Comparison of representative ranges based on U.S. patient population and literature reference intervals for urinary trace elements

Trimester-Specific Urinary Strontium Concentrations during Pregnancy and Longitudinally Assessed Fetal Growth: Findings from a Prospective Cohort

BACKGROUND

Studies have claimed that strontium (Sr) is associated with fetal growth, but the research evidence is insufficient.

OBJECTIVES

Our study aimed to evaluate associations of trimester-specific urinary Sr concentrations with fetal growth parameters and birth size indicators.

METHODS

In this prospective cohort, 9015 urine samples (first trimester: 3561, 2nd trimester: 2756, 3rd trimester: 2698) from 3810 mothers were measured for urinary Sr levels using inductively coupled plasma mass spectrometry (ICP-MS) and adjusted to urine specific gravity. We calculated standard deviation scores (SD-scores) for ultrasound-measured fetal growth parameters (head circumference, abdominal circumference, femur length, and estimated fetal weight) at 16, 24, 31, and 37 wk of gestation and birth size indicators (birth weight, birth length, and Ponderal index). Generalized linear models and generalized estimating equations models were used. Models were adjusted for potential covariates (gestational age, maternal age, body mass index, parity, passive smoking during pregnancy, education, folic acid supplements use, physical activity, maternal and paternal height, and infant sex).

RESULTS

Positive associations of naturally logarithm-transformed Sr concentrations with fetal growth parameters and birth size indicators were observed. With each doubling increase in the urinary ln-Sr level in all 3 trimesters resulting in a percent change in SD-scores fetal growth parameters at 24, 31, and 37 wk of gestation and birth size indicators, 5.09%-8.23% in femur length, 7.57%-11.53% in estimated fetal weight, 6.56%-10.42% in abdominal circumference, 6.25% in head circumference, 5.15%-7.85% in birth weight, and 5.71%-9.39% in birth length, respectively. Most of the above statistical results could only be observed in male fetuses.

CONCLUSIONS

Our findings suggest a potential association between Sr concentration and increased fetal growth, but these results and underlying mechanisms need further confirmation and clarification.

The variability of arsenic in blood and urine of humans

BACKGROUND

Humans are exposed to inorganic and organic arsenic. The total arsenic (As) concentration in urine is a commonly used biomarker of exposure. However, little is known about variability of As in biological fluids and the diurnal variation of As excretion.

OBJECTIVES

Main objectives were to assess the variability of As in urine, plasma (P-As), whole blood (B-As), and the blood cell fraction (C-As), and to assess diurnal variation of As excretion.

METHODS

Six urine samples were collected at fixed times during 24 h on two different days around one week apart among 29 men and 31 women. Blood samples were collected when the morning urine samples were delivered. The intra-class correlation coefficient (ICC) was calculated as the ratio of the between-individuals variance to the total observed variance.

RESULTS

Geometric mean (GM) 24 h urinary excretions of As (U-As_24 h) were 41 and 39 µg/24 h on the two days of sampling. Concentrations of B-As, P-As and C-As were highly correlated with U-As_24 h and As in first void morning urine. No statistically significant differences were observed for the urinary As excretion rate between the different sampling times. A high ICC was observed for As in the cellular blood fraction (0.803), while ICC for first morning urine corrected for creatine was low (0.316).

CONCLUSIONS

The study suggests that C-As is the most reliable biomarker for use in exposure assessment of individual exposure. Morning urine samples have low reliability for such use. No apparent diurnal variation was observed in the urinary As excretion rate.

Associations of co-exposure to polycyclic aromatic hydrocarbons and metals with hyperuricemia risk in Chinese coke oven workers: Mediating roles of oxidative damage

Ubiquitous polycyclic aromatic hydrocarbons (PAHs) and metals could induce hyperuricemia and oxidative damage individually, while their co-exposure effects on hyperuricemia risk and the potential roles of oxidative damage in these health outcomes remain poorly understood. We conducted a cross-sectional study in 1379 coke oven workers. We evaluated the levels of PAH-metal exposure and oxidative damage by urinary monohydroxy-PAHs, plasma benzo [a]pyrene-7,8-diol-9,10-epoxide-albumin (BPDE-Alb) adducts, urinary metals, urinary 8-iso-prostaglandin-F2α, and urinary 8-hydroxydeoxyguanosine (8-OH-dG). The subjects were classified into cases of hyperuricemia and controls by the levels of blood uric acid. We found that the sum of multiple hydroxyphenanthrene (ΣOH-Phe) was robustly associated with the increase in hyperuricemia risk, while rubidium and strontium had robust protective associations with hyperuricemia risk (P_trend<0.05). The risk association of ΣOH-Phe was weaker in workers with high levels of rubidium and strontium [P for modifying effect (P_ME) < 0.030]. The protective association of strontium was more pronounced in workers with higher ΣOH-Phe (P_ME = 0.014). We also found that 8-OH-dG was a risk factor for hyperuricemia (P_trend = 0.006) and mediated 10.13% of the elevated hyperuricemia risk associated with ΣOH-Phe. Our findings suggested that individual PAHs and metals, as well as their co-exposure, may influence hyperuricemia risk among coke oven workers, with oxidative DNA damage playing a potential mediating role in their associations.

Effects of Bismuth Exposure on the Human Kidney-A Systematic Review

The effects of bismuth toxicity on the kidney-the main organ responsible for blood filtration-were systematically reviewed. This review was motivated by availability of several sources of bismuth in contact with humans including environmental, medications, dental materials, and cosmetics, potentially leading to kidney filtration of this chemical. No previous studies have systematically reviewed the literature considering this association. A total of 22 studies with a total of 46 individuals met the inclusion criteria, 19 being case reports with only one patient enrolled. The included studies publication dates ranged from 1961 to 2021 and the countries of publication were the United States of America, United Kingdom, Germany, Turkey, Switzerland, and Canada. Bismuth sources affecting the kidneys were uniquely reported as from medical purposes and mostly associated to overdoses with several symptoms, apparently with dose-dependent consequences. Patient history of renal impairment seemed to affect the outcome of the case. Several therapies were conducted following bismuth intoxication, and few studies performed renal biopsies describing its histological findings. It is crucial to reconsider the nephrotoxicity of bismuth compounds, mainly in patients with previous history of renal impairment.

Associations between urinary heavy metal concentrations and blood pressure in residents of Asian countries

BACKGROUND

Previous studies have suggested that exposures to heavy metals (arsenic, cadmium, lead, and selenium) may be associated with differences in blood pressure. However, the findings of these studies have been inconsistent. This study was performed to examine the associations between urinary heavy metal concentrations and blood pressure among residents of four Asian countries (Bangladesh, Indonesia, Nepal, and Vietnam).

METHODS

This cross-sectional study examined 1899 adults in four Asian countries. Urinary concentrations of heavy metals were measured by inductively coupled plasma mass spectrometry. A questionnaire survey was administered regarding individual characteristics. Anthropometric measurements (height and weight) were performed. Systolic and diastolic blood pressures were measured after a short rest. Multiple linear regression models were applied to investigate associations between urinary heavy metal concentrations and blood pressure after adjustments for age, sex, and body mass index.

RESULTS

The geometric means of the urinary concentrations of arsenic, cadmium, lead, and selenium were 84.6, 0.885, 2.09, and 16.5 μg/g creatinine, respectively. The urinary arsenic concentrations were slightly higher than those typically reported in non-polluted populations, while urinary cadmium, lead, and selenium concentrations were equivalent or slightly lower. The urinary lead concentrations were positively associated with both systolic and diastolic blood pressure, but urinary selenium concentrations were negatively associated with them.

CONCLUSIONS

Variations in the urinary concentrations of lead and selenium were associated with blood pressure at low levels of exposure/intake.

Impact of modernization on urinary concentrations of arsenic, cadmium, lead, and selenium in rural residents of Northern Laos

OBJECTIVES

The impacts of modernization on toxic heavy metal exposure and essential trace element intake in indigenous populations of subsistence societies are unknown. We assessed urinary trace element concentrations in rural residents of Northern Laos and examined associations with levels of modernization.

METHODS

A cross-sectional study was conducted comprising 380 residents of three villages in Northern Laos with different levels of modernization. We surveyed general characteristics and measured the weight and height of 341 participants. Arsenic, cadmium, lead, and selenium concentrations were measured in spot urine samples by inductively coupled plasma mass spectrometry. We examined associations between urinary trace element concentrations and variables related to modernization (village, roofing material, possessions index [total number of possessions], and body mass index [BMI]) using multilevel analyses with household as a random effect, after adjusting for sex, age, and smoking status.

RESULTS

Urinary concentrations of arsenic and cadmium were high, while those of lead and selenium were low in comparison to previous reports of populations in non-contaminated regions or without excess/deficiency. We observed associations between urinary trace element concentrations and village-level modernization: lead and selenium concentrations were higher in more modernized villages and cadmium concentration was highest in the least modernized village. Urinary arsenic concentration was not predicted by the modernization level of a village, although we observed significant differences among villages. In addition, urinary selenium concentration was higher in participants inhabiting more modernized houses.

CONCLUSION

Modernization of villages may impact toxic heavy metal exposure and selenium intake in rural residents of Northern Laos.

Development and validation of a biomonitoring method to measure As, Cr, and Ni in human urine samples by ICP-UCT-MS

We developed an inductively coupled plasma mass spectrometry (ICP-MS) method using Universal Cell Technology (UCT) with a PerkinElmer NexION ICP-MS, to measure arsenic (As), chromium (Cr), and nickel (Ni) in human urine samples. The advancements of the UCT allowed us to expand the calibration range to make the method applicable for both low concentrations of biomonitoring applications and high concentrations that may be observed from acute exposures and emergency response. Our method analyzes As and Ni in kinetic energy discrimination (KED) mode with helium (He) gas, and Cr in dynamic reaction cell (DRC) mode with ammonia (NH₃) gas. The combination of these elements is challenging because a carbon source, ethanol (EtOH), is required for normalization of As ionization in urine samples, which creates a spectral overlap (⁴⁰Ar¹²C⁺) on ⁵²Cr. This method additionally improved lab efficiency by combining elements from two of our previously published methods(Jarrett et al., 2007; Quarles et al., 2014) allowing us to measure Cr and Ni concentrations in urine samples collected as part of the National Health and Nutrition Examination Survey (NHANES) beginning with the 2017-2018 survey cycle. We present our rigorous validation of the method selectivity and accuracy using National Institute of Standards and Technology (NIST) Standard Reference Materials (SRM), precision using in-house prepared quality control materials, and a discussion of the use of a modified UCT, a BioUCell, to address an ion transmission phenomenon we observed on the NexION 300 platform when using higher elemental concentrations and high cell gas pressures. The rugged method detection limits, calculated from measurements in more than 60 runs, for As, Cr, and Ni are 0.23 μg L-1, 0.19 μg L-1, and 0.31 μg L-1, respectively.

Normal variability of 22 elements in 24-hour urine samples - Results from a biobank from healthy non-smoking adults

BACKGROUND

Urine is often used for biomonitoring the exposure to elements. However, most studies report concentrations in spot urine samples, which may not accurately mirror the "gold standard" of complete 24-h (24 h) urine samples. There are relatively few data published for 24 h samples, and little information on the within- and between person variability.

OBJECTIVES

The present study aimed at assessing variability within and between individuals in 24 h excretion for a number of elements in adults from the general population and the typical 24 h excretion of these elements. In addition, we assessed concentrations adjusted for creatinine and specific gravity (SG), and associations between elements.

METHODS

60 healthy non-smokers (31 women and 29 men) from Sweden, aged 21-64 years, collected all urine during 24 h (split into six separate samples) on two occasions, about one week apart. Concentrations of As, Br, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, P, Pb, S, Sb, Se, Sn, U, V, W, and Zn in urine were analyzed by inductively coupled plasma sector-field mass spectrometry (ICP-SF-MS) and 24 h excretion rates were calculated for each day. The ratio of between-individual variance and the total variance, the intra-class correlation (ICC) was calculated based on natural log-transformed 24 h excretion. Correlation coefficients were calculated between excretion rates (mass/24 h), and concentrations adjusted for creatinine and SG.

RESULTS

Geometric means (GM), and 90-percentiles are presented for each element. The 24 h excretion was higher in men than in women for most elements, and the difference was statistically significant for Cr, Cu, Fe, Li, P, Pb, S, Se, U, V, and Zn. However, for Cd and Co, the excretion was higher in women. Variability between days was low for Cd, Co, Hg, Pb, Sn, Se, V, and Zn (ICC 0.75-0.90), highest for Cr (ICC = 0.3) and Sb (ICC = 0.18), and moderate for the other elements. Spearman's rank correlation coefficients were about 0.8-0.9 for 17 elements, and 0.3-0.7 for Br, Cu, P, S, Se. Excretion of P and S were highly correlated, and also associated with excretion of most of the other elements, especially Cu, Se, V, and Zn. A high correlation was also found between As and Hg, between Mo and W, as well as between Cr, Fe and Mn.

CONCLUSIONS

These data present normal variability of 24 h excretion of a number of elements, and can also be used as updated reference levels for elements with no or limited previous literature available. Information on variability within- and between individuals is important to know when designing studies with urine levels of elements used as exposure biomarker in studies of associations with health outcomes.

Urinary biomarker of strontium exposure is positively associated with semen quality among men from an infertility clinic

Experimental studies have shown that nonradioactive strontium (Sr), in the form of Sr²⁺, have a positive effect on semen quality, but human evidence is lacking. This study aimed to examine the associations between nonradioactive Sr exposure and semen quality in Chinese men (n = 394). We recruited men who presented at an infertility clinic in Wuhan, China to seek for semen parameter analyses. Urinary Sr concentration as an exposure biomarker was measured using inductively coupled plasma mass spectrometer. We estimated the associations between urinary Sr concentrations and semen parameters using multivariable logistic and linear regression models. In multivariable linear regressions models, positive dose-response associations were estimated for sperm concentration, motility, and count across increasing urinary Sr quartiles (all p for trends<0.05), and the consistent positive associations were also observed for urinary Sr concentration modeled as a continuous exposure. In multivariable logistic models, decreased risks of below-reference sperm concentration, motility, and count were also estimated across increasing urinary Sr quartiles (all p for trends<0.05). Our results suggest that nonradioactive Sr exposure may have a beneficial effect on semen quality, but more investigations are warranted to confirm the results.

Urinary profiles of selected metals and arsenic and their exposure pathway analysis in four large floodplains of Pakistan

In context of fragile geological conditions and rapid urbanization, element exposure via dietary (food, water) and non-dietary (dust, soil) routes into human population at different land use settings is a major concern in the Indus floodplains (FPs) of Pakistan. In current study, several important trace elements including arsenic (As), chromium (Cr), manganese (Mn), cobalt (Co), cadmium (Cd), nickel (Ni), copper (Cu) and lead (Pb) were analyzed in the paired human urine, food, water and dust samples collected from main FPs of Pakistan. Daily intake estimation and regression analysis were used to evaluate the relationships between internal exposure, exposure routes of studied trace elements and different land use settings. High concentrations of urinary As, Cr, Cu, Mn, and Cd were detected in the general male population of the studied floodplains (FPs). Moreover, the levels (μg/L) of urinary As increased gradually from FP1 (12.8), FP2 (18), FP3 (61) to FP4 (71). Regression analysis showed that As contaminated water was correlated with elevated urinary As concentrations in FP3 and FP4, and water Cr and Mn was significantly associated with urinary Cr and Mn concentrations in FP2. Moreover, the associations of food Mn and urinary Mn were found in FP1. Over all, cumulative estimated daily intake (EDI) values from water, dust and food from all the flood plains showed that Mn had the highest values (6.6, 9.2, 14.4 μg/kg/day) followed by water As (1.98 μg/kg/day), dust Cu (1.5 μg/kg/day) and Pb (1.7 μg/kg/day). Studied floodplains were moderately to highly polluted in terms of studied trace elements (As, Cr, Cu, Mn, and Cd) contamination especially in FP3 and FP4. The results will contribute to improve the knowledge and information on current exposure of Pakistani male adults to the different contaminants.

Metal Concentration Assessment in the Urine of Cigarette Smokers Who Switched to Electronic Cigarettes: A Pilot Study

Background: E-cigarettes (ECs) seem to be a less harmful alternative for conventional cigarettes, however, very little is still known about the exposure to some elements, which are the components of this device and may contaminate the nicotine liquid. The aim of this study is to assess whether e-cigarette users are more exposed to 12 elements detected in aerosol than non-smokers and conventional cigarette smokers, using their concentrations in urine as exposure biomarkers. Methods: A cross-sectional, group-based survey was carried out using 90 volunteers classified into groups of non-smokers, EC-only users, dual EC users-cigarette smokers and cigarette-only smokers. Using inductively coupled plasma mass spectrometry (ICP-MS) and electrothermal atomic absorption spectrometry (ETAAS), Cr, Ni, Co, Ag, In, Mn, Ba, Sr, V, Sb, Cd and Pb levels were measured in spot urine samples. Among the selected groups, a comparison was made using the analysis of covariance and correlations with EC usage pattern were assessed by multiple linear regression. Results: Element concentrations in urine of EC-users were not significantly different from the levels found in non-smokers and smokers. Only in the case of Ba, Ni and Sb was a significant correlation found in relation to some e-cigarette usage patterns. Conclusion: Transfer of the investigated elements to the EC aerosol was not found to be a substantial source of exposure in EC users who quitted smoking.

Association between serum thallium in early pregnancy and risk of gestational diabetes mellitus: The Ma'anshan birth cohort study

BACKGROUND

High blood glucose has been noted in case reports of acute thallium poisoning, however, effects of low-level exposure of thallium on risk of gestational diabetes mellitus (GDM) has not been explored yet.

OBJECTIVES

We aimed to explore the association of serum thallium concentration (STC) in early pregnancy and risk of GDM.

METHODS

Data of 3013 women from the Ma'anshan birth cohort study (MABC), China was used. STC was measured by inductively coupled plasma mass spectrometry (ICP-MS). Multivariate logistic regression was performed to the association of STC and risk of GDM. Stratified analysis was carried out according to maternal age and pre-pregnancy BMI.

RESULTS

We documented 383 incident GDM (12.7%). The STC ranged from 0.011 to 0.232 μg/L with a median of 0.062 μg/L. Women with advanced age and higher pre-pregnancy BMI tended to have higher level of STC. Individuals in GDM-group have higher level of STC than that in non-GDM group (P =  0.007). Maternal STC in early pregnancy was associated with risk of GDM, but the association attenuated to non-significance after adjusted for pre-pregnancy BMI. In the advanced age (>30 years) group, STC was significantly associated with risk of GDM in a dose-response manner (P for trend <0.05). Compared with the Quintile 1, the odds ratios (ORs) (95% confidence interval, CI) of Quintile 2, Quintile 3, Quintile 4, and Quintile 5 were 1.48 (0.62-3.53), 2.70 (1.21-6.03), 2.85 (1.29-6.31), 2.30 (1.05-5.05) in the most adjusted model (including pre-pregnancy BMI).

CONCLUSIONS

Our study was the first study to demonstrate an association of maternal STC in early pregnancy and risk of GDM, and the association was partly mediated by pre-pregnancy BMI. This association exhibited as an age-dependent manner. Our study highlights even very low-level of thallium exposure could already pose a threat to human's health.

The cross-sectional and longitudinal associations of chromium with dyslipidemia: A prospective cohort study of urban adults in China

Chromium exposure can induce altered lipoprotein metabolism in animals, but the health effects of chromium on dyslipidemia in humans have not been fully evaluated. In this study, we aimed to investigate the cross-sectional and longitudinal effects of urinary chromium on lipid levels and dyslipidemia risk among urban adults from two cities in China. A total of 3762 urban adults from the Wuhan-Zhuhai cohort were included in the initial investigation, and followed up three years later. Urinary chromium concentration was measured at baseline and repeated at follow-up. Associations of urinary chromium concentration with lipid levels and risk of dyslipidemia were analyzed by generalized linear and binary logistic regression models, respectively. We found significant relationships between increased urinary chromium concentration and both reduced triglyceride (TG) level and elevated high-density lipoprotein cholesterol (HDL-C) level at baseline and follow-up. In the cross-sectional analysis, each 1-unit increase in log-transformed urinary chromium was associated with a 0.25 mmol/L decrease in TG and a 0.05 mmol/L increase in HDL-C (P < 0.05); also, downward trends for odds ratios of hyperTG (TG level ≥ 1.7 mmol/L) and hypoHDL-C (HDL-C level < 1.0 mmol/L) were significantly associated with increasing quartiles of urinary chromium (P trend < 0.05). In the longitudinal analysis, each 1-unit increase in log-transformed urinary chromium concentration was associated with a 3% and 6% decrease in the risk of developing hyperTG and hypoHDL-C, respectively (P > 0.05). Our study indicated that significant dose-response relationships between urinary chromium concentration and lipid levels were observed at baseline and at follow-up.

Chromium in Postmortem Material

Recently, considerable attention has been paid to the negative effects caused by the presence and constant increase in concentration of heavy metals in the environment, as well as to the determination of their content in human biological samples. In this paper, the concentration of chromium in samples of blood and internal organs collected at autopsy from 21 female and 39 male non-occupationally exposed subjects is presented. Elemental analysis was carried out by an electrothermal atomic absorption spectrometer after microwave-assisted acid digestion. Reference ranges of chromium in the blood, brain, stomach, liver, kidneys, lungs, and heart (wet weight) in the population of Southern Poland were found to be 0.11-16.4 ng/mL, 4.7-136 ng/g, 6.1-76.4 ng/g, 11-506 ng/g, 2.9-298 ng/g, 13-798 ng/g, and 3.6-320 ng/g, respectively.

Environmental tin exposure in a nationally representative sample of U.S. adults and children: The National Health and Nutrition Examination Survey 2011-2014

Tin is a naturally occurring heavy metal that occurs in the environment in both inorganic and organic forms. Human exposure to tin is almost ubiquitous; however, surprisingly little is known about factors affecting environmental tin exposure in humans. This study analyzed demographic, socioeconomic and lifestyle factors associated with total urinary tin levels in adults (N = 3522) and children (N = 1641) participating in the National Health and Nutrition Examination Survey (NHANES) 2011-2014, a nationally representative health survey in the United States. Urinary tin levels, a commonly used biomarker of environmental tin exposure, were determined by inductively coupled plasma mass spectrometry (ICP-MS). Detection frequencies of tin were 87.05% in adults and 91.29% in children. Median and geometric mean levels of urinary tin in the adult population were 0.42 μg/L and 0.49 μg/L, respectively. For children, median and geometric mean levels of urinary tin were 0.60 μg/L and 0.66 μg/L, respectively. Age was identified as an important factor associated with urinary tin levels. Median tin levels in the ≥60 year age group were almost 2-fold higher than the 20-39 year age group. Tin levels in children were 2-fold higher than in adolescents. Race/ethnicity and household income were associated with tin levels in both adults and children. In addition, physical activity was inversely associated with urinary tin levels in adults. These results demonstrate that total tin exposures vary across different segments of the general U.S.

POPULATION

Because the present study does not distinguish between organic and inorganic forms of tin, further studies are needed to better characterize modifiable factors associated with exposures to specific tin compounds, with the goal of reducing the overall exposure of the U.S.

POPULATION

Human biomonitoring of eight trace elements in urine of residents living in rural areas along the Yangtze River, China

The rapid economic development and industrialization have made heavy metal contamination a great public concern, especially in China. However, the levels of heavy metals in human body, especially those susceptible to the effect of industrial progression, are rarely explored. In this study, eight elements in 2643 urinary samples of individuals living in rural areas along the Yangtze River were determined through inductively coupled plasma optical emission spectrometry (As, Cr, Cu, Fe, Mn, Pb, and Zn) and TAS-990 atomic absorption spectrophotometry (Cd). Two-level regression model was applied to explore the potential factors associated with the level of the eight trace elements. After adjusting for urinary creatinine, the geometric means were 77.5, 10.98, 14.39, 13.00, 0.59, 1.51, 489.62, and 1.80 μg/g for As, Cr, Cu, Fe, Mn, Pb, Zn, and Cd, respectively. The level of eight elements varied among individual and familial characteristics. Compared with domestic and international results, the rural residents living in riverside areas had higher level of As, Cd, Cr, Fe, and Zn. Therefore, industrial progression followed by economic development has resulted in high body burden of heavy metals. Targeted public health policies should be made to improve the local environment and the recognition of potential risk factors.

Assessment of exposure to cadmium, lead, manganese, and nickel in workers from foundries

Objectives:

In this study, biological exposure indicators were used to assess the exposure of workers to cadmium (Cd), lead (Pb), manganese (Mn), and nickel (Ni) in nonferrous metal smelters.

Methods:

A total of 273 male participants (178 exposed and 95 nonexposed control group), working in nonferrous metal foundries located in southern Brazil, were evaluated based on biological indicators, environmental levels, and different types of work performed by the participants. Blood Pb (BPb), urinary Cd (UCd), urinary Mn (UMn), and urinary Ni (UNi) levels were quantified by graphite furnace atomic absorption spectrometry with Zeeman background correction.

Results:

Significant differences between the exposed and nonexposed groups were observed for all of the analyzed elements. The average levels of BPb were higher than the recommended occupational exposure level. Relatively low concentrations were found for UCd, UMn, and UNi.

Conclusions:

Although metal production is an important segment of the Brazilian economy, information related to employee health in this sector is scarce. The environmental levels are determinant in occupational exposure in foundries. In companies where air levels of Pb, Cd, and Mn were above the established limits, the different types of activity did not represent an important influence on the biological levels found among workers. In situations with low air levels of these metals, the workers from the “melting” sector were actually more vulnerable.

Human biomonitoring of metals in adults living near a waste-to-energy incinerator in ante-operam phase: Focus on reference values and health-based assessments

The human biomonitoring (HBM) of metals is a part of the ongoing project SPoTT for the longitudinal health surveillance of the population living near a waste-to-energy (WTE) incinerator (Turin, Italy). The HBM of metals in the SPoTT population aimed to evaluate: i) reference values (RVs) before the WTE incinerator started operation; ii) differences in exposure by variables; iii) variations respect to other HBM studies; iv) exposure that exceeds the available health-based benchmarks as the Biomonitoring Equivalents (BEs) for urine Cd and Human Biomonitoring (HBM-I and HBM-II) values for urine Hg, Tl, and blood Pb; v) risk assessment by generating hazard quotients (HQs) for the single metal and hazard index (HI) for the co-occurrence of metals. Eighteen metals in urine and Pb in blood were determined by sector field inductively coupled plasma mass spectrometry. Metal concentrations were comparable with RVs reported in other countries, except for slightly higher As, Be, Ir, Pd, Pt, Rh, and Tl levels. Smoking was associated with Cd; age with Pb; drinking bottled water with As and Cd; consumption of fish with As and Hg; amalgams with Hg and Sn; dental restorations with Pd and Pt; use of jewelry with Co and Rh, and piercing with Ni. While HQs for urine Cd, Hg, Tl and blood Pb suggested that adverse effects were unlikely, the HQ value raised the question of whether additive interactions of these metals could produce health concern. The obtained HBM data can be an early warning for accumulations of metals and identification of subgroups at risk.

Preeclampsia and toxic metals: a case-control study in Kinshasa, DR Congo

BACKGROUND

Preeclampsia is frequent in Kinshasa (Democratic Republic of Congo), especially during the dry season. We tested whether preeclampsia was associated with exposure to environmental metals.

METHODS

Using a case-control design, 88 women hospitalized with preeclampsia (cases) and 88 healthy pregnant women from the antenatal clinic (controls) were included in the study; 67 and 109 women were enrolled during the rainy and dry season, respectively. The concentrations of 24 elements were quantified by inductively coupled plasma mass spectrometry (ICP-MS) in 24-h urine collections. Differences in the urinary excretion of metals were investigated between cases and controls, and the interaction with season was assessed.

RESULTS

Cases and controls were well matched regarding age, parity and duration of pregnancy. In controls, the urinary concentrations of most elements were substantially higher than reference values for adults from industrially developed countries, e.g. for lead: geometric mean (GM) 8.0 μg/L [25(th)-75(th) percentile 3.1-13.8]. The daily urinary excretions of 14 metals were significantly higher in women with preeclampsia than in control women, e.g. for lead: GM 61 μg/day (25(th)-75(th) percentile 8-345) in women with preeclampsia vs 9 μg/day (25(th)-75(th) percentile 3-21) in controls (p < 0.001). A significant interaction was found between season and preeclampsia for several elements, with higher urinary excretions in preeclamptic women than controls during the dry season, but not during the rainy season.

CONCLUSIONS

This study revealed not only that women with preeclampsia excrete higher amounts of several toxic metals, especially lead, than control women, but also that this excretion exhibits seasonal variation, thus possibly explaining the high incidence and seasonal variation of preeclampsia in Kinshasa. Although the exact sources of this exposure are unknown, these findings underscore the need for preventing environmental exposures to lead and other toxic metals.

Nickel exposure is associated with the prevalence of type 2 diabetes in Chinese adults

BACKGROUND

Nickel exposure can induce hyperglycaemia in rodents, but little is known about its association with abnormal glucose metabolism in humans. We aimed to investigate the association of nickel exposure with the prevalence of type 2 diabetes in Chinese adults.

METHODS

A total of 2115 non-institutionalized men and women aged 55 to 76 years from Beijing and Shanghai were included, and urinary nickel concentration was assessed by inductively coupled plasma mass spectroscopy. The prevalence of type 2 diabetes was compared across urinary nickel quartiles. Fasting plasma glucose, insulin, lipids, C-reactive protein and glycated haemoglobin A1c, as well as urinary albumin and creatinine were measured.

RESULTS

The median concentration of urinary nickel was 3.63 mg/l (interquartile range: 2.29–5.89 mg/l), and the prevalence of diabetes was 35.3% (747 cases/2115 persons). Elevated levels of urinary nickel were associated with higher fasting glucose, glycated haemoglobin A1c, insulin and homeostatic model assessment of insulin resistance (all P<0.01). The odds ratios (95% confidence interval) for diabetes across the increasing urinary nickel quartiles were 1.27 (0.97–1.67), 1.78 (1.36–2.32) and 1.68 (1.29–2.20), respectively (referencing to 1.00), after multivariate adjustment including lifestyle factors, body mass index and family history of diabetes (P for trend <0.001). The association remained unchanged after further controlling for urinary creatinine and C-reactive protein (P for trend <0.001).

CONCLUSIONS

Increased urinary nickel concentration is associated with elevated prevalence of type 2 diabetes in humans.

Zinc Supplementation in a Randomized Controlled Trial Decreased ZIP4 and ZIP8 mRNA Abundance in Peripheral Blood Mononuclear Cells of Adult Women

Zinc plays an integral role in numerous cellular processes including regulation of gene expression. This randomized placebo-controlled trial in adult women evaluated the effects of 20 mg Zn for 23 days. The mRNA abundance of zinc transporters (ZnT1/ZIP3/ZIP4/ZIP8) and metallothionein (MT1) from peripheral blood mononuclear cells was determined by real-time quantitative polymerase chain reaction. In paired samples (n = 6-9), the ZIP4 (P = 0.036) and ZIP8 (P = 0.038) mRNA abundance decreased following zinc supplementation. ZnT1, ZIP3, and MT1 mRNA abundance did not change significantly. The mean ± standard deviation plasma zinc concentration (by inductively coupled plasma mass spectrometry) at baseline was 680 ± 110 μg/L for the zinc group (n = 24) and 741 ± 92 μg/L for the placebo group (n = 23). At endpoint, plasma zinc in the zinc group increased to 735 ± 80 μg/L (P < 0.01) while in the placebo group (717 ± 100 μg/L) it did not change significantly from baseline. The change in mRNA abundance highlights the importance of further investigating ZIP4 and ZIP8 mRNA abundance as potential zinc status biomarkers.

Optimization and Validation of an ETAAS Method for the Determination of Nickel in Postmortem Material

In this article, optimization and validation of a procedure for the determination of total nickel in wet digested samples of human body tissues (internal organs) for forensic toxicological purposes are presented. Four experimental setups of the electrothermal atomic absorption spectrometry (ETAAS) using a Solaar MQZe (Thermo Electron Co.) were compared, using the following (i) no modifier, (ii) magnesium nitrate, (iii) palladium nitrate and (iv) magnesium nitrate and ammonium dihydrogen phosphate mixture as chemical modifiers. It was ascertained that the ETAAS without any modifier with 1,300/2,400°C as the pyrolysis and atomization temperatures, respectively, can be used to determine total nickel at reference levels in biological materials as well as its levels found in chronic or acute poisonings. The method developed was validated, obtaining a linear range of calibration from 0.76 to 15.0 μg/L, limit of detection at 0.23 µg/L, limit of quantification at 0.76 µg/L, precision (as relative standard deviation) up to 10% and accuracy of 97.1% for the analysis of certified material (SRM 1577c Bovine Liver) and within a range from 99.2 to 109.9% for the recovery of fortified liver samples.

Interdependence between urinary cobalt concentrations and hemoglobin levels in pregnant women

Cobalt is an essential trace element but may cause toxic effects upon occupational or environmental exposure. Women accumulate more cobalt than men at similar exposure levels which may be related to higher metabolic iron loss. During pregnancy these losses are much stronger but their influence on cobalt intake has not been studied. We have studied the associations between changes in hemoglobin and cobalt urinary excretion during pregnancy. 391 pairs of urine and blood samples from pregnant women were collected during the 12th and 32nd weeks of pregnancy and were analyzed for cobalt and hemoglobin. Mean concentrations of urinary cobalt were 0.73 and 1.6 µg/g creatinine during the first and third trimesters, respectively (p<0.001). 84% of pregnant women had higher levels of cobalt in the third than in the first trimester. Cobalt concentrations were negatively associated to hemoglobin levels in the third trimester (p<0.05). Women with higher iron decreases between both trimesters had significant cobalt increases between these two periods. This correspondence involved a statistically significant difference in third trimester mean cobalt concentrations of anemic and non-anemic women, 1.8 and 1.5 µg/g creatinine, respectively (p<0.05). No significant differences between these two groups were found during the first trimester. These results were used to construct generalized additive models both in normal and anemic women. The strong association between the changes of both iron status and cobalt urine levels found in pregnant women may be related to higher intestinal absorption of cobalt at iron depletion such as in the last pregnancy period when iron body demands are high. Possible toxicity effects of these cobalt increases along pregnancy should be considered in cases of populations occupationally or environmentally exposed to this metal.

Urinary concentrations of toxic and essential trace elements among rural residents in Hainan Island, China

BACKGROUND

Toxic element exposure and essential trace element consumption may have changed after the Chinese economy transformed to a market-oriented system. The objectives of this study were to measure urinary concentrations of toxic (arsenic, cadmium, lead) and essential trace (selenium, zinc, copper) elements among rural residents in Hainan, China and to examine if variations in economic development are linked to differences in toxic and trace element exposure.

METHODS

We conducted a questionnaire-based survey and undertook anthropometric measurements of residents aged ≥20 years (n = 599). Urinary samples were collected and analyzed using inductively coupled plasma mass spectrometry.

RESULTS

The median (μg/g creatinine) element concentrations were: arsenic, 73.2; cadmium, 1.8; lead, 3.1; selenium, 36.5; zinc, 371; and copper, 11.0. Intra-community variation in element concentrations was explained by age (arsenic, cadmium, zinc and copper), sex (arsenic, cadmium and selenium: higher in females; zinc: higher in males), body mass index (cadmium) and individual involvement in the market economy as indexed by agrochemical use (lead and selenium). The degree of community-level economic development, which was determined by the proportion of people living in better housing among the study communities, was positively associated with cadmium concentration.

CONCLUSIONS

The degree of community-level economic development was positively associated with urinary cadmium concentration while individual involvement in the market economy was positively associated with lead and selenium.

Impact of aging on urinary excretion of iron and zinc

PROJECT

Data about the influence of aging on urinary excretion of iron and zinc are scarce. The objective of the present study was to compare the concentration of zinc and iron in the urine of healthy elderly subjects and younger adults.

PROCEDURE

Seven healthy elderly subjects and seven younger adults were selected and submitted to biochemical, clinical, and nutritional tests. After a fasting period, 12-hour urine was collected for the determination of iron and zinc concentrations by graphite furnace atomic absorption spectrophotometry.

RESULTS

Urinary zinc and iron concentrations of the elderly subjects were not significantly different from that of younger adults. However, the total zinc and iron urinary clearance in 24 hours for the elderly was significantly higher compared with that of younger adults.

CONCLUSION

There is an increase in urinary iron and zinc clearance with aging. The values reported in this manuscript may be used as references in future studies.

Study of selenium intake and disposition in various matrices based on mathematical algorithms derived from pooled biomonitoring data

Biomonitoring is increasingly used to assess exposure to selenium (Se) in the population. However, there is little harmonization among protocols used in the different studies (varying biological matrices, differences in expression of results (concentrations versus amounts, units)). This makes inter-comparison of biomonitoring results across studies difficult. From a public health risk perspective, it also becomes challenging to estimate baseline levels in biological matrices for populations exposed by various sources. The aim of this study was thus to perform a systematic analysis of the relationship between Se intakes and biological concentrations based on published data. Inclusion and exclusion criteria were used and led to select 75 published biomonitoring data in humans from an extended review of Se biomonitoring studies. This represents 8 628 individuals who provided biological samples aiming at documenting Se exposure and/or Se concentrations in two or more biological matrices. Mathematical algorithms that relate Se intakes to biological concentrations and establish matrix-to-matrix associations were derived from these pooled biomonitoring data. Logarithmic regressions showed good correlations between Se intakes and whole blood concentrations (R(2)=0.884), plasma concentrations (R(2)=0.863) and urinary excretion rates (R(2)=0.958). Blood and plasma concentrations were also strongly related (R(2)=0.874), as were whole blood concentrations and urinary excretion rates (R(2)=0.953). The interpretation of the log-regression coefficients allowed illustrating Se physiology. Se concentrations in plasma tend to plateau when daily intake exceed 150 μg/d, whereas Se in urine increases rapidly above this threshold. The application of the algorithms to other independent data sets in order to reconstruct past Se intakes confirmed that interpretation of results on the basis of Se in integuments may be misleading if external contamination is not avoided. This approach based on pooled data covered a wide range of exposure and the large number of data integrated increased the level of confidence of results.

Application of ICP-OES to the determination of barium in blood and urine in clinical and forensic analysis

Exposure to barium (Ba) mostly occurs in the workplace or from drinking water, but it may sometimes be due to accidental or intentional intoxication. This paper presents a reliable, sensitive method for the determination of Ba in blood and urine: inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave digestion of samples. The overall procedure was checked using Seronorm Whole Blood L-2, Trace Elements Urine and spiked blood and urine samples (0.5-10 µg/mL of Ba). The accuracy of the whole procedure (relative error) was 4% (blood) and 7% (urine); the recovery was 76-104% (blood) and 85-101% (urine). The limits of detection and quantification (Ba λ = 455.403 nm) were 0.11 and 0.4 µg/L of Ba, respectively; precision (relative standard deviation) was below 6% at the level of 15 µg/L of Ba for blood. This method was applied to a case of the poisoning of a man who had been exposed at the workplace for over two years to powdered BaCO3, and who suffered from paralysis and heart disorders. The concentrations of Ba, in μg/L, were 160 (blood), 460 (serum) and 1,458 (urine) upon his admission to the hospital, and 6.1 (blood) and 4.9 (urine) after 11 months (reference values: 3.34 ± 2.20 µg/L of Ba for blood and 4.43 ± 4.60 µg/L of Ba for urine).

Determination of reference concentrations of strontium in urine by inductively coupled plasma atomic emission spectrometry

OBJECTIVE

The aim of this study was to establish reference concentrations of urinary strontium by inductively coupled plasma atomic emission spectrometry (ICP-AES).

METHODS

For the determination of strontium, urine samples were collected from healthy Japanese (n=146; 115 males, 31 females; mean age, 33±9 years; age range, 18 to 58 years). The urine samples stored at or below -20°C were thawed with incubation at 40°C for 30 min and sediments were dissolved by vigorous shakings. Then, the samples were centrifuged at 3000 g for 5 min, and the supernatant was directly aspired into a P-5200-3600/1200 ICP-AES system from Hitachi Ltd., Tokyo, Japan.

RESULTS

A steeper increase in the S/N ratio and a good effective linearity of the calibration line was obtained at 407.771 nm in the range of 0-300 μg/L strontium standard solution. Urine samples having the same background signal as that of 18 MΩ cm ultrapure blank water, a good correspondence of the single peak pattern of the spectra, accuracy and precision of spike recovery were also confirmed. Urinary strontium concentrations showed a log-normal distribution and a geometric mean concentration of 143.9 μg/L, with 5-95% confidential interval of 40.9-505.8 μg/L.

CONCLUSION

The results of this study will be useful as guidelines for the biological monitoring of strontium in normal subjects and in individuals therapeutically or environmentally exposed to strontium.

An overview of boron, lithium, and strontium in human health and profiles of these elements in urine of Japanese

The biological, medical and environmental roles of trace elements have attracted considerable attention over the years. In spite of their relevance in nutritional, occupational and toxicological aspects, there is still a lack of consistent and reliable measurement techniques and reliable information on reference values. In this review our understandings of the urinary profilings of boron, lithium and strontium are summarized and fundamental results obtained in our laboratory are discussed.Over the past decade we have successfully used inductively coupled plasma emission spectrometry for the determination of reference values for urinary concentrations of boron, lithium and strontium. Taking into account the short biological half-life of these elements and the fact that their major excretion route is via the kidney, urine was considered to be a suitable material for monitoring of exposure to these elements. We confirmed that urinary concentrations of boron, lithium and strontium follow a lognormal distribution. The geometric mean reference values and 95% confidence intervals were 798 μg/l (398-1599 μg/l) for boron, 23.5 μg/l (11.0-50.5 μg/l) for lithium and 143.9 μg/l (40.9-505.8 μg/l) for strontium. There were no discrepancies between our values and those previously reported. Our reference values and confidential intervals can be used as guidelines for the health screening of Japanese individuals to evaluate environmental or occupational exposure to these elements.

Twenty-four-hour urinary trace element excretion: reference intervals and interpretive issues

Background

Introduction of inductively coupled plasma mass spectrometry (ICP-MS) into clinical laboratories has led to an increasing application of analyses to risk assessment for toxicity from environmental exposure to trace elements, and in occupational monitoring. Interpretation of results from random urine samples may be problematic and measurement of excretion over 24 h is sometimes preferable. Recent reference data are sparse.

Methods

Twenty-four-hour urine samples from 111 healthy adults from the renal stones clinic in Southampton, UK, were analysed for 31 trace elements using ICP-MS and for zinc using atomic absorption spectroscopy. Non-parametric 0.95 coverage intervals were determined for trace element excretion per 24 h and as a ratio to creatinine, for the full study cohort and separately for men ( n = 77) and women ( n = 34).

Results

Beryllium was undetectable in 95% of samples, bismuth in 87% and uranium in 75%. In comparison with published ranges, reference intervals for this cohort were higher for molybdenum, tin and vanadium, and for arsenic due to inclusion of fish arsenicals. Aluminium, chromium, iron, lead and mercury were lower. In our cohort, 24-h excretion of 17 elements was significantly higher in men than in women. However, when expressed as trace element to creatinine ratios, the situation reversed strikingly. Because of their lower creatinine excretion, ratios for 18 elements were significantly higher for women.

Conclusions

New adult reference intervals were obtained for 24-h urine trace element excretion. Trace element:creatinine ratios must be used cautiously, with separate ranges for men and women.

Urinary strontium and the risk of breast cancer: a case-control study in Guangzhou, China

Strontium has been widely used in industries like electronic and pharmacy. It has a carcinogenic potential, however, and no study has been conducted to evaluate its effects on cancer risk. The aim of this study was to explore the possible association between strontium and breast cancer risk in a case-control study including 240 incident invasive breast cancer patients and 246 age-matched controls. We measured the urinary concentrations of strontium by inductively coupled plasma mass spectrometry, and conducted face-to-face interviews to obtain information on potential breast cancer risk factors. Multivariable analysis was used to estimate the association. Creatinine-adjusted levels [median (25th, 75th) μg/g] of strontium were 155.59 (99.05, 230.70) in the breast cancer patients and 119.62 (81.97, 163.76) in the controls. Women in the highest tertile of strontium showed 124% increased risk of breast cancer, when compared with those in the lowest tertile after adjustment for the potential risk factors [OR (95% CI): 2.24 (1.42-3.81)]. This association was particularly strong for HER2 positive breast cancer [OR (95% CI): 10.92 (3.53-33.77)], and only occurred among premenopausal women. These results suggest a potential role of strontium in the development of breast cancer and urge further studies on the environmental contamination and the physiological and pathological mechanisms of strontium.

A trace metal survey of non-occupationally exposed Gauteng residents

Specific reference values for background levels of body burden of trace metals are not available for South Africa. Currently, laboratories measuring trace metal levels in workers use internationaly established values for comparison. A preliminary cross-sectional survey of 107 non-occupationally exposed volunteers of both genders and all races provided blood and urine samples. The samples were collected with consideration for possible routes of contamination. Seven metals were measured in blood and ten in urine. Reference ranges for a Gauteng population were then calculated using the central 95% of data to provide lower and upper limits, which were then compared to international limits. The trace metal levels described had both lower and higher reference ranges in blood and urine compared to international studies. This reflects the differences in the environments. Statistically significant differences in metal levels were observed by gender. The differences in detected trace metal levels in our sample as compared to other published data demonstrate the need for the establishment of local reference values for laboratories. The establishment of local 95% reference ranges would also allow South Africa to determine its exposure levels compared to those internationally. This would assist with establishing pollution control priorities.

Zinc in postmortem body tissues and fluids

Data on zinc concentration in the human body may be used to interpret the results obtained in cases of chronic and acute poisonings with zinc compounds, i.e., in clinical and forensic toxicology. In this paper, the concentrations of zinc in human tissues and body fluids obtained from autopsy cases concerning non-poisoned people (n = 203), aged from 14 to 80 years, between 1995 and 2008, are presented. The following values were found by the flame atomic absorption method (mean ± SD, median, range, in microgram per gram or microgram per milliliter): brain 10.3 ± 1.36, 10.2, 7.99-13.8 (n = 48); stomach 14.2 ± 3.63, 13.6, 8.00-22.5 (n = 71); intestines 15.7 ± 5.22, 15.8, 8.36-28.1 (n = 35); liver 39.6 ± 16.1, 36.6, 16.0-78.8 (n = 109); kidney 33.8 ± 10.1, 31.8, 16.4-60.9 (n = 93); lung 12.0 ± 3.88, 11.0, 6.13-18.7 (n = 26); spleen 14.7 ± 2.53, 14.6, 11.4-18.3 (n = 5); heart 26.5 ± 3.63, 26.7, 22.5-31.8 (n = 5); blood 6.81 ± 1.21, 7.00, 4.02-8.68 (n = 50); urine 0.69 ± 1.70, 0.60, 0.39-1.00 (n = 5), and bile 4.92 ± 1.64, 3.75, 3.20-7.09 (n = 9). The accuracy of the method was checked through the use of SRM Bovine Liver 1577b (certified: 127 ± 16 μg Zn/g, found: 117 ± 0.7 μg Zn/g (n = 6)).

Magnesium, calcium, and trace elements excretion in 24-h urine

Urine is a clinical specimen often used in medical diagnostics for monitoring of elements concentrations and kidneys function. We determined the contents of magnesium (Mg), calcium (Ca), zinc (Zn), copper (Cu), iron (Fe), lead (Pb), and cadmium (Cd) in 74 samples of 24-h urine (from 46 women and 28 men). The measurements were realized by the atomic absorption spectrometry (AAS) with atomization in the flame (FAAS) and in the graphite furnace (GFAAS). The received results were the subject of statistical analysis including the sex and age of volunteers. Moreover, correlations between the elements and the relationships between age and amounts of excreted elements with urine were tested. We found the statistically significant higher content of Zn in men's urine than in women(')s one. Moreover, both adult women and men (>18 years) excreted much more Ca in urine in comparison to young subjects. Only in case of Pb the significant positive correlation between its amount in 24-h urine of all donors and age was stated. The correlation analysis has shown the significant positive relationships between Ca-Mg, Ca-Fe, Mg-Fe, Cu-Fe, Cu-Cd, Fe-Cd, and Pb-Cd in total samples of urine. Basing on our results, we concluded that the gender and age of donors may impact on the elemental status of 24-h urine.

High Zn content of Randall's plaque: a μ-X-ray fluorescence investigation

Kidney stone disease, or nephrolithiasis, is a common ailment. Among the different risk factors usually associated with nephrolithiasis are dehydration, metabolic defects (especially with regard to calcium and oxalate). The presence of a mineral deposit at the surface of the renal papilla (termed Randall's plaque) has all been recently underlined. Of note, Randall's plaque is made of the calcium phosphate, carbapatite, and serves as a nucleus for kidney stone formation. The process by which apatite nanocrystals nucleate and form Randall's plaque remains unclear. This paper deals with the possible relationship between trace elements and the formation of this mineral. The investigation has been performed on a set of Randall's plaques, extracted from human kidney stones, through μ-X-ray diffraction and μ-X-ray fluorescence analyses in order to determine the chemical composition of the plaque as well as the nature and the amount of trace elements. Our data provide evidence that Zn levels are dramatically increased in carbapatite of RP by comparison to carbapatite in kidney stones, suggesting that calcified deposits within the medullar interstitium are a pathological process involving a tissue reaction. Further studies, perhaps including the investigation of biomarkers for inflammation, are necessary for clarifying the role of Zn in Randall's plaque formation.

Multiple metals exposure in a small-scale artisanal gold mining community

Urinary metals were characterized in 57 male residents of a small-scale gold mining community in Ghana. Chromium and arsenic exceeded health guideline values for 52% and 34%, respectively, of all participants. About 10-40% of the participants had urinary levels of aluminum, copper, manganese, nickel, selenium, and zinc that fell outside the U.S. reference range. Exposures appear ubiquitous across the community as none of the elements were associated with occupation, age, and diet.

Cadmium dietary intake and biomarker data in French high seafood consumers

Seafood and especially mollusks are known to be a rich source of cadmium (Cd), but little data are available concerning French seafood contamination and Cd exposure of French populations. The objective was then to assess food intake and biological level of Cd in high consumers of seafood, and to determine the impact of the consumption of self-fished mollusks on urinary Cd. Seafood consumption levels of 80 products were assessed for 1011 high consumers aged 18 and over in four French coastal areas, thanks to a validated food frequency questionnaire (FFQ). According to a total diet study approach, seafood samples were collected taking into account preservation methods and supply habits. Food samples were analyzed for Cd. Exposure was assessed by crossing consumption data with contamination data. Total blood and urine samples were collected from 380 subjects of the cohort and analyzed for Cd. The impact of the self-collected mollusks consumption on the Cd biological level adjusted for creatinine was assessed by a multivariate linear regression model. The mean dietary intake of Cd is 2.44+/-3.34 microg/kg bw/wk and the mean urinary Cd (U-Cd) level is 0.65+/-0.45 microg/g creatinine, and is significantly higher in women than in men (P<0.05). The consumption of self-fished mollusks is significantly negatively associated with U-Cd (r=-0.11 [-0.185, -0.009], P=0.03). The results of this study indicate that the biological Cd levels remain below the standards, and also suggest a protective effect of self-fishing, which inspires confidence about the high consumer health safety in terms of Cd exposure.

Normalisation of spot urine samples to 24-h collection for assessment of exposure to uranium

For dose assessment of workers at Nuclear Research Center Negev exposed to natural uranium, spot urine samples are analysed and the results are normalised to 24-h urine excretion based on 'standard' man urine volume of 1.6 l d(-1). In the present work, the urine volume, uranium level and creatinine concentration were determined in two or three 24-h urine collections from 133 male workers (319 samples) and 33 female workers (88 samples). Three volunteers provided urine spot samples from each voiding during a 24-h period and a good correlation was found between the relative level of creatinine and uranium in spot samples collected from the same individual. The results show that normalisation of uranium concentration to creatinine in a spot sample represents the 24-h content of uranium better than normalisation to the standard volume and may be used to reduce the uncertainty of dose assessment based on spot samples.

Heavy elements in urinary stones

The presence and role of heavy metals in urinary stones is debated. We investigated the distribution of trace heavy metals in 78 calculi of well-defined composition by means of microfluorescence X analysis using synchrotron radiation. Seven elements were identified, the most abundant being Zn and Sr which together accounted for 91% of the heavy metal content of stones. The other heavy metals were Fe, Cu, Rb, Pb and Se. Zn and Sr were virtually confined to calcium-containing stones, whereas only trace amounts were found in uric acid or cystine stones. Among calcium stones, Zn and Sr were more abundant in calcium phosphate than in calcium oxalate stones and, in the latter, in weddellite than in whewellite stones. Fe, Cu and Rb were much less abundant and also found mainly in calcium stones. Pb was significantly less abundant than in previous studies, thus suggesting a rarefaction of Pb in the environment, and appreciable amounts of Se were found only in cystine stones. In conclusion, the preponderance of Zn and Sr, both bivalent ions, in calcium-containing stones suggests a substitution process of calcium by metal ions with similar charge and radius rather than a contribution of the metals to stone formation. Further studies are needed to examine the relationships between urine concentration in calcium or other solutes and the amount of Zn and Sr in calcium stones.

Comparison of urinary amino acids and trace elements (copper, zinc and manganese) of recent neurolathyrism patients and healthy controls from Ethiopia

OBJECTIVE

The irreversibly crippling disease neurolathyrism is caused by prolonged over-consumption of Lathyrus sativus seed. The molecular mechanism of toxicity is unclear and more biochemical information is needed.

METHODS

The urinary amino acids from 5 recent patients and 9 healthy subjects in Ethiopia were analysed by HPLC after PITC (phenyl isothiocyanate) derivatisation. The trace elements Cu, Zn and Mn of urine and seeds were determined by atomic absorption spectroscopy.

RESULTS

The free amino acids aspartic acid, glycine, beta-aminoisobutyric acid, arginine, alpha-aminoadipic acid and phenylalanine were statistically higher (p<0.05) in urine from patients than in urine from control subjects. The trace element Cu was also statistically higher (p<0.05) in patient urine.

CONCLUSION

The amino acid metabolism of the neurolathyrism patients is disturbed by over-consumption of grass pea seeds. The high concentrations of Cu found in the patient urine might indicate the involvement of trace elements in the aetiology of neurolathyrism.