace metals, zinc (Zn), chromium (Cr), manganese (Mn) and iron (Fe), in three types of arable soils (Brown Lowland soil, Andosol and Brown Forest soil) amended with chemical fertilizers (CHF), cattle farmyard manure (CFM) and pig farmyard manure (PFM) over a 5-year period. Two methods were used to determine the total amount of trace metals: the instrumental neutron activation analysis (INAA), as a non-destructive measurement, and the concentrated acid digestion method (CADM), as a destructive measurement. Results of soil analyses using both INAA and CADM indicated that PFM application resulted in a considerable increase in the amount of Zn in arable soils compared with CHF application, unlike CFM application. Results obtained from the two methods were not fully in agreement for Cr. Based on INAA, soil accumulation of Cr from CFM and PFM applications was not significant in any soil type. In contrast, based on CADM, Cr accumulation was relatively higher in the Brown Forest soil with PFM than with CHF application. The soil types and treatments exerted various effects on Cr, Mn and Fe concentrations. The 5-year application of animal manure did not result in a considerable increase in Cr, Mn and Fe concentrations in soils, whereas longer-term application may lead to a gradual accumulation of Cr and Fe depending on the soil and manure types. The use of CADM in the present study may not always be adequate to assess the accumulation of trace metals in soils amended with CFM and PFM because of the conditions of the measurements, such as sensitivity, dilution level or type of instrument, and not because of the digestion method. The types of soil and manure affect trace metal accumulation in arable soils, and elements in the manure relate to the ability of soils to retain trace metals. It is important that the results of non-destructive and destructive measurements, obtained using INAA and CADM, be evaluated properly.

Metabolic measures of male southern toads ( Bufo terrestris) exposed to coal combustion waste

Southern toads ( Bufo terrestris) are found in coal fly ash collection basins associated with coal-burning electrical power plants. These basins contain large amounts of trace metals and organisms found in these basins are known to accumulate large quantities of metals. Studies on a variety of organisms exposed to trace metals found that they experience a significant increase in standard metabolic rate. We experimentally exposed southern toads to metal-contaminated sediment and food and measured changes in standard and exercise metabolic rates as well as changes in body, liver and muscle mass, blood glucose, and corticosterone. We found that toads exposed to trace metal contamination gained significantly less mass (18.3 %) than control toads (31.3%) when food was limited and experienced significantly decreased RQ after exercise. However, contaminated toads did not experience changes in standard (x¯ control = 0.114 ± 0.016 mL O 2 g − 1 h − 1 ; x¯ ash = 0.109 ± 0.013 mL O 2 g − 1 h − 1 , p = 0.08) or exercise metabolic rates (x¯ control = 0.53 ± 0.06 mL O 2 g − 1 h − 1 ; x¯ ash = 0.44 ± 0.04 mL O 2 g − 1 h − 1 , p = 0.47) plasma glucose levels ( p = 0.6), and hepatic or muscle percentage indices ( p > 0.2 in all cases) whether food was limited or not.

TRACE METALS BINDING TO HUMIC AND FULVIC ACIDS FROM SURFACIAL SEDIMENTS OF LAKE MANZALAH, EGYPT.

Twelve sediment samples were collected from Lake Manzalah during summer, 2004 to examine the influence of dissolved humic and fulvic acids on the distribution of trace metals in surficial sediments of the Lake. Trace metal concentrations in the humic acid extracted from the Lake sediments showed considerably high contents of iron (1046-3069 ng/g); copper (234-1498 jig/g) and zinc (110-394 jig/g) . The other trace metals (Co, Cd, Cr, Ni and Mn) revealed low concentrations, ranging from 11.3 to 156 ixgJg. The metal concentrations in fulvic acid were in the following order; Fe (465-2767 ^Lg/g); Cu (49.6-250.6 jag/g); Zn (49.3-186.6 ng/g); Cd (39.6-80.8 pg/g); Ni (20.4-153.4 jxg/g); Co (12.5-78.0 jxg/g); Mn (11.8-55.9 ^ig/g) and Cr (9.1-39.6 ng/g). The values of Cu and Cd percentage associated with the humic acid were high comparing with that reported in the other metals. This relative percentage was decreased for the same metals in association with fiilvic acid. In general, the results indicated that the amounts of trace metals in humic acids decreased as follows: Fe > Cu >Zn > Ni > Co > Cd > Mn > Cr. While in fulvic acid the order was: Fe > Cu >Zn > Cd > Ni > Co > Mn > Cr.

Geogenic sources and sinks of trace metals in the Larsemann Hills, East Antarctica: Natural processes and human impact

To evaluate the extent of human impact on a pristine Antarctic environment, natural baseline levels of trace metals have been established in the basement rocks of the Larsemann Hills, East Antarctica. From a mineralogical and geochemical point of view the Larsemann Hills basement is relatively homogeneous, and contains high levels of Pb, Th and U. These may become soluble during the relatively mild Antarctic summer and be transported to lake waters by surface and subsurface melt water. Melt waters may also be locally enriched in V, Cr, Co, Ni, Zn and Sn derived from weathering of metabasite pods. With a few notable exceptions, the trace metal concentrations measured in the Larsemann Hills lake waters can be entirely accounted for by natural processes such as sea spray and surface melt water input. Thus, the amount of trace metals released by weathering of basement lithologies and dispersed into the Larsemann Hills environment, and presumably in similar Antarctic environments, is, in general, not negligible, and may locally be substantial. The Larsemann Hills sediments are coarse-grained and contain minute amounts of clay-size particles, although human activities have contributed to the generation of fine-grained material at the most impacted sites. Irrespective of their origin, these small amounts of fine-grained clastic sediments have a relatively small surface area and charge, and are not as effective metal sinks as the abundant, thick cyanobacterial algal mats that cover the lake floors. Thus, the concentration of trace metals in the Larsemann Hills lake waters is regulated by biological activity and thawing–freezing cycles, rather than by the type and amount of clastic sediment supply.

A kinetic approach to predict soil trace metal bioavailability: preliminary results

The presence of large amounts of trace metals creates a hazard in some soils that is strongly related to the speciation of these metals. The aim of this work was to apply an operationally defined fractionation based on kinetics, which could distinguish “labile” (quickly extracted) and “non-labile” (or slowly labile i.e. slowly extracted) cations by using the extraction kinetics of trace metals by EDTA. This kinetic fractionation was applied to 10 unpolluted soil samples from Burgundy (France) in order to determine their labile concentrations of lead and cadmium. According to this method, cadmium was found to be more mobile than lead, with respect to both labile concentration and the kinetic constants. Moreover, it was also found that the labile concentration of cadmium was related (R 2=0.6) to its concentration in wheat shoots; however, no such correlation was found for lead.

Release of trace metals, sulfate and complexed cyanide from soils contaminated with gas-purifier wastes: A microcosm study

Deposited gas-purifier wastes are commonly contaminated with trace metals, sulfate and cyanide (CN) compounds. We investigated their release from three soils contaminated with gas-purifier wastes into solution in microcosm experiments under varying redox conditions ( E H 170–620 mV). The soils differed in pH (2.2; 4.9; 7.4) and featured low amounts of trace metals, but large amounts of total S and total CN. The pH governed trace metal release in the case of the acidic soil and CN release in the case of the slightly alkaline soil. The redox potential controlled trace metal and CN release in the case of the moderately acidic soil. Sources of dissolved SO 4 2− were dissolution of gypsum, desorption from Fe oxides and probably oxidation of elemental S. The geochemical behaviors of trace metals (soluble under acidic and reducing conditions) and CN (soluble under alkaline and oxidizing conditions) were diametrically opposed.

PIXE analysis for bioaccumulation studies of trace elements

Bioaccumulation by micro-alga in the ocean was simulated in nutritive seawater containing known amounts of trace metals, and the concentration factors for Fe, Zn and Cd were measured by PIXE. Trace transition metals in nearshore seawater were removed by Chelex-100. Then a culture solution was prepared by adding known amounts of trace metals and nutritive salts to the purified seawater. Marine micro-algae ( Nannochloropsis sp., and Phaeodactylum sp., ) were purely cultured in the culture solution. An interested metal ion was added to the culture solution (0.01-5.0 mg/l). Alga in 10 ml of the culture solution was collected on a polycarbonate filter (pore size: 1.0 µm) by suction filtration and subjected to 2.9 MeV proton bombardment. Na, Mg, Al, Si, P, S, Cl, K, Ca, Cr, Mn, Fe, Zn and Cd were simultaneously determined. PIXE multi-element analysis was possible using less than 1 mg of analytical sample. The quantity of the metal in the alga was increased in proportion to the concentration in the culture solution. The concentration factors for Zn, Fe and Cd were measured, e.g., 10200±300 ml/g to Zn for Phaeodactylum . The trend of the affinity for the trace metals in the case of Nannochloropsis was Fe 3+ >Zn 2+ >Pb 2+ >Cd 2+ .

Mass Spectral Analyses of Labile DOTA-NHS and Heterogeneity Determination of DOTA or DM1 Conjugated Anti-PSMA Antibody for Prostate Cancer Therapy

Prostate specific membrane antigen (PSMA) is a well-characterized glycoprotein overexpressed on the surface of prostate cancer cells. The novel radiopharmaceutical 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA) radiolabeled with Yttrium (90Y) or Indium (111In) conjugated with anti-PSMA genetically engineered humanized monoclonal antibody (huJ591) has been investigated to target prostate cancer cells. The immunoconjugate of huJ591 with the analog of the cytotoxic drug maytansine, DM1 (N2'-deacetyl-N2'-(3-mercapto-1-oxopropyl)-maytansine) has also been developed at Millennium Pharmaceuticals. Activation of the DOTA molecule, resulting in 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid mono-(N-hydroxysuccinimidyl) ester (DOTA-NHS), allows conjugation with the anti-PSMA antibody through lysine residues in the antibody. The objectives of the study were to characterize the unstable chemical properties of DOTA-NHS before bioconjugation with huJ591, evaluate the binding profiles of DOTA to huJ591, and calculate trace metal elements (which may disturb 90Y or 111In labeling efficacy to the DOTA-huJ591 conjugate). A novel LC/MS/MS (Liquid Chromatography/Mass Spectrometry/Mass Spectrometry) quantitation method was developed to monitor the stability of DOTA-NHS in solid form and its bioconjugation chemistry reactions. Meanwhile, metal analysis was quantified by Inductively Coupled Plasma Mass Spectrometry (ICP/MS) to estimate the amounts of trace metals in DOTA-NHS and ensure radiolabeling efficiency of the conjugate at the radiopharmacy. MALDI-TOF MS (Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry) was used to identify levels of DOTA or DM1conjugation in DOTA-huJ591 and DM1-huJ591 conjugates, respectively.

Enhanced Phytoextraction: II. Effect of EDTA and Citric Acid on Heavy Metal Uptake by Helianthus annuus from a Calcareous Soil

High biomass producing plant species, such as Helianthus annuus, have potential for removing large amounts of trace metals by harvesting the aboveground biomass if sufficient metal concentrations in their biomass can be achieved. However, the low bioavailability of heavy metals in soils and the limited translocation of heavy metals to the shoots by most high biomass producing plant species limit the efficiency of the phytoextraction process. Amendment of a contaminated soil with ethylene diamine tetraacetic acid (EDTA) or citric acid increases soluble heavy metal concentrations, potentially rendering them more available for plant uptake. This article discusses the effects of EDTA and citric acid on the uptake of heavy metals and translocation to aboveground harvestable plant parts in Helianthus annuus. EDTA was included in the research for comparison purposes in our quest for less persistent alternatives, suitable for enhanced phytoextraction. Plants were grown in a calcareous soil moderately contaminated with Cu, Pb, Zn, and Cd and treated with increasing concentrations of EDTA (0.1, 1, 3, 5, 7, and 10 mmol kg−1 soil) or citric acid (0.01, 0.05, 0.25, 0.442, and 0.5 mol kg−1 soil). Heavy metal concentrations in harvested shoots increased with EDTA concentration but the actual amount of phytoextracted heavy metals decreased at high EDTA concentrations, due to severe growth depression. Helianthus annuus suffered heavy metal stress due to the significantly increased bioavailable metal fraction in the soil. The rapid mineralization of citric acid and the high buffering capacity of the soil made citric acid inefficient in increasing the phytoextracted amounts of heavy metals. Treatments that did not exceed the buffering capacity of the soil (<0.442 mol kg−1 soil) did not result in any significant increase in shoot heavy metal concentrations. Treatments with high concentrations resulted in a dissolution of the carbonates and compaction of the soil. These physicochemical changes caused growth depression of Helianthus annuus. EDTA and citric acid added before sowing of Helianthus annuus did not appear to be efficient amendments when phytoextraction of heavy metals from calcareous soils is considered.

Metals distribution in the organic and inorganic fractions of soil: a case study on soils from Sicily

The content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, has been determined in the organic and inorganic fraction of eight soil samples from Sicily. A modified type-Tessier sequential extraction procedure has been used to recognize metals in five different fractions categorised as follows: (a) exchangeable metals, (b) metals bound to carbonates, (c) metals bound to iron and manganese oxides, (d) metals bound to organic matter, and (e) metals in residual fraction. The mineralogical composition of soils samples was characterized by X-ray diffraction. Humic substances were extracted by means of an alkaline extraction procedure. It has been found that both the mineralogical composition and the different content of humic fraction of organic matter in the soils investigated are responsible for the observed trace metal distribution. The obtained data show that a significant amount of trace metals is bound to the organic fraction where different binding sites are present simultaneously. In particular, Pb and Cu seem to be the elements more tightly linked to the organic fraction of soils, whilst cadmium is mostly concentrated into the iron and manganese oxides fraction. The presence of clay minerals in soil is significant for metal distribution, playing a fundamental role in binding metal ions. Besides, it has been observed that the calcophile metal mobility is strongly dependent on the presence of sulfide phases. Applying the Risk Assessment Code to the analyzed soils, it appears that they contain, generally, less than 30% of metals in the exchangeable and carbonate fractions. Calcic brown soil from Piano Zucchi exhibits a medium up to very high risk for Pb, Cd, Co, Zn and Mn. It also been recognized the elevated presence of Cd in the exchangeable and carbonate fractions of andic brown soil on volcanites from Pachino.