Time-resolved monitoring of heavy-metal intoxication in single hair by laser ablation ICP-DRCMS

One night with Venus, a lifetime with mercury : Analyses of heavy metals in Franz Schubert's hair are consistent with syphilis treatment

Samples from three strands of Franz Schubert's hair, which are very likely to be authentic due to their well-documented origin and the chain of custody that is still valid today, were analyzed in terms of molecular biology and heavy metal content. The two hair samples presumably taken from the deceased's head showed matching molecular biological parameters, while the sample taken 35 years after his burial did not contain any usable DNA. Heavy metal analyses along the hair samples using LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) with a temporal resolution of 4-5 h revealed significantly increased mercury and lead concentrations in all samples with a decreasing tendency towards the time of death. Taking the different storage conditions into account, the patterns of metal concentrations in the samples match well, suggesting that all three samples came from the same individual. The results of our research support the suggestion, often made in the literature, that Franz Schubert underwent cutaneous treatment with mercury for syphilitic illness many months before his death.

Microchemistry of Single Hair Strands Below and Above the Scalp: Impacts of External Contamination on Cuticle and Cortex Layers

External contamination of hair is the most significant challenge to it becoming an accepted matrix for monitoring endogenous metal exposure and nutritional deficiency. Here we use laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to quantify elemental concentrations in hair strands below and above the scalp in the cuticle and cortex layers to determine the extent of external contamination in a reference population. Evidence of hair strand contamination occurred for barium, calcium, iron, magnesium, and strontium in both the outer cuticle and the inner cortex layers, with increasing concentrations from root to tip. Aluminum, boron, copper, lead, and manganese showed significant contamination in the cuticle layer only, suggesting some protection of the inner cortex. Phosphorus and potassium decreased outside the scalp suggesting loss by washing, while chromium, mercury, selenium, sodium, titanium, and zinc showed no evidence of loss or external contamination above the scalp. The results clearly show that for most elements, hair chemistry above the scalp is unreliable for use in interpretation of endogenous exposures or deficiencies, and that the below-scalp portion provides a more accurate monitoring tool. This is the first paper to provide a reference range of elemental hair chemistry that is not impacted by the external environment.

Pre-cleaning of hair is not beneficial in LA-ICP-MS studies of chronic metal exposure

Chronic exposure to toxic metals is a serious global health concern. However, population-wide biomonitoring is costly and carries several sampling constraints. Though hair sampling can be a useful way to assess environmental exposure, external contamination is a long-standing concern, and a pre-cleaning step prior to metal quantification has long been recommended despite a lack of evidence for its efficacy. In this study, we quantified the spatial distribution of 16 elements in unwashed human hair samples using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), then tested how two common pre-cleaning treatments (Triton-ethanol, Triton-nitric acid) affected metal content in external and interior layers of hair using LA-ICP-MS. We show that elements differ in their spatial distribution across hair and that pre-cleaning is not consistent in its effect on element concentrations and decreases interior concentrations of some elements. We demonstrate that differences among individuals can be quantified reliably with LA-ICP-MS analysis of interior concentrations of unwashed hair. Our study tests the widespread notion that pre-cleaning is essential in analyses of hair for environmental exposure to metals, and examines the benefits of a unified approach to analysis of metals in hair using LA-ICP-MS.

Metal distributions in human hair strand cross-section: Advanced analysis using LA-ICP-MS in dentistry

Human hair is a biomarker that is crucial in investigating toxic metal exposures. Thirteen elements (Li, Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Ag, Ba, and Hg) commonly found in hair strands from dentistry environments were investigated using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Previous studies have employed partial ablation along hair strands to avoid contamination from mounting materials. The partial ablation can be problematic if element chemistry within the hair is not homogeneous. In this study, element variations along cross-sections of human hair strands were investigated. A number of elements showed internal variations with most elements enriched at the cuticle, emphasizing the importance of complete ablation for the characterization of human hair element chemistry. Complete and partial ablation LA-ICP-MS results were verified against solution nebulization SN-ICP-MS. Complete LA-ICP-MS showed a better agreement with SN-ICP-MS. Therefore, the developed LA-ICP-MS method can be applied to monitor the health of dental workers and students exposed to dental environments.

Morphological and chemical profiling for forensic hair examination: A review of quantitative methods

Within the past two decades, there have been many studies for quantitative analysis on human hair samples. Microscopical and chemical analysis techniques have been used to analyze various aspects of hair regarding biological, chemical, anthropological, cosmetic, and forensic applications. Studies have attempted to develop quantification methods to increase the evidentiary value of hair in forensic casework. The literature reviewed in this paper provides some of the current techniques used for forensic examinations and quantitative methods. Although microscopical analysis has been scrutinized in the past, using chemical and microscopical techniques can provide a myriad of information. The extraction of DNA from hair provides high-value evidence; however, it may not be readily available and may yield inconclusive results. Hair analysis can be used for many forensic applications such as comparison, toxicology, and exposure analysis. In this article, we will review published research material regarding chemical and microscopical techniques for human hair analysis. Aspects considered for this review were the sample size requirement for analysis and the destructive nature of the instrumental method. This review will focus on both macro and micro quantitative methods for human hair analysis.

Advancing Exposomic Research in Prenatal Respiratory Disease Programming

Disease programming reflects interactions between genes and the environment. Unlike the genome, environmental exposures and our response to exposures change over time. Starting in utero, the respiratory system and related processes develop sequentially in a carefully timed cascade, thus effects depend on both exposure dose and timing. A multitude of environmental and microbial exposures influence respiratory disease programming. Effects result from toxin-induced shifts in a host of molecular, cellular, and physiologic states and their interacting systems. Moreover, pregnant women and the developing child are not exposed to a single toxin, but to complex mixtures.

Whiskers provide time-series of toxic and essential trace elements, Se:Hg molar ratios, and stable isotope values of an apex Antarctic predator, the leopard seal

In an era of rapid environmental change and increasing human presence, researchers need efficient tools for tracking contaminants to monitor the health of Antarctic flora and fauna. Here, we examined the utility of leopard seal whiskers as a biomonitoring tool that reconstructs time-series of significant ecological and physiological biomarkers. Leopard seals (Hydrurga leptonyx) are a sentinel species in the Western Antarctic Peninsula due to their apex predator status and top-down effects on several Antarctic species. However, there are few data on their contaminant loads. We analyzed leopard seal whiskers (n = 18 individuals, n = 981 segments) collected during 2018-2019 field seasons to acquire longitudinal profiles of non-essential (Hg, Pb, and Cd) and essential (Se, Cu, and Zn) trace elements, stable isotope (ẟ15N and ẟ13C) values and to assess Hg risk with Se:Hg molar ratios. Whiskers provided between 46 and 286 cumulative days of growth with a mean ~ 125 days per whisker (n = 18). Adult whiskers showed variability in non-essential trace elements over time that could partly be explained by changes in diet. Whisker Hg levels were insufficient (<20 ppm) to consider most seals being at "high" risk for Hg toxicity. Nevertheless, maximum Hg concentrations observed in this study were greater than that of leopard seal hair measured two decades ago. However, variation in the Se:Hg molar ratios over time suggest that Se may detoxify Hg burden in leopard seals. Overall, we provide evidence that the analysis of leopard seal whiskers allows for the reconstruction of time-series ecological and physiological data and can be valuable for opportunistically monitoring the health of the leopard seal population and their Antarctic ecosystem during climate change.

Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Imaging in Biology

Elemental imaging gives insight into the fundamental chemical makeup of living organisms. Every cell on Earth is comprised of a complex and dynamic mixture of the chemical elements that define structure and function. Many disease states feature a disturbance in elemental homeostasis, and understanding how, and most importantly where, has driven the development of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) as the principal elemental imaging technique for biologists. This review provides an outline of ICP-MS technology, laser ablation cell designs, imaging workflows, and methods of quantification. Detailed examples of imaging applications including analyses of cancers, elemental uptake and accumulation, plant bioimaging, nanomaterials in the environment, and exposure science and neuroscience are presented and discussed. Recent incorporation of immunohistochemical workflows for imaging biomolecules, complementary and multimodal imaging techniques, and image processing methods is also reviewed.

Human Hair as a Possible Surrogate Marker of Retained Tissue Gadolinium: A Pilot Autopsy Study Correlating Gadolinium Concentrations in Hair With Brain and Other Tissues Among Decedents Who Received Gadolinium-Based Contrast Agents

OBJECTIVES

We used laser ablation inductively coupled plasma mass spectrometry to quantify gadolinium in hair samples from autopsy cases with gadolinium-based contrast agent (GBCA) exposure. Hair gadolinium data were correlated with gadolinium concentrations in brain, skin, and bone tissues from the same case to investigate a potential noninvasive method for gadolinium quantification and monitoring.

MATERIALS AND METHODS

Medical records from autopsy cases at our institution were screened for history of GBCA exposure. Cases with exposure to a single type of GBCA with the most recent injection occurring within 1 year were identified and included in the study. The concentration of gadolinium in hair samples was analyzed by laser ablation inductively coupled plasma mass spectrometry, and brain (globus pallidus, dentate nucleus, white matter), bone, and skin tissues were analyzed by bulk inductively coupled plasma mass spectrometry. The mean of the maximum value in the hair samples was used to generate a representative measurement of the hair gadolinium concentration for each case. A linear regression analysis between each tissue type and hair was conducted to assess for possible correlation.

RESULTS

Tissue and hair samples from 18 autopsies (16 cases with exposure to GBCA, 2 controls) were included in the study. Comparing the different tissues revealed good correlation between some tissue types. The best model fit occurred between white matter and hair (R = 0.83; P < 0.0001) followed by the comparison between dentate nucleus and hair (R = 0.72; P < 0.0001) and dentate nucleus and skin (R = 0.70; P < 0.0001).

CONCLUSIONS

A significant correlation in this study between hair gadolinium concentrations and brain and skin gadolinium concentrations suggests that hair may serve as a safe and effective biomonitoring tissue for patients who receive GBCA injections.

Beethoven's death-the result of medical malpractice?

Two different strands of hair taken from Beethoven’s head after his death were examined for heavy metals using scanning electron microscopy (SEM) and laser ablation-ICP-MS (inductively coupled plasma–mass spectroscopy). The results revealed the presence of small lead particles on the surface of Beethoven’s hairs and fluctuating lead levels in hair medulla along the length of the hair due to alternating lead exposure, with an average lead exposure of 100 times the normal value. The time-line attached to the peaks of these fluctuating values correlate with the pneumonia treatment and the paracenteses performed, including the subsequent treatment of the procedure wounds. While the administration of lead-containing drugs and treatments had been proven to resolve the pneumonia, it had simultaneously caused massive liver failure, accelerated by pre-existing cirrhosis. The question as to whether Beethoven’s death was a case of malpractice can only be answered from a forensic point of view ex ante, since the state of the medical knowledge of the time has to be taken into account.

Variability in hair gadolinium concentrations among decedents who received gadolinium-based contrast agents

This study utilized laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to quantify gadolinium in the hair of autopsy cases that had received gadolinium-based contrast agents (GBCAs) before death. Consecutive autopsy cases were reviewed for GBCA injections and subjects who received a single type of GBCA in the year before death were included. Hair samples were analyzed using LA-ICP-MS as a line scan technique and parameters were optimized to maximize instrument sensitivity, accuracy, and precision. Linear regression analyses between hair measures and gadolinium dose were executed. LA-ICP-MS analysis produced a time-resolved record of GCBA exposure, with the position of the gadolinium peak maxima along the hair shaft providing a good estimate for the day that GBCA injection occurred (R2 = 0.46; p = 0.0022); however, substantial within and between subject variation in the position of the GBCA peak was observed. Average area under the curve for gadolinium peaks in the hair samples was a better predictor of gadolinium dose (R2 = 0.41; p = 0.0046), compared to the average of peak maxima concentration. Correlation between area under the curve and dose suggests that LA-ICP-MS analysis of hair may be an effective method to evaluate gadolinium levels in subjects in vivo after exposure to GBCAs. This study demonstrates that analysis of human hair using techniques with high spatial resolution such as LA-ICP-MS has excellent potential to reveal time-dependent signatures of past exposures.

Occupational exposure of platinum-based anti-cancer drugs: five-year monitoring of hair and environmental samples in a single hospital

Background

Occupational exposure to chemotherapeutic agents in hospitals is a critical issue. Here, we focused on occupational exposure to platinum-based anti-cancer drugs (PDs) by evaluating platinum concentrations in hair and environmental workplace samples to monitor the risk among workers.

Methods

Hospital workers who dealt with or without PDs, patients treated with PDs, and non-medical office workers outside the hospital donated hair samples and completed a questionnaire regarding their history of handling PDs, including any incidents. Hair samples were collected and surface wipe sampling was performed in July 2010 and April 2015, before and after moving to a new building and introducing a revised safety program in August 2010. Samples were analyzed by inductively coupled plasma-mass spectrometry.

Results

Platinum concentrations in hair from PDs-handling workers was significantly higher than in non-PDs-handling workers (P = 0.045), although 50 times lower than that from PDs-treated patients. Platinum concentrations in the hospital environment had decreased at the second survey 5 years later but had not changed significantly in the hair samples from hospital workers.

Conclusion

Platinum concentrations in hair are likely dependent on the frequency of handling PDs. Reduced environmental contamination from PDs did not influence platinum levels in hospital workers’ hair. Continuous monitoring by measuring platinum concentrations in the environment and in hair would provide information regarding these issues.

Mercuric chloride poisoning: symptoms, analysis, therapies, and autoptic findings. A review of the literature

Among mercury-related intoxications, the re-emerging of mercuric chloride poisoning has been recently described in literature. Only sparse data, reporting the clinical symptoms, the anatomo-pathological findings, the analytical procedures or the treatment have been published and no exhaustive analysis of all these factors exists in literature. The classic symptoms associated with toxicity of mercuric chloride is a combination of renal, gastrointestinal (GI) and central nervous system (CNS) damages, eventually leading to death. Fatalities related to exposure to mercuric chloride have been reported since the nineteenth century. To date, there have been 45 published cases in the medical literature in which the intoxication or the death is attributed to mercuric chloride. In this review, we will describe the modern medical treatments, with particular attenztion to the developments of the lasts two decades, in order to provide an exhaustive description of the clinical symptoms, the post-mortem findings, and the analytical procedures to act out when mercuric chloride intoxication occurs. The analysis of the data obtained permitted us to accurately describe all the organs and apparatus involved in mercuric chloride intoxication. The target organs were the kidneys, the GI tract and the CNS. A description of the analytical procedures for the determination of mercuric chloride in biological materials, to carry out in vivo and in post-mortem samples has also been described.

Editor's Highlight: Variation in Methylmercury Metabolism and Elimination Status in Humans Following Fish Consumption

Evaluating the potential for methylmercury (MeHg) toxicity relies on accurately predicting the mercury (Hg) body burden that results from eating fish. Hg body burden is directly determined by the slow elimination kinetics of MeHg in the human body (kel = 0.014 days-1 or t1/2 =50 days). Existing studies on MeHg half-life in humans demonstrate a wide range values (t1/2 = 30 to >150 days) and has lead to uncertainty in the derivation of a regulatory standard for acceptable daily oral intake. The causes of variation in MeHg toxicokinetics in humans remain little explored. Here we characterize variation in human MeHg metabolism and elimination rate (kel) in 37 adult volunteers who consumed 3 fish meals. We determined MeHg elimination rates via longitudinal Hg analysis in single hairs using laser ablation inductively coupled plasma mass spectrometry. We also measured MeHg metabolism (biotransformation) via speciation of fecal Hg. We find an average kel = 0.0157 days-1 (t1/2 = 44 days) amongst a more than 2-fold variation in kel across the cohort (0.0248-0.0112 days-1; t1/2 = 28-62 days). Although MeHg biotransformation varied widely between individuals, it showed a positive association with elimination rates across the cohort. A more than 2-fold change in kel over a period of 2 years was seen in some individuals. In 2 individuals, who received antibiotic for unrelated health issues, elimination rate was seen to slow significantly. Associations of kel with age, body mass index, gender, and fish eating habits were not observed. We establish that a measure of methylmercury metabolism and eliminaiton status (MerMES) can reduce uncertainty in determining an individual's MeHg toxicokinetics subsequent to eating fish.

Details of a thallium poisoning case revealed by single hair analysis using laser ablation inductively coupled plasma mass spectrometry

Heavy metals pose significant morbidity and mortality threats to humans in connection with both acute and chronic exposure. The often-delayed manifestations of some toxic effects and the wide-spectrum of symptoms caused by heavy metal poisoning may perplex the clinical diagnosis and, when involved in crimes, complicate the forensic investigation. To investigate the original intoxication process of a thallium poisoning case, which occurred in China more than two decades ago, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to analyze several hairs of the victim from before, during and after the poisoning period. Ablation line scans of the entire length of a ∼7cm hair revealed ∼4months of repeated exposure to thallium with increased doses and frequency toward the end, while scan of a ∼0.7cm hair revealed ∼2weeks of constant ingestions of large doses of thallium accompanied by elevated amount of lead. The endogenous origin of thallium was confirmed by the preservation of the same longitudinal distribution profile in the inner part of hair, but the source of lead could not be unambiguously determined due to the intrinsic limitation of hair analysis to distinguish ingested lead from exogenous contaminants. The overall thallium distribution profiles in the analyzed hairs suggested both chronic and acute thallium exposures that correlated well with the sequential presentation of a plethora of symptoms experienced by the victim. Aligning the time-resolved thallium peaks with symptoms also provided clues on possible routes of exposure at different poisoning stages. This work demonstrated the capability of using single hair LA-ICP-MS analysis to reconstitute a prolonged and complicated heavy metal poisoning case, and highlighted the necessity of assessing multiple elements in the medico-legal investigation of suspicious heavy metal poisonings.

Distribution and health risk assessment to heavy metals near smelting and mining areas of Hezhang, China

Mining and smelting areas in Hezhang have generated a large amount of heavy metals into the environment. For that cause, an evaluative study on human exposure to heavy metals including Co, Ni, Cu, Zn, Cr, As, Cd, Pb, Sb, Bi, Be, and Hg in hair and urine was conducted for their concentrations and correlations. Daily exposure and non-carcinogenic and carcinogenic risk were estimated. Sixty-eight scalp hair and 66 urine samples were taken from participants of different ages (6-17, 18-40, 41-60, and ≥ 65 years) living in the vicinity of an agricultural soil near mine and smelting areas. The results compared to the earlier studies showed an elevated concentration of Pb, Be, Bi, Co, Cr, Ni, Sb, and Zn in hair and urine. These heavy metals were more elevated in mining than in smelting. Considering gender differences, females were likely to be more affected than male. By investigating age differences in this area, high heavy metal concentrations in male's hair and urine existed in age of 18-40 and ≥ 66, respectively. However, females did not present homogeneous age distribution. Hair and urine showed a different distribution of heavy metals in different age and gender. In some cases, significant correlation was found between heavy metals in hair and urine (P > 0.05 and P > 0.01) in mining area. The estimated average daily intake of heavy metals in vegetables showed a great contribution compared to the soil and water. Non-carcinogenic and carcinogenic risk values of total pathways in mining and smelting areas were higher than 1 and exceeded the acceptable levels. Thus, the obtained data might be useful for further studies. They can serve as a basis of comparison and assessing the effect of simultaneous exposure from heavy metals in mining and smelting areas, and potential health risks from exposure to heavy metals in vegetables need more consideration.

Determination of arsenic and lead in single hair strands by laser ablation inductively coupled plasma mass spectrometry

The purpose of this study was to develop matrix-matched hair standards and a LA-ICP-MS technique for determination of the As and Pb in a single human hair using single spot scan mode. These results could subsequently be used to infer when the element entered the body. This study was conducted in two parts. First, a method was developed and validated for the elemental analysis of hair by LA-ICP-MS. A calibration strategy in LA-ICP-MS was developed using prepared matrix-matched laboratory hair standards doped with analytes of interest at a defined concentration. The use of hair strand standards enables calibration curves to be obtained by plotting the analyte ion (M⁺) intensity normalized to³⁴S⁺(the ratio M⁺/³⁴S⁺) as a function of the concentration determined by ICP-MS of the acidic digests. The linear correlation coefficients (R²) of the calibration curves for the analytes As and Pb were typically between 0.9970 and 0.9998, respectively. Second, an actual hair was measured using the developed method. The spatial distribution of As along the hair was observed in a hair sample from a leukaemia patient treated with arsenic trioxide (As₂O₃). The actual and estimated times over which the drug entered the body were compared and discussed.

Evidence of the direct adsorption of mercury in human hair during occupational exposure to mercury vapour

We have found clear evidence of direct adsorption of mercury in human hair after the occupational exposure to mercury vapour. We have performed both longitudinal analysis of human hair by laser ablation ICP-MS and speciation analysis by gas chromatography ICP-MS in single hair strands of 5 individuals which were occupationally exposed to high levels of mercury vapour and showed acute mercury poisoning symptoms. Hair samples, between 3.5 and 11cm long depending on the individual, were taken ca. three months after exposure. Single point laser ablation samples of 50μm diameter were taken at 1mm intervals starting from the root of the hairs. Sulfur-34 was used as internal standard. The ratio (202)Hg/(34)S showed a distinct pattern of mercury concentration with much lower levels of mercury near the root of the hair and high levels of mercury near the end of the hair. In all cases a big jump in the concentration of mercury in hair occurred at a given distance from the root, between 32 and 42mm depending on the individual, with a high and almost constant concentration of mercury for longer distances to the root. When we took into account the rate of hair growth in humans, 9-15mm/month, the jump in mercury concentration agreed approximately with the dates when the contamination occurred with the new growing hair showing much lower mercury concentration. In some cases the concentration of mercury at the tip of the hair was ca. 1000 times higher than that near the root. Additionally, speciation studies confirmed that mercury in all hair samples was present as inorganic mercury. The only explanation for these results was the direct adsorption of mercury vapour in hair at the time of exposure.

Mercury Accumulation in Harbour Seals from the Northeastern Pacific Ocean: The Role of Transplacental Transfer, Lactation, Age and Location

Mercury (Hg) bioaccumulates in the aquatic food chain in the form of methylmercury, a compound well known for its neurotoxicity. We analyzed total mercury (THg) in hair collected from 209 harbour seals captured at 10 sites in British Columbia (Canada) and Washington State (USA) between 2003 and 2010. In addition, laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) allowed for a highly refined analysis of THg accumulation over time by examining nine whiskers taken from 4- to 6-week-old pups. We estimate that THg concentrations in pups increased sharply at a point corresponding to mid- to late gestation of their time in utero (4.7 ± 0.8 and 6.6 ± 1.3 µg/g dry weight (dw), respectively), and then again at the onset of nursing (8.1 ± 1.3 µg/g dw). These abrupt changes highlight the importance of both pre- and post-natal THg transfer from the mother to the growing fetus and the newborn pup. While THg levels varied among sites, hair analyses from seals collected at the same site demonstrated the influence of age in THg accumulation with pups (5.3 ± 0.3 µg/g) and juveniles (4.5 ± 0.5 µg/g) having lower levels than those in adults (8.3 ± 0.8 µg/g). Our results revealed that 33 % of the pups sampled (n = 167) had THg levels that surpassed a mammalian hair threshold for neurochemical alterations. This study suggests that Hg could represent a health concern to marine wildlife, especially as atmospheric emissions of this toxic element from human activities in the Pacific Rim and worldwide continue.

Methods for Individualized Determination of Methylmercury Elimination Rate and De-Methylation Status in Humans Following Fish Consumption

Methylmercury (MeHg) exposure via fish in the diet remains a priority public health concern. Individual variation in response to a given MeHg exposure and the biotransformation of MeHg that follows complicate our understanding of this issue. MeHg elimination from the human body occurs slowly (elimination rate (kel) approximately 0.01 day(-1) or approximately 70 days half-life [t1/2]) and is a major determinant of the Hg body burden resulting from fish consumption. The underlying mechanisms that control MeHg elimination from the human body remain poorly understood. We describe here improved methods to obtain a MeHg elimination rate via longitudinal Hg analysis in hair using laser ablation-inductively coupled plasma-mass spectrometry. We measured MeHg elimination rates in eight individuals following the consumption of 3 fish meals in two 75-day trials separated by a 4-month washout period. In addition, since MeHg biotransformation to inorganic Hg (I-Hg) is associated with Hg excretion, we speciated Hg in feces samples to estimate individual MeHg de-methylation status. We observed a wide range of MeHg elimination rates between individuals and within individuals over time (kel = 0.0163-0.0054 day(-1); estimated t1/2 = 42.5-128.3 days). The ratio of MeHg and I-Hg in feces also varied widely among individuals. While the %I-Hg in feces was likely influenced by dental amalgams, findings with subjects who lacked amalgams suggest that faster MeHg elimination is associated with a higher %I-Hg in feces indicating more complete de-methylation. We anticipate these methods will contribute to future investigations of genetic and dietary factors that influence MeHg disposition in people.

Using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to characterize copper, zinc and mercury along grizzly bear hair providing estimate of diet

We enhanced an existing technique, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), to function as a non-lethal tool in the temporal characterization of trace element exposure in wild mammals. Mercury (Hg), copper (Cu), cadmium (Cd), lead (Pb), iron (Fe) and zinc (Zn) were analyzed along the hair of captive and wild grizzly bears (Ursus arctos horribilis). Laser parameters were optimized (consecutive 2000 μm line scans along the middle line of the hair at a speed of 50 μm/s; spot size=30 μm) for consistent ablation of the hair. A pressed pellet of reference material DOLT-2 and sulfur were used as external and internal standards, respectively. Our newly adapted method passed the quality control tests with strong correlations between trace element concentrations obtained using LA-ICP-MS and those obtained with regular solution-ICP-MS (r(2)=0.92, 0.98, 0.63, 0.57, 0.99 and 0.90 for Hg, Fe, Cu, Zn, Cd and Pb, respectively). Cross-correlation analyses revealed good reproducibility between trace element patterns obtained from hair collected from the same bear. One exception was Cd for which external contamination was observed resulting in poor reproducibility. In order to validate the method, we used LA-ICP-MS on the hair of five captive grizzly bears fed known and varying amounts of cutthroat trout over a period of 33 days. Trace element patterns along the hair revealed strong Hg, Cu and Zn signals coinciding with fish consumption. Accordingly, significant correlations between Hg, Cu, and Zn in the hair and Hg, Cu, and Zn intake were evident and we were able to develop accumulation models for each of these elements. While the use of LA-ICP-MS for the monitoring of trace elements in wildlife is in its infancy, this study highlights the robustness and applicability of this newly adapted method.

The effect of plasma reactions on arsenic measurement by ICP spectrometry

Inductively coupled plasma mass spectrometry (ICP-MS) is of great value to researchers concerned with inorganic analytical chemistry as well as to engineers performing elemental analysis. However, the effects of the plasma reactions on ICP spectrometry are still incompletely understood and they sometimes introduce severe problems for measurements, such as spectral interferences. When we determine arsenic (As) by ICP-MS or ICP-AES, we observe two interesting plasma phenomena; one is the incoherent molecular formation (IMF) effect in the plasma, and the other the selective and partial oxygenation of ions with O2 gas in a dynamic reaction cell. The mechanisms of the IMF effect and selective oxygenation of As with a reaction gas were investigated and the techniques to remove their influence on As determination are discussed.

Grizzly bear hair reveals toxic exposure to mercury through salmon consumption

Mercury obtained from the diet accumulates in mammalian hair as it grows thus preserving a record of mercury intake over the growth period of a given hair segment. We adapted a microanalysis approach, using laser ablation inductively coupled plasma mass spectrometry, to characterize temporal changes in mercury exposure and uptake in wild and captive grizzly bears. Captive grizzlies fed diets containing known and varied amounts of mercury provided data to allow prediction of Hg ingestion rates in wild bears. Here, we show, for the first time, that 70% of the coastal grizzly bears sampled had Hg levels exceeding the neurochemical effect level proposed for polar bears. In a context where the international community is taking global actions to reduce Hg emissions through the "Minamata Convention on Mercury", our study provides valuable information on the exposure to mercury of these grizzly bears already under many threats.

Hair analysis as a biomonitor for toxicology, disease and health status

Hair analysis receives a large amount of academic and commercial interest for wide-ranging applications. However, in many instances, especially for elemental or 'mineral' analysis, the degree of success of analytical interpretation has been quite minimal with respect to the extent of such endeavors. In this critical review we address the questions surrounding hair analysis with specific intent of discovering what hair concentrations can actually relate to in a biogenic sense. This is done from a chemistry perspective to explain why and how elements are incorporated into hair and their meaning. This includes an overview of variables attributed to altering hair concentrations, such as age, gender, melanin content, and other less reported factors. Hair elemental concentrations are reviewed with regard to morbidity, with specific examples of disease related effects summarized. The application of hair analysis for epidemiology and etiology studies is enforced. A section is dedicated specifically to the area of population studies with regards to mercury, which highlights how endogenous and exogenous incorporation relies on species dependant metabolism and metabolic products. Many of the considerations are relevant to other areas of interest in hair analysis, such as for drug and isotopic analysis. Inclusion of a table of elemental concentrations in hair should act as a valuable reference (298 references).

Biomonitoring of essential and toxic metals in single hair using on-line solution-based calibration in laser ablation inductively coupled plasma mass spectrometry

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been established as a powerful and sensitive surface analytical technique for the determination of concentration and distribution of trace metals within biological systems at micrometer spatial resolution. LA-ICP-MS allows easy quantification procedures if suitable standard references materials (SRM) are available. In this work a new SRM-free approach of solution-based calibration method in LA-ICP-MS for element quantification in hair is described. A dual argon flow of the carrier gas and nebulizer gas is used. A dry aerosol produced by laser ablation (LA) of biological sample and a desolvated aerosol generated by pneumatic nebulization (PN) of standard solutions are carried by two different flows of argon as carrier or nebulizer gas, respectively and introduced separately in the injector tube of a special ICP torch, through two separated apertures. Both argon flows are mixed directly in the ICP torch. External calibration via defined standard solutions before analysis of single hair was employed as calibration strategy. A correction factor, calculated using hair with known analyte concentration (measured by ICP-MS), is applied to correct the different elemental sensitivities of ICP-MS and LA-ICP-MS. Calibration curves are obtained by plotting the ratio of analyte ion M(+)/(34)S(+) ion intensities measured using LA-ICP-MS in dependence of analyte concentration in calibration solutions. Matrix-matched on-line calibration in LA-ICP-MS is carried out by ablating of human hair strands (mounted on a sticky tape in the LA chamber) using a focused laser beam in parallel with conventional nebulization of calibration solutions. Calibrations curves of Li, Na, Mg, Al, K, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Sr, Mo, Ag, Cd, I, Hg, Pb, Tl, Bi and U are presented. The linear correlation coefficients (R) of calibration curves for analytes were typically between 0.97 and 0.999. The limits of detection (LODs) of Li, V, Mn, Ni, Co, Cu, Sr, Mo, Ag, Ba, Cd, I, Hg, Pb, Bi and U in a single hair strand were in the range of 0.001-0.90 μg g(-1), whereas those of Cr and Zn were 3.4 and 5.1 μg g(-1), respectively. The proposed quantification strategy using on-line solution-based calibration in LA-ICP-MS was applied for biomonitoring (the spatial resolved distribution analysis) of essential and toxic metals and iodine in human hair and mouse hair.

Laser ablation-inductively coupled plasma mass spectrometry in archaeometric research

Laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) is a solid sampling technique in continuous expansion in all types of research fields in which direct multi-elemental or isotopic analysis is required. In particular, this technique shows unique characteristics that made its use recommended in many archaeometric applications, where valuable solid artifacts are often the target samples, because it offers flexibility to achieve spatially resolved information with high detection power and a wide linear range, in a fast and straightforward way, and with minimal sample damage. The current review provides a systematic survey of publications that reported the use of LA-ICPMS in an archaeological context, highlights its main capabilities and limitations and discusses the most relevant parameters that influence the performance of this technique for this type of application.

Aluminium, cadmium and lead concentration in the hair of tobacco smokers

In the research, the contents of heavy metals, Al, Cd and Pb, in the hair of individuals who reside in similar environmental conditions were spectrometrically determined with the use of atomic emission spectrometry–inductively coupled plasma spectrophotometer. The relation to their tobacco smoking habit, age and sex was established. It was observed that the level of all three determined elements was generally higher in the hair of smokers in comparison to hair of non-smokers in both younger and older age groups. In addition, it has been observed that, in the group of elderly people over 50 years old, there was an increase in the content of aluminium, cadmium and lead both in smokers and non-smokers, irrespective of their sex. The sex-related differences in the content of the investigated elements were not unidirectional, and only in few cases did they reveal statistical significance.

Trace element profiles in single strands of human hair determined by HR-ICP-MS

Trace element analysis of human hair has the potential to reveal retrospective information about an individual's nutritional status and exposure. As trace elements are incorporated into the hair during the growth process, longitudinal segments of the hair may reflect the body burden during the growth period. We have evaluated the potential of human hair to indicate exposure or nutritional status over time by analysing trace element profiles in single strands of human hair. The hair strands from five healthy and occupationally unexposed subjects were cut into 1-cm long segments starting from the scalp. By using high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS), we achieved profiles of 12 elements in single strands of human hair, namely, Ag, As, Au, Cd, Cu, Hg, Fe, Pb, Se, Sr, U and Zn. We have shown that trace element analysis along single strands of human hair can yield information about essential and toxic elements, and for some elements, can be correlated with seasonal changes in diet and exposure. The information obtained from the trace element profiles of human hair in this study substantiates the potential of hair as a biomarker.

History of individuals of the 18th/19th centuries stored in bones, teeth, and hair analyzed by LA-ICP-MS--a step in attempts to confirm the authenticity of Mozart's skull

A cranium stored in the Stiftung Mozarteum in Salzburg/Austria which is believed to be that of Mozart, and skeletal remains of suspected relatives which have been excavated from the Mozart family grave in the cemetery in Salzburg, have been subjected to scientific investigations to determine whether or not the skull is authentic. A film project by the Austrian television ORF in collaboration with Interspot Film on this issue was broadcast at the beginning of the "Mozart year 2006". DNA analysis could not clarify relationships among the remains and, therefore, assignment of the samples was not really possible. In our work this skull and excavated skeletal remains have been quantified for Pb, Cr, Hg, As, and Sb content by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to obtain information about the living conditions of these individuals. A small splinter of enamel (less than 1 mm(3)) from a tooth of the "Mozart cranium" was also available for investigation. Quantification was performed by using spiked hydroxyapatite standards. Single hair samples which are recorded to originate from Mozart have also been investigated by LA-ICP-MS and compared with hair samples of contemporary citizens stored in the Federal Pathologic-Anatomical Museum, Vienna. In general, Pb concentrations up to approximately 16 mug g(-1) were found in the bone samples of 18th century individuals (a factor of 7 to 8 higher than in recent samples) reflecting elevated Pb levels in food or beverages. Elevated Pb levels were also found in hair samples. The amount of Sb in the enamel sample of the "Mozart cranium" (approx. 3 mug g(-1)) was significantly higher than in all the other tooth samples investigated, indicating possible Sb ingestion in early childhood. Elevated concentrations of elements in single hair samples gave additional information about possible exposure of the individuals to heavy metals at a particular point in their life.

Analysis of mercury in sequential micrometer segments of single hair strands of fish-eaters

Although it has been established that mercury (Hg) can be detected in single hair strands using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), calibration remains a challenge due to the lack of well-characterized matrix-matched standards. We concurrently evaluated two strategies for quantifying Hg signals in single hair strands using LA-ICP-MS. The main objective was to obtain time-resolved Hg concentrations in single hair strands of fish-eaters that would correspond to the changes of their body burden over time. Experiments were conducted using hair samples collected from 10 individuals. The first experiment involved the construction of a calibration curve with four powdered hair standard reference materials (SRMs) with a range of Hg concentrations (0.573-23.2 mg/kg). An internal standard, sulfur, as 34S, was applied to correct for ablation efficiency for both the hair strands and the SRMs. Results showed a linear relationship (R2 = 0.899) between the ratio of 202Hg to 34S obtained by LA-ICP-MS and the certified total Hg concentration in the SRMs. Using this calibration curve, average Hg concentrations of 10 shots within a 1-cm segment of a hair strand were calculated and then compared to the total Hg concentrations in the matched 1-cm segment as measured by cold vapor atomic absorption spectrometry (CV-AAS). A significant difference (p < 0.05) was observed. The difference could be attributed to the highly variable ablation/sampling process caused by the use of the laser on the hair powder SRM pellets and the difference in the physical properties of the SRMs. An alternative approach was adopted to quantify consecutive 202Hg to 34S ratios by calibrating the signals against the average Hg concentration of the matched hair segment as measured by CV-AAS. Consecutive daily Hg deposition in single hairs of fish eaters was determined. Results showed that apparent daily changes in Hg concentrations within a hair segment that corresponds to 1 month of hair growth. In addition, a significant decreasing or increasing time-trend was observed. The difference between the minimum and maximum Hg concentration within each individual corresponded to a change of 26-40%. Our results showed that LA-ICP-MS can be used to reconstruct time-resolved Hg exposure in micrometer segments of a single hair strand.

State of the art in hair analysis for detection of drug and alcohol abuse

Hair differs from other materials used for toxicological analysis because of its unique ability to serve as a long-term storage of foreign substances with respect to the temporal appearance in blood. Over the last 20 years, hair testing has gained increasing attention and recognition for the retrospective investigation of chronic drug abuse as well as intentional or unintentional poisoning. In this paper, we review the physiological basics of hair growth, mechanisms of substance incorporation, analytical methods, result interpretation and practical applications of hair analysis for drugs and other organic substances. Improved chromatographic-mass spectrometric techniques with increased selectivity and sensitivity and new methods of sample preparation have improved detection limits from the ng/mg range to below pg/mg. These technical advances have substantially enhanced the ability to detect numerous drugs and other poisons in hair. For example, it was possible to detect previous administration of a single very low dose in drug-facilitated crimes. In addition to its potential application in large scale workplace drug testing and driving ability examination, hair analysis is also used for detection of gestational drug exposure, cases of criminal liability of drug addicts, diagnosis of chronic intoxication and in postmortem toxicology. Hair has only limited relevance in therapy compliance control. Fatty acid ethyl esters and ethyl glucuronide in hair have proven to be suitable markers for alcohol abuse. Hair analysis for drugs is, however, not a simple routine procedure and needs substantial guidelines throughout the testing process, i.e., from sample collection to results interpretation.