Determination Of Lead In Blood Research Articles

Analytical Procedure for Determination of Lead in Blood and Urine by Atomic Absorption Spectrometry

Lead is one of the natural constituents of earth found in soils, plants, and water. Lead predominantly a concern for neurological toxic effect particularly in children due to its irreversible neurological damage. The common spectroscopic methods in trace element analysis in biological fluids are dithizone extraction, polarography, spectral analysis, atomic absorption spectrometry (AAS), inductively coupled plasma atomic emission spectrometry. A graphite furnace atomic absorption spectrophotometer is a valuable, simpler, and cost-effective spectrometric technique for the identification of lead absorbance in the human system. The GF-AAS method can be employed for the measurement of lead percentage in whole blood and urine, and the results acquired are helpful in biological monitoring and clinical diagnostic of work related to surrounding lead exposure. The paper reports the average lead concentration, and calibration graphs for standards as well as absorbance against lead concentration, which will be productive in future for analytical determination of lead in blood and urine.

Biomonitoring of exposure of Algerian population to lead

Lead poisoning, is currently recognized as a real public health problem. The WHO classifies lead as one of 10 chemicals of serious public health concern. The assessment and management of health risks and public health interventions are largely based on a detailed knowledge of exposure of the general population. Biomonitoring has become an essential tool in environmental health. In Algeria, to date, no study on the evaluation of lead impregnation has been carried out at the national level. The main objective of this work is to assess the exposure of the general Algerian population to lead This is a cross-sectional study with a descriptive aim, carried out over the entire Algerian national territory, on a population aged between 3 and 74 years old. It was carried out on a representative sample of households. The survey lasted three years. A questionnaire, a clinical examination and a blood sample were carried out for each individual. Analytical methods for the determination of lead in whole blood by ICP-MS were optimized and validated. Generalized linear regression models were used to determine the factors influencing lead levels measured in blood samples. The study population, spread over 39 wilayas and 121 districts, consists of 3674 individuals. The mean lead levels were 28.27 μg/L [27.38–29.17], the median was 22.22 μg/L, and the 95th percentile was 73.83 μg/L. The prevalence of elevated blood lead levels (≥100 μg/L) in the study population was 2.2%. A blood lead value of 75 μg/L was proposed as the Reference Exposure Value (REL) for Algeria. Blood lead levels were influenced by age, gender, wilaya of residence, dietary habits such as consumption of canned food and the way in which water is conserved for daily consumption. The use of kohl has been confirmed as a potential source of lead exposure especially among women. Recommendations have been issued to reduce the blood lead levels of the general population in Algeria in terms of limitation of lead in the sources of exposure, installation of an effective health monitoring system and also an adequate management of lead poisoning.

A microplasma optical emission spectrometry pen for point-of-care diagnosis of child blood lead

Blood lead levels (BLL) of children have attracted considerable attention due to their putative impact on intelligence decline. However, most methods used for the determination of blood lead typically require expensive, bulky, high power and gas consuming instrumentation, limiting their application for a point-of-care diagnosis. Herein we report the development and testing of a portable ballpoint discharge microplasma optical emission spectrometer (BD-OES pen) device having the potential to fill this needed measurement capability. The BD-OES pen utilizes a compact ballpoint-pen format integrating point-discharge microplasma, which permits the determination of child BLL requiring no more than 100 μL blood while providing high specificity, sensitivity and satisfactory limit of detection (0.73 μg L−1). The handheld BD-OES pen is successfully used to diagnose BLL of 16 asymptomatic children on-site, two of whom had excessive the normal BLL. The pen may aid the on-site and rapid diagnosis of childhood BLL, particularly in low-income areas.

Determination of lead in blood by graphite furnace atomic absorption spectrometry with Zeeman background correction: Improving a well-established method to support a lower blood lead reference value for children

Lead is ubiquitous in the environment and exposure can have adverse health effects even at low concentrations, particularly in young children. Blood Pb levels are the best indicator of recent Pb exposure. The Centers for Disease Control and Prevention (CDC) recently lowered the blood Pb reference value from 5 μg/dL to 3.5 μg/dL, based on data calculated from the 97.5th percentile of children 1–5 years old in the National Health and Nutrition Examination Survey (NHANES). The established method for determining Pb in blood by GFAAS has an estimated detection limit (LOD) of ≈1 μg/dL. This presents an analytical challenge for its clinical use in the US, given that the current population mean blood Pb level is 0.82 μg/dL. Accuracy and precision may be insufficient to quantitate low blood Pb levels in the 1–5 μg/dL range, which is essential now that the CDC blood Pb reference value is 3.5 μg/dL.The original GFAAS method for blood Pb published in 1993 has been significantly improved to achieve a lower LOD of 0.2 μg/dL, with the ability to quantitate blood Pb levels down to 1 μg/dL. This method is fit for the purpose of detecting blood Pb levels currently, with excellent accuracy and precision in the 1–5 μg/dL range. Results from analyzing SRMs, PT materials and human blood samples were in good agreement between two different GFAAS platforms, as well as with results obtained by ICP-MS. The improvements provide evidence of an GFAAS method capable of achieving lower LODs with improved accuracy and precision at lower blood Pb levels, which can support the lower blood Pb reference value for children at 3.5 μg/dL.

Optimization of a GF-AAS method for lead testing in blood and urine: A useful tool in acute abdominal pain management in emergency.

Suspicion of lead poisoning is confirmed by its concentration in blood and protoporphyrin red blood cells. At low concentrations, lead influences the synthesis of the heme in the sense of lowering it. Acute and chronic lead intoxication is extremely polymorphic in regards to its clinical manifestations, with digestive, hematological, cardiovascular, renal hepatic and neurological features. The aim of the study was to evaluate the presence of lead in human whole blood and urine harvested before and during chelation treatment in the case of lead poisoning. An atomic absorption spectroscopic method for the analysis of lead was developed using graphite furnace atomic absorption spectrophotometer (GF-AAS), Varian Spectra AA-880 with a hollow cathode lead lamp and a deuterium lamp for background correction, coupled to a GTA-100 atomizer and a programmable sample dispenser. Standard calibration solutions were used for the range 10-100 µg/l. The linearity range was 10.0 to 100.0 µg/l with the correlation coefficient of 0.999. We established that the method can be applied for the determination of lead in whole blood and urine, and the results obtained are useful for monitoring chelation therapy in cases of acute lead poisoning, a neglected cause of abdominal colic pain in an emergency situation.

Highly sensitive determination of cadmium and lead in whole blood by electrothermal vaporization-atmospheric pressure glow discharge atomic emission spectrometry

In this study, a fast and simple method for highly sensitive detection of Cd and Pb elements based on atmospheric pressure glow discharge atomic emission spectrometry (APGD-AES) coupling with tungsten coil electrothermal vaporization (ETV) was proposed. A small amount of sample (10 μL) was dropped onto the tungsten coil, followed by drying, pyrolysis and vaporization procedures, and then the vaporized analyte was transported to APGD for excitation. The whole procedure took approximately 3 min. Multi-step heating of the ETV unit can separate matrices and solvents from the analyte, providing an advantage in detecting samples with complex matrix. Under the optimal experimental conditions, limits of detection of 0.4 μg L−1 (4 pg) for cadmium and 1.2 μg L−1 (12 pg) for lead were obtained, with relative standard deviations of 20 μg L−1 Cd and 100 μg L−1 Pb both being <5%. The accuracy of the ETV-APGD-AES system was verified by the determination of heavy metals in whole blood standard sample (GBW(E)090,251) and the practicability of the ETV-APGD-AES system were demonstrated by the determination of heavy metals in human whole blood. The results obtained by this instrument agree well with the standard values and those obtained by ICP-MS.

Where are we at with lead? Current levels, time trend, and determinants of blood lead in New Zealand children and adults.

A national biomonitoring survey was conducted in 2014-2016, to determine current blood lead levels (BLL) in New Zealand children and adults and identify determinants of BLL. Blood samples were provided by 191 children (age 5-18) and 304 adults (age 20-65) and analysed for BLL using inductively coupled mass spectroscopy. Linear regression on log-transformed BLL was used to assess associations between BLL and demographic and lifestyle factors collected via questionnaire. The geometric mean (GM) BLL was 0.86μg/dl (95%CI 0.80-0.92) for children and 1.31μg/dl (1.23-1.39) for adults, representing a 90% reduction in BLL over the past 36 years. For children, shellfish consumption was associated with 20% higher BLL. Adult BLLs were positively associated with age, beer consumption, spirits consumption, having roof water as the home's water supply, and having worked in glass manufacturing. Determinants of reduced BLL were tofu and canned food consumption. For women, menopause was associated with 34% higher BLL. Although significant reductions in New Zealanders' BLL have been achieved in the past decades, this study identified several additional opportunities to reduce further background exposure to lead. In particular, consideration needs to be given to reducing lead levels in New Zealand roof water supplies.

Elemental and isotopic determination of lead in whole blood by ISIS-ICP-MS

Objective: To establish a method for determination of lead and istope ratios in the blood by ISIS-ICP-MS. Methods: After wet digestion, the blood sample was on-line addition of thallium as internal standard and analyzed by ISIS-ICP-MS. Results: The limit of detection was 0.03 μg/L and the lower limit of quantification was 0.08 μg/L. The detection concentration was 0.45 μg/L and the minimum quantitative concentration was 1.49 μg/L. The relative standard deviations (RSD) were 0.3%~1.7%. The recovery was between 91.0% and 103.4%. The precision of the major lead isotope ratios was better than 0.3%. The calibrated isotope ratios of the standard liquid are close to the certificate. Conclusion: The method has a low detection limit, good precision and high accuracy, it is feasible for determination of lead concentration and isotope ratios in the bloune.

Analysis on occupational health laboratories' proficiency testing program for determination of bovine blood lead and urinary cadmium

Objective: To analyze the results obtained from the proficiency testing program for determination of bovine blood lead and urinary cadmium, so as to evaluate the proficiency of the laboratories, and improve the detection and quality control capability of occapational health laboratory. Methods: Prepared 3 levels of lead samples with bovine blood as base material, taking Technical Norm of Primary Reference Material as Operating standard, 60, 80, 180 μg/L were used as the standard concentration. All samples were made for 200 bottles. Normal urine were used to prepared 3 levels of cadmium samples with 5.0, 7.0, 10.0 μg/L as standard concentration, then 3 level of samples were made for 200 bottles respectively. Blood lead and urinary cadmium samples were sent to each laboratory in the form of sample pairs. One-way ANOVA was used to investigate the homogeneity. The results of each laboratory were statistically analyzed by robust statistical method, and the detection ability of the laboratory was evaluated by the Z ratio score method. By consulting the test reports and original records of each participating laboratory, the reasons for the unsatisfactory results were analyzed. Results: The statistical F of the uniformity of blood lead 1.42, 1.37 and 2.85, F<3.13, P were 0.294, 0.314 and 0.059, respectively in 31 labs. There is no statistical significance in the difference of blood lead (P>0.05). And urine cadmium was less than the critical value (P>0.05). In all, 31 laboratories participated in the test of blood lead, and 28 loboratories paticipated in urine cadmium verification. The statistical F of the uniformity of urinary cadmium 1.90, 1.35 and 1.19, F<3.13. The homogeneity of the samples were in accordance with the requirements of proficiency testing program. The satisfactory rate of the results for blood lead was 84% (26/31) , and the satisfactory rate of urinary cadmium was 93% (26/28) . In the test of blood lead, 21 of the 31 laboratories were controlled by the standard material method. Totally, 20 of them get an satisfactory level, the rate was 95%. Conclusion: Most of the laboratory test results were satisfactory, which showed that the detection capability for blood lead and urine cadmium was good. The main causes of unsatisfactory results were detection methods, tools of quality control ortraceability standards.

Haematological and antioxidant enzyme response to Lead toxicity in male Wistar rats

The study evaluated the haematological and some antioxidant enzymes response to lead toxicity in male Wistar rats. Twenty male Wistar rats were divided into four groups viz., A, B, C and D. Group A served as the control while groups B, C and D were treated with 200, 300 and 400 ppm of lead (Pb) as lead acetate, respectively. Doses were orally administered in divided doses by intubation to ensure that each rat had the specified doses, after which they have access to water and feed. At the end of two weeks of treatment, blood samples were collected via the median canthus into heparinised tubes for blood lead determination and haematological analysis after which the remaining blood was centrifuged to obtain the plasma for determination of malonydialdehyde, catalase, superoxide dismutase and peroxidase levels. There was a significant increase in blood lead concentrations ranging from 2.15±0.10 µg/dl to 9.21±0.05 µg/dl which was dose dependent while decreases in packed cell volume and the red blood cell counts ranging from 32-53% and 15-52%,respectively. At the highest dose of 400 ppm of lead there was significant decrease in the neutrophils and lymphocytes. There was significant (P<0.05) dose dependent increases in malondialdehyde while the activities of catalase, peroxidase and superoxide dismutase were significantly (P<0.05) reduced. In conclusion, lead disrupts the haematological system leading to generation of free radicals that overwhelm the antioxidant enzymes thus leading to oxidative stress.

A real-time-range potentiostat coupled to nano-Au-modified microband electrode array for high-speed stripping determination of human blood lead

A novel method of real-time-range measurement, characterized by pre-sampling forecast and balanced-range switching, is introduced in this study. According to this method, raw current signals in biosensing procedures may be measured and recorded with real-time-optimized instrumental settings. A low-cost and high-performance potentiostat is developed to validate the proposed method. The transient process of real-time-range measurement is investigated to optimize sampling interval and circuit parameters. Typical time consumption of a sampling cycle is less than 100μs, which makes high-speed and real-time-range measurement possible. The proposed method also brings excellent current resolution that is better than 0.8pA. It improves weak signals in stripping determinations, and is particularly suitable for biological samples. As-fabricated potentiostat, coupled to a nano-Au-modified microband electrode array, is adopted in high-speed stripping determinations towards human blood lead levels (HBLLs). Accuracy and precision of this method are validated with certified reference material (CRM). Obtained values (4.31 ± 0.18μgL−1) meet with certified levels of CRM (4.24 ± 0.11μgL−1). Coefficient of variation percent (CV %) is no more than 5.0% for intra- or inter-assay analyses. Finally, this method is utilized for human population based study. Two groups of data, from this method and inductively coupled plasma mass spectrometry (ICP-MS), are analyzed using a statistic tool of t-test, and no statistically significant difference is found.

Human Biomonitoring of Lead Exposure.

After a chronic exposure, lead accumulates in the human body, especially in bones and teeth. Critical effects of lead affect the nervous system, reproduction, fertility as well as genotoxicity and carcinogenicity [1]. Analyses of lead concentrations in human biological material are performed using inductively coupled plasma mass spectrometry and atomic absorption spectrometry, but also electrochemical methods and X-ray fluorescence spectroscopy. The predominant sample matrices include blood and bone, as well as urine, hair, nail, and saliva. To characterize first biological effects, diverse parameters are discussed as "biomarkers of effect". These include δ-aminolevulinic acid dehydratase (ALAD) and erythrocyte porphyrins (EPs) in blood as well as δ-aminolevulinic acid (ALA) in urine and plasma and coproporphyrin in urine. However, biomarkers of effect alone are not sufficiently sensitive for an early detection of a health impairment caused by lead. In summary, lead in blood is the most prominent and best validated biomarker for a lead exposure. A recommended diagnostic strategy for revealing lead-induced effects is the determination of lead in whole blood combined with the analysis of different effect parameters like ALA and coproporphyrin in urine and ALAD and zinc protoporphyrin (ZPP) in blood.

Lead concentrations in whole blood, serum, saliva and house dust in samples collected at two time points (12 months apart) in Santo Amaro, BA, Brazil

Whole Blood Lead Level (BLL) is the main marker used to verify lead contamination. The present study explores how BLL is associated with lead concentrations in serum, saliva and house dust. Samples were collected twice from Santo Amaro, BA, Brazil, a region that was contaminated by a lead smelter in the past; a time interval of 12 months was allowed between the two collections. It is noteworthy that the following measures have recently been taken to diminish exposure of the population to lead: streets have been paved with asphalt, and educational campaigns have been launched to reduce exposure to contaminated dust.Results: Compared with the first time point, all the samples collected at the second time point contained lower lead concentration (p<0.05), which suggested that the adopted measures effectively reduced exposure of the population to lead present in contaminated soil and dust. Statistically significant correlations only existed between lead in blood collected in the first year and lead in blood collected in the second year (Spearman's r=0.55; p<0.0001; n=62), and lead in house dust collected in the first year and lead in house dust collected in the second year (Spearman's r=0.5; p<0.0001; n=59).Conclusions: Results support the validity of lead determination in blood and in house dust to assess lead exposure over time. However, lead in blood and lead in dust did not correlate with lead in serum or lead in saliva.

Levels of Lead and Mercury in Population Environmentally Exposed

Levels of Lead and Mercury in Population Environmentally ExposedAbstract Number:2483 Fátima Moreira, Fernanda Bergamini*, Andrea Sobral, Leda Jesus, Sayonara Azevedo, and Regina Gomes Fátima Moreira Oswaldo Cruz Foundation/National School of Public Health, Brazil, E-mail Address: [email protected] Search for more papers by this author , Fernanda Bergamini* Oswaldo Cruz Foundation/National School of Public Health, Brazil, E-mail Address: [email protected] Search for more papers by this author , Andrea Sobral Oswaldo Cruz Foundation/National School of Public Health, Brazil, E-mail Address: [email protected] Search for more papers by this author , Leda Jesus Oswaldo Cruz Foundation/National School of Public Health, Brazil, E-mail Address: [email protected] Search for more papers by this author , Sayonara Azevedo Oswaldo Cruz Foundation/National School of Public Health, Brazil, E-mail Address: [email protected] Search for more papers by this author , and Regina Gomes Oswaldo Cruz Foundation/National School of Public Health, Brazil, E-mail Address: [email protected] Search for more papers by this author AbstractSome regions in Mato Grosso State, Brazil, are significant sources of water and sediment to the Brazilian Pantanal, one of the most important ecological reserves in the world. Mining, cattle breeding and agriculture are carried out near this biome. Currently there are 14 mines and 200 large loaves, working in gold extraction. At the peak of activity, sediment and biota of some rivers had high degree of mercury contamination as well as high concentrations of the metal were also found in human urine, air, soil and dust samples. Deforestation threatens biodiversity and also contributes to the emission of lead into the environment. The aim was to assess levels of lead in blood and mercury in urine from an environmentally exposed population. Atomic absorption spectrometry was used for the determination of lead in blood (Pb-B) and mercury in urine (Hg-U) from residents in Pantanal. Student’s t test, Mann-Whitney, Spearman and ANOVA were used in the statistical analysis with a confidence interval of 95%. All samples showed levels within the reference range for the general population, with means equal to 2.82 ± 1.5 µg dL-1 for Pb-B (n = 119) and 1.41 ± 0.98 µg L-1 for Hg-U (n = 109). A comparison of Pb-B with site of collection (p = 0.01), work activities (p = 0.01) and consumption of milk produced in the region (p = 0.05) showed significant differences between these variables. Moreover, Hg-U levels differ only with respect to the occupation of the participants (p = 0.01). Positive associations between Pb-B and site of collection (p = 0.01), occupation of the subjects (p = 0.05) and consumption of milk produced in the region (p = 0.01) were found. However, a positive association was only between Hg-U and professional activity (p = 0.05) and body mass index (p = 0.01). Exposure to lead appears to originate from burnings while exposure to mercury comes from gold mining. Measures are needed to protect the local population from exposure to these metals.

Working towards accreditation by the International Standards Organization 15189 Standard: how to validate an in-house developed method an example of lead determination in whole blood by electrothermal atomic absorption spectrometry.

Laboratories working towards accreditation by the International Standards Organization (ISO) 15189 standard are required to demonstrate the validity of their analytical methods. The different guidelines set by various accreditation organizations make it difficult to provide objective evidence that an in-house method is fit for the intended purpose. Besides, the required performance characteristics tests and acceptance criteria are not always detailed. The laboratory must choose the most suitable validation protocol and set the acceptance criteria. Therefore, we propose a validation protocol to evaluate the performance of an in-house method. As an example, we validated the process for the detection and quantification of lead in whole blood by electrothermal absorption spectrometry. The fundamental parameters tested were, selectivity, calibration model, precision, accuracy (and uncertainty of measurement), contamination, stability of the sample, reference interval, and analytical interference. We have developed a protocol that has been applied successfully to quantify lead in whole blood by electrothermal atomic absorption spectrometry (ETAAS). In particular, our method is selective, linear, accurate, and precise, making it suitable for use in routine diagnostics.

Diode laser thermal vaporization ICP MS with a simple tubular cell for determination of lead and cadmium in whole blood

A low-cost diode laser thermal vaporization sample introduction system to ICP MS for determination of lead and cadmium in whole blood.

Development of a New Method for the Determination of Manganese, Cadmium, Mercury and Lead in Whole Blood and Amniotic Fluid by Inductively Coupled Plasma Mass Spectrometry

Development of a New Method for the Determination of Manganese, Cadmium, Mercury and Lead in Whole Blood and Amniotic Fluid by Inductively Coupled Plasma Mass Spectrometry

Nutrients intake as determinants of blood lead and cadmium levels in Colombian pregnant women

To evaluate the relationship between nutrients intake in the first trimester of pregnancy and blood levels of lead and cadmium during the first and third trimesters of gestation. A total of 381 pregnant women were enrolled. Blood lead and cadmium were measured using electrothermal atomic absorption spectrometry, and dietary intake was assessed using 24-h recall questionnaire. Lead levels in the first trimester were negatively correlated with cadmium levels in the two trimesters, and levels of both metals correlated positively in the third trimester. Zinc and calcium intakes were negatively associated with blood lead during third trimester. Thiamine and folic acid intakes were negatively and positively associated (respectively) with blood lead at third trimester with marginal significance. Fat, niacin, and vitamin B12 intakes were significantly and positively associated with blood cadmium at first trimester. Folic acid and zinc intakes showed positive and marginally significant associations with blood cadmium without adjustments. At third trimester, blood cadmium was negatively associated to ascorbic acid intake, and positively associated with iron intake with a marginal significance. Possible acute and late effects of nutrients intake in blood lead and cadmium levels could be related with associations exclusively observed in the first and third trimester. This study represents the first exploration of relationships among a wide range of nutrients intake in the first trimester of pregnancy with blood lead and cadmium in first and third trimester of gestation. Further studies are required to confirm the findings mentioned herein.

Dosage of cadmium and lead in human blood by anodic stripping voltammetry

The objective is the determination of the conditions operating optimal to determine the concentration of the cadmium and the lead dissolved in the human blood. An electroanalytical method has been developed for the determination of lead and cadmium in whole blood by differential pulse anodic stripping voltammetry (DPASV) on a hanging mercury drop electrode (HMDE). The best conditions were found to be electrolyte support perchloric acid 0.02M, the accumulation potential is -900mV, and the accumulation time is 320s. The obtained limits of detection are equal to 0.46 and 0.08ng/mL respectively for the lead and the cadmium. The developed method was validated by the analysis of reference materials certified by total blood.

Application of Zeeman Graphite Furnace Atomic Absorption Spectrometry with High-Frequency Modulation Polarization for the Direct Determination of Aluminum, Beryllium, Cadmium, Chromium, Mercury, Manganese, Nickel, Lead, and Thallium in Human Blood

Determination of aluminum (Al), beryllium (Be), cadmium (Cd), chromium (Cr), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), and thallium (Tl) concentrations in human blood using high-frequency modulation polarization Zeeman graphite furnace atomic absorption spectrometry (GFAAS) was performed. No sample digestion was used in the current study. Blood samples were diluted with deionized water or 0.1 % (m/v) Triton X-100 solution for Tl. Dilution factors ranged from 1/5 per volume for Be and Tl to 1/20 per volume for Cd and Pb. For Tl, Cd, and Hg, noble metals (gold, platinum, rhodium, etc.) were applied as surface modifiers. To mitigate chloride interference, 2 % (m/v) solution of NH(4)NO(3) was used as matrix modifier for Tl and Ni assessment. The use of Pd(NO(3))(2) as oxidative modifier was necessary for blood Hg and Tl measurement. Validation of the methods was performed by analyzing two-level reference material Seronorm. The precision of the designed methods as relative SD was between 4 and 12 % (middle of a dynamic range) depending on the element. For additional validation, spiked blood samples were analyzed. Limits of detection (LoDs, 3σ, n = 10) for undiluted blood samples were 2.0 μg L(-1) for Al, 0.08 μg L(-1) for Be, 0.10 μg L(-1) for Cd, 2.2 μg L(-1) for Cr, 7 μg L(-1) for Hg, 0.4 μg L(-1) for Mn, 2.3 μg L(-1) for Ni, 3.4 μg L(-1) for Pb, and 0.5 μg L(-1) for Tl. The LoDs achieved allowed determination of Al, Cd, Cr, Mn, Ni, and Pb at both toxic and background levels. Be, Hg, and Tl could be reliably measured at toxic levels only. The methods developed are used for clinical diagnostics and biological monitoring of work-related exposure.