Exposure determinants of cadmium in European mothers and their children.

The metal cadmium (Cd) is a widespread environmental pollutant with documented adverse effects on the kidneys and bones from long-term environmental exposure, but with insufficiently elucidated public health consequences such as risk of cardiovascular disease, hormone-related cancer in adults and developmental effects in children. This study is the first pan-European human biomonitoring project that succeeded in performing harmonized measurements of Cd in urine in a comparable way in mother-child couples from 16 European countries. The aim of the study was to evaluate the overall Cd exposure and significant determinants of Cd exposure. A study population of 1632 women (24-52 years of age), and 1689 children (5-12 years of age), from 32 rural and urban areas, was examined within a core period of 6 months in 2011-2012. Women were stratified as smokers and non-smokers. As expected, smoking mothers had higher geometric mean (gm) urinary cadmium (UCd; 0.24 µg/g crea; n=360) than non-smoking mothers (gm 0.18 µg/g crea; n=1272; p<0.0001), and children had lower UCd (gm 0.065 µg/g crea; n=1689) than their mothers at the country level. Non-smoking women exposed to environmental tobacco smoke (ETS) at home had 14% (95% CI 1-28%) higher UCd than those who were not exposed to ETS at home (p=0.04). No influence of ETS at home or other places on UCd levels was detected in children. Smoking women with primary education as the highest educational level of the household had 48% (95% CI 18-86%) higher UCd than those with tertiary education (p=0.0008). The same observation was seen in non-smoking women and in children; however they were not statistically significant. In children, living in a rural area was associated with 7% (95% CI 1-13%) higher UCd (p=0.03) compared to living in an urban area. Children, 9-12 years had 7% (95% CI 1-13%) higher UCd (p=0.04) than children 5-8 years. About 1% of the mothers, and 0.06% of the children, exceeded the tolerable weekly intake (TWI) appointed by EFSA, corresponding to 1.0 µg Cd/g crea in urine. Poland had the highest UCd in comparison between the 16 countries, while Denmark had the lowest. Whether the differences between countries are related to differences in the degree of environmental Cd contamination or to differences in lifestyle, socioeconomic status or dietary patterns is not clear.

Mercury analysis in hair: Comparability and quality assessment within the transnational COPHES/DEMOCOPHES project.

Human biomonitoring (HBM) is an effective tool for assessing actual exposure to chemicals that takes into account all routes of intake. Although hair analysis is considered to be an optimal biomarker for assessing mercury exposure, the lack of harmonization as regards sampling and analytical procedures has often limited the comparison of data at national and international level. The European-funded projects COPHES and DEMOCOPHES developed and tested a harmonized European approach to Human Biomonitoring in response to the European Environment and Health Action Plan. Herein we describe the quality assurance program (QAP) for assessing mercury levels in hair samples from more than 1800 mother-child pairs recruited in 17 European countries. To ensure the comparability of the results, standard operating procedures (SOPs) for sampling and for mercury analysis were drafted and distributed to participating laboratories. Training sessions were organized for field workers and four external quality-assessment exercises (ICI/EQUAS), followed by the corresponding web conferences, were organized between March 2011 and February 2012. ICI/EQUAS used native hair samples at two mercury concentration ranges (0.20-0.71 and 0.80-1.63) per exercise. The results revealed relative standard deviations of 7.87-13.55% and 4.04-11.31% for the low and high mercury concentration ranges, respectively. A total of 16 out of 18 participating laboratories the QAP requirements and were allowed to analyze samples from the DEMOCOPHES pilot study. Web conferences after each ICI/EQUAS revealed this to be a new and effective tool for improving analytical performance and increasing capacity building. The procedure developed and tested in COPHES/DEMOCOPHES would be optimal for application on a global scale as regards implementation of the Minamata Convention on Mercury.

Alkali dilution of blood samples for high throughput ICP-MS analysis-comparison with acid digestion.

OBJECTIVES: The direct dilution of blood with alkali has been introduced as an alternative to acid digestion for improvement of the analytical productivity when measuring trace elements using inductively coupled plasma mass spectrometry (ICP-MS). This study compared these two sample preparation methods for the ICP-MS determination of multiple elements in human blood and serum. METHODS: Aliquots (0.2 or 0.5 mL) of human whole blood and serum samples, including reference samples (whole blood and serum), were subjected to alkali dilution (ammonia solution) or acid digestion (nitric acid). The samples were then analysed for their concentrations of Li, B, Mg, P, S, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Sb, Cs, Ba, Pb and U with a quadrupole ICP-MS instrument equipped with a collision/reaction cell. RESULTS: Analysis of the reference materials showed that the alkali dilution and acid digestion methods provided equally good agreement with the reference values for Mg, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Mo, Cd, Sb and Pb. The alkali dilution method generally gave better agreement with the reference values for Li, B, P, S, K, Cr and U, whereas acid digestion gave better agreement for Ca, Fe, Sr and Cs. Strong associations (R(2)>0.90) between the two methods were obtained for the concentrations of Li, B, Mn, Co, Cu, As, Se, Rb, Sr, Mo, Cd, Cs and Pb in the collected human whole blood and for Li, B, Mg, P, S, K, Fe, Co, Cu, Zn, As, Se, Rb, Sr, Sb and Cs in the collected serum. CONCLUSIONS: The results suggest that the alkali dilution method is suitable for the determination of Li, B, Mn, Co, Cu, Zn, As, Se, Rb and Sr in whole blood and serum; Mo, Cd and Pb in whole blood; and Sb in serum by ICP-MS. Acid digestion is preferred for Fe and for low concentrations of Cs.

Formal recycling of e-waste leads to increased exposure to toxic metals: an occupational exposure study from Sweden.

Electrical and electronic waste (e-waste) contains multiple toxic metals. However, there is currently a lack of exposure data for metals on workers in formal recycling plants. The objective of this study was to evaluate workers' exposure to metals, using biomarkers of exposure in combination with monitoring of personal air exposure. We assessed exposure to 20 potentially toxic metals among 55 recycling workers and 10 office workers at three formal e-waste recycling plants in Sweden. Workers at two of the plants were followed-up after 6 months. We collected the inhalable fraction and OFC (37-mm) fraction of particles, using personal samplers, as well as spot samples of blood and urine. We measured metal concentrations in whole blood, plasma, urine, and air filters using inductively coupled plasma-mass spectrometry following acid digestion. The air sampling indicated greater airborne exposure, 10 to 30 times higher, to most metals among the recycling workers handling e-waste than among the office workers. The exposure biomarkers showed significantly higher concentrations of chromium, cobalt, indium, lead, and mercury in blood, urine, and/or plasma of the recycling workers, compared with the office workers. Concentrations of antimony, indium, lead, mercury, and vanadium showed close to linear associations between the inhalable particle fraction and blood, plasma, or urine. In conclusion, our study of formal e-waste recycling shows that workers performing recycling tasks are exposed to multiple toxic metals.

Maternal urinary iodine concentration up to 1.0 mg/L is positively associated with birth weight, length, and head circumference of male offspring.

Adequate iodine status in early life is crucial for neurodevelopment. However, little is known about the effects of maternal iodine status during pregnancy on fetal growth. The present study investigated the potential impact of maternal iodine status during pregnancy on offspring birth size. This large prospective cohort study was nested in a Bangladeshi population-based randomized supplementation trial in pregnant women [MINIMat (Maternal and Infant Nutrition Interventions in Matlab)]. Urine samples obtained at 8 wk of gestation from 1617 women were analyzed for iodine and other elements, such as arsenic and cadmium, using inductively coupled plasma mass spectrometry. Anthropometric measurements at birth included weight, length, and head and chest circumference. Maternal urinary iodine concentrations (UICs) ranged from 0.020 to 10 mg/L, with a median of 0.30 mg/L. Below ∼1.0 mg/L, UIC was significantly positively associated with birth weight and length. Birth weight and length increased by 9.3 g (95% CI: 2.9, 16) and 0.042 cm (95% CI: 0.0066, 0.076), respectively, for each 0.1-mg/L increase in maternal UIC. No associations were observed between UIC and head or chest circumference. When we stratified the analyses by newborn sex, the positive associations between maternal UIC (<1 mg/L) and measurements of size at birth were restricted to boys, with no evidence in girls. Among boys, the mean weight, length, and head circumference increased by 70 g (P = 0.019), 0.41 cm (P = 0.013), and 0.28 cm (P = 0.031) for every 0.5-mg/L increase in maternal UIC. Maternal iodine status was positively associated with weight, length, and head circumference in boys up to ∼1 mg/L, which is well above the recommended maximum concentration of 0.5 mg/L. The associations leveled off at UIC ≥ 1 mg/L. Our findings support previous conclusions that the advantages of correcting potential iodine deficiency outweigh the risks of excess exposure.

Arsenic exposure affects plasma insulin-like growth factor 1 (IGF-1) in children in rural Bangladesh.

BACKGROUND: Exposure to inorganic arsenic (As) through drinking water during pregnancy is associated with lower birth size and child growth. The aim of the study was to assess the effects of As exposure on child growth parameters to evaluate causal associations. METHODOLOGY/FINDINGS: Children born in a longitudinal mother-child cohort in rural Bangladesh were studied at 4.5 years (n=640) as well as at birth (n=134). Exposure to arsenic was assessed by concurrent and prenatal (maternal) urinary concentrations of arsenic metabolites (U-As). Associations with plasma concentrations of insulin-like growth factor 1 (IGF-1), calcium (Ca), vitamin D (Vit-D), bone-specific alkaline phosphatase (B-ALP), intact parathyroid hormone (iPTH), and phosphate (PO4) were evaluated by linear regression analysis, adjusted for socioeconomic factor, parity and child sex. Child U-As (per 10 µg/L) was significantly inversely associated with concurrent plasma IGF-1 (ß=-0.27; 95% confidence interval: -0.50, -0.0042) at 4.5 years. The effect was more obvious in girls (ß=-0.29; -0.59, 0.021) than in boys, and particularly in girls with adequate height (ß=-0.491; -0.97, -0.02) or weight (ß=-0.47; 0.97, 0.01). Maternal U-As was inversely associated with child IGF-1 at birth (r=-0.254, P=0.003), but not at 4.5 years. There was a tendency of positive association between U-As and plasma PO4 in stunted boys (ß=0.27; 0.089, 0.46). When stratified by % monomethylarsonic acid (MMA, arsenic metabolite) (median split at 9.7%), a much stronger inverse association between U-As and IGF-1 in the girls (ß=-0.41; -0.77, -0.03) was obtained above the median split. CONCLUSION: The results suggest that As-related growth impairment in children is mediated, at least partly, through suppressed IGF-1 levels.

Elevated manganese concentrations in drinking water may be beneficial for fetal survival.

BACKGROUND: Elevated exposure to the essential element manganese (Mn) can be toxic. Manganese concentrations in ground water vary considerably, and reported associations between Mn and early-life mortality and impaired development have raised concern. We assessed the effects of drinking water Mn exposure during pregnancy upon fetal and infant survival. METHODS: In this population-based cohort study, we identified the outcomes of pregnancies registered between February 2002 and April 2003 in Matlab, Bangladesh. Using inductively coupled plasma mass spectrometry, we measured the concentrations of Mn and other elements in the pregnant women's drinking water. RESULTS: A total of 1,875 women were included in the analysis of spontaneous abortions (n=158) and 1,887 women in the perinatal mortality analysis (n=70). Water Mn ranged from 3.0-6,550 µg/L (median=217 µg/L). The adjusted odds ratio (OR) for spontaneous abortion was 0.65 (95% CI 0.43-0.99) in the highest water Mn tertile (median=1,292 µg/L) as compared to the lowest tertile (median=56 µg/L). The corresponding OR for perinatal mortality was 0.69 (95% CI 0.28-1.71), which increased to 0.78 (95% CI 0.29-2.08) after adjustment for BMI and place of delivery (home/health facility; n=1,648). CONCLUSIONS: Elevated water Mn concentrations during pregnancy appear protective for the fetus, particularly in undernourished women. This effect may be due to the element's role in antioxidant defense.

Environmental exposure to metals and children's growth to age 5 years: a prospective cohort study.

In this prospective cohort study, based on 1,505 mother-infant pairs in rural Bangladesh, we evaluated the associations between early-life exposure to arsenic, cadmium, and lead, assessed via concentrations in maternal and child urine, and children's weights and heights up to age 5 years, during the period 2001-2009. Concurrent and prenatal exposures were evaluated using linear regression analysis, while longitudinal exposure was assessed using mixed-effects linear regression. An inverse association was found between children's weight and height, age-adjusted z scores, and growth velocity at age 5 years and concurrent exposure to cadmium and arsenic. In the longitudinal analysis, multivariable-adjusted attributable differences in children's weight at age 5 years were -0.33 kg (95% confidence interval (CI): -0.60, -0.06) for high (≥95th percentile) arsenic exposure and -0.57 kg (95% CI: -0.88, -0.26) for high cadmium exposure, in comparison with children with the lowest exposure (≤5th percentile). Multivariable-adjusted attributable differences in height were -0.50 cm (95% CI: -1.20, 0.21) for high arsenic exposure and -1.6 cm (95% CI: -2.4, -0.77) for high cadmium exposure. The associations were apparent primarily among girls. The negative effects on children's growth at age 5 years attributable to arsenic and cadmium were of similar magnitude to the difference between girls and boys in terms of weight (-0.67 kg, 95% CI: -0.82, -0.53) and height (-1.3 cm, 95% CI: -1.7, -0.89).

Metals and trace element concentrations in breast milk of first time healthy mothers: a biological monitoring study.

BACKGROUND: Breast milk is the best source of nutrition for the newborn infant. However, since all infants cannot be breast-fed, there is a need for background data for setting adequate daily intakes. Previously, concentration data on major essential elements and some toxic elements in breast milk, based on different analytical techniques, have been published. There is no recent study on a large number of metals and trace elements in breast milk, using a sensitive analytical method for determination of low element concentrations. METHODS: Breast milk concentrations of 32 metals and elements in early lactation (days 14-21) were determined in a random sample of first time Swedish mothers (n = 60) using inductively coupled plasma mass spectrometry (ICPMS). RESULTS: There were small inter-individual concentration variations in the macroelements Ca, K, Mg, P and S, and striking similarities across studies and over time, supporting a tight regulation of these elements in breast milk. Large inter-individual and over time differences were detected for Na concentrations, which may reflect an increase in salt consumption in Swedish women. Large inter-individual differences were also detected for the microelements Co, Cr, Mn and Mo, and the toxic metals As, Cd, Pb, Sb and V. Arsenic and B were positively correlated with fish consumption, indicating influence of maternal intake on breast milk concentrations. Observed differences in breast milk element concentrations across studies and over time could be attributed to the timing of sampling and a general decline over time of lactation (Cu, Fe, Mo, Zn), a possible lack of regulation of certain elements in breast milk (As, B, Co, Mn, Se) and time trends in environmental exposure (Pb), or in some cases to differences in analytical performance (Cr, Fe). CONCLUSIONS: This study provides reliable updated information on a number of metals and elements in breast milk, of which some have not previously been reported.

Early-life exposure to lithium and boron from drinking water.

The transfer of lithium and boron from exposed mothers to fetuses and breast-fed infants was investigated in areas in northern Argentina and Chile with up to 700 µg lithium/L and 5-10 mg boron/L in drinking water. Maternal and cord blood concentrations were strongly correlated and similar in size for both lithium (47 and 70 µg/L, respectively) and boron (220 and 145 µg/L, respectively). The first infant urine produced after birth contained the highest concentrations (up to 1700 µg lithium/L and 14,000 µg boron/L). Breast-milk contained 40 and 60% of maternal blood concentrations of lithium and boron, respectively (i.e. about 30 and 250 µg/L, respectively, in high exposure areas), and infant urine concentrations decreased immediately after birth (120 µg lithium/L and 920 µg boron/L). We conclude that lithium and boron easily passed the placenta to the fetus, and that exclusively breast-fed infants seemed to have lower exposure than formula-fed infants.

Gender and age differences in mixed metal exposure and urinary excretion.

BACKGROUND: Little is known about the variation in exposure to toxic metals by age and gender and other potential modifying factors. We evaluated age and gender differences by measurements of metal/element concentrations in urine in a rural population in Matlab, Bangladesh, in three age groups: 8-12 (N=238), 14-15 (N=107) and 30-88 (N=710) years of age, living in an area with no point sources of metal exposure but where elevated water arsenic concentrations are prevalent. RESULTS: We found marked differences in urine concentrations of metals and trace elements by gender, age, tobacco use, socioeconomic and nutritional status. Besides a clearly elevated urinary arsenic concentration in all age groups (medians 63-85 µg As/L), and despite the low degree of contamination from industries and traffic, the urine concentrations of toxic metals such as cadmium and lead were clearly elevated, especially in children (median 0.31 µg Cd/L and 2.9 µg Pb/L, respectively). In general, women had higher urinary concentrations of toxic metals, especially Cd (median 0.81 µg/L) compared to men (0.66 µg/L) and U (median 10 ng/L in women, compared to 6.4 ng/L in men), while men had higher urinary concentrations of the basic and essential elements Ca (69 mg/L in men, 30-50 years, compared to 52 mg/L in women), Mg (58 mg/L in men compared to 50 mg/L in women), Zn (182 µg/L in men compared to 117 µg/L in women) and Se (9.9 µg/L in men compared to 8.7 µg/L in women). Manganese was consistently higher in females than in males in all age groups, suggesting a biological difference between females and males in Mn metabolism. Increasing socioeconomic status decreased the toxic metal exposure significantly in children and especially in men. Poor iron status was detected in 17% of children, adolescents and women, but only in 6% of men. Also zinc deficiency was more prevalent in females than in males. CONCLUSIONS: Women and children seemed to be more at risk for toxic metal exposure than men and at the same time more vulnerable to micronutrient deficiency. Higher concentrations of the toxic metals in urine in women are likely to reflect an increased gastrointestinal absorption of these metals at micronutrient deficiency, such as low body iron stores and Zn deficiency. Higher urinary concentrations of the essential elements in men likely reflect a better nutritional status. There is a need for information on exposure, lifestyle and socioeconomic factors, stratified by gender and age, for the purpose of conducting balanced risk assessment and management that considers such differences.

Persistent exposure to arsenic via drinking water in rural Bangladesh despite major mitigation efforts.

OBJECTIVES: Elevated arsenic levels in tube-well water in Bangladesh have prompted extensive mitigation projects. We evaluated the effectiveness of long-term mitigation efforts by longitudinally measuring arsenic exposure in pregnant women and their children, the most susceptible population groups. METHODS: The study was nested in a population-based nutrition intervention in Matlab, Bangladesh. Mother-child pairs (n = 1951) were followed from 2001 to 2003, beginning in early gestation and continuing to 5 years postpartum. We measured arsenic concentrations in urine (U-As) of the 5-year-old children by using high-performance liquid chromatography online with hydride generation and inductively coupled plasma mass spectrometry and compared them with earlier childhood U-As and maternal U-As during pregnancy. RESULTS: Children had elevated U-As at 5 years old (median = 51 µg/L, 5th-95th percentiles = 16-355 µg/L), and U-As distribution was similar to that observed in the mothers during gestation. Children's U-As at 5 years old significantly correlated with their U-As at 1.5 years old and to maternal U-As during early and late gestation. CONCLUSIONS: Despite major mitigation efforts, arsenic exposure remains highly elevated in rural Bangladesh. Further mitigation strategies are required and must be rigorously evaluated for long-term efficacy.

The association between active/passive smoking and toxic metals among pregnant women in Greece.

Exposure to toxic metals during pregnancy may have detrimental effects on foetal development. We assessed the role of sociodemographic characteristics and active and passive smoking on blood concentrations of metals (As, Cd, Pb, Hg, Sb, U, Mn and Mo). Venous blood drawn from 50 pregnant women, randomly selected from the mother-child birth cohort 'Rhea'. Extensive questionnaire data on active and passive smoking were collected. Urinary cotinine was measured to validate self-reported exposure and non-smoking status. Smokers had higher concentrations of Cd (1.0 µg/L) as compared with non-smokers (0.29 µg/L, P < 0.001) and a tendency for higher As and Hg. Among non-smokers, blood As and Hg concentrations were also associated with exposure to passive smoking in public venues and the family home and to overall greater secondhand smoke (SHS) exposure (As: 0.97µg/L among heavy-exposed compared with 0.20 µg/L among the low-exposed, P < 0.05; Hg: 2.1 µg/L vs. 0.9 µg/L respectively, P < 0.05). Controlling for fish and seafood intake altered the statistical significance but not the direction of the above associations. Smoking was associated with higher Cd concentrations in pregnant women, although the association between passive smoking and elevated As and Hg concentrations was indicative, however inconclusive.

High concentrations of essential and toxic elements in infant formula and infant foods - A matter of concern.

This study assessed concentrations in and intake of toxic and essential elements from formulas and foods intended for infants during their first 6months of life. Concentrations of the essential elements Ca, Fe, Zn, Mn and Mo were significantly higher in most formulas than in breast milk. Daily intake of Mn from formula varies from ten up to several hundred times the intake of the breast fed infant, levels that may be associated with adverse health effects. One portion of infant food provided significantly more Fe, Mn, Mo, As, Cd, Pb and U than one feeding of breast milk, but less Ca, Cu and Se. Rice-based products in particular contained elevated As concentrations. Drinking water used to mix powdered formula may add significantly to the concentrations in the ready-made products. Evaluation of potentially adverse effects of the elevated element concentrations in infant formulas and foods are warranted.

Arsenic methylation efficiency increases during the first trimester of pregnancy independent of folate status.

Exposure to inorganic arsenic during pregnancy may negatively influence the offspring, though efficient metabolism of arsenic to dimethylarsinic acid (DMA) likely reduces the health risks. This study aimed to evaluate methylation of arsenic over the entire pregnancy and the influence of nutritional status. We studied longitudinally the arsenic metabolite pattern in the urine of 324 pregnant women exposed to arsenic via drinking water and food in rural Bangladesh. Metabolism of arsenic to DMA increased markedly over the course of pregnancy, with the greatest improvement occurring in the first trimester, along with a marked decrease in the most risk-associated monomethylated metabolite. This improvement in methylation was not associated with nutritional status, including vitamin B(12) and folate. Efficient methylation to DMA was associated with improved urinary excretion of arsenic, relative to blood arsenic concentrations, indicating that micronutrient-independent up-regulation of arsenic metabolism already in early pregnancy may provide protection for the fetus.

High-level exposure to lithium, boron, cesium, and arsenic via drinking water in the Andes of northern Argentina.

Elevated concentrations of arsenic in drinking water are common worldwide, however, little is known about the presence of other potentially toxic elements. We analyzed 31 different elements in drinking water collected in San Antonio de los Cobres and five surrounding Andean villages in Argentina, and in urine of the inhabitants, using ICP-MS. Besides confirmation of elevated arsenic concentrations in the drinking water (up to 210 microg/L), we found remarkably high concentrations of lithium (highest 1000 microg/L), cesium (320 microg/L), rubidium (47 microg/L), and boron (5950 microg/L). Similarly elevated concentrations of arsenic, lithium, cesium, and boron were found in urine of the studied women (N=198): village median values ranged from 26 to 266 microg/L of arsenic, 340 to 4550 microg/L of lithium, 34 to 531 microg/L of cesium, and 2980 to 16,560 microg/L of boron. There is an apparent risk of toxic effects of long-term exposure to several of the elements, and studies on associations with adverse human health effects are warranted, particularly considering the combined, life-long exposure. Because of the observed wide range of concentrations, all water sources used for drinking water should be screened for a large number of elements; obviously, this applies to all drinking water sources globally.

Skin deposition of nickel, cobalt, and chromium in production of gas turbines and space propulsion components.

Skin exposure to nickel, cobalt, and chromium may cause sensitization and allergic contact dermatitis and it is known that many alloys and platings may release significant amounts of the metals upon contact with skin. Occupational exposure to these sensitizing metals has been studied in different settings with regards to airborne dust and different biological end points, but little is known about deposition on skin from airborne dust and direct contact with materials containing the metals. In this study, skin deposition was studied in 24 workers in an industry for development and manufacturing of gas turbines and space propulsion components. The workers were employed in three departments, representing different exposure scenarios: tools sharpening of hard metal items, production of space propulsion structures, and thermal application of different metal-containing powders. A novel acid wipe sampling technique was used to sample metals from specific skin surfaces on the hands and the forehead of the workers. Total amounts of nickel, cobalt, and chromium were measured by inductively coupled plasma mass spectrometry. The result showed that nickel, cobalt, and chromium could be detected on all skin surfaces sampled. The highest level of nickel was 15 microg cm(-2) h(-1), the highest for cobalt was 4.5 microg cm(-2) h(-1), and for chromium 0.6 microg cm(-2) h(-1). The three departments had different exposures regarding the metals. The highest levels of nickel on the skin of the workers were found in the thermal applications department, cobalt in the tools sharpening department, and chromium in the space propulsion components department. In conclusion, the workers' exposure to the metals was more likely to come from direct skin contact with items, rather than from airborne dust, based on the fact that the levels of metals were much higher on the fingers than on the back side of the hands and the forehead. The skin exposure levels of nickel and cobalt detected are judged capable to induce sensitization and elicit allergic contact dermatitis.

Impaired arsenic metabolism in children during weaning.

BACKGROUND: Methylation of inorganic arsenic (iAs) via one-carbon metabolism is a susceptibility factor for a range of arsenic-related health effects, but there is no data on the importance of arsenic metabolism for effects on child development. AIM: To elucidate the development of arsenic metabolism in early childhood. METHODS: We measured iAs, methylarsonic acid (MA) and dimethylarsinic acid (DMA), the metabolites of iAs, in spot urine samples of 2400 children at 18 months of age. The children were born to women participating in a population-based longitudinal study of arsenic effects on pregnancy outcomes and child development, carried out in Matlab, a rural area in Bangladesh with a wide range of arsenic concentrations in drinking water. Arsenic metabolism was evaluated in relation to age, sex, anthropometry, socio-economic status and arsenic exposure. RESULTS: Arsenic concentrations in child urine (median 34 microg/L, range 2.4-940 microg/L), adjusted to average specific gravity of 1.009 g/mL, were considerably higher than that measured at 3 months of age, but lower than that in maternal urine. Child urine contained on average 12% iAs, 9.4% MA and 78% DMA, which implies a marked change in metabolite pattern since infancy. In particular, there was a marked increase in urinary %MA, which has been associated with increased risk of health effects. CONCLUSION: The arsenic metabolite pattern in urine of children at 18 months of age in rural Bangladesh indicates a marked decrease in arsenic methylation efficiency during weaning.

Breast-feeding protects against arsenic exposure in Bangladeshi infants.

BACKGROUND: Chronic arsenic exposure causes a wide range of health effects, but little is known about critical windows of exposure. Arsenic readily crosses the placenta, but the few available data on postnatal exposure to arsenic via breast milk are not conclusive. AIM: Our goal was to assess the arsenic exposure through breast milk in Bangladeshi infants, living in an area with high prevalence of arsenic-rich tube-well water. METHODS: We analyzed metabolites of inorganic arsenic in breast milk and infant urine at 3 months of age and compared them with detailed information on breast-feeding practices and maternal arsenic exposure, as measured by concentrations in blood, urine, and saliva. RESULTS: Arsenic concentrations in breast-milk samples were low (median, 1 microg/kg; range, 0.25-19 microg/kg), despite high arsenic exposures via drinking water (10-1,100 microg/L in urine and 2-40 microg/L in red blood cells). Accordingly, the arsenic concentrations in urine of infants whose mothers reported exclusive breast-feeding were low (median, 1.1 microg/L; range, 0.3-29 microg/L), whereas concentrations for those whose mothers reported partial breast-feeding ranged from 0.4 to 1,520 microg/L (median 1.9 microg/L). The major part of arsenic in milk was inorganic. Still, the infants had a high fraction (median, 87%) of the dimethylated arsenic metabolite in urine. Arsenic in breast milk was associated with arsenic in maternal blood, urine, and saliva. CONCLUSION: Very little arsenic is excreted in breast milk, even in women with high exposure from drinking water. Thus, exclusive breast-feeding protects the infant from exposure to arsenic.

Evaluation of the three most commonly used analytical methods for determination of inorganic arsenic and its metabolites in urine.

This work compares the three most common analytical methods for determination of inorganic arsenic and its metabolites in urine: high performance liquid chromatography coupled to either inductively coupled plasma mass spectrometry or atomic fluorescence spectrometry via hydride generation (high performance liquid chromatography-hydride generation-inductively coupled plasma mass spectrometry (HPLC-HG-ICPMS) and HPLC-HG-atomic fluorescence spectrometry (AFS), respectively) and atomic absorption spectrometry coupled to HG (HG-atomic absorption spectrometry (AAS)). This was done with the focus to find alternatives to ICPMS, the investment and running costs of which are rather high. Between-laboratory comparison of HPLC-HG-ICPMS and HPLC-HG-AFS showed good agreement for inorganic arsenic, methylarsonate (MA) and dimethylarsinate (DMA) (R(2)=0.91, R(2)=0.92 and R(2)=0.90, respectively, N=86). Within-laboratory comparisons of HPLC-HG-AFS, HPLC-HG-ICPMS and HG-AAS showed good agreement for all arsenic species and the sum of inorganic arsenic and its metabolites in urine (HPLC-HG-ICPMS versus HPLC-HG-AFS: R(2)=0.95; HG-AAS versus HPLC-HG-AFS: R(2)=0.95 and HPLC-HG-ICPMS versus HG-AAS: R(2)=0.97; N=89). HPLC-HG-AFS was found to be a simple, but high quality alternative to HPLC-HG-ICPMS for the speciation and quantification of inorganic arsenic and its metabolites in urine at arsenic concentrations above 10microgL(-1). Because of its considerably lower costs compared to HPLC-HG-ICPMS, it may be a good alternative in laboratories where the high cost of ICPMS is not justified in relation to the intended use of the instrument.