Comparison between acetic acid and landfill leachates for the leaching of Pb(II), Cd(II), As(V), and Cr(VI) from cementitious wastes

The Toxicity Characteristic Leaching Procedure (TCLP) has been widely used to characterize the suitability of solid wastes for disposal in landfills. However, the widespread application of this test for the assessment of wastes disposed in different landfill types is often questionable. This paper investigates the leaching profiles of cement-stabilized heavy metal ions, namely, Pb (II), Cd (II), As(V), and Cr(VI), using acetic acid and leachates from municipal and nonputrescible Australian landfill sites. The leaching profiles of Pb, Cd, As, and Cr using acetic acid were found to be similar to the nonputrescible landfill leachate and differed markedly from the municipal solid waste (MSW) leachate. The additional presence of high amounts of organic and inorganic compounds in the municipal landfill leachate influenced the leaching profiles of these metal ions as compared to the acetic acid and the nonputrescible systems. It is postulated that the organic compounds present in the municipal landfill leachate formed complexes with the Pb and Cd, increasing the mobility of these ions. Moreover, the organic compounds in the municipal landfill leachate induced a reducing environment in the leachate, causing the reduction of Cr(VI) to Cr(III). It was also found that the presence of carbonates in the municipal landfill leachate affected the stability of calcium arsenate, with the carbonate competing with arsenate for calcium at high pH, forcing arsenate into the solution.     

Multielemental analysis of purpleback flying squad using high resolution inductively coupled plasma-mass spectrometry (HR ICP-MS)

Forty-four elements were analyzed in 21 tissues of purpleback flying squid, Sthenoteuthis oualaniensis, by high resolution inductively coupled plasma-mass spectrometry (HR ICP-MS) and inductively coupled plasma atomic emission spectrophotometry (ICP-AES). Greater concentrations of V, Fe, Co, Ni, Cu, Ag, Cd, Pb, and Bi were found in liver, pancreas, and ink sac than in other tissues. Ink sac concentrated remarkable levels of Ca and Sr in addition to the above-mentioned elements. Several alkalis, alkaline earth, and rare earth elements preferentially accumulated in muscle. Among the hard tissues, accumulation of V and U in beak, Ni, Zn, and Cd in gladius and Cr in skin was prominent. K, Rb, Cs, Pb, Bi and some transition elements (V, Co, Cu, Zn, Ag, Cd) were significantly (p < 0.05) higher in the livers of adult than in juvenile squids. Sodium, alkaline earth, and rare earth elements were higher in the livers of juveniles than in adult squids.     

元素含量分析应用于进口四产区香米产地鉴别

利用元素分析建立四个产地香米的鉴别方法。利用电感耦合等离子体质谱法和电感耦合等离子体光谱法对来自泰国、越南、柬埔寨、巴基斯坦四个地区的220份香米进行包括钙、铁、钾、镁、锌、硼、铝、铬、锰、钴、镍、铜、砷、锶、硒、镉、铯、钡、铅19种元素在内的含量分析。通过判别分析建立判别模型。判别模型自校验交叉校验准确率100%,拥有极高的准确率。     

The physicochemical characterization,equilibrium, and kinetics of heavy metal ions adsorption from aqueous solution by arrowhead plant (Sagittaria trifolia L.) stalk

The arrowhead plant stalk (APS) has been investigated as a novel biosorbent for removal of Cd(II), Pb(II), and Cr(III) ions from aqueous solution. The surface physicochemical properties favorable for metals adsorption were systematically characterized. The Langmuir isotherm fitted well with Cd(II) and Pb(II) adsorption process onto APS while Dubinin–Radushkevich model best described Cr(III) sorption. The maximal adsorption capacities of APS for Cd(II), Pb(II), and Cr(III) were up to 38.2, 97.1, and 23.5 mg·g^?1, respectively. The adsorption kinetic data of individual metal fitted the pseudo‐second order model best. The adsorption of Cd(II) was exothermic, whereas the Pb(II) and Cr(III) underwent endothermic reaction. Overall, this investigation indicated, for the first time, APS is a potentially efficient biosorbent applied in Cd(II), Pb(II), and Cr(III) adsorption. It is also helpful for further utilizing the abundant quantity of APS which were abandoned in dietary arrowhead processing.

Practical applications

The growing food industry around world generates large quantity of by‐products. The high value‐added utilization of food processing by‐products is one of the most important area in food industry. An attempt was made in present study to use the food by‐product, arrowhead plant stalk (APS), as a novel biosorbent for removing Cd(II), Pb(II), and Cr(III) ions. In present study, it was evidenced that the adsorption capacities of APS for Cd(II), Pb(II), and Cr(III) were obviously higher than those of most reported agricultural by‐products. This finding is significant for sustainable utilization of food crop arrowhead plant and elimination of environmental issues arising from the abandoned arrowhead plant stalk.     

Determination of the Metals by ICP-MS in Wild Mushrooms from Yunnan, China

The elemental contents of Li, Cs, U, Co, As, Sr, Cd, Ba, Pb, Sb in 157 wild-grown mushrooms were determined by inductively coupled plasma mass spectrometry (ICP-MS). The mushrooms including 9 species were collected from 5 counties in Yunnan province, China. Based on the findings for the results from the certified reference materials GBW10014 (cabbage) and GBW10016 (tea), the data from the sample mushrooms were corrected. The contents of investigated trace elements in mushroom samples were determined as μg/g dry weight (dw) in the range of 0.030 to 13 for Li, 0.070 to 8.1 for Cs, 0.0010 to 0.28 for U, 0.040 to 5.4 for Co, 0.070 to 44 for As, 0.28 to 86 for Sr, and 0.15 to 23 for Cd. The maximum contents were 58, 11, and 0.11 for Ba, Pb, and Sb, respectively. The minimum contents of Ba, Pb, and Sb were below the detection limit of the method used. Practical Application: The analysis of 9 species wild-grown edible mushrooms in different regions provides the useful information to evaluate the levels of elements or of the toxic heavy metals, such as Cd, As in wild-grown edible mushrooms which grew in different regions of China for consumers and other interested groups, especially for the regulators.     

Polycysteine and other polyamino acid functionalized microfiltration membranes for heavy metal capture

Polycysteine and other polyamino acid functionalized microfiltration membrane sorbents work exceptionally well for the removal and recovery of toxic heavy metals from aqueous streams. These are high capacity sorbents (0.3-3.7 mg/cm2) with excellent accessibility and selectivity for heavy metals, such as Hg(II), Pb(II), and Cd(II) over nontoxic components such as calcium. Polycysteine functionalized membranes work particularly well for metals such as Hg(II) and Cd(II), even in high total dissolved solids containing streams. Parameters such as permeate flow rate,feed metal concentration, and counterion (for Hg(II)) have also been found to influence sorbent behavior. For multicomponent systems, polyglutamic acid functionalized membranes have been found to selectively sorb Pb(II) versus Cd(II). Selective sorption of Cr(III) has also been observed with actual waste streams containing several heavy metals, hardness, and high sodium (2,000 mg/L). The high capacity, site accessibility, and ease of regeneration of these membrane-based sorbents make them ideal for environmental separations when volume reduction or selective recovery is required.     

Contribution of municipal effluents to metal fluxes in the St. Lawrence River

The contribution of urban effluents to the total metal fluxes carried toward the sea by the St. Lawrence, a major world river, is 60% for Ag; 8-13% for Cu, Zn, Mo, Cd, and Bi; and less than 3% for all other measured elements (Al, V, Cr, Mn, Fe Co, Ni, As, Rb, Sr, Zr, Cs, Ba, W, Re, Pb, Th, U). This is inferred from measurements at the Montreal wastewater treatment plant. Except for Ag, municipal effluents do not weigh heavily on the St. Lawrence River metal budget, likely because of the physical-chemical primary treatment applied to most effluents. Compared to direct atmospheric deposition on the surface of the river, effluents would contribute half as much Pb and one-tenth as much Zn. In contrast, effluents deliver twice as much Cd and six times as much Cu as the atmosphere. Stable Pb isotope ratios (206Pb/207Pb, 206Pb/208Pb) in suspended particulate matter from the river indicate that the total Pb content in the river water is three times higher than the pristine level. The ratios of Cr, Ni, Cu, Zn, and Cd to Al in suspended particulate matter are high as compared to pre-industrial sediments, which suggeststhattrace elementfluxes are higher today. To decrease metal levels in the St. Lawrence River further will be a challenge since the sources of metals are not well-known.     

Cadmium,lead and some other trace elements in Larch Bolete mushrooms (Suillus grevillei) (Klotzsch) Sing., collected from the same site over two years

The aim of this study was to examine the status of some trace metals accumulated in the flesh of Suillus grevillei mushrooms collected from the same site over two successive years. Total Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr and Zn contents of fruiting bodies were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) with ultrasonic cross-flow nebuliser. A difference (p < 0.05) was found in the contents of Cd, Cr, Cu, Fe, K, Na, Ni, Pb, Rb and Sr in caps and Fe, Na, P and Rb (p < 0.05) in stipes (Ag, Cd, Co, Cr, Ni and Pb were not determined in stipes). Natural fluctuations in trace elements’ content of Suillus grevillei collected from the same site over time is a variable that needs to be considered when assessing minerals’ nutritional status of mushrooms.     

Multi-element determination in some foods and beverages using silica gel modified with 1-phenylthiosemicarbazide

ABSTRACT

1-Phenylthiosemicarbazide bonded modified silica gel (PTC-SG) was synthesised and characterised by FTIR, SEM and elemental analysis for a novel separation/preconcentration of multiple elements based on solid phase extraction. The analytical parameters including pH of solutions, amounts of PTC-SG, flow rates of sample, eluent type and sample volume were optimised. The adsorption capacities of PTC-SG were found to be 7.9, 6.4, 6.3, 8.3, 7.2, 8.9 and 6.6 mg/g for Cu(II), Cd(II), Pb(II), Co(II), Cr(III), Ni(II) and Mn(II), respectively. The limit of detection (LOD) was calculated as 3x the standard deviation(s) of the reagent blank (k = 3, N = 21) and the LOD values were obtained to be 0.98 µg L^?1 (Cu), 0.65 µg L^?1 (Cd), 0.57 µg L^?1 (Pb), 1.12 µg L^?1 (Co), 1.82 µL^?1 (Cr), 1.67 µg L^?1 (Ni) and 0.55 µg L^?1 (Mn). Certified reference materials were used to test the validation of the present method. The new solid phase extraction method was successfully applied to determination of the amount of multiple elements in food and beverage samples.     

Distribution of selected trace elements in the major fractions of donkey milk

The aim of this study was to evaluate the concentrations of Zn, Cu, Mn, Se, Mo, Co, Li, B, Ti, Cr, Rb, Sr, Cd, and Pb in donkey milk and their distribution in major milk fractions (i.e., fat, casein, whey proteins, and aqueous phase). Individual milk samples were provided by 16 clinically healthy lactating donkeys. Subsequent centrifugation, ultracentrifugation, and ultrafiltration were carried out to remove fat, casein, and whey proteins to obtain skim milk, a supernatant whey fraction, and the aqueous phase of milk, respectively. Concentrations of the elements were measured in whole milk and fractions by inductively coupled plasma-mass spectrometry, and the concentrations associated with fat, casein, and whey proteins were then calculated. The effect of removal of fat, casein, and whey proteins was determined by repeated-measures ANOVA. The fat fraction of donkey milk carried a small (～4.5% to 13.5%) but significant proportion of Mo, Co, Ti, Cr, and Sr. The casein fraction in donkey milk carried almost all milk Zn, a majority of Cu and Mn, and most of Mo, Ti, and Sr. Relevant proportions, between 20% and 36%, of Se, Co, and Cr were also associated with caseins. The majority of Se, Co, Li, B, Cr, and Rb, and relevant proportions of Mn, Mo, Ti, and Sr were found in soluble form (ultracentrifuged samples) and distributed between whey proteins and the aqueous phase of milk (ultrafiltered samples). Whey proteins in donkey milk carried the majority of milk Se and Co. All Li and B was present in the aqueous phase of milk, which also contained most Rb and Cr, and 17% to 42% of Mn, Se, Mo, Co, Ti, and Sr.     

Contribution to the study of avocado honeys by their mineral contents using inductively coupled plasma optical emission spectrometry

Avocado honey samples were analyzed by inductively coupled plasma optical emission spectrometric. First, the botanical origin of the honeys was confirmed by melissopalynological analysis. Twenty-four minerals were quantified for each honey sample. The elements Al, Ba, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Se, Si and Zn were detected in all samples; seven elements were very abundant (Ca, K, Mg, Na, P, S and Si), six were not abundant (Al, Cu, Fe, Li and Zn) and 11 were trace elements (As, Ba, Cd, Co, Cr, Mo, Ni, Mo, Pb, Se, Sr and V).     

Elemental Content and Total Antioxidant Activity of <Emphasis Type="Italic">Salvia fruticosa</Emphasis>

The determination of 18 elements (V, Cr, Cu, Co, Se, Sr, Sn, Sb, Ba, Bi, Pb, Cd, As, Ni, Mn, Fe, Mg and Zn) in leaves, flowers and the infusion from Salvia fruticosa, a sage grown in Greece, is described. For this purpose, flame atomic absorption spectrometry has been used for the determination of Fe, Mg, Zn and inductively coupled plasma-mass spectrometry has been used for the determination of V, Cr, Cu, Co, Se, Sr, Sn, Sb, Ba, Bi, Pb, Cd, As, Ni, Mn using ⁴⁵Sc ⁷²Ge, ¹¹⁵In and ²³²Th as internal standards. The elemental content was found to be in the range of 0.01 (Bi)-30.8 (Mn) mg/Kg (leaves), 0.30 (Bi)-39.1 (Mn) mg/Kg (flowers), 0.003 (Sb)-20.4 (Mn) mg/Kg (infusion) for V, Cr, Cu, Co, Se, Sr, Sn, Sb, Ba, Bi, Pb, Cd, As, Ni, Mn and in the range of 0.07 (Zn)-3.21 (Mg) g/kg (leaves) for Fe, Mg and Zn. The majority of the samples were collected from six sites in the island Crete and transplanted and grown in a model farm. Chemometric techniques were used to investigate the original site classification according to their elemental content, and it was proved that the initial cultivation sites were characterized by only five elements (Sb, V, Zn, Cd and Cr). The application of factor analysis revealed significant correlation between certain elements, denoting their common sources. In addition, the total antioxidant activity of the herbal preparation was determined by measuring the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. Microwave-assisted extraction (MAE) was used to extract total antioxidants and the effect of temperature, time and solvent in the extraction efficiency was investigated. The determination of the antioxidant activity was based on the % inhibition of the absorbance signal of the radical DPPH at 515 nm, after the addition of herbal’s extract. The IC₅₀ values were found to be in the range of 10.6–40.1 mg/L.     

Precipitates on granular iron in solutions containing calcium carbonate with trichloroethene and hexavalent chromium

Mineralogical examination, using scanning electron microscopy (SEM), X-ray diffractometry (XRD), and optical microscopy, was conducted on the Fe0-bearing reactive materials derived from long-term column experiments undertaken to assess the treatment capacity of Fe0 under different geochemical conditions. The columns received either deionized water or solutions of differing dissolved calcium carbonate concentrations, together either with trichloroethene (TCE) or hexavalent chromium (Cr(VI)). The major reaction product in the columns receiving deionized water was magnetite-maghemite, and for the columns receiving dissolved calcium carbonate, the main products were iron hydroxy carbonate and aragonite. Replacement of Fe0 by reaction products occurred mainly at the edges of the Fe0 particles, and penetrative replacement was focused along cracks and along and around graphitic inclusions. Fibrous or flake-shaped iron hydroxy carbonate mostly replaced the edges of the Fe0 particles. Aragonite had needle-shaped morphology, and some occurred as clusters of crystals. Aragonite was deposited on iron hydroxy carbonate, thus providing at least a partial armoring effect. The mineral was also observed to cement groups of Fe0 particles into compact aggregates. The Cr was present mostly as Cr(III) in Cr(III)-Fe(III) (oxy)hydroxides and in trace amounts in iron hydroxy carbonate.     

Partitioning of metal species during an enriched fuel combustion experiment. speciation in the gaseous and particulate phases

Combustion processes are the most important source of metal in the atmosphere and need to be better understood to improve flue gas treatment and health impact studies. This combustion experiment was designed to study metal partitioning and metal speciation in the gaseous and particulate phases. A light fuel oil was enriched with 15 organometallic compounds of the following elements: Pb, Hg, As, Cu, Zn, Cd, Se, Sn, Mn, V, Tl, Ni, Co, Cr, and Sb. The resulting mixture was burnt in a pilot-scale fuel combustion boiler under controlled conditions. After filtration of the particles, the gaseous species were sampled in the stack through a heated sampling tube simultaneously by standardized washing bottles-based sampling techniques and cryogenically. The cryogenic samples were collected at -80 degrees C for further speciation analysis by LT/GC-ICPMS. Three species of selenium and two of mercury were evidenced as volatile species in the flue gas. Thermodynamic predictions and experiments suggest the following volatile metal species to be present in the flue gas: H2Se, CSSe, CSe2, SeCl2, Hg(0), and HgCl2. Quantification of volatile metal species in comparison between cryogenic techniques and the washing bottles-based sampling method is also discussed. Concerning metal partitioning, the results indicated that under these conditions, at least 60% (by weight) of the elements Pb, Sn, Cu, Co, Tl, Mn, V, Cr, Ni, Zn, Cd, and Sb mixed to the fuel were found in the particulate matter. For As and Se, 37 and 17%, respectively, were detected in the particles, and no particulate mercury was found. Direct metal speciation in particles was performed by XPS allowing the determination of the oxidation state of the following elements: Sb(V), Tl(III), Mn(IV), Cd(II), Zn(II), Cr(III), Ni(II), Co(II), V(V), and Cu(II). Water soluble species of inorganic Cr, As, and Se in particulate matter were determined by HPLC/ICP-MS and identified in the oxidation state Cr(III), As(V), and Se(IV).     

微波消解-电感耦合等离子体质谱法测定虾皮中28种元素

目的建立电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)测定虾皮中K、Na、Ca、Mg、Fe、Mn、Cu、Zn、P、Li、Al、V、Cr、Co、Ni、As、Rb、Sr、Se、Mo、Ag、Cd、Pb、Ba、Ga、Cs、Ti、Bi 28种元素含量的分析方法。方法采用硝酸-过氧化氢消解体系,通过在线加入Ge、Rh、Re内标进行基体效应校正,碰撞反应池模式(kinetic energy discrimination,KED)消除多原子离子干扰,以国家标准物质大虾(GBW 10050)为研究对象,验证方法准确度。结果方法检出限为0.001-0.681 mg/kg,相对标准偏差(relative standard deviations,RSD)为0.6%~8.2%,各元素标准曲线线性关系良好,相关系数r²大于0.999,样品回收率为87.4%~110.0%。虾皮中常量元素K、Na、Ca、Mg等含量较高,Pb、Cd、Cr等重金属元素含量较低,Al、As需根据其存在形态评估可能存在的健康安全风险。结论该方法准确高效,灵敏度高,可应用于虾皮样品分析。     

Linking cesium and strontium uptake to kaolinite weathering in simulated tank waste leachate

Weathering behavior of kaolinite was studied in batch systems under geochemical conditions characteristic of tank waste released to the vadose zone at the Hanford Site, WA (0.05 M Al(T), 2 M Na+, 1 M N03-, pH approximately 14, Cs+ and Sr2+ present as co-contaminants). Time series experiments were conducted from 0 to 369 d, with initial Cs+ and Sr2+ concentrations ranging from 10(-5) to 10(-3) M. Dissolution of kaolinite increased soluble Si and Al to maximum levels at 7 d (Cs and Sr concentrations of 10(-5) and 10(-4) M) or 33 d (Cs and Sr concentrations of 10(-3) M). Subsequent precipitation of Si and Al was coupled to the formation of oxalate-extractable solids that incorporated Cs and Sr. Strontium sorption was nearly complete within 24 h for initial Sr concentrations (Sr0) < or = 10(-4) whereas Cs uptake increased over the full year of the experiment for all initial Cs concentrations. Spectroscopic analyses revealed neoformed solids including the zeolite Na-Al silicate (Al-chabazite), and feldspathoids sodium aluminum nitrate silicate (NO3-sodalite), and sodium aluminum nitrate silicate hydrate (NO3-cancrinite), which can incorporate Cs. Single-pulse 27Al solid-state nuclear magnetic resonance (NMR) spectroscopyyielded first-order rate constants (k)for mineral transformation that decreased from 3.5 x 10(-3) to 2 x 10(-3) d(-1) as Cs and Sr concentrations were increased from 10(-5) to 10(-3) M. Discrete strontium silicate solids were also observed. The incongruent dissolution of kaolinite promoted the sequestration of contaminants into increasingly recalcitrant solid phases over the 1-yr time period.     

Removal of cadmium from wastewaters by aragonite shells and the influence of other divalent cations

The effect of dissolved Zn, Co, Pb, Mg, and Ca on the uptake of cadmium by biogenic aragonite was investigated. Experiments were performed in batch-reactors using metal-cadmium-bearing solutions and shell fragments with diameters in different ranges, the solid/liquid ratio being 10 grams per liter. Different initial concentrations of cadmium and metals (1.0-0.005 mM) were used. Uptake takes place via heterogeneous nucleation of metal-bearing crystallites onto the shell surfaces. Cadmium removal occurs by surface precipitation of otavite. Under the conditions used here, Co and Ca as well as Pb < or = 0.3 mM and Zn < or = 0.3 mM do not have a significant effect on the removal of cadmium. At higher concentrations, Pb and Zn outcompete Cd for the dissolving carbonate ions and thus decrease significantly the Cd removal rates. In contrast, Mg has a slight enhancing effect. Pb and Zn are removed faster than Cd, precipitating as PbCO3, Pb3(CO3)2(OH)2, and Zn5(CO3)2(OH)6. Within 24-72 h, the concentrations of lead, cadmium, and zinc decrease until approximately 0.5 microM, and the presence of aragonite buffers the solution to a pH above 8 avoiding redissolution. The study demonstrates the high effectiveness of biogenic aragonite in removing Cd and other metals from polluted waters.     

Chemical equilibria model of strontium-90 adsorption and transport in soil in response to dynamic alkaline conditions

Strontium-90 is a major hazardous contaminant of radioactive wastewater and its processing sludges at many Department of Energy (DOE) facilities. In the past, such contaminated wastewater and sludge have been disposed in soil seepage pits, lagoons, or cribs often under highly perturbed alkaline conditions (pH > 12) where 90Sr solubility is low and its adsorption to surrounding soil is high. As natural weathering returns these soils to near-neutral or slightly acidic conditions, the adsorbed and precipitated calcium and magnesium phases, in which 90Sr is carried, change significantly in both nature and amounts. No comprehensive computational method has been formulated previously to quantitatively simulate the dynamics of 90Sr in the soil-groundwater environment under such dynamic and wide-ranging conditions. A computational code, the Hydrologic Utility Model for Demonstrating Integrated Nuclear Geochemical Environmental Responses (HUMDINGER), was composed to describe the changing equilibria of 90Sr in soil based on its causative chemical reactions including soil buffering, pH-dependent cation-exchange capacity, cation selectivity, and the precipitation/dissolution of calcium carbonate, calcium hydroxide, and magnesium hydroxide in response to leaching groundwater characteristics including pH, acid-neutralizing capacity, dissolved cations, and inorganic carbonate species. The code includes a simulation of one-dimensional transport of 90Sr through a soil column as a series of soil mixing cells where the equilibrium soluble output from one cell is applied to the next cell. Unamended soil leaching and highly alkaline soil treatments, including potassium hydroxide, sodium silicate, and sodium aluminate, were simulated and compared with experimental findings using large (10 kg) soil columns that were leached with 90Sr-contaminated groundwater after treatment. HUMDINGER's simulations were in good agreement with dynamic experimental observations of soil exchange capacity, exchangeable cations, total 90Sr, and pH values of layers within the soil columns and of column effluents.     

<Emphasis Type="SmallCaps">l</Emphasis>-Cysteine Functionalized Silica Gel as an Efficient Adsorbent for the Determination of Heavy Metals in Foods by ICP-MS

A novel l-cysteine functionalized silica gel adsorbent (SG-Cys) was successfully synthesized and characterized by Fourier transform infrared (FTIR) spectra and elemental analysis. An efficient method for simultaneous determination of heavy metals [V (V), Cr (VI), Cu (II), As (V), Cd (II), and Pb (II)] was developed by inductively coupled plasma-mass spectrometry (ICP-MS) coupled with pre-concentration with the prepared SG-Cys adsorbent. The experimental parameters, including the solution pH, sample flow rate, eluent volume, eluent type, and concentration, have been systematically optimized to obtain higher enrichment factors of target ions. Under the optimum conditions, the enrichment factors of V (V), Cr (VI), Cu (II), As (V), Cd (II), and Pb (II) reached 123, 100, 86, 106, 97, and 94, respectively, and the detection limits were as low as 1.8–3.7 ng L^?1. The proposed method has been applied to the determination of trace heavy metals in water, rice, wheat, corn, and tea samples, which exhibited a satisfactory recovery in the range of 90.6–106.0 %.     

Trace elements in farmed fish (Cyprinus carpio,Ctenopharyngodon idella and Oncorhynchus mykiss) from Beijing: implication from feed

Concentrations of 30 trace elements, Li, V, Cr, Mn, Fe, Ni, Cu, Mo, Zn, Se, Sr, Co, Al, Ti, As, Cs, Sc, Te, Ba, Ga, Pb, Sn, Cd, Sb, Ag, Tm, TI, Be, Hg and U in major cultured freshwater fish species (common carp-Cyprinus carpio, grass carp-Ctenopharyngodon idella and rainbow trout-Oncorhynchus mykiss) with the corresponding feed from 23 fish farms in Beijing, China, were investigated. The results revealed that Fe, Zn, Cu, Mn, Sr, Se were the major accumulated essential elements and Al, Ti were the major accumulated non-essential elements, while Mo, Co, Ga, Sn, Cd, Sb, Ag, Tm, U, TI, Be, Te, Pb and Hg were hardly detectable. Contents of investigated trace elements were close to or much lower than those in fish from other areas in China. Correlation analysis suggested that the elemental concentrations in those fish species were relatively constant and did not vary much with the fish feed. In comparison with the limits for aquafeeds and fish established by Chinese legislation, Cd in 37.5% of rainbow trout feeds and As in 20% of rainbow trout samples exceeded the maximum limit, assuming that inorganic As accounts for 10% of total As. Further health risk assessment showed that fish consumption would not pose risks to consumers as far as non-essential element contaminants are concerned. However, the carcinogenic risk of As in rainbow trout for the inhabitants in Beijing exceeded the acceptable level of 10^?4, to which more attention should be paid.