Furnace Atomic Absorption Research Articles

Determination of lead ions in fish and oyster samples using a nano-adsorbent of functionalized magnetic graphene oxide nanosheets-humic acid and the flame atomic absorption technique.

This study aims at the functionalization of magnetic graphene oxide nanosheets and the binding of humic acid as a lead complex ligand. Graphene oxide nanosheets possess a large surface area and various carboxylic acid groups which can be activated easily by activating agents. Therefore, they are suitable to be used for the extraction of heavy metals. To have a better process of extracting lead ions, magnetic graphene oxide was used in this research. Humic acid, as a lead metal complex agent, has an amine functional group which can be bound to modified graphene oxide from one side. The process of constructing the nano-adsorbent proposed for the preconcentration of lead ions as well as its characterization was studied by infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV-visible), field emission scanning electron microscopy (FESEM), and vibrating sample magnetometry (VSM). The designed nano-adsorbent was tested to measure lead ions in simulated and real samples of sea water, fish, and oysters. The detection limit obtained in the simulated samples was 0.07μg/L, and the linear range was 0.2-12μg/L. The apparatus used to measure the ions was a flame atomic absorption device. In the analysis of the real samples, the values obtained through flame atomic absorption were compared with those obtained through furnace atomic absorption. The proposed technique is advantageous due to being cheap, precise, and sensitive for the trace measurement of lead ions.

Evaluation of Essential Metals and Arsenic in Poultry Feeds and Litters of Different Poultry Farms

The current study was aim to evaluate the speciation of arsenic (total arsenic “TAs”, arsenite “AsIII” and arsenate “AsV”) and total contents of essential metals in the feeds and litters of branded poultry feed using farms (BPF) and non-branded poultry feed utilizing farms (NBPF) at Hyderabad Sindh, Pakistan. The TAs and essential metals determined by graphite furnace and flame atomic absorption spectrometry (GF and FAAS), respectively. Whereas, the AsIII and AsV separated by solvent extraction followed by GF-AAS. The high levels of sodium, potassium, and zinc were observed in branded poultry feeds whilst calcium and iron contents were higher in non-branded poultry feed. The contents of total arsenic in poultry feed samples of both branded and non-branded poultry feed utilizing farms were within the NRC permissible limits (30.0 mg/kg) except NBPF-1 and NBPF-4. Total As in all poultry litter samples were found under the permitted monthly average dose of As (41.0 mg/kg) for agronomical application expert poultry litter samples of BPF-1, NPBF-2, and NPBF-3. The daily accumulation of total As from feed to boilers were also studied.

Multivariate Statistical Characterisation of Soil Quality in the Lower Danube River Riparian Areas

Increasing anthropogenic influences on the environment has caused negative changes in natural ecosystems and soil contamination with potentially toxic metals has become a worrying issue at global level, due to the negative impact on the environment and human health. For the purpose of assessing soil contamination in the riparian areas of the Lower Danube River, a number of 144 soil samples were collected twice a year, in the period of June 2013 � December 2016, from 9 monitoring locations, from 0.05 m and 0.3 m depths, and the following indicators: Cr, Cu, Mn, Ni, Pb, Zn, including Ca, Mg, Corg, SO42- and humus content have been monitored. The soil was sampled, conserved and analysed according to the European standards in force. Metal concentrations were determined using flame (FAAS) and graphite furnace (GFAAS) atomic absorption spectrometry after �aqua regia� digestion of dried, homogenised and 0.5 mm sieved soil sub-samples. Comparing the average concentration values of the analysed potentially toxic metals, a decreasing tendency following the order Cr]Pb]Ni]Cu]Zn]Mn was observed and by reporting the average values at the normal limits, the order Zn]Cu]Mn]Ni]Pb]Cr of magnitude was obtained. To investigate possible correlations and interdependencies of potentially toxic metals content in the riparian soil, multivariate statistical methods were used. After applying Principal Component Analysis (PCA), 3 main components were identified, with a combined share of about 74 % of the original data-set variance. It was observed that during the monitoring period the average values of the all monitored elements from the studied soils were slightly below the normal reference values, according to the national legislation.

Comparison of L-Histidine Effects on Nickel Translocation into the Shoots of Different Species of the Genus Alyssum

The work dealt with the influence of free L-histidine on nickel (Ni) translocation into the shoots of the hyperaccumulator plants Alyssum murale, A. fallacinum, A. corsicum, A. tenium, A. lesbiacum, A. bertolonii, A. pintodasilvae, and A. obovatum and of the closely related non-hyperaccumulator Aurinia saxatilis (formerly Alyssum saxatile). The Ni concentration in the xylem sap was determined by graphite furnace or flame atomic absorption spectrophotometry. If plants were not treated with L-histidine or L-alanine, the highest Ni concentration was found in the xylem sap of A. murale and A. corsicum. When the plants were pretreated with L‑histidine, the Ni loading into the xylem vessels increased in only two hyperaccumulator species, A. pintodasilvae and A. obovatum, and in the non-hyperaccumulator A. saxatilis. The plant pretreatment with L-alanine did not increase the Ni level in the xylem sap. This indicates that the stimulation of Ni xylem loading is histidine-specific and not characteristic of any amino acid. Therefore, the role of histidine in the selective nickel accumulation in the shoots may considerably differ even in closely related plant species of one genus. This may presumably be accounted for by both different contents of endogenous histidine in the roots and specific patterns of the metal transport and distribution in different species.

A simple electrochemical hydride generation apparatus for the determination of inorganic arsenic in food samples with an atomic fluorescence spectrometer

A simple electrochemical hydride generation (EcHG) apparatus was developed for arsenic determination by atomic fluorescence spectrometry. The apparatus consists of two graphite tubes (as the atomizer in graphite furnace atomic-absorption spectrometry) that were used as cathode and anode cells and are connected together in series by an insulated plastic pipe, an AC to DC power wall plug adapter (12 V 2 A) used with portable computers, and a gas-liquid separator. The apparatus did not include an ion-exchange membrane, and an analyte solution containing thiourea and hydrochloric acid was used for both electrolytes without a specific anode only solution. The experimental results showed that EcHG efficiencies and detection limits depended on the output voltage and the concentration of HCl and thiourea used. Under the optimized conditions (solution flow rate of 3 ml mim−1, carrier argon gas flow rate of 400 ml min−1, a 12 V 2 A DC power adapter, and concentrations of thiourea and HCl of 1%(m/v) and 10%(v/v), respectively), the limit of detection of arsenic was 0.3 ng ml−1 (3σ), and the relative standard deviation was 4% for ten consecutive measurements of a 40 ng ml−1 As(III) standard solution. The calibration curve was linear up to 100 ng ml−1. The accuracy of the method was verified by the determination of arsenic in two certified reference materials (GBW10045 for rice flour and GBW10015 for spinach), and the results were in good agreement with the certified values.

Zinc and Manganese of serum were negatively, but Copper positively influenced by Iron elevation in diet of male Wistar rats.

The purpose of the study was to determine the effect of dietary iron on distribution of zinc, manganese, copper, calcium and magnesium in the body of Wistar rats. Commercial Sangak, an Iranian traditional flat bread was used in this study. It was prepared by additionof yeast and sourdough. Different doses of iron (35, 70, 140, and 210 mg/kg per diet) were added to bread vehicle for 30 days with or without baking soda (250 mg/kg per diet). The concentrations of the above elements were determined by graphite furnace and flame atomic absorption spectroscopy. Serum zinc and manganese concentrations were significantly lower (P < 0.05) in rats that received higher concentrations of iron compared to the controls. Serum iron, and copper concentrations increased significantly (P < 0.05) with an increase in dietary iron compared to the controls. Increments of dietary concentrations of iron raised the concentration of iron, zinc and manganese in the feces, and lowered the concentration of copper and calcium in the feces (P < 0.05). Diets that contained baking soda showed a statistically significant increase in phytic acid (P < 0.05). Lower serum iron was seen in rats that received baking soda with diet of the control group. Conversely, feces iron and zinc were increased in this group. It is concluded that iron absorption might interfere with zinc and manganese because of similar physicochemical properties. Knowledge about these interactions is essential when supplementation of some elements is recommended in populations with a high risk of some deficiencies such as iron and zinc.

Mechanism of Copper Uptake from Blood Plasma Ceruloplasmin by Mammalian Cells.

Ceruloplasmin, the main copper binding protein in blood plasma, has been of particular interest for its role in efflux of iron from cells, but has additional functions. Here we tested the hypothesis that it releases its copper for cell uptake by interacting with a cell surface reductase and transporters, producing apoceruloplasmin. Uptake and transepithelial transport of copper from ceruloplasmin was demonstrated with mammary epithelial cell monolayers (PMC42) with tight junctions grown in bicameral chambers, and purified human 64Cu-labeled ceruloplasmin secreted by HepG2 cells. Monolayers took up virtually all the 64Cu over 16h and secreted half into the apical (milk) fluid. This was partly inhibited by Ag(I). The 64Cu in ceruloplasmin purified from plasma of 64Cu-injected mice accumulated linearly in mouse embryonic fibroblasts (MEFs) over 3-6h. Rates were somewhat higher in Ctr1+/+ versus Ctr1-/- cells, and 3-fold lower at 2°C. The ceruloplasmin-derived 64Cu could not be removed by extensive washing or trypsin treatment, and most was recovered in the cytosol. Actual cell copper (determined by furnace atomic absorption) increased markedly upon 24h exposure to holoceruloplasmin. This was accompanied by a conversion of holo to apoceruloplasmin in the culture medium and did not occur during incubation in the absence of cells. Four different endocytosis inhibitors failed to prevent 64Cu uptake from ceruloplasmin. High concentrations of non-radioactive Cu(II)- or Fe(III)-NTA (substrates for cell surface reductases), or Cu(I)-NTA (to compete for transporter uptake) almost eliminated uptake of 64Cu from ceruloplasmin. MEFs had cell surface reductase activity and expressed Steap 2 (but not Steaps 3 and 4 or dCytB). However, six-day siRNA treatment was insufficient to reduce activity or uptake. We conclude that ceruloplasmin is a circulating copper transport protein that may interact with Steap2 on the cell surface, forming apoceruloplasmin, and Cu(I) that enters cells through CTR1 and an unknown copper uptake transporter.

Clinical Evaluation of Deferasirox For Removal of Cr+6 Ions In Rats

The present research aimed to characterize the potential efficiency of deferasirox in removing chromium after its administration for 60 days following two doses of 15 and 30 mg/kg Cr +6 to the body weight of the male Wistar rats every day. After chromium administration some abnormal clinical signs such as red staining around the eyes, greenish mottling on the liver, weakness and loss of hair and weight, were ob- served in rats. Deferasirox was given orally to different groups of rats for a period of one week immediately after chromium administration. After chelation therapy, animals were anesthetized with ether vapors and then chromium and iron concentrations in various tissues were determined by graphite furnace and flame atomic absorption spectrometry methods, respectively. The chelation therapy results showed that deferasirox was able to remove chromium ions from the body and at the same, iron levels in tissues and clinical symptoms were also reduced.

Flow injection on-line solid phase extraction for ultra-trace lead determination with hydride generation electrothermal atomic absorption spectrometry

The efficiencies of two types of chelating resins were evaluated and optimized for the extraction and determination of lead by flow injection graphite furnace and hydride generation atomic absorption spectrometry (FI-HG-ETAAS) in environmental water samples. The optimum analytical conditions were examined and the analytical features of each method were revealed and compared in terms of sensitivity, selectivity and accuracy. Lead determination by FI-HG-ETAAS using [1,5-bis(2-pyridyl)-3-sulphophenyl methylene] thiocarbonohydrazide immobilised on aminopropyl-controlled pore glass (PSTH-cpg, 55 nm) provides a detection limit of 3.0 ng l−1 lead with a relative standard deviation (R.S.D.) of 2.5% at the 50 ng l−1 level (n = 10) compared to silica gel funtionalized with methylthiosalicylate (TS-gel) which provides a detection limit of 82 ng l−1. Under the optimal experimental conditions, with the use of PSTH-cpg and a tungsten–rhodium coated graphite furnace, an enhancement factor of 20 was obtained with a sample consumption of 6.4 ml, while an enhancement factor of 3.5 was obtained with the use of TS-gel. Both methods have been applied to the determination of low levels of lead in environmental water samples. The results obtained show good agreement with certified or expected values.

Methodological Validation for the Determination of Ca, Cr, Mg and Mn in Umbilical Cord and Maternal Blood (City of Vale do Paraíba, São Paulo, Brazil)

This investigation focused on the validation o f the methodology used in determining the presence of specific elements in human blood. Concentrations of macro- and micronutrients in umbilical b lood (UCB) samples fro m 37 lactating volunteers who gave birth in the city of Taubate , State of Sa o Paulo, Brazil. The determinations of Ca and Mg were carried out in a flame ato mic absorption spectrometer (FAAS) and those of Cr and Mn in a graphite furnace ato mic absorption spectrometer (GFAAS). A procedure for preparing samples was optimized and evaluated. Standard addition methods and determinations by ICP OES were used to validate the analytical procedures. An acetylene/air mixture was optimized at 2.0/17.0 L min-1 (Ca and Mg). Pyrolysis and atomizat ion temperatures for Cr were at 1400° C and 2100° C, respectively, for Mn at 1300° C and 1700° C, respectively. The most efficient chemical modifier was a solution containing 5 g of Pd + 3  g of Mg(NO3)2. Characteristic masses for Cr and Mn were 2.6 and 2.7 pg, respectively. The methods presented high analytical efficiency in the determination of Ca, Cr, Mg and Mn (recovery fro m 98.68% to 108.22 %). M inimal data variations in repeatability and reproducibility indicated significient precision and accuracy for the proposed methodology. The placenta did not block transport of elements fro m mother to fetus. The contents of the elements analyzed in the UCB were co mpared to those detected in maternal blood (M B). Most of the children exh ibited normal weight (fro m 2.5 to 3.0 kg) as per the Brazilian Min istry of Health standards. Such results indicate that the levels of concentrations of the elements in the UCB did not affect the weights of the neonates.

Determination of strontium in rat plasma and plasma ultrafiltrate by Zeeman Furnace atomic absorption spectroscopy and its application to a pharmacokinetic study

A rapid and sensitive analytical assay for the determination of total strontium concentrations in rat plasma was developed and validated. The total strontium levels were determined by use of graphitefurnace atomic-absorption spectrometry (GF-AAS) with Zeeman correction, 1000°Ci n ashing temperatures and 2700°C in atomization temperatures after 3.5% HNO 3 protein precipitation. The accuracy was between 95.46 and 102.24% (intra-day variation), and 101.74 and 102.15% (inter-day variation). The precision was between 1.86 and 8.24% (intra-day variation), and 1.27 and 11.20% (interday variation). Linear calibration curves were obtained over the concentration range 0.2 to 10 μg/ml(r = 0.9993). Validation data were within the acceptable limits for analytical methods. This assay was successfully applied to evaluate the pharmacokinetics of strontium fructose 1, 6-diphosphate (Sr-FDP), a new compound in rats and free strontium after plasma ultrafiltrate was also performed by direct determination. Significantly different pharmacokinetics between total and free strontium were observed that provided more information for the pharmacokinetic study of Sr-FDP. Key words : Graphite furnace atomic-absorption spectrometry (GFAAS), strontium fructose 1, 6-diphosphate, strontium, ultrafiltrate, anti-osteoporosis.

Lack of ceruloplasmin expression alters aspects of copper transport to the fetus and newborn, as determined in mice

Copper transport and accumulation were studied in virgin and lactating C57BL/6 mice, with and without expression of ceruloplasmin (Cp), to assess the importance of Cp to these processes. One hour after i.p. injection of tracer (64)Cu, liver and kidney accounted for 80% of the radioactivity, and mammary gland 1%, while in lactating Cp+/+ mice 2-4 days post partum, uptake by mammary gland was 9-fold higher and that of liver and other organs was decreased, with (64)Cu rapidly appearing in milk. Parallel studies in Cp-/- mice (siblings from same colony) gave virtually identical results. However, their milk contained less (64)Cu, and actual copper contents determined by furnace atomic absorption were less than half those for milk from normal dams. Liver copper concentrations of pups born to Cp-/- dams also were half those of pups from wild type dams. Copper in pup brains was unaffected; but iron concentrations were reduced. We conclude that absence of Cp, while not affecting entry of exchangeable copper from the blood into the mammary gland, does have a significant effect on the availability of this metal to the newborn through the milk and in the form of stores accumulating in gestation.

Determination of Cd in Water Samples by Hollow-Fiber–Supported Liquid-Membrane Extraction Coupled with Thermospray-Flame–Furnace Atomic-Absorption Spectrometry

ABSTRACT A new method of hollow-fiber–supported liquid-membrane extraction (HF-SLME) coupled with thermospray-flame–furnace atomic-absorption spectrometry (TS-FF-AAS) for the determination of cadmium in water samples was developed. 1-Octanol was immobilized in the pores of the polypropylene hollow fiber as liquid membrane and used as the acceptor solution. Cd was selectively extracted from water samples into 1-octanol that filled the inner part of hollow fiber as the acceptor solution. The authors evaluated in detail some parameters that influence extraction and determination, such as the concentration of sodium diethyldithiocarbamate (DDTC), pH of samples, stirring rate, extraction time, flow rate of the pump, and interferences. Under optimized conditions, an enrichment factor of 146 could be obtained. In combination with thermospray-flame–furnace atomic-absorption spectrometry, a very low limit of detection (LOD) (5 ng L−1) was achieved. The relative standard deviation (RSD) was 4.3% for five determinations of 0.1 ng mL−1 cadmium. The accuracy of this method was validated by determination of certified reference water samples (GBW(E) 08607 and GSBZ(E) 50009-88). The proposed method was also applied to the determination of cadmium in tap water and river water, with the recoveries in the range of 90–96% for spiked samples.

Aluminum concentration in serum of children on long-term parenteral nutrition and in parenteral nutrition solution components

summary Background & Aims: Aluminum is a contaminant of parenteral nutrition solutions. Children who receive long-term parenteral nutrition are at risk of aluminum overload in tissues and its toxic effect. The aim of this study was to assess the incidence of aluminum overloading in those children and the level of aluminum contamination in parenteral nutrition solutions. Methods: A furnace atomic absorption was used to assess serum aluminum concentration in 24 patients, aged 2–20 years. These patients had received parenteral nutrition therapy ranging from 2 years to 14.7 years. Aluminum concentrations were also determined in parenteral nutrition solution components. Results: We found increased amount of aluminum concentration in calcium gluconate (6000 mg/l), in trace element (Addamel :7 00mg/l), amino acid solution (10% Primene :6 0mg/l), lipid-soluble vitamins (Vitalipid :5 00mg/l), and lipids emulsions (20%ClinOleic :1 10mg/l, Lipofundin MCT/LCT :5 5mg/l). Aluminum intake from parenteral nutrition was 5.81–29.64 mg/kg/day, a dose exceeding the safety limit of 5 mg/kg/day. We found increased aluminum concentration (>20 mg/l) in serum of 10 patients; 7

Removal of vanadium by combining desferrioxamine and deferiprone chelators in rats

Investigations were conducted to evaluate the ability of two chelators, desferrioxamine (DFO), and deferiprone (1,2-dimethy1-3-hydroxypyride-4-one, L1), for the excretion of vanadium after a period of administration of vanadium salts in 6-week-old male Wistar rats. Immediately after 60 days of vanadium administration, the rats received chelators (L1, DFO or L1 + DFO) for a period of 1 week. Chelators were given orally (L1), intraperitoneally (DFO), or both to different groups of rats at two different dosage levels. After chelation therapy, animals were sacrificed by exsanguination from abdominal aorta. Blood, kidney, liver, and heart samples were collected and prepared for determination of vanadium and iron concentrations by graphite furnace and flame atomic absorption spectroscopy (GF AAS, and F AAS) methods, respectively. These chelators significantly enhanced the urinary and biliary excretion of vanadium and restored the altered levels of iron. Furthermore, the hypothesis that these two known chelators might be more effective in removing vanadium from the body as a combined treatment than as monotherapy also was tested in this study. Although there is no significant difference between these two chelators in reducing the vanadium concentration, combination therapy (L1 + DFO) may cause higher efficacy and lower toxicity compared with monotherapies. Collectively, the results indicate that the designed procedure might be useful for preliminary in vivo testing of the efficiency of a chelating agent. However, our findings regarding the efficacy of combination therapy should be confirmed in more experiments. This preliminary study does not provide all answers to the magnitude of the efficiency of chelating agents in vanadium toxicity, and thus, further research is warranted.

Evaluation of the effect of cadmium on rat organs and investigation of diethyl carbamate as an oral drug in treatment of cadmium toxicity

The effect of diethyl carbamate as a chelating agent on the excretion of cadmium was evaluated in cadmium-poisoned Wistar rats following food and drink administration. The present research aimed to characterize the potential efficiency of diethyl carbamate as an oral drug chelator after cadmium administration for 60 days. This chelator significantly enhanced the urinary and biliary excretion of cadmium and restored the altered levels of iron. Diethyl carbamate was given orally to different groups of rats for a period of 1 week immediately after cadmium administration. After chelation therapy, animals were killed by exsanguination from abdominal aorta. Blood, kidneys, spleen, and heart samples were collected and prepared for determination of cadmium. Cadmium and iron concentrations in different issues were determined by graphite furnace and flame atomic absorption spectrometry (GFAAS and FAAS) methods, respectively. The chelation therapy results showed that diethyl carbamate was able to remove cadmium ions from different tissues while iron concentration returned to normal level and clinical symptoms were also reduced. In summary, we can conclude that diethyl carbamate could mobilize and promote the excretion of cadmium in rat organs and reduce the side-effects and general symptoms of toxicity. Moreover, it might be useful for preliminary testing of the efficiency of chelating agents in the human body. However, these results should be confirmed in a different experimental model before extrapolation to other systems. This testing procedure of course does not provide all the relevant answers for evaluating the efficiency of chelating agents in cadmium toxicity.

MultiSimplex optimization of on-line sorbent proconcentration and determination of iron by FI-AAS and microcolumn of immobilized ferron

A simple flow injection on-line separation and proconcentration system for determination of iron in milk and water samples were developed. Ferron was physically immobilized on alumina particles in the pH range of 2.5–6 and was used as sorbent in microcolumn preparation. Deposition of iron was effected by processing a standard or solution of analyte at pH range of 3–6 on the microcolumn. Injection of 300 μl of HNO 3 (5 mol l −1) served to elute the retained species to FAAS. Different factors affecting the performance of the system were optimized by MultiSimplex and univariable methods. MultiSimplex program based on the simplex algorithm allowed the simultaneous study of the variables affecting immobilization, sorption or elution process. The capacity of the sorbent under working condition was found to be 989.0 μg irons per gram of packing material. A sample volume of 20 and 40 ml resulted in preconcentration factors of 65 and 129, respectively. Precision ( n = 6) at 125 and 50 μg l −1 were 2.0 and 2.9%, respectively. With 20 ml sampling volume a detection limit of 1.06 μg l −1 was determined. The method was applied to determination of iron in tap water, river water, rain water, spring water, infant dry formula milk, human and cow milk. The accuracy was assessed through recovery experiments, independent analysis by furnace atomic absorption, and analysis of certified reference alloy.

Correlation and distribution of elemental markers of origin in the production of Bryndza sheep cheese

The successful classification of Bryndza, a typical Slovak national sheep cheese, from nine different Slovak producing regions, was based on canonical discriminant analysis. Elemental markers of origin (Ba, Cr, Cu, Hg, Mg, Mn, Ni and V) were determined by graphite furnace (GF) and flame atomic absorption spectrometry (AAS). High correlations of elemental markers were found between pasture soil, grass, and Bryndza cheese originated from different regions. The concentration of these markers in pasture soils, grasses, as well as in all the milk and Bryndza cheese-making process was monitored. Their content in sheep milk, lumpy cheese, whey, boiled sheep whey and final Bryndza cheese was significantly correlated with the soil elemental markers. The final product was only slightly contaminated by the individual elements during the Bryndza production, without any significant influence on the Bryndza origin classification and/or traceability.

Environmental lead exposure increases micronuclei in children

The objective of this pilot study was to investigate the contribution of environmental exposures to lead in the development of cytogenetic damage detected as the frequency of micronuclei (MN) in children. The other aim was to apply the MN assay in combination with fluorescence in situ hybridization (FISH) using a pan-centromeric chromosome probe to elucidate the formation mechanism of induced MN. The examined population was composed of 9-year-old children (n = 92), living in the region where non-ferrous ores are extracted and processed. The non-exposed group consisted of 49 children of the same age from an unexposed recreational area. Exposure to lead was assessed by determination of lead concentrations in blood (PbB) by atomic absorption spectrophotometry, whereas the level of selenium (Se) in serum was detected by using graphite furnace atomic-absorption spectrometry. The frequency of MN was determined by the cytokinesis-block MN assay and fluorescence in situ hybridization performed using a specific pan-centromeric probe. Environmental exposure to lead resulted in significantly increased levels of PbB (5.29 +/- 2.09 versus 3.45 +/- 1.20 microg/dl in controls), although the average level was much below the value of the biological exposure limit = 10 microg/dl. A negative correlation between lead in blood and Se in serum concentrations (P = 0.006) was found for the pooled study population. The results showed a significant difference (P < 0.0001) in the level of MN between the exposed and control group (standard MN test: 2.96 +/- 2.36 versus 1.16 +/- 1.28; FISH technique: 3.57 +/- 3.02 versus 1.43 +/- 1.69, respectively). The frequencies of both centromere-positive (C+MN) and centromere-negative (C-MN) micronuclei were significantly increased in exposed children; however, the contribution of C+MN in the total number of MN in peripheral blood lymphocytes of exposed children was significantly higher than in the controls what may suggest a pro-aneugenic effect of the exposure to lead. The results of multiple regression analysis indicated that the exposure to lead was an important factor affecting the increase in MN frequency what was confirmed by significant correlation between the PbB and MN levels. In conclusion, our results suggest that the exposure to lead may be associated with an increased frequency of MN, especially of C+MN; however, the influence of other factors (e.g. vitamins and minerals in the diet) cannot be excluded.

Lead content of dietary calcium supplements available in Brazil

The lead and calcium content of calcium supplements available in Brazil were determined by graphite furnace and flame atomic absorption spectrometry, respectively. Samples were microwave-digested in concentrated HNO3. Citric acid was used as a chemical modifier in the lead analysis. Supplements were classified into six categories: oyster industrialized (OI, n = 4), oyster prepared in pharmacy (OP, n = 3), refined industrialized (RI, n = 6), refined prepared in pharmacy (RP, n = 3), bone meal (B, n = 3), and dolomite (D, n = 4). Lead levels (µg g−1 of measured calcium) were higher in D products (2.33), followed by OI, RP, OP, and RI products (1.46, 1.32, 1.29, 0.75), while B products had levels lower than the limit of quantification (0.02 µg g−1 unit weight). Daily lead intake of eight supplements exceeded the limit of California, USA (1.5 µg g−1 calcium), but none exceeded the federal limit of USA (7.5 µg g−1 calcium) or the provisional tolerable lead intake by FAO/WHO (25 µg kg−1 per week).