Efectos genotóxicos asociados a metales pesados en una población humana de la región de La Mojana, Colombia, 2013 / Genotoxic effects in a human population exposed to heavy metals in the region of La Mojana, Colombia, 2013

Introducción. En Colombia, la minería es una actividad económica importante; sin embargo, genera grandes cantidades de residuos que contienen elementos potencialmente tóxicos, como los metales pesados, que contaminan los ecosistemas y ponen en riesgo la salud humana. La región de La Mojana es una de las zonas más ricas en biodiversidad del planeta y se ha visto sometida a procesos de contaminación muy relacionados con la minería de oro que se desarrolla en sus alrededores. Objetivo. Evaluar la genotoxicidad en una población expuesta a residuos de metales pesados en la región de La Mojana. Materiales y métodos. Se evaluaron los efectos genotóxicos y su relación con la concentración de metales pesados (mercurio, cadmio y plomo) en muestras de sangre de la población expuesta y el grupo de control. El grupo expuesto lo conformaron habitantes de los municipios de Guaranda, Sucre, Majagual y San Marcos; en el grupo de control se incluyó a habitantes del municipio de Montería. Se determinó el daño en el ADN mediante el ensayo cometa en condiciones alcalinas. Las concentraciones de mercurio se establecieron mediante espectrometría de absorción atómica con vapor frío, en tanto que las de cadmio y plomo se determinaron por espectrometría de absorción atómica en horno de grafito. Resultados. Las concentraciones de los metales sobrepasaron los límites permitidos por la Organización Mundial de la Salud. Se evidenciaron efectos genotóxicos posiblemente asociados a la presencia de los metales en la sangre. Se encontraron asociaciones significativas (p<0,05) entre la presencia de mercurio y de cadmio, y el daño en el ADN. Conclusión. Estos resultados sugieren que el daño genético registrado en pobladores de la región de La Mojana, Colombia, puede estar asociado a la presencia de los metales estudiados en las muestras de sangre.

Introduction: Mining is an economically important activity in Colombia which generates large quantities of residues containing potentially toxic elements such as heavy metals. These contaminate ecosystems and place human health at risk. La Mojana lies within one of the most biodiversity-rich zones on Earth and has been subjected to processes of contamination closely related to gold mining activities in the surrounding areas. Objective: To evaluate genotoxicity in the population of La Mojana region exposed to heavy metals. Materials and methods: Genotoxic effects and their relationship with concentrations of heavy metals (mercury, cadmium and lead) in blood were evaluated among an exposed population and a control group. The exposed group comprised inhabitants of the municipalities of Guaranda, Sucre, Majagual and San Marcos; inhabitants of the municipality of Montería were chosen as a control group. DNA damage was determined using the alkaline comet assay. Concentrations of mercury were determined by cold vapor atomic absorption spectrometry, and those of cadmium and lead by graphite furnace atomic absorption spectrometry. Results: Concentrations of the heavy metals exceeded the limits permitted by the World Health Organization. Genotoxic effects were found in the exposed population, possibly associated with the presence of these metals in blood. Significant associations (p<0.05) were found between mercury and cadmium levels and damage to DNA. Conclusion: These results suggest that the genetic damage recorded among inhabitants of the region of La Mojana, Colombia, may be associated with the presence of heavy metals in the blood.

Primary headaches interfere with the efficacy of temporomandibular disorders management

OBJECTIVES: This cross-sectional study aimed to evaluate the influence of Primary Headache (PH) on efficacy of a Temporomandibular Disorders (TMD) conservative therapy and its association with the presence of self-reported parafunctional habits. SAMPLE AND METHODS: Sample was composed of 400 medical records, divided into four groups: I) Muscular TMD (n=64); II) Muscular TMD+PH (n=48); III) Muscular TMD+Articular TMD (n=173); IV) Muscular TMD+Articular TMD+PH (n=115). All groups had undergone a TMD therapy for three months with a stabilization appliance and counseling for habits and behavioral changes, with no specific headache management. Current pain intensity and existence or not of self-reported bruxism were assessed. Repeated measures ANOVA and Chi-Square test followed by Odds were used for statistical analysis, with a significance level of 5%. RESULTS: results of this study showed that: (1) A conservative therapy with stabilization appliance and counseling for habits and behavioral changes was effective in the TMD pain relief; (2) Groups with an additional diagnosis of PH had worsened the pain improvement significantly; and (3) no association between the presence of self-reported bruxism and PH was found. CONCLUSIONS: this study could elucidate the important effect that headache may have on the TMD management. .

Environmental Heavy Metal Exposure and Chronic Kidney Disease in the General Population

Lead (Pb), mercury (Hg), and cadmium (Cd) are common heavy metal toxins and cause toxicological renal effects at high levels, but the relevance of low-level environmental exposures in the general population is controversial. A total of 1,797 adults who participated in the KNHANES (a cross-sectional nationally representative survey in Korea) were examined, and 128 of them (7.1%) had chronic kidney disease (CKD). Our study assessed the association between Pb, Hg, Cd exposure, and CKD. Blood Pb and Cd levels were correlated with CKD in univariate logistic regression model. However, these environmental heavy metals were not associated with CKD after adjustment for age, sex, BMI, smoking, hyperlipidemia, hypertension, diabetes, and these metals in multivariate logistic regression models. We stratified the analysis according to hypertension or diabetes. In the adults with hypertension or diabetes, CKD had a significant association with elevated blood Cd after adjustment, but no association was present with blood Pb and Hg. The corresponding odds ratio [OR] of Cd for CKD were 1.52 (95% confidence interval [CI], 1.05-2.19, P=0.026) in adults with hypertension and 1.92 (95% CI, 1.14-3.25, P=0.014) in adults with diabetes. Environmental low level of Pb, Hg, Cd exposure in the general population was not associated with CKD. However, Cd exposure was associated with CKD, especially in adults with hypertension or diabetes. This finding suggests that environmental low Cd exposure may be a contributor to the risk of CKD in adults with hypertension or diabetes.

Blood Mercury and Insulin Resistance in Nondiabetic Koreans (KNHANES 2008-2010)

PURPOSE: Blood mercury levels are associated with inflammation, and chronic low-grade inflammation is a cause of insulin resistance. This study aimed to investigate the association between serum mercury and insulin resistance. MATERIALS AND METHODS: Subjects from the 2008-2010 Korean National Health and Nutrition Examination Survey were selected (n=29235) and the relevant data of 5388 subjects (2643 males and 2745 females) were analyzed cross-sectionally. Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) was compared according to blood mercury quartiles, and the odds ratio (OR) of having the highest quartile of HOMA-IR according to blood mercury quartiles was calculated. RESULTS: Blood mercury levels in men and women were 29.4 nmol/L and 20.5 nmol/L, respectively, and fasting blood sugar (FBS), insulin, and HOMA-IR were significantly correlated with blood mercury levels. The correlation was stronger in men than in women. In men, FBS and HOMA-IR showed step-wise increases as the quartiles of blood mercury increased; only HOMA-IR differed significantly in the third and fourth blood mercury quartiles, compared to the first quartile. In women, however, both FBS and HOMA-IR differed significantly in the third and fourth blood mercury quartiles, compared to the first quartile. Among men, the OR of being in the highest HOMA-IR quartile was greatest for the highest blood mercury quartile (OR=1.720, 95% CI; 1.172-2.526), compared with the lowest quartile. CONCLUSION: In this large population-based study, blood mercury levels were weakly correlated with HOMA-IR and may be a risk factor for insulin resistance in nondiabetic Koreans.

Occupational exposure to mercury: air exposure assessment and biological monitoring based on dispersive ionic liquid-liquid microextraction

Exposure to mercury [Hg] as a heavy metal can cause health effects. The objective of this study was to assess occupational exposure to Hg in a chlor-alkali petrochemical industry in Iran by determining of Hg concentrations in air, blood and urine samples. The study was performed on 50 exposed subjects and 50 unexposed controls. Air samples were collected in the breathing zone of exposed subjects, using hopcalite sorbents. Analysis was performed using a cold vapor atomic absorption spectrophotometer [CV-AAS] according to NIOSH analytical method 6009. For all participants, blood and urine samples were collected and then transferred into sterile glass tubes. After micro-extraction with ionic liquid and back extraction with nitric acid, Hg concentrations in blood and urine samples were determined by CV-AAS. The mean concentration of air Hg was 0.042 +/- 0.003 mg/m[3]. The mean concentrations of Hg in blood and urine samples of exposed subjects were significantly higher than unexposed controls [22.41 +/- 12.58 versus 1.19 +/- 0.95 micro g/l and 30.61 +/- 10.86 versus 1.99 +/- 1.34 micro g/g creatinine, respectively]. Correlation of air Hg with blood Hg, urine Hg and blood Hg-urine Hg ratio were significant statistically [P< 0.05]. The values of Hg in blood and urine samples of chlor-alkali workers were considerably high. Correlation coefficients showed that blood Hg and blood Hg-urine Hg ratio are better indicators than urine Hg for assessing occupationally exposed workers in terms of current exposure assessment

Relationship between Dietary Mercury Intake and Blood Mercury Level in Korea

This study was performed to evaluate the effect of dietary factors for mercury exposure by comparing with blood mercury concentration. Study population consisted of 1,866 adults (839 men and 1,027 women) in randomly-selected 30 districts in southeast Korea. Dietary mercury intake was calculated from food frequency questionnaire (FFQ) on seafood items and 24 hr recall record. Blood mercury concentration was measured with atomic absorption spectrometry. Mean age of the subjects was 43.5 +/- 14.6 yr. The FFQ showed that mercury-laden fish (tuna, shark) and frequently-eating fish (squid, belt fish, mackerel) were important in mercury intake from fish species. The recall record suggested that fish and shellfish was a highest group (63.1%) of mercury intake and had a wide distribution in the food groups. In comparison with the blood mercury concentration, age group, sex, household income, education, drinking status and coastal area were statistically significant (P < 0.001). In multiple regression analysis, coefficient from the FFQ (beta = 0.003) had greater effect on the blood mercury than the recall record (beta = 0.002), but the effect was restricted (adjusted R2 = 0.234). Further studies with more precise estimation of dietary mercury intake were required to evaluate the risk for mercury exposure by foods and assure risk communication with heavily-exposed group.

Inappropriate Survey Design Analysis of the Korean National Health and Nutrition Examination Survey May Produce Biased Results / 예방의학회지

OBJECTIVES: The inherent nature of the Korean National Health and Nutrition Examination Survey (KNHANES) design requires special analysis by incorporating sample weights, stratification, and clustering not used in ordinary statistical procedures. METHODS: This study investigated the proportion of research papers that have used an appropriate statistical methodology out of the research papers analyzing the KNHANES cited in the PubMed online system from 2007 to 2012. We also compared differences in mean and regression estimates between the ordinary statistical data analyses without sampling weight and design-based data analyses using the KNHANES 2008 to 2010. RESULTS: Of the 247 research articles cited in PubMed, only 19.8% of all articles used survey design analysis, compared with 80.2% of articles that used ordinary statistical analysis, treating KNHANES data as if it were collected using a simple random sampling method. Means and standard errors differed between the ordinary statistical data analyses and design-based analyses, and the standard errors in the design-based analyses tended to be larger than those in the ordinary statistical data analyses. CONCLUSIONS: Ignoring complex survey design can result in biased estimates and overstated significance levels. Sample weights, stratification, and clustering of the design must be incorporated into analyses to ensure the development of appropriate estimates and standard errors of these estimates.

Longitudinal assessment of mercury exposure in schoolchildren in an urban area of the Brazilian Amazon / Avaliação longitudinal da exposição ao mercúrio em crianças de uma área urbana na Amazônia brasileira

This study was a longitudinal assessment of mercury exposure in schoolchildren in an urban area of the Brazilian Amazon. The study population consisted of 90 children whose exposure levels were assessed by testing mercury levels in the umbilical cord blood and mothers' blood samples in 2000-2001, and in the children's hair and blood samples. The study also used a questionnaire on demographic and socioeconomic data, fish consumption, and self-reported disease history. Mean mercury level in hair in 2010 was approximately 1µg/g, ranging up to 8.22µg/g, similar to 2004 and 2006. These figures can be explained by low fish consumption. Mean blood mercury levels at birth exceeded 10µg/L, ranging up to nearly 60µg/L, which indicates mercury transfer across the placenta. There was a significant increase in blood mercury from 2004 to 2006 (p < 0.001), suggesting exposure through air pollution. The main exposure to mercury was during pregnancy.

O objetivo deste estudo foi realizar avaliação longitudinal da exposição de crianças de uma área urbana da Amazônia brasileira ao mercúrio (Hg). A população foi composta por 90 crianças, cuja exposição foi avaliada desde o nascimento por meio das análises dos teores de Hg no sangue do cordão umbilical e no sangue das mães em 2000/2001, e em amostras de cabelo e sangue das crianças. Os procedimentos incluíram também um questionário com informações demográficas, socioeconômicas, sobre consumo de peixes e morbidade referida. A média dos teores de Hg no cabelo em 2010 foi próxima a 1µg/g e sua amplitude 8,22µg/g, semelhantes aos anos 2004 e 2006, podendo ser explicada pela baixa ingestão de peixes. A média dos teores de Hg no sangue das crianças ao nascer ultrapassou 10µg/L e sua amplitude atingiu quase 60µg/L, indicando transferência do Hg através da barreira placentária. Ocorreu aumento significativo dos teores de Hg no sangue entre 2004 e 2006 (p < 0,001), sugerindo a possibilidade de exposição atmosférica ao Hg. O principal período de exposição ao Hg ocorreu durante a gestação.

Limiares auditivos em crianças expostas a mercúrio no período pré-natal / Hearing thresholds in children exposed to mercury in the prenatal period

OBJETIVO: Avaliar os limiares auditivos de crianças com histórico de exposição ao mercúrio durante o período pré-natal. MÉTODOS: Foram avaliadas 90 crianças com idades entre 8 e 10 anos, de ambos os gêneros, categorizadas em dois grupos de acordo com os níveis de exposição pré-natal ao mercúrio. O grupo de estudo foi composto por 57 crianças que apresentaram níveis de mercúrio no cordão umbilical iguais ou superiores a 8 µg/L, e o grupo de comparação por 33 crianças que apresentaram níveis de mercúrio no cordão umbilical inferiores a 8µg/L. Os procedimentos incluíram um questionário, audiometria tonal liminar, pesquisa do limiar de recepção de fala e análise das doses de mercúrio no cordão umbilical coletadas ao nascimento. RESULTADOS: O grupo de estudo apresentou mediana de mercúrio no cordão umbilical de 14,63 µg/L, e mediana dos limiares tonais das frequências de 500 Hz, 1 kHz e 2 kHz de 10 dB em ambas orelhas. O grupo de comparação apresentou mediana de mercúrio no cordão umbilical de 4,88 µg/L, e mediana dos limiares tonais das frequências de 500 Hz, 1 kHz e 2 kHz de 10 dB em ambas orelhas. Quando comparados os limiares auditivos, tanto pela média tritonal quanto para cada frequência isoladamente, não foram observadas diferenças significativas entre os grupos. CONCLUSÃO: As crianças apresentaram limiares auditivos dentro dos padrões de normalidade e não foi observada diferença significativa entre os limiares auditivos das crianças expostas e não-expostas ao mercúrio no período pré-natal.

PURPOSE: To evaluate hearing thresholds in children with a history of exposure to mercury during the prenatal period. METHODS: Participants were 90 children of both genders with ages from 8 to 10 years, divided into two groups according to prenatal mercury exposure levels. The study group was composed by 57 children who had mercury levels in the umbilical cord equal or above 8 µg/L, and the comparison group comprised 33 children who had mercury levels in the umbilical cord below 8 µg/L. Investigation procedures included the application of a questionnaire, pure-tone audiometry, speech reception threshold, and mercury level analysis in cord blood collected at birth. RESULTS: The study group showed a median mercury level in the umbilical cord of 14.63 µg/L, and the median threshold for 500 Hz, 1 kHz and 2 kHz in pure-tone audiometry was 10 dB for both ears. The comparison group had a median cord blood mercury level of 4.88 µg/L, and the median threshold for 500 Hz, 1 kHz and 2 kHz in pure-tone audiometry was 10 dB for both ears. When the hearing thresholds were compared, both by the tritonal mean and by each frequency separately, there were no significant differences between groups. CONCLUSION: The children had hearing thresholds within normal limits and there was no significant difference between the hearing thresholds of children exposed and not exposed prenatally to mercury.

Analysis of Methylmercury Concentration in the Blood of Koreans by Using Cold Vapor Atomic Fluorescence Spectrophotometry

BACKGROUND: Methylmercury is an organic form of mercury that is highly toxic to humans. Here, we present and establish a novel method to detect methylmercury concentrations in the blood of Koreans. METHODS: Methylmercury concentration was analyzed with an automated methylmercury analytic system (MERX, Brooks Rand Co., USA) using cold vapor atomic fluorescence spectrophotometry (CVAFS). A variety of biological materials were digested in methanolic potassium hydroxide solution. The analysis method was validated by examination of certified reference material (955c, National Institute of Standard and Technology, USA). We randomly selected 30 Korean adults (age 20 yr or older) to analyze total blood mercury and methylmercury concentrations. RESULTS: The detection limit and methylmercury recovery rate using this method were 0.1 pg/L and, 99.19% (range: 89.33-104.89%), respectively. The mean blood concentration of methylmercury was 4.54+/-2.15 microg/L (N=30). The mean proportion of methylmercury to the total mercury concentration was 78.27% (range: 41.37-98.80%). CONCLUSIONS: This study is the first report to analyze blood methylmercury concentration using CVAFS in Korea. We expect that this method will contribute to the evaluation of mercury exposure and the assessment of the toxicological impact of mercury in future studies.

Relationship Between Blood Mercury Concentration and Waist-to-Hip Ratio in Elderly Korean Individuals Living in Coastal Areas / 예방의학회지

OBJECTIVES: This study investigated the relationship between the blood mercury concentration and cardiovascular risk factors in elderly Korean individuals living in coastal areas. METHODS: The sample consisted of 477 adults (164 males, 313 females) aged 40 to 65 years who visited a Busan health promotion center from June to September in 2009. The relationship between blood mercury concentration and cardiovascular risk factors including metabolic syndrome, cholesterol profiles, blood pressure, body mass index (BMI), waist circumference and waist-to-hip ratio (WHR), was investigated. Variables related to blood mercury concentration were further evaluated using multiple regression analysis. RESULTS: The blood mercury concentration of the study population was 7.99 (range, 7.60 to 8.40) microg/L. In males, the blood mercury concentration was 9.74 (8.92 to 10.63) microg/L, which was significantly higher than that in females (7.21, [6.80 to 7.64] microg/L). The blood mercury concentration of the study population was related to several cardiovascular risk factors including low-density lipoprotein (LDL) cholesterol (p=0.044), high-density lipoprotein (HDL) cholesterol (p=0.034), BMI (p = 0.006), waist circumference (p = 0.031), and WHR (p < 0.001). In males, the blood mercury concentration was significantly correlated with WHR in the multiple regression analysis. CONCLUSIONS: In males, the blood mercury concentration was related to waist-to-hip ratio, which is a central obesity index and cardiovascular risk factor. Our finding suggests that cardiovascular disease risk in males was increased by mercury exposure via an obesity-related mechanism.

The Effect of Exposure Factors on the Concentration of Heavy Metals in Residents Near Abandoned Metal Mines / 예방의학회지

OBJECTIVES: This study assessed the factors that have an influence on the residents exposed to heavy metals, and we utilized the findings to establish the proper management of abandoned metal mines in the future. METHODS: For a total of 258 residents who lived close to abandoned mines in Gangwon-province and Gyeonggi-province, the exposure factors and biomarkers in their blood and urine were comparatively analyzed via multiple regression analysis. RESULTS: The blood levels of lead and mercury and the cadmium levels in urine were found to be higher in the study group than that in the average Korean. For the blood levels of heavy metals according to each exposure factor, all of them were found to be significantly higher in both of the group residing for a longer period of time and the group living closer to the source of pollutants. Multiple regression analysis disclosed that all the heavy metals, except lead, in their blood were significantly reduced in proportion to the increased distance of inhabitancy from the mines. Their other biomarkers were within the normal ranges. CONCLUSIONS: We found that the distance between the residential village and the mines was a factor that affects the blood level of heavy metals in the villagers. This finding could be an important factor when developing a management model for the areas that surround abandoned metal mines. (ED note: I much like this important study.)

Blood Mercury Concentration and Related Factors in an Urban Coastal Area in Korea / 예방의학회지

OBJECTIVES: This study was carried out for the purpose of evaluating the blood mercury concentration of the residents of Busan, Korea, as well as the relationship between the mercury concentration and the pattern of fish consumption along with other epidemiological factors. METHODS: Two hundred ninety-three subjects (147 men and 146 women), who were aged 40 years or more, were recruited into this study between June and October 2009. The mean age of the subjects was 54.3 years (with a range of 40-70 years). Mercury concentrations in blood samples were measured using a gold-amalgam collection method. RESULTS: The geometric mean concentration of mercury in the total subjects was 8.63 microgram/L [range: 1.48~45.71 microgram/L]. The blood mercury concentration of the men (9.55 microgram/L) was significantly higher than that of the women (7.76 microgram/L). The blood mercury concentration of those who eat fish more than 4 times per week was higher than others, and was statistically significant (male p = 0.0019, female p = 0.0002). According to the multiple analysis, the blood mercury concentration was significantly affected by the consumed fish but other epidemiological factors were not related. CONCLUSIONS: It was found that the subjects who have consumed a large amount of fish may have high blood mercury concentration. It appears that fish consumption can influence blood mercury concentration. Therefore, guidelines for fish consumption that will decrease blood mercury concentration might be necessary in Korea.

Avaliação dos níveis sanguíneos do hormônio tireoidiano ativo (T3) e do estado nutricional relativo ao selênio de mulheres residentes em área de exposição ao mercúrio / Assessment of thyroid hormone (T3) levels and selenium status of women living in mercury exposure area

Este trabalho teve por objetivo avaliar, em seres humanos, se a exposição ao mercúrio acarreta alterações no estado nutricional relativo ao selênio que possam interferir na ativação do hormônio tireoidiano T₃. Estas alterações poderiam ocorrer pela redução da disponibilidade do selênio, uma vez que este mineral é considerado um fator protetor contra a intoxicação pelo mercúrio, realizando ligações com o metal e desta forma, inibindo sua absorção; e portanto, a conversão do hormônio tiroidiano T₄ em T₃ poderia ser prejudicada, tendo em vista que é dependente de selenoproteínas. Alguns estudos têm avaliado a relação entre mercúrio e selênio na população brasileira, no entanto, não têm observado qual o efeito desta interação nos hormônios tiroidianos. A importância deste estudo está em detectar se existem estas alterações, e se elas forem observadas, sugerir formas de melhorar o estado nutricional relativo ao selênio, para minimizar a contaminação por mercúrio e os problemas acarretados pela redução dos níveis circulantes do hormônio tiroidiano ativo. Nesta pesquisa foram formados três grupos, um em Cubatão, um em Novo Airão na região amazônica e, como grupo controle, um em São Paulo. Foi observado que os grupos de Cubatão e São Paulo não se encontram em risco de intoxicação por mercúrio. Já o grupo formado em Novo Airão apresentou teores altos do metal. A ingestão de selênio em todos os grupos apresentou índices de inadequação de consumo acima dos 30%, no entanto, todos se apresentaram adequados em relação aos parâmetros bioquímicos do mineral, e também em relação às concentrações dos hormônios tireoidianos. Nesta pesquisa foi observado que na região amazônica, apesar dos valores elevados de mercúrio, este não provocou efeito no estado nutricional relativo ao selênio e no metabolismo normal dos hormônios tireoidianos. Mais estudos são necessários para que a dinâmica entre selênio e mercúrio seja completamente elucidada...

The aim of this work was to assess, in human beings, if mercury exposure may lead to changes in selenium status that may interfere with the conversion of active thyroid hormone T₃. Changes in selenium status could occur for a reduction in its bioavailability, once the mineral is considered as a protection factor against mercury intoxication, by bounding to the metal and inhibiting its absorption, and so disturbing the conversion of T₄ to T₃, witch is dependent on selenoproteins. Some researches have assessed the relationship between mercury and selenium in Brazilian population, but these studies did not observed the effects of this interaction in the thyroid hormones concentrations. This research is important because it might detect if there is such interaction, and if it is observed, may suggest viable ways to ameliorate selenium status, reduce mercury contamination risk and the problems that might occur due to reduction on active thyroid hormones concentration. For this research three groups were formed, one in the city of Cubatão, one in Novo Airão in the amazon region, and, as a control group, one in São Paulo city. Is has been observed that the groups of Cubatão and São Paulo are not in risk for mercury intoxication. However, in Novo Airão, the levels of Mercury found were high. Analysis of selenium intake in all groups show that in all of than inadequate rate intake was over 30%, however, in every group biomarkers for selenium were adequate, as well as the thyroid hormone levels. Hence, this study observed that in Amazon region, in spite of high mercury levels, there is no effect in selenium status and in the thyroid hormone. Further investigations are needed to fully elucidate mercury and selenium interaction, especially in regions were an acute exposure to the metal might happen, when the consequences of this mey be deleterious to selenium status and its functions.

Valores de referência para chumbo, cádmio e mercúrio em população adulta da Região Metropolitana de São Paulo / Reference values for lead, cadmium and mercury in blood of adults from the Metropolitan Area of São Paulo

O uso de biomarcadores para avaliar a exposição da população humana a contaminantes ambientais, a biomonitorização humana (BH), fornece uma relação direta entre exposição à substância química e a dose interna. Os resultados da BH da população geral devem ser comparados com valores de referência (VR), obtidos de um grupo definido da população geral e derivados por método estatístico. Esses VR, em geral, determinam o limite superior da exposição basal. O objetivo deste estudo foi derivar VR de chumbo, cádmio e mercúrio em sangue para a população adulta da Região Metropolitana de São Paulo (RMSP), e verificar associação entre os níveis desses metais no sangue e variáveis sócio-demográficas e de estilo de vida. Foram coletadas amostras de doadores de sangue em 9 postos de coleta em 2006, que residiam na RMSP, não fumantes e sem exposição ocupacional aos metais estudados. Informações sobre as variáveis de interesse foram obtidas por meio de questionário. Os VR derivados correspondem ao limite superior do IC95% do P95, e foram para homens de 18 a 39 anos 59,73 g/L para Pb, 0,41 g/L para Cd e 4,30 g/L para Hg; para mulheres 47,09 g/L para Pb, 0,48 g/L para Cd e 3,71 g/L para Hg. Para homens de 40 a 65 anos 79,84 g/L para Pb, 0,35 g/L para Cd e 5,10 g/L para Hg; para mulheres 63,10 g/L para Pb, 0,44 g/L para Cd e 6,10 g/L para Hg. Os VR de chumbo mostraram-se inferiores aos derivados para a população de Londrina (Brasil), foram semelhantes aos da República Checa e Alemanha, mas superiores aos do estudo populacional dos EUA (NHANES). Os VR de Cd foram bem inferiores aos das populações desses países, cujos valores estão acima de 1 g/L. Os VR de Hg foram semelhantes aos dos EUA e superiores aos da Alemanha e República Checa. Os níveis de Pb e Cd em sangue apresentaram associação significativa com sexo e faixa etária. Homens apresentaram 50% mais chumbo em sangue, e indivíduos entre 40 e 65 anos apresentaram 23% mais chumbo em relação aos de 18 a 39 anos...

The use of biomarkers to assess the exposure of humans to environmental contaminants, human biomonitoring (HB), provides a direct relationship between chemical exposure and internal dose. The results of the HB of the general population should be compared with reference values (RV) obtained in a defined group of the general population and derived by statistical methods. These RV generally determine the upper limit of the exposure baseline. The aim of this study was to derive RV for lead, cadmium and mercury in blood of adults from the Metropolitan Area of Sao Paulo (MASP) (Brazil), and to investigate the association between blood metals and sociodemographic and lifestyle factors. Samples from blood donors were collected in 9 blood centers in 2006, they were residents in the MASP, non smokers, and without any occupational exposure to the studied metals. Information about variables of interest was obtained by questionnaire. The RV derived for men aged 18 to 39 years were 59,73 g/L for Pb, 0,41 g/L for Cd e 4,30 g/L for Hg; for women 47,09 g/L for Pb, 0,48 g/L for Cd and 3,71 g/L for Hg. For men aged 40 and 65 years 79,84 g/L for Pb, 0,35 g/L for Cd and 5,10 g/L for Hg; for women 63,10 g/L for Pb, 0,44 g/L for Cd and 6,10 g/L for Hg. The RV for lead appeared to be lower than those derived for the population of Londrina (Brazil), were similar to the Czech Republic and Germany, but higher than the one observed in a study of the U.S. population (NHANES). Conversely, RV for Cd were well below of those from these countries, which have values above 1 g/L. The RV for Hg were similar to the U.S and higher than the value in Germany and in the Czech Republic. The levels of Pb and Cd in blood showed a significant association with sex and age. Men had 50% more lead in blood, and individuals between 40 and 65 years old showed 23% more lead than those in 18 to 39 years old. The variable most related to the levels of Hg was fish consumption...

Detection of some toxic heavy metals in meat and offal of slaughtered cattle in Tanta abattoir, Gharbia governorate

A lot of one hundred and twenty random samples of meat, liver and kidney were collected from young and old slaughtered cattle [20 of each] at Tanta slaughter house, Gharbia governorate, Egypt, for detection of some heavy metal residues as Lead, cadmium and mercury by using Atomic absorption spectrometer. The results revealed that the highest mean value of lead concentration was recorded as 0.606 +/- 0.190 mg/kg wet weight in weight in old slaughtered cattle liver, while the lowest mean value of lead concentration was 0.036 +/- 0.016 mg/ kg wet weight in meat samples of young slaughtered cattle. More over, the highest mean value of cadmium concentration was recorded in as slaughtered cattle 1.752 +/- 0.469 mg/kg wet weight in kidney sample, while the lowest value of cadmium level in young slaughtered cattle was 0.858 +/- 0.133 mg/kg wet weight in meat samples. Regarding the mercury concentration in slaughtered cattle the highest level was recorded in liver of old aged cattle 0.499 +/- 0.171 mg/kg wet weight, whilemean the lowest results were recorded in meat sample of young aged slaughtered cattle as 0.218 + 0.041, All the obtained results of lead cadmium and mercury were compared with the permissible limsts of FAO/WHQ [1992] and ES [1993] and public health hazards of such toxic heavy metals were discussed. Hygienic measures and awareness programs were implemented to avoid contamination of meat and offal with such toxic heavy meals

Human mercury exposure and adverse health effects in the Amazon: a review / Exposição humana ao mercúrio e efeitos adversos à saúde na Amazônia: uma revisão

This paper examines issues of human mercury (Hg) exposure and adverse health effects throughout the Amazon region. An extensive review was conducted using bibliographic indexes as well as secondary sources. There are several sources of Hg (mining, deforestation, reservoirs), and exposure takes place through inhalation or from fish consumption. There is a wide range of exposure, with mean hair-Hg levels above 15µg/g in several Amazonian communities, placing them among the highest reported levels in the world today. Dietary Hg intake has been estimated in the vicinity of 1-2µg/kg/day, considerably higher than the USEPA RfD of 0.1µg/kg/day or the World Health Organization recommendation of 0.23µg/kg/day. Neurobehavioral deficits and, in some cases, clinical signs have been reported both for adults and children in relation to Hg exposure in several Amazonian countries. There is also some evidence of cytogenetic damage, immune alterations, and cardiovascular toxicity. Since fish provide a highly nutritious food source, there is an urgent need to find realistic and feasible solutions that will reduce exposure and toxic risk, while maintaining healthy traditional dietary habits and preserving this unique biodiversity.

Este artigo examina questões sobre exposição humana ao mercúrio (Hg) e seus efeitos adversos à saúde na Amazônia, com base em extensa revisão da literatura. Diferentes bioindicadores revelam uma ampla faixa de exposição, com teores médios de Hg em cabelo acima de 15µg/g em diversas comunidades amazônicas, situando-as dentre as mais expostas no mundo atualmente. Taxas de ingestão diária de Hg foram estimadas em alguns estudos e situam-se entre 1-2µg/kg/dia, consideravelmente acima das doses de referência estabelecidas pela USEPA (0,1µg/kg/dia) ou pela OMS (0,23µg/kg/dia). Déficits neurocomportamentais e, em alguns casos, sinais clínicos relacionados à exposição mercurial têm sido relatados tanto em adultos quanto em crianças de diversos países amazônicos. Há também evidências de dano citogenético, mudanças imunológicas e toxicidade cardiovascular. Visto que peixe é altamente nutritivo e há diversas fontes de Hg nesta região, existe uma necessidade urgente de encontrar soluções realistas e viáveis capazes de reduzir os níveis de exposição e de risco tóxico, ao mesmo tempo mantendo os hábitos alimentares tradicionais, preservando a biodiversidade píscea e frutífera e melhorando a saúde das populações desfavorecidas e afetadas.

Antineuronal antibodies in autistic children: relation to blood mercury

It was recently suggested that autism, a severe neuro developmental disorder, may involve an autoimmune pathogenesis. Mercury [Hg] is a potential risk factor for autoimmunity in autistic children. We sought to investigate the expression of antineuronal antibodies, as an index of autoimmunity to brain, in autistic children. The potential relationship between blood mercury and these antibodies was also investigated. Forty autistic children [20 with mild to moderate and 20 with severe disease] were studied in comparison to 40 healthy children. After complete clinical and neuropsychiatric evaluation, serum antineuronal antibodies and blood Hg levels were estimated. Autistic children had significantly higher seropositivity for antineuronal antibodies [67.5%] than healthy controls [5%]. Similarly, the former group had significantly higher blood Hg levels than the latter [p<0.0001]. Seropositivity of antineuronal antibodies had a significant positive association with elevated blood Hg. which was found in 70% of autistic children, [p<0.0001]. In addition, the two markers were positively associated with some parameters such as the family history of autoimmunity, autistic severity and some important clinical manifestations of autism [mental retardation, behavioral abnormalities and autistic regression] as well as EEG abnormalities. Autism may be, in part, one of the pediatric autoimmune neuropsychiatric disorders. Such autoimmunity may be triggered by environmental Hg exposure. Further studies are warranted to enforce these concepts. If these assumptions could be proved, routine assessment of serum antineuronal antibodies and blood mercury in autistic children would be mandatory Studies assessing the role of immunotherapy and Hg chelators as new therapeutic modalities for autism are also recommended

Diagnóstico de la contaminación por mercurio en el personal de una unidad odontológica de Caracas, Venezuela / Diagnosis of the mercury contamination among a dental unit staff from Caracas, Venezuela

El mercurio genera afecciones nerviosas, comportamentales, renales, inmunes y sexuales, entre otras. El personal que labora en la práctica odontológica, expuesto crónicamente a vapores de mercurio, constituye una población de riesgo toxicológico. El objetivo de este trabajo fue determinar el contenido de mercurio presente en el personal odontológico de un hospital venezolano, con el fin de evaluar el riesgo ocupacional. Para ello se colectaron muestras de sangre y orina del personal que labora en la Unidad Odontológica, los días lunes y viernes de cada semana durante cuatro semanas. El contenido de mercurio fue determinado mediante Espectroscopía de Absorción y Fluorescencia atómica con vapor frío. Mediante análisis de varianza se probaron estadísticamente las hipótesis relacionadas con la similitud en los valores de mercurio para los diferentes grupos humanos analizados y para los diferentes períodos de muestreo. Los niveles de mercurio en las muestras de orina del personal analizado resultaron por debajo del nivel umbral reseñado por la Organización Mundial de la Salud en 50 ug/L (ppb) de Hg. En muestras de sangre, el 21por ciento de la población evaluada presentó niveles superiores al valor umbral de 15 ug/L (ppb) de Hg. Se encontraron diferencias significativas en el contenido de mercurio de sangre y orina entre los grupos laborales. El contenido de mercurio presente en la muestras de sangre del 21 por ciento de la población evaluada revela que este grupo está en riesgo toxicológico al metal, recomendándose análisis más exhaustivos en estas personas.

Mercury generates nervous, behavior, immune and sexual affections, among others. The personnel working in dentistry, exposed chronically mercury steam, constitutes population in toxicological risk. The objective of this work was to determine mercury present in dentistry personnel of Venezuelan hospital, for evaluating the occupational risk. Blood and urine samples were collected of the personnel working in this Unit Dentistry, the days Monday and Friday of every week during four weeks. The mercury content was determined by means of spectroscopy of absorption and atomic fluorescence with cold steam. By means of variance analysis the hypotheses related to the similarity in the values of mercury for different analyzed human groups and different periods from sampling were proven statistically. Mercury levels in urine samples of analyzed personnel are underneath the level threshold reviewed by the Health World Organization in 50 ?g/L (ppb) Hg. 21% of evaluated population present levels superior to value threshold of 15 ppb of Hg in blood samples. Blood and urine mercury content between the labor groups were significantly differences. Mercury content present in blood samples of 21% of evaluated population reveals this group is in toxicological risk to metal, recommending more exhaustive analyses in these people.