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A method for the extraction of emulsified water associated with crude oil was developed, in order to determine the composition of its major cations by inductively coupled plasma optical emission spectrometry (ICP OES) and anions by ion chromatography (IC). The method is suitable to crude oils with water content as low as 0.4% (w/w) and the recovery of elements was satisfactory (80–115%), except in the case of Ba 2+ , possibly due to the presence of insoluble BaSO 4 in the crude oils. Concentrations of dissolved Na + , Cl − , Ca 2+ and Sr 2+ show good agreement in interlaboratory results of three crude oils and between replicates (0.05–16%), whereas SO 4 2− and Ba 2+ results were more scattered. The emulsified waters had contributions of formation and injection waters and these were reflected in their ions distributions. In the 30 crude oil samples investigated, NaCl was the predominant salt and the correlations of Br − , Ca 2+ and Sr 2+ concentrations to Cl − concentration showed low values, indicating that the origin of the dissolved ions was through dissolution of halite by rock buffering processes. The contribution of injection and formation waters was observed in the [Br − ] versus [Cl − ] plot and the potential of scale formation is discussed through log correlation of [Ba 2+ ] versus [SO 4 2− ]. The overall method is fast and does not require the use of a time consuming reactor, making it a good one for a first evaluation of the aqueous phase composition during petroleum exploration and production.

Teeth and otoliths are metabolically inert structures that preserve a chronology of chemical variations that may be related to the environmental histories experienced by each organism. Because of the natural decrease of barium (Ba) and increase of strontium (Sr) bioavail- ability in water with increasing salinity, these elements may be especially useful to track habitat use in aquatic organisms. Therefore, we tested whether the Ba/Ca and Sr/Ca ratios in the teeth of dolphins represent a salinity gradient. The main aim was to determine whether these elements can be used as a natural tag for different aquatic environments. Teeth from 2 freshwater dolphins (Inia geoffrensis and Sotalia fluviatilis) and 2 marine species (S. guianensis and Pontoporia blainvillei) from Brazil and Uruguay were analyzed using a Laser Ablation Inductively Coupled Plasma-Mass Spectrometer. Intensity ratios of 138 Ba/ 43 Ca and 86 Sr/ 43 Ca were measured along a line that covered all growth increments in the dentin from the second year of life onwards. Teeth from the freshwater species had mean Ba/Ca values tenfold higher than marine dolphins, confirm- ing the inverse relationship between salinity (and thus ambient Ba/Ca) and elemental ratios in teeth. Furthermore, Ba/Ca ratios could also differentiate dolphins from lower-salinity estuarine areas from those in areas with minimal freshwater discharge. No significant differences were found for Sr/Ca values. Results presented encouraging indications for the application of this tech- nique as a potential new tool for studying habitat use in aquatic mammals.

In this study, we analyzed the Sr:Ca and Ba:Ca ratios of the otoliths of 139 Lycengraulis grossidens individuals sampled along the southwestern Atlantic Ocean, including two freshwater areas, to describe patterns of habitat use and their latitudinal organization. Otolith sections were analyzed by laser ablation inductively coupled plasma mass spectrometry along core-to-edge transects. Otolith edge analysis revealed significant differences in Sr:Ca and Ba:Ca ratios between fish from freshwater habitats and those from estuarine/marine habitats, indicating that these ratios may be used to describe habitat use patterns. Lifetime transects of Sr:Ca and Ba:Ca indicate at least four distinct habitat use patterns: freshwater residents, estuarine/marine residents, and two distinct diadromous/nomadic types. Most individuals (88.6%) sampled at northern latitudes in sheltered marine bays and the coastal ocean were estuarine/marine residents, whereas at southern latitudes, most individuals were diadromous (72.5%). We also identified landlocked populations in the Uruguay River and in Mirim Lagoon. These results suggest that L. grossidens exhibits flexible habitat use strategies and may use freshwater, estuarine and marine environments throughout their lifetime.

Life-long strontium patterns in otoliths of the sciaenid Micropogonias furnieri caught in the southwestern Atlantic Ocean were examined to evaluate estuarine dependency and habitat use. Otolith Sr concentrations were on average 820 ± 55 μg g−1 for freshwater, 1,751 ± 101 μg g−1 for estuarine, and ranged from 2,000 to over 4,000 μg g−1 for marine waters. The examination of life-long otolith Sr revealed that 71 % of the marine-sampled fish moved toward brackish waters from age 0 to age 1, and that estuarine egress ranged from ages 2.1 to 4.1 years depending on the sampling area. Three different long-term patterns of Sr accumulation were observed and inferred to be the result of ontogeny and habitat shifts. Given that an estuarine Sr signature was consistently present in all sampled fish, M. furnieri is suggested to be a true estuarine-dependent species during its early life history.

The present work is a continuation of a research study performed at our laboratory aiming at the multielement analysis of rock samples (basalts and shale) by inductively coupled plasma mass spectrometry in combination with laser ablation using borate glasses as analytical targets. Argon, nitrogen–argon mixtures and helium were evaluated as cell gases, the latter confirming its better performance. Different operational parameters of the laser, such as gas flow, energy, focus, scanning speed and sampling frequency were optimized. External calibration was made with standards prepared by fusion of geological reference materials (basalts 688 and BCR-2, obsidian SRM 278, and shale SGR-1) of different mass fractions in the meta–tetra borate matrix. Coefficients of determination ( R 2 ) were > 0.99 for 30 elements from o total of 40 determined. Method validation was then performed using additional certified reference materials (BHVO-2, BIR-1, SCo-1) produced as borate targets in a similar way. Accuracies were better than 10% for most of the elements studied and analytical precisions, calculated from the residual standard deviations of calibration curves were, typically, between 6% and 10%. Additionally, the semiquantitative TotalQuant® technique was applied, which gave, within the expected uncertainty for this calibration technique, concordant results when compared to the quantitative external calibration procedure. Both methods were then used for the analysis of marine shale samples, which are of great geological interest in petroleum prospecting.

A method was developed for the determination of V and Ni as tetrapyrroles by High Performance Liquid Chromatography hyphenated to Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS) using reversed phase and elution gradient. Chlorinated solvents and tetrahydrofuran were investigated as regard to separation time and ICP-MS detection efficiencies. The final elution gradient program started from pure methanol to a mixture of 20:80 (v/v) chloroform:methanol. External quantification of V and Ni with inorganic standards by flow injection ICP-MS, used online with HPLC, resulted in 95% of recoveries. The Limits of Detection for V during methanol elution and for Ni during the 20% chloroform gradient elution were evaluated by their minimum detectable concentrations, which were, respectively, 5 μg L− 1 and 8 μg L− 1. The methodology was applied to polar and resin fractions separated from a Brazilian crude oil and a sediment extract from an oil-polluted area in the Guanabara Bay, Rio de Janeiro, Brazil. Vanadium as tetrapyrroles represented the totality of V content in the polar fraction, whereas Ni was in different polar forms in the resin and sediment extract.

The determination of trace metals in lubricating oils using atomic spectrometric methods is reviewed. The importance of such analyses for technical diagnostics as well as the specific sample characteristics related to the analyte form (metallo-organic and metal particles) is discussed. Problems related to sample pre-treatment for appropriate sample introduction and calibration are addressed as well as the strategies to overcome them. Recent trends aimed at simplifying sample manipulation are presented. The applications and scope of AAS, ICP OES and ICP MS techniques for the determination of trace metals in lubricating oil is individually discussed, as well as some present instrumental trends.

A literature review on the determination of trace elements in crude oil and heavy molecular mass fractions (saturates, aromatics, resins and asphaltenes) by ICP-MS, ICP OES and AAS is presented. Metal occurrences, forms and distributions are examined as well as their implications in terms of reservoir geochemistry, oil refining and environment. The particular analytical challenges for the determination of metals in these complex matrices by spectrochemical techniques are discussed. Sample preparation based on ashing, microwave-assisted digestion and combustion decomposition procedures is noted as robust and long used. However, the introduction of non-aqueous solvents and micro-emulsions into inductively coupled plasmas is cited as a new trend for achieving rapid and accurate analysis. Separation procedures for operationally defined fractions in crude oil are more systematically applied for the observation of metal distributions and their implications. Chemical speciation is of growing interest, achieved by the coupling of high efficiency separation techniques (e.g., HPLC and GC) to ICP-MS instrumentation, which allows the simultaneous determination of multiple organometallic species of geochemical and environmental importance.

The uptake of Cr, Mn, Ni, Cu, Zn, Cd and Pb in soft tissue of Perna perna mussels and their shells has been studied in aquarium experiments in which mussels were exposed for 30 or 60 days to seawater spiked with different concentrations of these contaminants (125 and 500 μg L−1). Tissue samples were analyzed after acid digestion by conventional solution nebulization ICP–MS. Laser ablation ICP–MS was used for the quantitative determination of trace elements in different areas of the corresponding shells. With the exception of Mn and Zn, all other elements studied showed a significant concentration enhancements in soft tissue, with the magnitude of this enhancement following the order: Cr > Ni > Cd > Cu > Pb. A corresponding increase in most contaminants, although less pronounced, was also observed in the newly formed growth rings of mussel shells, contributing to the validation of Perna perna mussel shell as a bioindicator of toxic elements.

Aquatic macrophytes are well known accumulators for heavy metals, the reason why they are used as bioindicators for water quality and in phytoremediaton strategies. This study reports on the elemental concentrations in four free-floating aquatic macrophytes (S. auriculata; P. stratiotes; E. crassipes and E. azurea) growing in two water reservoirs (Santana e Vigario, Rio de Janeiro State, Brazil) of an electric power plant that receive input from the polluted Paraiba do Sul River. Filtered water samples and water suspended solids from these environments were also analysed. Inductively coupled plasma mass spectrometry was used as the principal method, allowing the determination of up to 41 elements, including the rare-earth elements (REEs) and other trace metals not assayed before in these macrophytes. The results show that all elements studied are accumulated by the macrophytes with concentration ratios (CR = [plant]: [water]) varying from about 1,000 to 200,000, based on the dry weight of the plant species. With a few exceptions, highest accumulations were observed in E. crassipes in which CRs increase in the sequence: Cu < Mo < Cr < Pb < Tl < Fe < La < Zn < Ce< Mn. Surprisingly high CRs (e.g. Ce: 74,000) and corresponding mass concentrations were observed for the rare-earth elements (e.g. ∑REE: 112 mg kg−1), also measured in the water suspended particle fraction. The results show that this fraction acts as an effective sink for trace metals in the aquatic system studied and seems to play also an important role in the transfer of metals from water to the plant species.

Meglumine antimoniate (MA), a pentavalent antimonial (SbV) drug, has been used for the treatment of leishmaniases for over half a century but there is almost no data on its safety and kinetics during pregnancy. This study was undertaken to investigate the developmental toxicity of MA as well as the transplacental transfer of antimony (Sb) in rats. Wistar rats (approximately 20 per group) were treated subcutaneously (s.c.) with MA (0, 75, 150, 300 mg SbV/(kg BW day)) during pregnancy (days 1-20). An untreated control group was evaluated as well. Caesarean sections were performed on day 21 and implantations, living and dead fetuses, and resorptions were recorded. Fetuses were weighed and fixed in Bouin's solution and one-third of each litter was examined for soft-tissue anomalies. The remaining fetuses were cleared and stained with Alizarin red S for skeleton evaluation. No adverse effect of MA on the mothers was noted at any dose level. No embryotoxicity was observed at the lowest dose but, at the highest dose, MA increased embryolethality, reduced fetal weight and augmented the occurrence of some soft-tissue and skeleton variations. Therefore, the no-observed-adverse-effect level for MA-induced embryotoxicity was 75 mg SbV/(kg BW day). In a separate group of rats treated with 300 mg SbV/(kg BW day) s.c. during whole pregnancy, blood (0.2 mL) was taken from the tail vein 1, 2, 4, 6, 12 and 24 h after treatment on day 1 and thereafter every other day immediately before drug injection. Blood was also taken from fetuses removed on day 21, 24h after the last injection of MA. Blood levels of Sb were determined by ICP-MS and results showed that most of administered Sb was eliminated rapidly (in less than 6 h), but nadir blood concentrations increased gradually during treatment from 1 to 2 microg/g, 24h after the first dose, up to approximately 38 microg/g after the 20th dose. Levels of Sb in fetal blood were as high as 10-15 microg/g, i.e. approximately 30% their mothers' nadir levels near term. These findings indicated that repeated administration of MA during gestation led to an accumulation of Sb in mothers and fetuses.

A new method for the speciation analysis of selenite (Se-IV), selenate (Se-VI), and selenocyanate (SeCN−) is described and first results are presented on the distribution of these species in wastewater samples from a Brazilian oil refinery plant. The method is based on the ion chromatographic separation of these species followed by on-line detection of 77Se, 78Se, and 82Se using quadrupole inductively coupled plasma-mass spectrometry (ICPMS). The system employed consisted of a HPLC pump equipped with a manual syringe loading injector, and an anion exchange column (Metrosep A Supp1), the latter interfaced with the ICPMS via a concentric nebulizer–cyclonic spray chamber sample introduction device. Several eluents already described in the literature for the speciation analysis of inorganic selenium were tested, permitting in most cases a good separation of Se(IV) and Se(VI), however, resulting all in very long residence times (> 30 min) and associated peak broadening for the SeCN− ion. This drawback could be effectively avoided by using as the mobile phase a solution of cyanuric acid (3 mmol L−1), modified with acetonitrile (2% v/v) and percchlorate acid (2.5 mmol L−1). Typical retention times (s) for the three analyte species were: selenite (210)

Scale inhibitors based on phosphinepolycarboxylic acid (PPCA) have been successfully used in offshore oil production for preventing deposition of barium and strontium sulfates. A system was developed for the automated pretreatment of PPCA-containing water samples, followed on-line or off-line by phosphorus determination using ICP mass spectrometry. During pretreatment, the previously acidified inhibitor solution is adsorbed on a C18-reversed phase column and then eluted with 0.025 mol l−1 borate solution. Using a 3.5-ml sample volume, analytical frequency in the on-line mode is about 9 samples per hour and 17 in off-line operation. Detection limit of phosphorus in the borate solution was 0.20 μg l−1, using a crossflow nebulizer and a Ryton® spray chamber. Recoveries were, typically, in the range of 90% to 100% and repeatability about 5%. The method has been applied for monitoring inhibitor concentrations during laboratory and field squeeze tests.

The purpose of this study was to determine the concentration and distribution of lead, calcium, iron, zinc, and copper in major fractions (fat, casein, whey) of mature milk from 38 nursing adult women with low environmental lead exposure. The potential associations between milk lead and maternal blood lead and between milk and blood lead and essential mineral data (nutritional status, dietary intake, and milk concentration) were investigated. Maternal blood lead (geometric mean, 60 microg/L) was negatively associated, although modestly, with dietary calcium intake (r=-0.32, p=0.02). Lead in whole milk (geometric mean, 1.2 microg/L) was positively associated with calcium in whole milk (r=0.56, p=0.005). Distribution of lead in milk fractions was 63%, 28%, and 9%, in whey, fat, and casein, respectively. Milk distribution of essential minerals was 67-76%, 17-18%, and 7-17% in whey, fat, and casein, respectively. Lead in milk whey was positively associated with lead in maternal blood (r=0.49, p=0.02). However, milk lead was not affected by nutritional status, dietary intake, and milk composition of the essential minerals. The high percentage of lead in the milk whey fraction, as seen for the essential minerals, suggests that most lead in human milk is bioavailable to the infant.

The contamination of sediments by organotins poses a threat to marine biota that may last long after release of the substances. The determination of tributyltin (TBT) and its decay products in sediment cores allows elucidation of concentration and degradation trends, and is a useful tool to support management decisions. In this study, organotin speciation was performed on cores from several locations in Guanabara Bay, Rio de Janeiro, to investigate contamination trends over the last 30 years in this area, which houses the second most important harbor in Brazil. TBT concentration in surface sediments ranged from 742 μg kg -1 (as tin) in the vicinity of a major shipyard to 14 μg kg -1 (as tin) in an environmental protection area. Organotins depth profiles were, in general, very irregular, lacking evidence that TBT degradation occurs at appreciable rates in these anoxic sediments. Decay most probably takes place predominantly in the water column and at the water-sediment interface before final burial in the sediments. Data from the least contaminated area was used to estimate a first-order degradation constant of -0.37 years -1 for dibutyltin.

A method was developed for the determination of trace elements in crude oil by inductively coupled plasma mass spectrometry (ICP-MS) after sample dissolution in toluene and subsequent ultrasonic nebulization (USN). Carbon build-up at the interface and ion lenses was minimized by optimization of the argon to oxygen ratio in the plasma and by the desolvating action of the USN. The analyte addition technique, combined with internal standardization ( 115 In), was the only calibration procedure capable to correct properly for signal suppression, especially observed in solutions with higher concentrations of asphaltenes. Analytical curves with good linearity ( r 2 >0.99), and solution detection limits (LOD–3σ) of ⩽0.1 μg l −1 for V, Ni, Co, Y, Mo, Cd, Ba and La, and in the range of 0.1–1 μg l −1 for Al, Ti, Fe, Zn, Sr, Ag, Sn and Pb were obtained. Method validation was performed by analyzing two certified reference materials. For National Institute for Standards and Technology (NIST) 1634c (V, Ni, Co), accuracy was approximately 10%, similar as observed for other 12 elements in NIST 1084a. Asphaltenes were separated from the oil bulk of crude oil samples from the Potiguar Basin (Brazil) using precipitation in heptane. The heptane-soluble fraction (maltenes) was separated by elution chromatography into three sub-fractions: (1) saturated and low molecular mass (MM) aromatics, (2) aromatics and low MM polar compounds, and (3) high MM polar compounds (resins). Trace elements were determined in these fractions after dissolution in toluene, by USN–ICP-MS. Mass balance calculations showed a significant increase of most elements (10–30 times) in the asphaltenic fraction, and in minor proportions in fraction 3, compared to the crude oil samples. Comparison with microwave-assisted acid decomposition showed good agreement, validating the proposed methodology and emphasizing its applicability for routine analysis of crude oil and other toluene soluble petroleum products.

Produced water samples from the Bacia de Campos oil field offshore Pargo and Pampo platforms were analyzed for Ba, 226 Ra, 228 Ra, V, Ni and Pb. The activity concentrations measured were in the range of 1.6-6.0 Bq/L for 226 Ra and 0.7-8.2 Bq/L for 228 Ra for both platforms. For Ba, V, Ni and Pb the concentrations measured were in the range of 5.6-25.7 mg/L, 0.15-0.46 µg/L, 4.85-12.14 µg/L and 4.04-12.37 µg/L. A strong correlation between barium and radium isotopes concentration was observed ( 226 Ra: R 2 = 0.897; 228 Ra: R 2 = 0.737). In order to evaluate the environmental impact from discharges of produced water into the sea, the seawater and sediment samples were collected at distances from 250 to 1000 m around the platforms. The seawater samples were analyzed for dissolved and particulate material and the sediment samples for total and leachable fraction. The results show that even for the shortest sampling distance (250 m) from the discharge point, Ba, 226 Ra, 228 Ra, V, Ni and Pb concentrations in se...

Results from a study are reported in which patients with leishmaniasis were monitored by whole blood, blood plasma, urine, and hair analysis, before, during, and after intramuscular administration of N-methyl meglumine antimoniate. Quadrupole ICP-MS was used for the detection of antimony and on-line ion chromatography for the separation of its species. After typically 30 consecutive daily injections of 5 mg antimony per kg of body weight, Sb concentrations of up to 250 microg L(-1) in whole blood and plasma, and 60 mg of Sb per gram of creatinine in urine, were measured 24 h after drug administration. Antimony in hair samples of these patients showed concentrations of up to 24 microg g(-1). Speciation studies of Sb5+ and Sb3+ in drug, urine, and plasma samples were performed by ion chromatography using a Hamilton PRP-100X anion exchange column and EDTA (2 or 20 mM, pH 4.7) as the mobile phases. Repeatability of elution time and peak area measurements for a 0.125 ng spike were1.2% and3.5%, respectively. Method detection limits for both species, using a 1:10 diluted urine or plasma sample, were typically 1.6 microg L(-1). The procedure was capable of separating the very intense drug peak from its inorganic species, thus permitting the first studies on the bio-transformation of N-methyl meglumine antimoniate to Sb5+ and Sb3+ in the human body.

Accuracy and repeatability of analytical results obtained by laser ablation (LA) inductively coupled plasma mass spectrometry (ICP-MS) critically depends on the availability of calibration standards, which should ideally have a matrix composition very close to the samples being analyzed. The preparation of synthetic obsidian standards (SOS) is described in this work, their minor and trace element composition (>40 elements), determined by solution nebulization ICP-MS and inductively coupled plasma optical emission spectrometry is presented and their performance in the quantitative and semiquantitative analysis of obsidians by LA-ICP-MS is discussed. Due to matrix matching of SOS and natural obsidians, internal standardization of the analyte intensities by 27Al or 29Si had no significant effect on the final results. Good analytical curves (r2>0.995) were obtained with the SOS series, permitting quantitative determination of a large number of trace elements in geological and archaeological samples with repeatabilities typically between 5 and 10% and adequate accuracies, as shown by the generally good agreement between solution nebulization and laser ablation data for the same samples. Results obtained in the fast semiquantitative mode of calibration were in most cases statistically not different from those obtained by the quantitative mode. This, for the routine analysis of a large number of samples attractive feature, was achieved by the use of 47 quantified elements in SOS for updating of the response factors. An example for the application of analytical methodologies introduced in this work is shown in provenance studies of archaeological obsidian artifacts from Ecuador.

The purpose of this study was to compare erythrocyte lead levels and relationship with biomarkers of bone turnover in pregnant (n = 68, 28–39 weeks of gestation), lactating (n = 45, 1–2 months post-partum) and control (n = 33) adult women with habitually low calcium intake (400–600 mg Ca/d) and low environmental lead exposure (blood lead levels

Analytical results obtained by ICP-MS of hair samples from a group of women from Rio de Janeiro city show that abnormal Ca and P concentrations in this compartment can be an indication of pathologies affecting the metabolism of these elements. The study was conducted initially on 900 women (outpatients, >40 years). From this group, approx. 24% showed anomalously high or low Ca concentrations in hair, in some cases correlated to anomalies of other elements. In 144 cases (16%), very high concentrations of Ca (up to 8,285 mg/kg) were measured, frequently correlated with a high concentration of P (up to 4,720 mg/kg), exceeding by far the reference intervals for this age/sex group. Follow-up studies of a few individuals from this group gave first indications that their abnormal hair compositions were related to endocrinologic pathologies affecting calcium/bone metabolism. Very low hair Ca-concentrations were observed in older women (72 cases, age >60 years) and related to senile osteoporosis. Complementary investigations of patients with recognized endocrinologic pathologies (hyperthyroidism, hyper- and hypoparathyroidism) and osteomalacia gave statistical support for the hypothesis that hair concentrations of Ca, P and various other trace elements are influenced characteristically by these diseases. In patients with hyperparathyroidism and hyperthyroidism, both elements showed significant increase in hair, whereas patients with rickets/osteomalacia had only elevated Ca concentrations, together with suspiciously high toxic levels of Cd and various other elements (Fe, Mn, Mg, Sr, Ba). Patients with hypoparathyroidism had significantly decreased Ca and P concentrations in hair. Statistical evaluation of these data by multivariant analysis (MANOVA) using a contrast matrix and by discriminant analysis showed that elemental hair anomalies can be used to diagnose correctly the above-mentioned pathologies, demonstrating the usefulness of hair analysis as a complementary tool for the detection of disturbances in calcium/bone metabolism.

This study presents and discusses groundwater colloid results from various geological formations ranging from crystalline to sedimentary, from organic rich to organic poor systems and from subsurface to very deep aquifers. Colloid presence and their potential mobility are justified on the basis of colloid stability properties in the investigated groundwaters. The colloid concentration is a function of pH, redox potential, concentrations of Na, K, Ca, Mg and organic carbon, as well as the status of the chemical and physical steady state of the hydrogeochemical system. The colloid properties are discussed with a non-site specific approach.

Water samples were collected in Middle Amazonia from the Amazon River, Rio Negro and 17 tributaries of Rio Negro. The analyses consisted of pH, conductivity, and dissolved organic (DOC) measurements, as well as plasma source mass spectrometry (ICP-MS). Factor analysis revealed three factors, which explained 94% of the total variance. A plot of factor scores presented a cluster containing mostly samples from the Rio Negro Basin. Ultrafiltration tests confirmed that organics from the Rio Negro have higher molecular mass than in the Amazon, and that some metals are associated with these compounds. Heavy rare-earth elements (REE) are enriched relative to light REE in the dissolved fraction of most rivers of the Negro Basin; the opposite occurred in suspended matter. Amostras de água foram coletadas no Rio Amazonas, no Rio Negro (Brasil) e em 17 afluentes do Rio Negro, na Amazônia Central. As análises consistiram em medidas de pH, condutividade, carbono orgânico (DOC) e espectrometria de massas com fonte de ICP. Através da análise multivariada as variáveis foram classificadas em três fatores, correspondentes a 94% da variância. O gráfico de escores de fatores mostrou que a maioria das amostras da Bacia do Rio Negro formam um grupo homogêneo. Testes de ultrafiltração confirmaram que o Rio Negro apresenta compostos orgânicos de massa molecular mais alta que o Rio Solimões, e que alguns metais encontram-se associados com estes compostos. Observou-se também que, nas águas da maioria dos rios da Bacia do Rio Negro, os elementos pesados das Terras Raras estão enriquecidos em relação aos elementos leves, enquanto o contrário ocorre no material particulado.

In this study, we compared the usefulness of a long-living sponge (Hymeniacidon heliophila, Class Demospongiae) and a short-living one (Paraleucilla magna, Class Calcarea) as biomonitors of metallic pollution. The concentrations of 16 heavy metals were analyzed in both species along a gradient of decreasing pollution from the heavily polluted Guanabara Bay to the less impacted coastal islands in Rio de Janeiro, SE Brazil (SW Atlantic). The levels of most elements analyzed were higher in H. heliophila (Al, Co, Cr, Cu, Fe, Mn, Ni, Hg, Ni, and Sn) and P. magna (Ni, Cu, Mn, Al, Ti, Fe, Pb, Co, Cr, Zn, and V) collected from the heavily polluted bay when compared with the cleanest sites. Hymeniacidon heliophila accumulates 11 elements more efficiently than P. magna. This difference may be related to their skeleton composition, histological organization, symbiont bacteria and especially to their life cycle. Both species can be used as a biomonitors of metallic pollution, but while Hymeniacidon heliophila was more effective in concentrating most metals, Paraleucilla magna is more indicated to detect recent pollutant discharges due to its shorter life cycle. We suggest that the complementary use of species with contrasting life histories can be an effective monitoring strategy of heavy metals in coastal environments.

Waters from two tributaries of the Amazon River, the Rio Negro and Rio Solimoes, were collected near Manaus (Brazil), and their dissolved organic carbon (DOC) were concentrated and size fractionated by ultrafiltration. Hollow fiber ultrafiltration columns were used to separate humic compounds (and associated metal ions) from larger volumes of water in the field. The metal composition of each fraction was determined primarily by ICP-AES, after preconcentration. Flat membrane ultrafiltration was used to obtain sharper molecular mass cut-off levels in the laboratory. About 30–40% of the DOC in the Rio Negro water was within the mass range of 1–10 kDa. This fraction was composed mainly of humic compounds, which are the carriers for most of the metal ions studied (e.g. Al, Fe, Ti, Cu, Mn, Zn, Ca, Mg). Humic and fulvic acids, isolated from these waters, were characterized by IR-spectrometry and potentiometric titrations. Water from the Rio Solimoes showed lower retention of DOC ( ≊ 20% ) and associated metal ions, probably due to the more pronounced sorption of the high-molecular mass humic compounds on suspended particles. Despite the high load of clay particles in this water, no evidence of such particles in colloidal size ranges was observed.

During ultrafiltration of humic compounds through Amicon YM2 flat membranes (cut-off level: 1 kDa), humic acid solutions presented retentions of 80–90% and fulvic acid of 60–70%. Fulvic acid retention on this membrane depends directly on pH and inversely on ionic strength. Calcein (2,7-Bis[bis(carboxymethyl)-aminomethyl]-fluorescein; 623 g/mol), an organic molecule tested for comparative purposes, exhibited a similar behavior. Experiments with humic acid were handicapped by precipitation or aggregation processes under low pH or high ionic strength conditions. Humic acid retention on PM10 membrane (cut-off level: 10 kDa) is the same as on YM2, despite the difference in cut-off levels. This anomalous result is attributed to the lipophilic character of the PM10 membrane. Both membranes are, therefore, highly efficient for the concentration of humic acid from typical freshwaters; a good recovery is also attained with fulvic acid on the YM2 membrane. Although YM2 is considered a hydrophilic, non-ionic membrane, salts containing polyvalent anions show high retentions under low ionic strength conditions, and the retention is proportional to the anion charge.

Plants and soils from a natural thorium and rare-earth element occurrence (Morro do Ferro, Brazil) were analyzed by alpha spectrometry (Th) and ICP-AES (REE), after pre-concentration of the elements by solvent extraction, co-precipitation and ion exchange procedures. Leaching experiments with humic acid solutions and different soils were performed to estimate the fraction of elements biologically available. High concentrations of the light rare-earth elements (LREE) and of Th, reaching some hundreds of μg/g-ash, were measured in plant leaves from the areas of the highest concentration of these elements in soil and in near-surface waters. Chondrite normalized REE plots of plant leaves and corresponding soils are very similar, suggesting that there is no significant fractionation between the REE during uptake from the soil solution and incorporation into the leaves. However, Ce-depletion was observed for some plant species, increasing forSolanum ciliatum in the sequence: leaves

Results are repoerted for238U,234U,232Th, and230Th determinations in 19 rock samples from a uranium mine, performed independently, byb three different laboratories. Uranium and thorium isotopoic activities were determkined by alpha spectrometry, after different pre-concentration and counting sample preparation techniques., Additionally, total concentrations of uranium were determined by fluorimetry and gamma spectreometry. the folloing conclusions could be drawn from this intercomparison test: (1) The results for238U specific activity agreed with the amjority of results within 10%. Lincar correlation coefficients between the three data sets were 0.999. However, for a few samples of much higher uranium concentrations, large deviations were observed, indicating problems of, sample heterogencity. (2) For the234U/238U activity ratio data, a still closer agreement was obtained (5%), as computation of the activity ratios did not, require information on the yield of the used tracer spike (232U). (3) The results for232Th specific activities and230Th/234U activity ratios showed larger deviastions between the three laboratories (typically up to 15%, in some cases still ore). Different Th-isotopes (228Th,234Th and229Th) have been used as yield tracers. The data indicates, however, that the observed deviations are not simply a consequence of a systematic difference in the calibration of the different spikes, but, probably cased by other errors such as incomplete sample dissolution, sample heterogencity, tec. The limitations of alpha spectrometry will be discussed and an application of the developed methods shown.

Antimony (Sb) disposition and toxicity was evaluated in Leishmania braziliensis-infected monkeys (Macaca mulatta) treated with a 21-d course of low (LOW) or standard (STD) meglumine antimoniate (MA) dosage regimens (5 or 20 mg Sb(V)/kg body weight/d im). Antimony levels in biological matrices were determined by inductively coupled plasma mass spectrometry (ICPMS), while on-line ion chromatography coupled to ICPMS was used to separate and quantify Sb species in plasma. Nadir Sb levels rose steadily from 19.6 ± 4 and 65.1 ± 17.4 ng/g, 24 h after the first injection, up to 27.4 ± 5.8 and 95.7 ± 6.6 ng/g, 24 h after the 21st dose in LOW and SDT groups, respectively. Subsequently, Sb plasma levels gradually declined with a terminal elimination phase half-life of 35.8 d. Antimony speciation in plasma on posttreatment days 1-9 indicated that as total Sb levels declined, proportion of Sb(V) remained nearly constant (11-20%), while proportion of Sb(III) rose from 5% (d 1) to 50% (d 9). Plasma [Sb]/erythrocyte [Sb] ratio was >1 until 12 h after dosing and reversed thereafter. Tissue Sb concentrations (posttreatment days 55 and 95) were as follows: >1000 ng/g in thyroid, nails, liver, gall bladder and spleen; >200 and

The abandoned industrial site at the Sepetiba Bay (SE-Brazil) is one of the most heavily contaminated sites on the earth's surface concerned to Zn, but also presents As in alarming concentrations. Vegetation on this site is scarce and under the surviving species Pityrogramma calomelanos and Nephrolepis biserrata are the most abundant ones. Total As concentrations up to 2271 mg kg-1 in P. calomelanos were determined, being this specie more efficient in arsenic accumulation than N. bisserata. The size exclusion chromatography (SEC) with UV-Vis detector coupled to inductively coupled plasma mass spectrometry (ICP-MS) was used to screen the distribution of As between different molar mass fractions. Highest concentration of As was found after extraction with TRIS-HCl, pH 7.4 (about 60-100% of total As) characterizing an association of this element with bioligands including phytochelatins and glutathione. O sítio industrial abandonado na Baía de Sepetiba (SE-Brasil) está entre os maiores passivos ambientais contaminados com Zn no mundo e o As também se encontra em concentrações alarmantes. A vegetação no local é escassa e das espécies que sobrevivem no local Pityrogramma calomelanos e Nephrolepis biserrata são as mais abundantes. Concentrações de As de até 2271 mg kg-1 foram detectadas na espécie Pityrogramma calomelanos, sendo que essa espécie foi mais eficiente que N. Bisserata no acúmulo desse elemento. Utilizou-se cromatografia de exclusão por tamanho (SEC) com detecção UV-Vis e espectrometria de massas com plasma indutivamente acoplado (ICP-MS) em sistema "on line" para monitorar a distribuição de As na fração orgânica. As maiores concentrações de As foram determinadas na fração extraída com TRIS-HCl, pH 7,4 (entre 60-100% da concentração total de As) mostrando uma evidente associação desse elemento com bioligantes, entre eles, fitoquelatinas e glutationa.

The origin of trace metals in petroleum is intimately connected with the origin of petroleum itself, one of the most exciting topics in chemistry and geology for the past 150 years. Because of its fluidity and consequent migration, the origin of petroleum is more difficult to interpret than that of most rocks. Biogenic and abiogenic models developed side by side, each championed by some of the greatest names in chemistry and geology. According to biogenic models, petroleum forms by thermal breakdown, in the presence of water, of complex, ultimately biogenic organic polymers (kerogen) (Tissot & Welte, 1984; Lewan, 1997). Conversely, according to abiogenic models, petroleum forms by reductive polymerization of simple carbon compounds such as CO and CO2. Experiments and calculations indicate that such polymerization is thermodynamically stable only at high temperatures and pressures (above 1300°C and 30 kbar; Kenney et al., 2002) but it takes place also at low temperatures (

As part of a major natural analogue study of relevance to radioactive waste disposal, natural decay series disequilibrium techniques were used to provide information on the mechanisms and rates of processes occurring at redox fronts in an extensive uranium deposit near Pocos de Caldas, Brazil. This topic is of direct relevance to waste disposal safety assessment in view of the postulated development of radiolysis-induced oxidizing conditions in respositories. The study confirmed the downwards displacement of uranium by oxidizing groundwater interacting with the reduced rock, resulting in downwards movement of the redox front, with associated cyclical oxidation-induced dissolution and reduction-induced redeposition of uranium generating enhanced uranium concentrations at the redox fronts. Deposition of uranium occurs on both sides of the redox fronts, with reduction to insoluble U4+ in the reduced rock and scavenging by secondary iron oxides being identified as the respective mechanisms of deposition. Radioactive disequilibrium considerations indicate that, while the uranium deposited in the oxidized rock is retained for times of at least 106 y, some slow redissolution does occur, possibly involving mainly preferential loss of 234U. Sequential leaching indicates that the redeposited uranium in both the oxidized and the reduced rock is more readily dissolved than the uranium in the unaltered reduced rock. It is concluded that the observed distributions of uranium were produced by diffusion in both directions away from the redox fronts in conjunction with groundwater flow downward along the direction of the fronts. Limited redistribution of thorium has occurred, but at a level at least two orders of magnitude less intense than that of uranium and there is a systematic separation of uranium from thorium with increasing depth in the rock. At two locations where the oxidized rock overlies the reduced rock, natural decay series disequilibrium indicated a rate of movement of the front of 2–20 m in 106 y, suggesting that the rate of movement of the redox front is controlled by the rate of regional erosion (about 12 m in 106 y). At a location where the reduced rock overlies the oxidized rock, the front was estimated to have moved less than 1 cm in 106 y. This location was also the site of the most intense mineralization of uranium in the samples studied. 226Ra mobility over distances of the order of 10 m was observed, along with preferential transfer of 226Ra from the reduced to the oxidized rock at the deeper redox fronts. The postulated maximum rate of far-field movement of a repository-related redox front of about 50 m in 106 y is concluded to be a realistic value for use in models. Scavenging of radionuclides by secondary minerals forming in oxidized rocks is identified as a potentially important retardation process which might not be apparent from purely thermodynamic considerations. The effect of a repository-related redox front would be initially to retard radionuclide movement by at least partial deposition at the front. If such a redox front were to penetrate a sufficient distance through the far field, it could, however, result in the breakthrough of a pulse of radionuclides to the near-surface zone.

The dissolved uranium isotopes in aquifer waters at the Osamu Utsumi uranium mine suggest that isotopically normal very deep water flows upwards and becomes mixed downward percolating oxidized water. The latter is acidic and enriched in leached uranium. This flow regime results in some uranium migrating downwards where it enriches the ore body at the redox front; some also escapes with surface run-off. At the present time there are no waters which have the uranium isotopic signatures which would be associated with flow-through redox fronts. The uranium isotopes in shallow aquifer waters at the Morro do Ferro thorium/rare-earth deposit confirm the inferred rapid flow rates, although the groundwater in the well at the base of the hill has elevated activity ratios suggesting an inflow from deeper aquifer waters. The thorium content of water in the Morro do Ferro aquifer is somewhat above normal for groundwaters because of percolation through the ore body. Uranium isotopic modelling of groundwater flow at both sites confirms the flow regimes as deduced from hydrogeological and geochemical studies, and supports interpretations of uranium dissolution and redeposition along redox fronts.

Data are presented on rare-earth elements (REE) in prefiltered ( 450 nm) from the Osamu Utsumi uranium mine and the Morro do Ferro thorium-REE-deposit. Groundwaters from both sites typically contain between 1–50 μg/l of total REE, but can reach values of up to 160 μg/l in the deepest borehole F4 (U-Mine: 150–415 m). Even higher REE concentrations of up to 29 mg/l were measured in acidic, sulfate-rich near-surface waters of the same site. The chondrite-normalized REE patterns in deeper, more reducing groundwaters and in their corresponding suspended particle fractions are similar to those observed in the bedrock (phonolites), indicating that bedrock leaching and secondary mineral sorption occurred without significant fractionation between these elements, in accordance with the only small variations in the stability constants of the expected REE-sulfate complexes in these waters. Groundwaters from the unsaturated zone of both sites show a very characteristic cerium depletion (less pronounced than that observed in the corresponding suspended particulate fractions), which is most probably related to the oxidation of Ce (III) under the prevailing E h -conditions of these waters (600 to 800 mV), and to sorption/precipitation reactions of the much less soluble Ce(IV) species. Coarse particulate matter (>450 nm ), composed mainly of amorphous ferric hydrous oxides, has a strong capacity for sorption of REE. This is shown by its very high REE concentrations, in some boreholes > 8,000 μg/g (total REE), and by the calculated association ratios R a (ml/g), which are in the order of 10 5 to 10 6 . The implications of these findings for the migration behavior of REE in both environments are discussed.

Data are presented on suspended particles and colloids in groundwaters from the Osamu Utsumi mine and the Morro do Ferro analogue study sites. Cross-flow ultrafiltration with membranes of different pore sizes (450 nm to 1.5 nm) was used to prepare colloid concentrates and ultrafiltrates for analyses of major and trace elements and U- and Th-isotopic compositions. Additional characterization of colloidal and particulate material was performed by ESCA, SEM and X-ray diffraction. The results indicate the presence of low concentrations of colloids in these waters (typically < 500 μg/l), composed mainly of iron/organic species. Minor portions of uranium and other trace elements, but significant fractions of the total concentrations of Th and REE in prefiltered waters (< 450 nm) were associated with these colloids. Suspended particles (> 450 nm), also composed mainly of hydrous ferric oxides and humic-like compounds, show the same trend as the colloids with respect to U, Th and REE associations, but elemental concentrations were typically higher by a factor of 1,000 or more. In waters of low pH and with high sulphate content, these associations are considerably lower. Due to the low concentrations of suspended particles in groundwaters from the Osamu Utsumi uranium mine (typically

This study compared the efficacies of two N -methylglucomine antimoniate (MA) dose regimens for treating macaques with Leishmania braziliensis -induced chronic skin disease. Whereas all animals treated with the full dose (20 mg MA/kg/day) were cured, 50% of the monkeys receiving a low-dose regimen (5 mg MA/kg/day) relapsed. The antimony concentrations in macaque plasma and tissue samples were greater in the full-dose group than in that receiving a subtherapeutic MA regimen. Our data also suggest the presence of drug-induced hepatic pathology.

At the radioactive uraniferous deposit of Espinharas of the northeast Brazilian shield, uranium mineralization is related to sodium metasomatism and episyenitization of amphibolite facies gneisses and intrusive microgranites. Two major groups of gneisses occur, granitic leucocratic gneisses and mesocratic biotite-amphibole gneisses, which have subconcordant structural relationships. The gneisses are cut by intrusive microgranite dikes of very variable dimensions. Uranium mineralization occurs in all three major rock types, in albitized and episyenitized zones discordant to the high-grade metamorphic foliation. These zones resulted from shearing stresses and fracturing that controlled the microgranite intrusions and the later percolation of the metasomatic mineralizing fluids along grain boundaries and microfractures. Uranium mineralization was particularly effective in the granitic gneisses. The metasomatism resulted in: (1) complete dissolution of quartz; (2) albitization of plagioclase and microcline; (3) chloritization and partial dissolution of biotite; (4) precipitation of coffinite (as the only U mineral), pyrite, chlorite, albite and carbonates, frequently associated with yttrium and rare earth element minerals (xenotime), partially filling the voids resulting from quartz dissolution. In the mesocratic biotite-amphibole gneisses there are epitactic overgrowth of blue riebeckitic amphiboles on primary amphibole. The mineralogical changes are associated with: Si and K (Rb) depletion; Na, U, Th, Nb, Zr, Y and heavy ree enrichment; Fe enrichment and oxidation. For the purpose of geochemical exploration and ore genesis the ree are of major importance: the light and intermediate ree precisely define the relationships of parent and mineralized rocks; U mineralization is associated with an enrichment of the heavy ree (Dy to Lu) and Y.

Trace element distribution patterns were determined in crude oils from onshore biodegraded reservoirs along a secondary migration trend (Potiguar Basin, Brazil). Samples were fractionated into asphaltenes, paraffins, aromatics and polars and resins for the determination of 22 trace elements by ICP-MS. Most of them are strongly enriched in the resin and asphaltene fractions, but V and Ni are also associated with the aromatic and polar fractions. V, Co, Ni and Mo were influenced by biodegrading processes and accumulate in the most affected and migrated samples. Variations of the Ni/V ratio in aromatics and polars, matching those of homohopane and gammacerane indexes in paraffin, evidenced also the influence of biodegradation. Very similar elemental distribution patterns in oil and corresponding asphaltenes were observed, suggesting that the latter fraction, more refractory than the original oil, can be used as a robust inorganic geochemical fingerprint for oil characterization. Perfis de distribuição de elementos traços foram determinados em óleos crus de reservatórios biodegradados situados ao longo de um caminho de migração secundaria (Bacia de Potiguar, Brasil). As amostras foram fracionadas em asfaltenos, parafinas, aromáticos e polares e resina para determinação de 22 elementos traços por ICP-MS. Esses se concentram nas frações de resina e asfaltenos, exceto V e Ni também encontrados na fração de aromáticos e polares. V, Co, Ni e Mo foram influenciados por processos de biodegradação e acumulam-se nas amostras mais afetadas e de maior distância de migração. Variações semelhantes da razão Ni/V nos aromáticos e polares e dos índices de homohopano e gamacerano nas parafinas evidenciaram também a influencia da biodegradação. As distribuições elementares foram similares para os óleos e seus asfaltenos, sugerindo que esses últimos, mais refratários que o óleo original, possam ser usados como uma ferramenta geoquímica inorgânica robusta de impressão digital para caracterização de óleos.

Capillary electrophoresis coupled to inductively coupled plasma mass spectrometry was used in a speciation study on disodium monomethylarsonate (DS-MMA(V)) and its metabolites in horses, to which the drug was administered by intramuscular injection on five consecutive days at a single arsenic dosage of 270 mg day(-1). Samples of urine, whole blood, plasma, and mane hair were analyzed before, during, and after drug administration. The data show that blood clearing and urinary excretion of MMA is a fast process following first-order kinetics with biological half-lives of about 38 h and 44 h for urine and plasma, respectively. In the time period of 9 days studied, the only metabolite detected in urine was dimethylarsinic acid (DMA(V)), which 4 days after the last drug administration accounted for up to 75% of the total excreted arsenic species. This shows, for the first time, that biomethylation of MMA(V) to DMA(V) is the principal metabolic pathway of this drug in horses. Although DS-MMA(V) was administered only during a short 5-day period, an up to six fold increase of arsenic could be measured in the newly grown mane hair.

A versatile preconcentration system for trace element determination by ICPMS was developed. It is composed of a commercial flow injection analysis system (FIAS) retrofitted with a home-made control unit containing three solenoid valves and working concomitantly with the FIAS, permitting selection and segmentation of sample, reagent, washing solution and elution flow. The knotted reactor used had a length of 200 cm and was made from 0.05 cm i.d. PTFE tubing. The method applies ammonium 1-pyrrolidinedithiocarbamate (APDC) as complexant, allowing the preconcentration and quantitative multi-element determination of Cu, Ni, V, Co, Nb, Mo, In, Sb and Bi. Ethanol and 4-methyl-2-pentanone were tested as eluents. Recovery tests using complex matrices and spike concentrations of 200 ng L-1 showed typical values in the range of 90% to 110%. Relative standard deviations were < 7% for elution with ethanol and < 5% with methyl isobutyl ketone. For simulated freshwater samples using 4-methyl-2-pentanone as an eluent, a sample loading rate of 5.0 ml min-1, and a preconcentration time of 60 s, detection limits (ng L-1) were in the range of 0.02 (Bi) to 30 (Cu). Under these conditions, analytical frequency was about 15 samples per hour. The feasibility of the method was demonstrated by the succesful analysis of wastewater and seawater certified reference materials.

Inductively coupled plasma mass spectrometry (ICP-MS) has been used for the determination of thorium and light rare-earth elements (LREEs) in soil and soil water samples from a mineral deposit (Morro do Ferro, Minas Gerais, Brazil). Size-exclusion chromatography (SEC) on-line coupled to ICP-MS and UV-detection was applied to verify possible association/complexation of these elements with organic matter in soil water separated by a centrifugation technique. Concentrations of DOC in soil waters are in the range of 10 to 500 mg L(-1) and correlate with the organic carbon content of the soil (r=0.950; p0.001). Concentrations of 30 to 40 microg L(-1) for the LREEs (La, Ce, Nd) and up to 14 microg L(-1) for Th were measured in soil waters of highest DOC content. SEC chromatograms of these waters showed the association of elements with different nominal high-molecular-mass ranges, characteristic of soil humic and fulvic acids:10,000 Da, with a retention time of about 10 min; 7000 to 8000 Da with retention times of 13 to 15 min; and 2000 to 4000 Da with retention times around 23 min. Elemental peaks associated with dissolved organic matter below 1000 Da were not observed, suggesting that complexation with simple plant organic acids or inorganic ligands is of minor importance in the environment studied in this work.

Produced water samples from different E&P offshore petroleum platforms, belonging to the Bacia de Campos oil field, Brazil, were analyzed for barium, 226Ra and 'Ra. The concentrations measured are in the range of 0.36-25.7 mg l(-1) for barium, 0.012-6.0 Bq l(-1) for 226Ra and

The purpose of this study was to evaluate the effect of calcium supplementation during lactation on changes in blood lead indices from late pregnancy to early lactation in women with low calcium intakes and low lead-exposure. Forty-seven women, non-occupationally exposed to lead and with habitually low calcium intake ( approximately 600 mg/d), participated in the study from 29 to 38 weeks of pregnancy to 7-8 weeks post-partum, non-supplemented (n=25) and supplemented (n=22) with calcium (500 mg/d) during 6 weeks after delivery. Erythrocyte lead (PbRBC) and in vitro reactivation with zinc of blood delta-aminolevulinic acid dehydratase (Zn-delta-ALAD% reactivation) were used as lead indices. In the non-supplemented group, PbRBC and Zn-delta-ALAD% reactivation increased significantly (P

Inductively coupled plasma mass spectrometry (ICP-MS) was used for the determination of major and trace element concentrations in scalp hair samples from a population group (N = 1091) of Rio de Janeiro city. From these results, preliminary 'normal' or reference intervals were calculated which are for several trace elements (e.g. B, V, Co, Ge, Mo, Au, As, Se, Sb, Th), but also for some minor elements (e.g. Ca, Mg) in disaccord with data published by five clinical laboratories which used inductively coupled plasma atomic emission spectrometry (ICP-AES). The limitations of ICP-AES in routine hair analysis is shown by comparison of detection limits for both methods and by results from two laboratory intercomparison exercises. It is evident from these data that published reference intervals have to be used with extreme caution and that their urgent revision, based on reliable data produced by the ICP-MS technique, is of extreme importance.