Blood cadmium, lead, manganese, mercury, and selenium levels in American Indian populations: The Strong Heart Study.

BACKGROUND: Many American Indian (AI) communities are in areas affected by environmental contamination, such as toxic metals. However, studies assessing exposures in AI communities are limited. We measured blood metals in AI communities to assess historical exposure and identify participant characteristics associated with these levels in the Strong Heart Study (SHS) cohort. METHOD: Archived blood specimens collected from participants (n = 2014, all participants were 50 years of age and older) in Arizona, Oklahoma, and North and South Dakota during SHS Phase-III (1998-1999) were analyzed for cadmium, lead, manganese, mercury, and selenium using inductively coupled plasma triple quadrupole mass spectrometry. We conducted descriptive analyses for the entire cohort and stratified by selected subgroups, including selected demographics, health behaviors, income, waist circumference, and body mass index. Bivariate associations were conducted to examine associations between blood metal levels and selected socio-demographic and behavioral covariates. Finally, multivariate regression models were used to assess the best model fit that predicted blood metal levels. FINDINGS: All elements were detected in 100% of study participants, with the exception of mercury (detected in 73% of participants). The SHS population had higher levels of blood cadmium and manganese than the general U.S. population 50 years and older. The median blood mercury in the SHS cohort was at about 30% of the U.S. reference population, potentially due to low fish consumption. Participants in North Dakota and South Dakota had the highest blood cadmium, lead, manganese, and selenium, and the lowest total mercury levels, even after adjusting for covariates. In addition, each of the blood metals was associated with selected demographic, behavioral, income, and/or weight-related factors in multivariate models. These findings will help guide the tribes to develop education, outreach, and strategies to reduce harmful exposures and increase beneficial nutrient intake in these AI communities.

Associations between welding fume exposure and blood hemostatic parameters among workers exposed to welding fumes in confined space in Chonburi, Thailand.

BACKGROUND: Occupational welding fumes contain varieties of toxic metal particles and may affect cardiovascular system like the Particulate Matters (PM). Few studies have focused on the effects of toxic metals on the hemodynamic balance; however, the reporting results were not consistent. This study aimed to investigate the association between toxic metals exposure (Chromium (Cr), Manganese (Mn) and Lead (Pb)) and blood hemostatic parameters status after a 3-week exposure cessation among workers exposed to welding fumes. METHODOLOGY: Structured interviews and biological samplings were conducted for 86 male workers without a history of Anemia and Cardiovascular diseases (CVDs) and working in a confined space to construct crude oil tanks. Metal levels of Cr, Mn and Pb in urine were measured during the working days using Inductively Coupled Plasma Mass Spectrometer (ICP-MS) method. The concentrations of hemostatic proteins in blood (White blood cell counts (WBC), Lymphocytes, Monocyte, Eosinophil, Neutrophil, Hematocrit (Hct) were assessed after a 3 weeks exposure cessation. Workers were divided into groups based on occupation type (welder group and non-welder group), and based on metal levels (high and low exposure groups) for comparison. Linear regression models were used to explore the association between metal exposure and multiple blood hemostatic parameters adjusted for age, Body Mass Index (BMI), and smoking status. RESULTS: Urine Mn and Cr level of the welder group was significantly higher than the non-welder group (Mn: 0.96 VS 0.22 ug/g creatinine, p < 0.001; Cr: 0.63 VS 0.22 ug/g creatinine, p < 0.01). The mean value of Hct in the welder group was 44.58 ± 2.84 vol%, significantly higher than the non-welder group (43.07 ± 3.31 vol%, p = 0.026). The median value of WBC in the high Mn-exposed group (6.93 ± 1.59 X 106 Cell/ml) was significantly lower than the low Mn-exposed group (7.90 ± 2.13 X 106 Cell/ml, p = 0.018). The linear regression analyses showed that there was a significantly negative association between log transformed WBC value and the Mn exposure groups (high and low) after adjusting for age, BMI, and smoking status (ß = - 0.049, p = 0.045), but no significant result was found between WBC and occupation types (welder and non-welder) (p > 0.05). Multiple linear regression analysis also showed positive association between Hct and occupational types (welder and non-welders) (ß = 0.014, p = 0.055). The other hemostatic parameters were not different from controls when divided by occupation type or metal level groups. CONCLUSIONS: Our results showed that welders were exposed to about 3 to 4 times higher Mn and Cr concentrations than non-welders. Moreover, one third of the non-welders were exposed to high-exposure groups of Mn and Cr metals. Regression models revealed a significant association of the WBC counts with the Mn exposure group. Therefore, we infer that Mn exposure may play a significant role on the blood hemostatic parameters of workers in the confined space. Hazard identification for non-welders should also be conducted in the confined space.

Health Risk Assessment and Source Apportionment of Mercury, Lead, Cadmium, Selenium, and Manganese in Japanese Women: An Adjunct Study to the Japan Environment and Children's Study.

Toxic element pollution is a serious global health concern that has been attracting considerable research. In this study, we elucidated the major routes of exposure to three toxic elements (mercury, cadmium, and lead) and two essential elements (manganese and selenium) through diet, soil, house dust, and indoor air and assessed the potential health risks from these elements on women from the coastal area of Miyagi prefecture, Japan. Twenty-four-hour duplicate diet, house dust, soil, and indoor air samples were collected from 37 participants. Cd, Pb, Mn, and Se concentrations were measured using inductively coupled plasma mass spectrometry, and Hg concentrations using cold vapor atomic absorption spectrometry. We found that soil and house dust were the primary reservoirs of these elements. Diet contributed most strongly to the daily intake of these elements, with mean values of 0.72, 0.25, 0.054, 47, and 0.94 µg/kg/day for Hg, Cd, Pb, Mn, and Se, respectively. The mean hazard quotient of Hg was 1.53, indicating a high potential health risk from Hg exposure in daily lives. The intakes of other elements were below the tolerable limits. Future studies with a larger sample size are warranted to confirm our findings.

Assessment of copper, iron, zinc and manganese status and speciation in patients with Parkinson's disease: A pilot study.

BACKGROUND: The objective of this pilot study was to assess iron (Fe), copper (Cu), zinc (Zn), and manganese (Mn) status (hair, serum, and urine) and speciation (serum) in Parkinson's disease (PD) patients. METHODS: A pilot study involving a total of 27 subjects (13 PD patients, 14 controls) was performed. Serum, urine, and hair metal content was assessed using ICP-MS. Speciation analysis of Cu, Zn, Fe, and Mn was performed using a hybrid HPLC-ICP-MS system. RESULTS: Group comparisons did not reveal any significant group difference in serum Cu, Zn, Fe, and Mn total metal level between PD patients and controls. Speciation analysis revealed a significant decrease in Cu/ceruloplasmin copper in association with elevation of low-molecular weight species (amino acids)-bound copper. It is proposed that in PD, binding of Cu(II) ions to ceruloplasmin is reduced and free copper ions coordinate with low molecular weight ligands. The level of Mn-albumin complexes in PD patients was more than 4-fold higher as compared to the respective value in the control group. The observed difference may be considered as a marker of redistribution between high and low molecular weight ligands. CONCLUSIONS: Metal speciation is significantly affected in serum of PD-patients. These findings are indicative of the potential role of metal metabolism and PD pathogenesis, although the exact mechanisms of such associations require further detailed studies.

Assessment of 12 Metals and Metalloids in Blood of General Populations Living in Wuhan of China by ICP-MS.

Assessment of trace element levels in general population from the specific area is of importance for nutritional and occupational monitoring. In the current study, baseline blood levels of 12 toxic and/or essential metals and metalloids, including arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), chromium (Cr), thallium (Tl), manganese (Mn), copper (Cu), Zinc (Zn), calcium (Ca), iron (Fe), and magnesium (Mg), in general populations (n = 477) of Wuhan in central China were investigated by using inductively coupled plasma mass spectrometry (ICP-MS). The geometric means for As, Cd, Pb, Hg, Cr, Tl, Mn, and Cu were measured as 2.25, 0.70, 17.84, 1.90, 0.36, < 0.05, 12.40, and 783.76 µg/L, respectively. The geometric means for Zn, Ca, Fe, and Mg were 5.85, 56.66, 488.98, and 39.44 mg/L, respectively. We found the men had higher blood As, Pb, Hg, Zn, Fe, and Mg levels but had lower blood Cu and Ca levels than the women (p < 0.05). Age-related difference were found for blood Cu, Zn, Ca, Mg, Pb, Mn, As, Cd, and Hg levels (p < 0.05). Moreover, many metal concentrations were found correlated, with the strongest correlations between the pairs Fe-Mg (r = 0.57), Fe-Zn (r = 0.42), As-Hg (r = 0.46), Ca-Cu (r = 0.34), Pb-Hg (r = 0.36), Pb-Cd (r = 0.31), Pb-As (r = 0.25), and Ca-Fe (r = - 0.23). Compared with reports from other countries, most of our results were consistent, except that As Pb, Hg, Mn, and Cu showed different blood levels with European, Korea, or Beijing areas. Our study would be of importance for nutritional, environmental, and/or occupational monitoring of these metals in human.

Assessment of blood levels of heavy metals including lead and manganese in healthy children living in the Katanga settlement of Kampala, Uganda.

BACKGROUND: Exposure to environmental heavy metals is common among African children. Although many of these metals are known neurotoxicants, to date, monitoring of this exposure is limited, even in countries such as Uganda that are undergoing rapid industrialization. An assessment of the burden and potential causes of metal exposure is a critical first step in gauging the public health burden of metal exposure and in guiding its elimination. METHODS: In May 2016, we enrolled 100 children between the ages of 6 and 59 months living in the Katanga urban settlement of Kampala, Uganda. We measured whole blood concentrations of antimony, arsenic, barium, cadmium, cesium, chromium, cobalt, copper, lead, manganese, nickel, selenium, and zinc. Applying reference cutoffs, we identified metals whose prevalence of elevated blood concentrations was > 10%. We also administered an environmental questionnaire to each child's caregiver to assess potential exposures, including source of drinking water, cooking location and fuel, materials used for roof, walls, and floor, and proximity to potential pollution sources such as main roads, garbage landfills, and fuel stations. We compared log-transformed blood metal concentrations by exposure category, using t-test for dichotomous comparisons and ANOVA for comparisons of three categories, using Tukeys test to adjust for multiple comparisons. RESULTS: The prevalence of high blood levels was elevated for six of the metals: antimony (99%), copper (12%), cadmium (17%), cobalt (19.2%), lead (97%), and manganese (36.4%). Higher blood manganese was significantly associated with having cement walls (p = 0.04) or floors (p = 0.04). Cadmium was greater among children who attended school (< 0.01), and cobalt was higher among children who lived near a garbage landfill (p = 0.01). CONCLUSIONS: Heavy metal exposure is prevalent in the Katanga settlement and may limit neurodevelopment of children living there. Future studies are needed to definitively identify the sources of exposure and to correct potential nutritional deficiencies that may worsen metal absorption.

An assessment of clinical laboratory performance for the determination of manganese in blood and urine.

BACKGROUND: Proficiency testing or external quality assessment schemes (PT/EQASs) are an important method of assessing laboratory performance. As each scheme establishes assigned values and acceptable ranges for the analyte according to its own criteria, monitoring of participant performance varies according to the scheme and can lead to conflicting conclusions. METHODS: Standard deviations (SDs) for PT were derived from Thompson's and biological variation models applied to blood and urine manganese (Mn) robust data from four EQASs from North America and Europe. The fitness for purpose was verified by applying these SDs to individual results. RESULTS: Using Thompson characteristic function the relationship between SD and Mn concentration, expressed in nmol/L was the square root of [19.72+(0.07712×Mn concentration2)] for blood and the square root of [6.772+(0.09852×Mn concentration2)] for urine. While the biological variation model was not suitable for urine, it produced an acceptable range for blood as ±54.4 nmol/L (assigned value ≤320 nmol/L) or 17% (assigned value >320 nmol/L). For blood, individual performance evaluated by the two approaches led to similar conclusions. CONCLUSIONS: The biological variation model can be used to propose quality specifications for blood, however it could not be applied to urine. The Thompson characteristic function model could be applied to derive quality specifications for Mn in urine and, to a lesser extent in blood. The more lenient quality specifications for blood highlight the difficulty of determining Mn in this matrix. Further work is needed to harmonize PT, such as using assigned ranges for the specimens.

Simplified sample preparation in the simultaneous measurement of whole blood antimony, bismuth, manganese, and zinc by inductively coupled plasma mass spectrometry.

OBJECTIVES: We developed and validated a simplified sample preparation for the analysis of antimony (Sb), bismuth (Bi), manganese (Mn), and zinc (Zn) in whole blood. This simplification included a reduction in sample volume, removal of a lengthy acidic digestion, and optimization of the internal standard. DESIGN AND METHODS: Measurement of Sb, Bi, Mn and Zn in whole blood was conducted using inductively coupled-plasma mass spectrometry. Method performance characteristics, including intra- and inter-assay imprecision, accuracy, linearity, AMR, sensitivity, carryover, sample stability and assay stability were determined in accordance with clinical laboratory standards. In addition, analytical and clinical recoveries were assessed to investigate comparability between goat blood matrix and pooled patient blood. RESULTS: Established assay performance characteristics included inter- and intra-assay imprecision <4.5% and carryover of <0.04% for all four elements, analytical measurement range of 1 to 25 µg/L (Sb and Bi), 1 to 80 µg/L (Mn), and 50 to 1500 µg/dL (Zn), limit of quantification of 1 µg/L (Sb, Bi, Mn) and 50 µg/dL (Zn) (coefficient of variation <14%), proportional bias of 0.96 and constant bias of -0.28 (Sb), 0.94 and -0.45 (Bi), 1.07 and -0.37 (Mn) and 0.96 and +18.05 (Zn) based upon repeat patient samples, proficiency testing samples, and comparison to an outside reference laboratory. CONCLUSION: This method overcomes the laborious acidic heat digestion previously used and replaces it with a simplified sample preparation involving an alkaline dilution. The method requires minimal sample preparation with the dilution of alkaline diluent and is validated to quantify Sb and Bi from 1 to 25 µg/L, Mn from 1 to 80 µg/L, and Zn from 50 to 1500 µg/dL in whole blood.

Avaliação da exposição ambiental ao manganês na população residenteno entorno de um estaleiro no município de Angra dos Reis, RJ / Assessment of environmental exposure to manganese in the resident population in the vicinity of a site in the municipality of Angra dos Reis, RJ

O manganês é um componente essencial no processo de soldagem, porconferir dureza e resistência, assim como na produção do aço, onde é usadocomo agente dessulfurante e redutor. Apesar de ser um elemento essencial ao homem, atuando na formação dos ossos e tecidos, função reprodutiva e metabolismo de carboidratos e lipídios, a exposição crônica ao Mn afeta, principalmente, o sistema nervoso central. Uma vez que solda e aço são essenciais para a construção e reparo de navios, essa indústria torna-se uma importante fonte de exposição ao referido metal. O objetivo deste trabalho foi avaliar a exposição ao manganês na população residente no entorno de um estaleiro em Angra dos Reis-RJ, que foi comparada a um grupo de moradores do município da Serra-ES. A coleta de dados foi realizada através da aplicação de um questionário padronizado fundamentado para o conhecimento das variáveis sócio-econômicas e fatores de risco para a exposição ao metal, resultando em universo amostral de 98 sujeitos e amostras de ar do local exposto. A técnica analítica utilizada para a determinação do manganês nosfluidos biológicos e nos filtros de ar foi a espectrometria de absorção atômica eletrotérmica. (...)

Assessment of personal exposure to manganese in children living near a ferromanganese refinery.

Airborne exposure to manganese (Mn) can result in neurologic effects. Stationary air sampling is the traditional technique to assess Mn exposure for communities, yet may not accurately reflect children's personal exposure. The goal of the study was to characterize personal exposure to Mn and PM(2.5) in a cohort of children ages 7-9 years residing near a ferromanganese refinery. A subset of children living in non-smoking households ages 7-9 enrolled in the Marietta Community Actively Researching Exposure Study during March-June 2009 and 2010 were invited to participate. Blood and hair were collected and analyzed for Mn. Participants wore a PM(2.5) sampler (Personal Modular Impactor) for 48 h. TWD was based on time spent at home and school and the distance of each from the refinery. Stationary outdoor air sampling was conducted 8 km from the refinery using a Harvard-type PM(2.5) impactor. The relationship between personal Mn exposure and TWD was examined by multiple regression adjusting for stationary air Mn concentration, wind speed and direction, and precipitation. Complete personal air sampling data were collected on 38 children. TWD ranged from 4.7 km to 28.5 km with a mean distance of 11.1 (4.7 sd) km. Mn concentration in personal air samples ranged from 1.5 ng/m3 to 54.5 ng/m3 (geometric mean, 8.1 ng/m3). TWD was a significant predictor of natural log personal air Mn concentration (lnMn) with an associated decrease of 0.075 lnMn for each km TWD (p<0.05, 95% CI -0.13 to -0.01). Personal Mn exposures were positively associated with stationary air Mn levels and inversely associated with wind speed. A child's location (home and school) relative to the refinery is a significant predictor of personal Mn exposure. Wind speed is also an important contributor to personal Mn exposure.

Effects of menopause on blood manganese levels in women: analysis of 2008-2009 Korean National Health and Nutrition Examination Survey data.

INTRODUCTION: We present data from the Korean National Health and Nutrition Examination Survey 2008-2009 on the association between blood manganese (Mn) levels and menopausal status in women. METHODS: The present analysis was restricted to female participants who completed the health examination survey, including blood Mn measurements (n=1826). Menopausal status was categorized into pre- and post-menopausal. Multivariable linear regression analyses were performed to determine whether menopausal status or serum ferritin were significant predictors of blood Mn level and to investigate whether menopausal status modifies the association between blood Mn and serum ferritin after adjusting for covariates. RESULTS: The geometric means (GMs) of blood Mn in the low and low-normal serum ferritin groups were significantly higher than the GM of blood Mn in the normal group. The GM of blood Mn in premenopausal women was significantly higher than in postmenopausal women Multivariable linear regression analyses showed that both serum ferritin and menopausal status were predictors of blood Mn, after adjusting for various covariates, and menopausal status acted as a modifier of the effect of ferritin on blood Mn levels. Blood Mn levels were 11.0% and 22.7% lower in premenopausal women when serum ferritin increased from 10 µg/dL to 60 and 100 µg/dL, respectively, but the decrease in blood Mn based on the increase in serum ferritin was minimal in postmenopausal women. DISCUSSION: To our knowledge, this is the first report that menopausal status was a predictor of blood Mn level after adjusting for serum ferritin. In conclusion, the present study showed that both serum ferritin and menopausal status were predictors of blood Mn, after adjusting for various covariates, and menopausal status acted as a modifier of the effect of ferritin on blood Mn levels.

[Value of manganese in human life (literature review)].

Manganese is an important element essential for human functioning. Pathogenesis of manganese intoxication remains unclear. Specification of differential diagnostic criteria is required for diagnosis of occupational manganese intoxication and ruling out Parkinson disease and secondary parkinsonism in the patients.

Assessment of reference ranges for blood Cu, Mn, Se and Zn in a selected Italian population.

The reference ranges for blood Cu, Mn, Se and Zn of 215 adult subjects non-occupationally exposed and living in the Nuoro province (Sardinia, insular Italy) were assessed. Metals were determined by sector field inductively coupled plasma mass spectrometry after microwave-assisted acid digestion of blood. The blood reference ranges estimated as P5-P95 percentiles (geometric mean, GM) were 776-1495µg/L (1036µg/L) for Cu; 4.73-17.0µg/L (8.91µg/L) for Mn; 106-185µg/L (140µg/L) for Se and 4686-8585µg/L (6418µg/L) for Zn. These results were then stratified for sex, age, alcohol consumption, smoking habit and living area. The GM value of Cu was significantly higher in females (1127µg/L) than in males (957µg/L). Age, alcohol intake, smoking habit and residential area did not influence blood Cu. The GM of Mn was significantly higher in females (9.98µg/L) respect to males (8.01µg/L) and in drinkers (9.67µg/L) compared to non-drinkers (8.38µg/L). The other variables did not change the Mn data. Selenium concentrations did not differ significantly as a function of individuals factors. With reference to Zn, males had GM of 6804µg/L and females of 6031µg/L, and more blood Zn was found in subjects consuming alcohol (6618µg/L) respect to abstainers (6155µg/L). In addition, blood Zn was not affected by age, smoking habit and place of living.

Avaliação da exposição a metais numa oficina de recuperação de armamento de uma organização militar / Exposure assessment to metals in an armament repair shop of a military organization

O objetivo deste estudo foi a avaliação da exposição ocupacional ao chumbo e manganês dos trabalhadores de uma oficina de recuperação de armamento de uma organização militar. O ar do ambiente de trabalho foi avaliado no monitoramento ambiental e os indicadores biológicos de dose interna, para chumbo e manganês, em sangue e na urina, foram utilizados no monitoramento biológico. A concentração de manganês e chumbo nos filtros e fluidos biológicos foi determinada por espectrometria de absorção atômica eletrotérmica. Os resultados do monitoramento ambiental indicaram níveis de Pb e Mn acima do TLV-TWA durante o processo de pintura (313,33 μg m-3) e solda (951 μg m-3). Os indicadores biológicos revelaram que cinco dos nove trabalhadores apresentam níveis de Pb-S que sugerem exposição ambiental ao chumbo (valores entre 5 e 10 μg dL-1). Pode-se concluir que existe uma pequena exposição ocupacional ao chumbo e ao manganês na oficina de tratamento superficial. Tal exposição é influenciada pelas condições meteorológicas e pela demanda variável de trabalho.

The aim of this study was the occupational exposure assessment to lead and manganese of workers in an armament repair shop of a military organization. The air of the working environment was assessed in the environmental monitoring while the internal dose biological indicators for lead and manganese, in blood and urine, were used in biological monitoring. Metals concentration in filters and biological fluids were determined by electrothermal atomic absorption spectrometry. The results of the environmental monitoring showed lead and manganese levels above the TLV-TWA during the process of painting (313.33 g m-3) and solder (951 μg m-3). The biological indicators revealed that five of the nine employees presented Pb-S levels that suggested an environmental exposure to lead (values between 5 and 10 μg dL-1). It can be concluded that there is a small occupational exposure to lead and manganese in the superficial treatment repair shop. This exposure is influenced by weather conditions and the variable demand of work.

Exposure-response relationship and risk assessment for cognitive deficits in early welding-induced manganism.

OBJECTIVE: The exposure-response relationship for manganese (Mn)-induced adverse nervous system effects is not well described. Symptoms and neuropsychological deficits associated with early manganism were previously reported for welders constructing bridge piers during 2003 to 2004. A reanalysis using improved exposure, work history information, and diverse exposure metrics is presented here. METHODS: Ten neuropsychological performance measures were examined, including working memory index (WMI), verbal intelligence quotient, design fluency, Stroop color word test, Rey-Osterrieth Complex Figure, and Auditory Consonant Trigram tests. Mn blood levels and air sampling data in the form of both personal and area samples were available. The exposure metrics used were cumulative exposure to Mn, body burden assuming simple first-order kinetics for Mn elimination, and cumulative burden (effective dose). Benchmark doses were calculated. RESULTS: Burden with a half-life of about 150 days was the best predictor of blood Mn. WMI performance declined by 3.6 (normal = 100, SD = 15) for each 1.0 mg/m3 x mo exposure (P = 0.02, one tailed). At the group mean exposure metric (burden; half-life = 275 days), WMI performance was at the lowest 17th percentile of normal, and at the maximum observed metric, performance was at the lowest 2.5 percentiles. Four other outcomes also exhibited statistically significant associations (verbal intelligence quotient, verbal comprehension index, design fluency, Stroop color word test); no dose-rate effect was observed for three of the five outcomes. CONCLUSIONS: A risk assessment performed for the five stronger effects, choosing various percentiles of normal performance to represent impairment, identified benchmark doses for a 2-year exposure leading to 5% excess impairment prevalence in the range of 0.03 to 0.15 mg/m3, or 30 to 150 microg/m3, total Mn in air, levels that are far below those permitted by current occupational standards. More than one-third of workers would be impaired after working 2 years at 0.2 mg/m3 Mn (the current threshold limit value).

Manganese exposure among smelting workers: blood manganese-iron ratio as a novel tool for manganese exposure assessment.

Unexposed control subjects (n = 106), power distributing and office workers (n = 122), and manganese (Mn)-exposed ferroalloy smelter workers (n = 95) were recruited to the control, low and high groups, respectively. Mn concentrations in saliva, plasma, erythrocytes, urine and hair were significantly higher in both exposure groups than in the controls. The Fe concentration in plasma and erythrocytes, however, was significantly lower in Mn-exposed workers than in controls. The airborne Mn levels were significantly associated with Mn/Fe ratio (MIR) of erythrocytes (eMIR) (r = 0.77, p < 0.01) and plasma (pMIR) (r = 0.70, p < 0.01). The results suggest that the MIR may serve as a useful biomarker to distinguish Mn-exposed workers from the unexposed, control population.

[Exposure assessment to metals in an armament repair shop of a military organization]. / Avaliação da exposição a metais numa oficina de recuperação de armamento de uma organização militar.

The aim of this study was the occupational exposure assessment to lead and manganese of workers in an armament repair shop of a military organization. The air of the working environment was assessed in the environmental monitoring while the internal dose biological indicators for lead and manganese, in blood and urine, were used in biological monitoring. Metals concentration in filters and biological fluids were determined by electrothermal atomic absorption spectrometry. The results of the environmental monitoring showed lead and manganese levels above the TLV-TWA during the process of painting (313.33 g m-3) and solder (951 microg m-3). The biological indicators revealed that five of the nine employees presented Pb-S levels that suggested an environmental exposure to lead (values between 5 and 10 microg dL-1). It can be concluded that there is a small occupational exposure to lead and manganese in the superficial treatment repair shop. This exposure is influenced by weather conditions and the variable demand of work.

Assessment of latent manganese toxicity as a prognostic factor following surgery for biliary atresia.

PURPOSE/BACKGROUND: The aim of this study was to investigate latent manganese toxicity in patients with biliary atresia and to use this tool to predict the prognosis of biliary atresia patients after Kasai's portoenterostomy. METHODS: 14 patients who underwent Kasai's portoenterostomy between 1993 and 2005 were included in the study. Whole blood manganese assays were performed using atomic adsorption spectroscopy (Philips PU 9200, Cambridge, UK) and verified by repeat analysis; these were done at the time of surgery and 6 months later. All blood samples were collected in an identical manner, blinded and then assayed by technicians. Whole blood manganese levels were correlated with the development of manganese deposits in the globus pallidus on T1-weighted images on magnetic resonance imaging (MRI) of the brain. Serum bilirubin of all 14 patients were noted both at the time of surgery and 6 months later. A hepatobiliary (HIDA) scan was done in all patients 6 months after Kasai's portoenterostomy. RESULTS: The bilirubin declined in all except 2 patients after surgery. Both these patients developed ascites and severe jaundice and 1 expired one year after surgery. HIDA scan was excretory in all 14 patients. Whole blood manganese ranged from 1.26 - 27.58 microg/dl (mean 4.63 +/- 7.00) at the time of surgery; the levels were normal in 11 patients and elevated in 3. The postoperative assay at 6 months after surgery demonstrated values from 1.08 - 74.46 microg/dl (mean 13.55 +/- 24.17); 4 patients showed an increase from the previous value. Globus pallidus hyperintensity on T1-weighted images was noted in 1 patient on MRI; this patient had a sharp rise in the postoperative manganese level. All other MRI examinations were normal. All 14 patients were neurologically intact. CONCLUSIONS: Although the study size is small, it shows that there is a risk of latent manganese toxicity in patients with biliary atresia who have undergone Kasai's portoenterostomy. Whole blood manganese assay in conjunction with brain MRI can be used to serially monitor these patients for early detection of these complications. This tool can be used for prognosis after Kasai's portoenterostomy and can also be extremely useful in selecting patients who will need a liver transplant on a priority basis.

Evaluation of MR signal index for the assessment of occupational manganese exposure of welders by measurement of local proton T1 relaxation time.

Magnetic resonance (MR) imaging has become a useful tool for the estimation of occupational exposure to manganese (Mn). However, validity of signal indices on T1-weighted imaging, a proxy measurement of T1 relaxation time shortening due to Mn deposition, needs to be evaluated in an occupationally exposed population. We performed MR imaging on 20 male welders and 10 age- and gender-matched, non-office workers in a shipyard. We measured the relative signal intensity ratio of the globus pallidus (GP) to the frontal white matter on T1-weighted MR images (pallidal index, PI). We also assessed the visual scale for the relative signal intensity of the GP, which was graded as 0-2 by a radiologist. We evaluated both signal index and visual scale in relation to the T1 relaxation time measured at the GP. Both PI and T1 relaxation time were significantly increased in the welders compared to the non-welders. T1 relaxation time began to decrease from visual scale 2, while PI began to increase from visual scale 1. Environmental Mn exposure indices correlated well with both T1 relaxation time and PI. However, blood Mn level correlated only with T1 relaxation time, and not with PI. T1 relaxation time correlated with PI only at the higher level of PI. These results indicate the possible inaccuracy of visual scoring and the discrepancy between T1 relaxation time and PI, especially at the lower level of signal intensity. Although both T1 and PI are good biomarkers for the environmental Mn exposure, non-linearity of the relationship between T1 and PI must be considered in the assessment of Mn exposure using MRI.

The nervous system effects of occupational exposure on workers in a South African manganese smelter.

Five hundred and nine production workers at a manganese (Mn) smelting works comprising eight production facilities and 67 external controls were studied cross-sectionally for Mn related neuroehavioural effects. Exposure measures from personal sampling included Mn in inhalable dust as cumulative exposure indices (CEI) and average intensity (INT). Biological exposure and biological effect measures included blood (MnB), urine (MnU) manganese and serum prolactin. Endpoints included items from the Swedish nervous system questionnaire (Q16), World Health Organisation neurobehavioural core test battery (WHO NCTB), Swedish performance evaluation system (SPES), Luria-Nebraska (LN), and Danish product development (DPD) test batteries, and a brief clinical examination. Potential confounders and effect modifiers included age, educational level, alcohol and tobacco consumption, neurotoxic exposures in previous work, past medical history, previous head injury and home language. Associations were evaluated by multiple linear and logistic regression modelling. Modelling assumptions were tested. Average exposure intensity across all jobs ranged from near 0 (0.06 microg/m3) for external controls to 5.08 mg/m3 for inhalable Mn, and was greater than the ACGIH TLV for 69% of subjects. Results from the large number of tests performed resolved into three groups. Group 1 shows differences between external unexposed referents and all the exposed and/or differences between internal low exposed referents and the rest of the exposed but no further exposure-response relationships. It includes the Santa Ana, Benton and digit-span tests from the WHO NCTB; the hand tapping and endurance tapping tests from the SPES; Luria-Nebraska item 2L; questionnaire items tired, depressed, irritated, having to take notes in order to remember things, and subjects' perception that they had sex less often than normal; a test of clinical abnormality; and increased sway under two conditions (eyes open without foot insulation, eyes open with foot insulation). Group 2 shows the presence of a more substantive exposure-response relationship. It consists of only two tests: and includes the WHO digit-symbol test (although the major impact is at low exposure and therefore counterintuitive, arguably placing this test in group 3) and the LN item 1R which has a step to a poorer score at high exposure. Group 3 contains the overwhelming majority of test results (almost all the questionnaire items, almost all the DPD tests including tremor, sway and diadochokinesia, and serum prolactin) which were either null or counterintuitive (did not make sense). The CEI was the strongest predictor of test abnormalities, except for the clinical test which was more strongly associated with blood manganese. Despite a comprehensive range of endpoints, and levels of exposure ranging from environmental to industrial, this large study of Mn workers found little convincing evidence for a continuum of effects, contributing further questions to current debates about the adequacy of the current ACGIH TLV.