Sampling Atomic Absorption Spectrometry Research Articles

Assessment of the Quality of Herbal Teas from Šabac, Serbia in Terms of the Content of Heavy Metals.

Chemical components of teas have received great interest because they are related to health. In this work, data on the determination of foreign matter, loss on drying/water content, total ash and ash insoluble in hydrochloric acid are presented. The content of seven heavy metals including Cu, Fe, Mn, Zn, Ni, Cd and Pb were determined by atomic absorption spectrometry in samples of several herbal teas: Matricariae flos, Thymi herba, Menthae piperitae folium, Betulae folium, Quercus cortex, Gentianae radix, Frangulae cortex, Althaeae radix, Uvae ursi folium and Glycyrrhizae radix collected from Šabac’s market, Serbia. The sample preparation procedure involved dry digestion and dissolution of the ash in 6M HCl and then in 0.1 M HNO3. Herbal teas showed the concentration of heavy metals Cu, Fe, Mn, Zn and Ni in the range: 2.9 ± 0.1 – 22.2 ± 0.9 mg/kg, 118.5 ± 1.1 – 755.5 ± 2.5 mg/kg, 19.0 ± 5.8 – 561.0 ± 1.9 mg/kg, 6.5 ± 0.4 – 242.5 ± 1.4 mg/kg and 2.5 ± 0.1 – 10 ± 1.1 mg/kg, respectively. The level of copper in all samples was uniform. The highest content of Fe was in Thymi herba, while Mn and Zn were at maximum in Betulae folium. The levels of toxic heavy metals Cd and Pb were below the detection limit. The obtained values were compared with data available from literature. The herbal tea samples analyzed contained essential heavy metals (Cu, Fe, Mn, Zn) and probably essential in trace (Ni), and could obey the daily dietary requirements. Noncancer health risk assessment detected that the herbal teas of Betulae folium and Frangulae cortex can manifest some health risk to consumers.

Moss Biomonitoring of Atmospheric Trace Element Pollution in the Republic of Moldova.

The moss biomonitoring technique was used for the assessment of air pollution in the Republic of Moldova, in the framework of the UNECE ICP Vegetation Programme. The content of 11 chemical elements (Al, V, Cr, Fe, Ni, Zn, As, Sb, Cd, Cu, and Pb) was determined by neutron activation analysis and atomic absorption spectrometry in samples collected in spring 2020. Distribution maps were built to identify the most polluted sites. The highest concentrations of elements in mosses were determined in the north-eastern, central, and western parts of the country. The main element associations were identified using factor analysis. Three factors were determined, of which one of mixed geogenic-anthropogenic origin and two of anthropogenic origin. A comparison of the data obtained in 2020 and 2015 showed a significant decrease in the concentrations of Cr, As, Sb, Cd, Pb, and Cu in 2020. The state of the environment was assessed using Contamination Factor and Pollution Load Index values, which characterized it as unpolluted to moderately polluted. Possible air pollution sources in the Republic of Moldova are resuspension of soil particles, agricultural practices, vehicles, industry, and thermal power plants.

Mercury Content in Central and Southern Adriatic Sea Sediments in Relation to Seafloor Geochemistry and Sedimentology.

Mercury contents were determined in surface sediments from the Central and Southern Adriatic Sea to gain insight into the processes, factors, and variables affecting its distribution. Mercury concentration was measured by thermal decomposition amalgamation atomic absorption spectrometry in samples collected by box-corer from Ancona to Santa Maria di Leuca during the CNR-PERTRE cruise (16/9-4/10/2016). Sediments were also evaluated for chemical-physical parameters (pH, Eh), biogeochemical composition (total carbon, inorganic carbon, total organic carbon, organic matter) and grain size. The average mercury concentration in the Adriatic Sea sediment was 0.053 mg/Kg (d.w.), range 0.011–0.12 mg/Kg (d.w.). Mercury content was mainly affected by grain size and organic matter (OM) distribution, whereas anthropic factors exerted a limited influence. Concentrations followed the distribution of sediment types (clay > silt > sand) due to Adriatic Sea hydrodynamics and were well below the regulatory limits in all samples.

Nitrogen doped nano porous graphene as a sorbent for separation and preconcentration trace amounts of Pb, Cd and Cr by Ultrasonic assisted in‐syringe dispersive micro solid phase extraction

Nitrogen doped nano porous graphene was used as an efficient sorbent in solid‐phase extraction process for simultaneous separation and pre‐concentration of metal ions lead (II), cadmium(II), and chromium(III)) in biological samples. Ultrasonic assisted in‐syringe dispersive micro solid phase extraction coupled with micro sampling atomic absorption spectrometry was utilized for the determination of metal ions. Nitrogen doped nano porous graphene was synthesized as a nano sorbent by chemical vapour deposition method. Methane and aniline were used as carbon and nitrogen sources. The characterization of sorbent was performed by field emission scanning electron microscope, transmission electron microscopy, atomic force microscope, fourier transform infrared, chemical element analysis and raman analysis. Effective parameters on the extraction efficiency such as pH, sorbent dosage, eluent volume and eluent concentration were optimized by central composite design and desirability function. Experimental results indicate that the optimal conditions for this extraction were pH = 6.4, 1.42 mg of sorbent, 100 μL of eluent, and 0.84 mol L‐1 of eluent concentration. The detection limits are as low as 1.5, 0.3 and 0.9 μg L‐1 for lead, cadmium, and chromium, respectively. The intra‐day precisions were 3.6, 4.38 and 2.94 and Inter‐day precision were 4.83, 5.26 and 4.52 for lead, cadmium, and chromium, respectively. Method performance was investigated by determination of mentioned heavy metals in complicated biological matrixes such as human plasma, urine and saliva samples with good recoveries.

Copper, Manganese and Zinc Bioaccumulation in Some Common Poaceae Species Along Romanian Black Sea Coast

Copper, manganese and zinc bioaccumulation potential was screened for three common Poaceae species, Hordeum murinum ssp. murinum L., Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev and Lollium perenne L., abundantly growing along the Romanian Black Sea Coastal area, Constanta County. The concentration of the selected heavy metals was analyzed though atomic absorption spectrometry in samples of aboveground plant organs and soils. To assess the potential for phytoaccumulation, the Biological Accumulation Coefficients (BAC) were calculated. Considering the minimal thresholds widely accepted in literature for Cu, Mn and Zn hyperaccumulators, none of the selected species can fit in this category. The highest average copper concentration was found in Hordeum murinum ssp. murinum L. (5.45 mg/kg). For manganese, the highest value was found in Lollium perenne L. (104.08 mg/kg), while for zinc, the maximum was reached in Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev, tissue (62.95 mg/kg). BAC values showed that all species are manganese excluders, with a remarkable maximum value of 0.55 in Lollium perenne. L. All species had average BAC above 1 for Cu and Zn, with a maximum in Leymus racemosus ssp. sabulosus (M. Bieb.) Tzvelev (4.85 and 2.98, respectively). However, there was a significant variation among individuals, usually, a high metal content in plant tissue being associated with low metal concentration in soil. The exception was Lollium perenne L., with BAC constantly above 1 (average BAC of 2.27 for Cu and 1.69 for Zn). These results emphasize a significant potential for phytostabilization of copper- and zinc-rich soils and open the way for heavy metals phytoextraction capacity studies of the Poaceae species along Romanian littoral.

Data relating to prenatal lead exposure and child IQ at 4 and 8 years old in the Avon Longitudinal Study of Parents and Children

As part of the Avon Longitudinal Study of Parents and Children (ALSPAC), measures of child IQ were collected by trained psychologists. The Wechsler Pre-school and Primary Scale of Intelligence – Revised UK edition (WPPSI) was used at age 4 years in a subsample of children enrolled in ALSPAC (the Children in Focus cohort), chosen at random from the last 6 months of ALSPAC births (about 10% of the participants). At age 8 years all children enrolled in the main cohort were invited to complete a short form of the Wechsler Intelligence Scale for Children (WISC)-III UK. Prenatal blood lead (B-Pb) concentrations were measured by inductively-couple plasma mass spectrometry in samples from women at a median gestation age of 11 weeks. Child blood lead was measured by atomic absorption spectrometry in samples from children attending the Children in Focus clinic at age 30 months. Maternal reports at 32 weeks’ gestation were used to generate data on a range of potential confounders. The data were used to determine the associations between prenatal exposure to lead and child IQ at 4 and 8 years. The effect of child B-Pb at 3 years as a moderator of these associations was tested. (For results, please see doi:10.1016/j.neuro.2017.07.003 Taylor et al., (2017)).

Levels of selected essential and non-essential metals in seeds of korarima (Aframomum corrorima) cultivated in Ethiopia

SummaryThe levels of essential (Ca, Mg, Fe, Zn, Cu, Co, Cr, Mn and Ni) and non-essential (Cd and Pb) metals were determined by flame atomic absorption spectrometry in samples of korarima (Aframomum corrorima) seeds and the corresponding soils collected from southern and southwestern Ethiopia. A wet digestion procedure involving the use of 3 mL of HNO3 (69-72%) and 1 mL of HClO4 (70%) were used to solubilize the metals from the korarima seed samples, and a modified aqua regia (HCl:HNO3) reagent with added hydrogen peroxide (6 mL of aqua regia and 1.5 mL of H2O2) was used for the soil samples. The levels of the nutrients in the korarima seed samples were in the following ranges: Ca (1794-2181); Mg (1626-2067); Mn (141-180); Fe (37-46); Zn (12-18); Ni (6.6-8.5); Cu (5.8-8.3); Cr (3.8-5.8) and Co (2.0-2.3) in µg g–1, respectively. The concentration of non-essential cadmium was in the range from 0.9-1 µg g–1 while that of lead was below the detection limit of the method. There was good correlation between the levels of some metals (Ni, Fe, Cd, Ca, Cu, Mg) in the korarima seeds and soil samples but poor correlation between other metals (Cr, Zn, Mn, Co).

Determination of the total mercury in contaminated soils by direct solid sampling atomic absorption spectrometry using an AMA-254 device and radiochemical neutron activation analysis

High total mercury (T-Hg) contents in soils, up to 25mgkg−1, were determined by two independent methods: a one-purpose atomic absorption spectrometer AMA-254 (Advanced Mercury Analyser) with direct solid sampling and radiochemical neutron activation analysis (RNAA), using sample masses of 10mg to 25mg and about 150mg, respectively. An excellent agreement between results of both methods was obtained. For quality control (QC) purposes, NIST SRM 2711 Montana Soil and NIST SRM 2711a were analyzed by both methods using the above sample masses. The results obtained compared with the NIST certified values within the uncertainty margins, thus proving the accuracy of the procedures employed. A new mercury value of 1.42mgkg−1±0.12mgkg−1 was determined in NIST SRM 1648a Urban Particulate Matter by RNAA. For achieving accurate results by the AMA-254 spectrometer, optimizing of the analytical procedure was necessary, consisting of analyzing small (10mg to 25mg) sample masses. It has been found that the cryogenic grinding used provided sufficiently representative and homogeneous samples. In view of the decomposition procedures employed in AMA-254 and RNAA procedures, it can be inferred that the mercury contained in QC samples was presumably bound in an organic fraction. A test in which HgS was analyzed by RNAA showed that even mercury present in sulfide form would be fully recovered using the procedures employed.

Determination of Cadmium, Chromium, Copper, Iron, Lead, Magnesium, Manganese, Potassium, and Zinc in Mint Tea Leaves by Electrothermal Atomizer Atomic Absorption Spectrometry in Samples Purchased at Local Supermarkets and Marketplaces

The concentrations of Cd, Cr, Cu, Fe, K, Mg, Mn, Pb, and Zn in 14 different samples of mint leaves (Mentha piperitae folium) and tea bags purchased in local supermarkets and marketplaces in Split, Croatia were determined. Electrothermal atomic absorption spectrometry (ETAAS) was applied in this work. Mint tea samples purchased at marketplaces contained: Cd (0.021–0.357 mg kg−1), Cr (<0.01–52.3 mg kg−1), Cu (3.23–5.56 mg kg−1), Fe (47.7–208 mg kg−1), K (7.47–21.7 g kg−1), Mg (2.16–15.9 g kg−1), Mn (24.2–667 mg kg−1), Pb (1.31–1.49 mg kg−1), and Zn (2.33–19.5 mg kg−1). Those ones purchased at supermarkets contained: Cd (0.19–0.34 mg kg−1), Cr (7.3–99 mg kg−1), Cu (1.70–5.21 mg kg−1), Fe (0.16–1.42 g kg−1), K (0.23–60.8 g kg−1), Mg (0.13–16.3 mg kg−1), Mn (0.30–0.93 mg kg−1), Pb (<0.01–1.73 mg kg−1), and Zn (<0.01–24.9 mg kg−1). In order to get a better insight into the elemental patterns in mint leaves, a One-Way ANOVA program R was used for statistical data analysis. The One-way ANOVA was performed with the amount of each metal as the dependent variable and market as the independent variable. The PCA (principal component analysis) was applied to analyze the grouping of mint leaves on supermarket and marketplace samples.

A rapid solid sampling method for determination of nickel and copper along human hair by ETAAS

A procedure for copper and nickel determination in scalp hair by solid sampling electrothermal atomic absorption spectrometric method was described. The hair samples (0.02 to 0.4 mg) were inserted directly on the platforms of solid sampling autosampler. The effects of pyrolysis temperature, atomization temperature, the amount of sample as well as addition of a modifier (Pd/Mg) and/or auxiliary digesting agents (hydrogen peroxide and nitric acid) and/or a surfactant (Triton X-100) on the determination of copper and nickel by solid sampling atomic absorption spectrometry were investigated. After optimization of parameters, the average recoveries of copper in two different certified reference hair samples were 105.7 and 97.6%. The recoveries of nickel in the both certified reference hair samples were in 95.2 and 96.4%. The limits of detection (3σ, N = 10) for copper and nickel were 22 ng/g and 35 ng/g, respectively. Heterogenous distribution of analyte in microscale for segmental analysis could be determined which is important to know that analyte quantity and time of poisoning of a person was exposed. For this purpose, 0.5 cm of pieces were cut along one or a few close strands and analyzed by solid sampling. This process could not be performed by wet-digestion method because 50 mg of sample is needed each time. Finally, the method was applied for the determination of copper and nickel concentrations in the hairs of different persons.

Comparison of action of mixed permanent chemical modifiers for cadmium and lead determination in sediments and soils by slurry sampling graphite furnace atomic absorption spectrometry

Slurry sampling atomic absorption spectrometry with electrothermal atomization was used to the determination of cadmium (Cd) and lead (Pb) in soils and sediments using permanent modifiers. Comparison of action of mixed permanent modifiers niobium (Nb)/iridium (Ir) and tungsten (W)/iridium (Ir) were studied in detail. The effect of amount of Ir, W and Nb on analytical signals of Cd and Pb was examined. The optimal amounts of modifiers for Cd and Pb determination were stated. Niobium carbide formation on graphite surface was studied for different pyrolysis temperatures. Finally for Cd determination in sediments and soils 200 μg of Nb mixed with 5 μg of Ir was used as permanent modifiers and 15 μg of Nb mixed with 200 μg of Ir for Pb determination. Suspensions were prepared in 5% HNO 3. The analytical procedure was optimized carefully basing on data from pyrolysis and atomization curves studies. Ammonium dihydrogen phosphate was used additionally as matrix modifier during Cd determination in samples in order to prevent interferences coming from matrix components. The analysis of CRMs confirmed the reliability of the proposed approach. The precision and accuracy of Cd and Pb determination by the described method for soils and sediments were acceptable.

Determination of tin in marine sediments by slurry sampling atomic absorption spectrometry with electrothermal atomization using a permanent modifier

Slurry sampling atomic absorption spectrometry with electrothermal atomization was used for the determination of tin in marine sediments. A mixture of 4 μg of iridium and 40 μg of tungsten and 12 μg of niobium alone were used as permanent modifiers. Suspensions were prepared in 7% nitric acid. The influence of amounts of tungsten on iridium removal from graphite tubes modified by iridium and the mechanism of atomization of tin in slurries were studied in detail. The effect of the amount of added iridium, tungsten and niobium on the analytical signal, and of the soil matrix on the background signal is described. In order to prevent interferences by sulfur compounds, barium chloride was added as a matrix modifier. Calibration was performed directly using aqueous standards. The analysis of certified reference materials confirmed the reliability of the approach. The precision and accuracy of the determination of tin in sediments by this method is acceptable.

Determination of trace mercury in geological samples by direct slurry sampling cold vapor generation atomic absorption spectrometry

A new method based on ultrasonic slurry sampling atomic absorption spectrometry (AAS) was established for the determination of trace mercury in geological samples by use of recently developed mercury cold vapor generation using formic acid under ultraviolet (UV) irradiation. The generated mercury cold vapor was rapidly separated from the matrix and swept into a T-tube for the measurement of atomic absorbance. Under the optimal experimental conditions, up to 1000-fold of Cu(II), Co(II), Ni(II), Cr(VI), Mn(II), Fe(III), and Zn(II) caused no significant interference with the determination of 50 µg L−1 Hg. The limit of detection at sub-ppb level was obtained for mercury. The method was applied to the determination of mercury in geological samples with satisfactory results.

Current Status of Direct Solid Sampling for Electrothermal Atomic Absorption Spectrometry—A Critical Review of the Development between 1995 and 2005

The literature about direct solid sampling (SS) and slurry sampling atomic absorption spectrometry (AAS) over the past decade has been surveyed critically. It became apparent that a very significant change had occurred, particularly in the relation between the two major techniques used for that purpose. In the 1990s, slurry sampling was typically considered the technique of choice, combining the significant advantages of the solid and the liquid sampling methods, at least in part because of the availability of a commercial accessory for automatic slurry sampling. The situation is completely inverted now, as the above accessory has been discontinued and rugged and reliable accessories for direct SS became available. Direct SS electrothermal (ET) AAS has been shown to provide the best limits of detection because of the absence of any dilution and a minimal risk of contamination. Calibration against aqueous standards appears to be feasible after careful program optimization. The absence of any significant sample handling makes SS ET AAS ideally suited for fast screening analyses. The introduction of high‐resolution continuum source AAS appears to open additional attractive features for SS ET AAS because of the significantly simplified optimization of furnace programs and the visibility of the spectral environment, which makes it easy to avoid spectral interferences. New calibration strategies make a “dilution” of samples unnecessary, which used to be one of the major limitations of SS ET AAS. Finally, direct SS analysis is an important contribution to clean chemistry, as practically no reagents are used.

Determination of antimony by electrochemical hydride generation atomic absorption spectrometry in samples with high iron content using chelating resins as on-line removal system

A method for the removal of the interference caused by iron on electrochemical generation of stibine is proposed. It consists of a chelating resin Chelex 100 column integrated into a flow injection system and coupled to the electrochemical hydride generator quartz tube atomic absorption spectrometer (EcHG-QT-AAS). Iron, as Fe(II), is retained in the column with high efficiency, close to 99.9% under optimal conditions. No significant retention was observed for Sb(III) under same conditions and a 97 ± 5% signal recovery was achieved. An electrochemical hydride generator with a concentric configuration and a reticulated vitreous carbon cathode was employed. The system is able to determine antimony concentrations in the range of ng ml −1 in presence of iron concentrations up to 400 mg l −1. The procedure was validated by analyzing PACS-2 marine sediments reference material with a 4% (w/w) iron content and a [Fe]:[Sb] ratio of 4000:1, which caused total antimony signal suppression on the electrochemical hydride generation system. A compost sample with high iron content (0.7%, w/w), was also analyzed. A good agreement was found on both samples with the certified value and the antimony concentration determined by ICP-MS, respectively.

Differential determination of trace amounts of arsenic(III) and arsenic(V) in seawater by solid sampling atomic absorption spectrometry after preconcentration by coprecipitation with a nickel–pyrrolidine dithiocarbamate complex

A sensitive and accurate method for the differential determination of trace amounts of arsenic(III) and arsenic(V) in water samples was described. It was found that arsenic(III) was coprecipitated quantitatively with a Ni–ammonium pyrrolidine dithiocarbamate (APDC) complex at the pH range of 2–3, but arsenic(V) was hardly coprecipitated with the Ni–PDC complex in the same pH condition. The coprecipitates obtained were directly measured by electrothermal atomic absorption spectrometry (ETAAS) using the solid sampling technique. In order to determine trace amounts of total arsenic, sodium thiosulfate and potassium iodide were used to reduce arsenic(V) to the trivalent state in the sample solution before coprecipitation. The concentration of arsenic(V) in the sample solution could be calculated by the difference in concentration between arsenic(III) and total arsenic in the sample solution. The coprecipitation conditions for trace amounts of arsenic(III) and arsenic(V) in water samples by the Ni–PDC complex were investigated in detail. The concentration factor by coprecipitation was reached at about 40 000 when 2 mg of nickel as a carrier element was added to 500 ml of the water sample. The proposed method was successfully applied to the determination of trace amounts of arsenic(III) and arsenic(V) in seawater, and the detection limit for arsenic, which was defined as the concentration calculated from three times of the standard deviation of the procedural blanks, was 0.02 ng/ml for 500 ml portions of water sample in the proposed method.

Investigation of air pollution in Chile using biomonitors

A project has been undertaken to carry out a long term study on atmospheric air pollution in Chile using biomonitors. Samples of different species of lichens were collected in clean areas (native forest), analyzed and transplanted to the Santiago Metropolitan Area. In addition, samples of Tillandsia recurvata were collected in the Metropolitan Area for comparison purposes. The preparation of the samples was done under controlled, cryogenic conditions and analyzed by neutron activation analysis and solid sampling atomic absorption spectrometry. As part of the routine QA/QC procedures, the analytical laboratories, have participated in intercomparison runs organized by the IAEA for the determination of trace and minor elements in two lichens samples. The present paper describes the activities carried out within the framework of this project.

Determination of antimony(iii) and total antimony by hydride generation atomic absorption spectrometry in samples of injectable drugs used for leishmaniasis treatment

A procedure for the determination of Sb(III) and total Sb in commercial samples of injectable drugs based on pentavalent antimony was proposed. The drugs studied in this work are currently used for leishmaniasis treatment in many countries. Determination of Sb was performed by hydride generation atomic absorption spectrometry under controlled conditions for the reaction medium. The following parameters were investigated: type and concentration of acid, sodium tetrahydroborate concentration and purge time. The chosen conditions for Sb(III) were: 4% (m/v) citric acid, 1% (m/v) sodium tetrahydroborate and 10 s (a pre-reduction step was performed using 10% m/v KI in 0.2% m/v ascorbic acid solution). The same parameters for total Sb determination were: 0.5 mol l−1 sulfuric acid, 4% (m/v) sodium tetrahydroborate and 10 s. Interference from As, Ni, Cu and Pb on the analytical signal for Sb(III) was also investigated. Two kinds of commercial drugs were analyzed. The trivalent Sb concentration varied from 1.7 to 3.1 mg l−1, corresponding to 1.6 to 2.8% for the total Sb. Recovery tests for Sb(III) showed values varying from 98.9 to 101.9%. The characteristic mass for Sb(III) was 0.22 ng and the detection limit (3s) was about 1.5 ng (absolute). The main advantage of the proposed procedure is to allow the determination of Sb(III) in the presence of a large excess of pentavalent Sb (about 2000 ng).

Analysis of metal cations and inorganic anions in olive oil mill waste waters by atomic absorption spectroscopy and ion chromatography. Detection of metals bound mainly to the organic polymeric fraction.

Metal cations were quantitatively detected by atomic absorption spectrometry in samples of olive oil mill waste waters obtained by a pressure process (omww(1)) (K, 17.1; Mg, 2.72; Ca, 2.24; Na, 0.40; Fe, 0.123; Zn, 0.0630; Mn, 0.0147; Cu, 0.00860 g L(-)(1)) and a centrifugation process (omww(2)) (K, 9.80; Mg, 1.65; Ca, 1.35; Na, 0. 162; Fe, 0.0330; Zn, 0.0301; Mn, 0.00910; Cu, 0.00980 g L(-)(1)). The inorganic anions, determined in the same samples by ion chromatography, proved to be Cl(-), H(2)PO(4)(-), F(-), SO(4)(2)(-), and NO(3)(-) (1.61, 1.05, 0.66, 0.52, and 0.023 g L(-)(1), respectively, in omww(1) and 0.61, 0.40, 0.25, 0.20, and 0.0090 g L(-)(1), respectively, in omww(2)). Most of the metal cations were revealed to be bound to the omww organic polymeric fraction (opf), composed of polysaccharides, phenol polymers, and proteins. Opf relative molecular weight was substantially estimated in the range between 1000 and 30000 Da for approximately 75% and in the range from 30000 to 100000 Da for approximately 25%. The free residual cations pool proved to be neutralized by the inorganic counteranions. Finally, the possible exploitation of this material in agriculture and in environmental biotechnology processes is also discussed in the light of its chemical and biochemical oxygen demand parameters.

Aluminum contents of human milk, cow's milk, and infant formulas.

Aluminum toxicity is well documented and contamination of milk formulas has been implicated as the source of accumulation in bone and brain tissues. The purpose of the current study was to evaluate the aluminum contents of human milk, cow's milk, and infant formulas. Aluminum contents were determined by atomic absorption spectrometry in samples of human milk in the colostrum, intermediate, and mature stages; infant formulas from eight manufacturers; and various types and brands of commercially available cow's milk. Mean aluminum concentration was lowest in human milk (23.4 +/- 9.6 microg/l), and did not differ significantly between colostrum, intermediate-stage and mature-stage milk. Mean aluminum concentration was 70 microg/l in cow's milk, and 226 microg/l in reconstituted infant formulas. Aluminum concentrations in infant formulas differed markedly among manufacturers; concentration in milk from one of the manufacturers was particularly high (mean, 551 microg/l; range, 302-1149 microg/l). These values are for milk reconstituted with aluminum-free water under laboratory conditions; formulas prepared with tap water in the University Hospital's infant-feeding unit had even higher aluminum content. Experiments showed that aluminum concentration in the high-aluminum milk could be reduced by more than 70% at the manufacturing stage, by using low aluminum components. The results of the present study support the recommendations for infant formula manufacturers to strive to reduce aluminum concentration in their products.