Biomarker Of Arsenic Exposure Research Articles

Biomarkers of arsenic exposure in biogeochemical provinces

Introduction. One of the direct methods of assessing the impact of contaminants on public health is the use of biological markers that allow determining the presence of a substance or its metabolite in human biological tissues and the dose received from all sources of this substance. 
 The purpose of this study was to determine the dependence of arsenic content in biological samples (hair) 
 of exposed residents on the level of its content in drinking water and to substantiate the effectiveness of the use of this biomarker in the conditions of a hydrogeochemical province in the Republic of Dagestan.
 Material and methods. During this research the arsenic content in the hair of the exposed residents was measured with further comparison of the data obtained with its content in drinking groundwater. To determine the arsenic content in the hair of the exposed residents, an atomic absorption method was used with preliminary preparation of biosubstrate samples. Socio-demographic data were obtained from a questionnaire. Statistical data processing was carried out using Microsoft Excel.
 Results. In the course of this study, a correlation was revealed between the arsenic content in the hair of the exposed residents and its content in the drinking water consumed, and a direct proportional relationship between these values was also revealed. Thus, with an increase in the concentration of arsenic in water by 
 0.1 mg/l, the arsenic content in the hair increases by 0.14 mkg/g. So, using of the hair of exposed residents as a biomarker of long-term exposure is recommended to small doses of arsenic in a biogeochemical province.
 limitation of the study is the small sample size. However, this does not prevent the assessment of the effectiveness of using hair as a biomarker of arsenic exposure and preliminary conclusions for subsequent in-depth analysis of biomonitoring in the conditions of biogeochemical provinces.
 Conclusion. As a rule, the content of natural toxic elements is characterized by trace amounts in the conditions of biogeochemical provinces. Biomonitoring will reveal the level of stress on the body and timely apply preventive methods before the clinical signs of intoxication are revealed.

Elevated arsenic level in fasting serum via ingestion of fish meat increased the risk of hypertension in humans and mice.

There has been a shortage of human studies to elucidate the association between serum arsenic levels and the prevalence of hypertension. This study multidirectionally investigated associations among arsenic exposure, dietary ingestion, and the risk of hypertension by combined human epidemiological and mouse experimental studies. This study focused on the total arsenic level in fasting serum, a biomarker of arsenic exposure. Associations among ingestion frequencies of 54 diet items of Japanese food separated into six categories, total arsenic level in fasting serum, and the prevalence of hypertension were investigated in 2709 general people in Japan. Logistic regression analysis demonstrated a dose-dependent association between serum arsenic level and hypertension and a positive association between the ingestion of fish meat and hypertension. Further analysis showed that the latter association was fully mediated by increased fasting serum arsenic levels in humans. Similarly, oral exposure to the putative human-equivalent dose of arsenic species mixture with the same ratios in a common fish meat in Japan increased systolic blood pressure and arsenic levels in fasting serum in mice. This interdisciplinary approach suggests that fish-meat ingestion is a potential risk factor for arsenic-mediated hypertension. Because the increased consumption of fish meat is a recent global trend, health risks of the increased ingestion of arsenic via fish meat should be further investigated.

Additive interaction of urinary total arsenic concentrations with being overweight/obesity on the risk of insulin resistance: NHANES 2007-2016.

Arsenic exposure has been associated with the risk of diabetes or insulin resistance (IR), which are also related with overweight/obesity. This study aimed to explore the interaction between arsenic exposure and being overweight/obesity on diabetes or IR risk. Data from the National Health and Nutrition Examination Survey (NHANES) in cycles 2007-2016 were used to assess the interaction between arsenic exposure and being overweight/obesity on IR or diabetes risk among adults. Urinary total arsenic concentrations (UTAs) were used as a biomarker for arsenic exposure. The homeostasis model of insulin resistance (HOMA-IR) was calculated to index IR. Survey-weighted logistic regression and restricted cubic spline (RCS) analyses were performed to determine the association and dose-response relationship between UTAs and IR or diabetes risk. Additive interaction was evaluated by relative excess risk due to interaction (RERI), attributable proportion of interaction (AP), and synergy index (S). A total of 3,133 participants were included. The median (interquartile range) UTAs were 6.61 (3.83, 13.95) μg/L. The adjusted OR of IR was 1.40 (95% CI: 0.99-1.97) for UTAs, comparing the highest with the lowest quartile. And significant additive interaction was observed between high UTAs and being overweight/obesity on IR risk (RERI = 2.47, 95% CI: 0.30-4.63; AP = 0.29, 95% CI: 0.07-0.50; S = 1.48, 95% CI: 1.03-2.13). Our results suggested that there might be a potential additive interaction between high UTAs with being overweight/obesity on diabetes risk (AP = 0.27, 95%CI: 0.04-0.51). Our results indicated an additive interaction between arsenic exposure and being overweight/obesity on IR risk.

Review On Arsenic Toxicity: Effect On Human Health And Biochemical Aspects

Looking at the global scenario, it has been found that a huge perccntage of population around the globe consider groundwater as their main source for drinking. But unfortunately, this main source is being heavily exposed to various heavy metals like mercury, cadmium, arsenic making it unfit for consumption, ultimately posing threat to human health out there. Although groundwater is considered as safe, but high concentrations of heavy metals like arsenic (As) (above the permissible limit) in ground water can pose risk to human health. Toxicity level of inorganic arsenic is more than the organic one. Arsenic contamination is having a worldwide effect. Arsenic is found to be carcinogcnic in nature, genotoxic as well as cytotoxic. Prolonged exposure to arsenic causes various health hazards like arsenicosis, skin cancer, pigmentation, neurobehavioral effects, impaired intellect and various other chronic illness. Creating awareness and providing proper medical care still remains a big challenge. The biomarkers of arsenic exposure include nails, hair, urine and blood sample. This paper provides an overall overview of ground water arsenic contamination, its health hazards, its toxicity and metabolism in human body. The paper also reviews various analytical techniques that are being used to detect arsenic, the collective steps required to eradicate this global problem and provide high quality safe drinking water for the future generations to come.

Urinary leucine aminopeptidase 3 in population environmentally exposed to airborne arsenic.

Environmental arsenic contamination is a major toxicological problem worldwide due to its carcinogenic and nephrotoxic potential. The purpose of this observational study was to determine the suspected association between urinary arsenic (uAs) and urinary leucine (or leucyl) aminopeptidase 3 (uLAP3) to evaluate uLAP3 as a candidate biomarker of exposure to airborne arsenic. A total of 918 adults occupationally and/or environmentally exposed to airborne arsenic were enrolled in the study. Baseline information (age; sex; history of smoking; alcohol, fish and seafood consumption) was gathered. Total uAs concentrations [μg/L] of 918 subjects, as well as the sum of arsenic species (ΣiAs) in 259 subjects, were obtained. Urinary LAP3 was measured by an immune-enzymatic assay using an ELISA kit. Urinary creatinine concentration was assessed with the IB/lAB/1289 research protocol (version II, 2015-09-17). The values of uAs and uLAP3 were recalculated per unit of creatinine. The association between uAs and uLAP3 was assessed using a logistic regression model adjusted for confounders. The study identified a positive correlation between the logarithm of uAs and the logarithm of uLAP3 in the study population (r = 0.1737, p < 0.0000) and between urinary creatinine and uLAP3 concentration not adjusted for creatinine level (r = 0.1871, p < 0.001). In the logistic regression model, there was also an association between increased (≥15 µg/L) uAs and decreased (below the 25th quartile) uLAP3 [OR uLAP3 = 1.22 (95% CI 1.03 to 1.44, p < 0.02)]. These data suggest that urinary LAP3 may be a potential biomarker of arsenic exposure, which warrants further study.

Association of Arsenic Exposure With Cardiac Geometry and Left Ventricular Function in Young Adults.

Arsenic exposure has been related to numerous adverse cardiovascular outcomes. The aim of this study was to investigate the cross-sectional and prospective association between arsenic exposure with echocardiographic measures of left ventricular (LV) geometry and functioning. A total of 1337 young adult participants free of diabetes mellitus and cardiovascular disease were recruited from the SHFS (Strong Heart Family Study). The sum of inorganic and methylated arsenic concentrations in urine (ΣAs) at baseline was used as a biomarker of arsenic exposure. LV geometry and functioning were assessed using transthoracic echocardiography at baseline and follow-up. Mean follow-up was 5.6 years, and median (interquartile range) of ΣAs was 4.2 (2.8-6.9) µg/g creatinine. Increased arsenic exposure was associated with prevalent LV hypertrophy, with an odds ratio (95% CI) per a 2-fold increase in ΣAs of 1.47 (1.05-2.08) in all participants and of 1.58 (1.04-2.41) among prehypertensive or hypertensive individuals. Measures of LV geometry, including LV mass index, left atrial systolic diameter, interventricular septum, and LV posterior wall thickness, were positively and significantly related to arsenic exposure. Among measures of LV functioning, stroke volume, and ejection fraction were associated with arsenic exposure. Arsenic exposure was related to an increase in LV wall thickness and LV hypertrophy in young American Indians with a low burden of cardiovascular risk factors. The relationship was stronger in participants with prehypertension or hypertension, suggesting that potential cardiotoxic effects of arsenic might be more pronounced in individuals already undergoing cardiovascular adaptive mechanisms following elevated systemic blood pressure.

Trends in urinary arsenic among the U.S. population by drinking water source: Results from the National Health and Nutritional Examinations Survey 2003–2014

BackgroundIn 2001, the United States revised the arsenic maximum contaminant level for public drinking water systems from 50µg/L to 10µg/L. This study aimed to examine temporal trends in urinary arsenic concentrations in the U.S. population from 2003 to 2014 by drinking water source among individuals aged 12 years and older who had no detectable arsenobetaine - a biomarker of arsenic exposure from seafood intake. MethodsWe examined data from 6 consecutive cycles of the National Health and Nutrition Examination Survey (2003–2014; N=5848). Total urinary arsenic (TUA) was calculated by subtracting arsenobetaine’s limit of detection and detectable arsenocholine from total arsenic. Additional sensitivity analyses were conducted using a second total urinary arsenic index (TUA2, calculated by adding arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid). We classified drinking water source using 24-h dietary questionnaire data as community supply (n=3427), well or rain cistern (n=506), and did not drink tap water (n=1060). ResultsGeometric means (GM) of survey cycles were calculated from multivariate regression models adjusting for age, gender, race/ethnicity, BMI, income, creatinine, water source, type of water consumed, recent smoking, and consumption of seafood, rice, poultry, and juice. Compared to 2003–2004, adjusted TUA was 35.5% lower in 2013–2014 among the general U.S. population. Stratified analysis by smoking status indicated that the trend in lower TUA was only consistent among non-smokers. Compared to 2003–2004, lower adjusted TUA was observed in 2013–2014 among non-smoking participants who used community water supplies (1.98 vs 1.16µg/L, p<0.001), well or rain cistern users (1.54 vs 1.28µg/L, p<0.001) and who did not drink tap water (2.24 vs 1.53µg/L, p<0.001). Sensitivity analyses showed consistent results for participants who used a community water supplier and to a lesser extent those who did not drink tap water. However, the sensitivity analysis showed overall exposure stayed the same or was higher among well or rain cistern users. Finally, the greatest decrease in TUA was among participants within the highest exposure percentiles (e.g. 95th percentile had 34% lower TUA in 2013/2014 vs 2003/2004, p<0.001). ConclusionsOverall, urinary arsenic levels in the U.S. population declined over a 12-year period that encompassed the adoption of the revised Arsenic Rule. The most consistent trends in declining exposure were observed among non-smoking individuals using public community water systems. These results suggest regulation and prevention strategies to reduce arsenic exposures in the U.S. may be succeeding.

Biomarkers of arsenic exposure in arsenic-affected areas of the Hetao Basin, Inner Mongolia

Seventy saliva samples, seventy urine samples, seventy nail samples, seventy hair samples, eight drinking water samples and ninety-three crop samples were collected from four villages of the Hetao Basin in Inner Mongolia to determine arsenic (As) exposure biomarkers and evaluate relationship between As uptake and human health risk. Trivalent As (As(III)), pentavalent As (As(V)), dimethylarsinic acid (DMA), arsenobetaine (AsB) and monomethylarsonic acid (MMA) were found in all urine samples. Only As(III) and As(V) were detected in saliva samples. In nail and hair samples, DMA, MMA, As(III) and As(V) were observed. Based on total As contents in crops and drinking water, the local residents' daily intake of total arsenic (TDIAs), the hazard quotient (HQ), and the cancer risk (R) were assessed. Male, older and cases of skin lesion participants generally had higher As contents in saliva, urine, nail and hair samples in relative to others. Salivary, urinary, nail and hair As were not significantly affected by body mass index (BMI) and smoking. Good correlations were observed between TDIAs and salivary, urinary, nail and hair As, showing that saliva, urine, nail and hair samples can be used as biomarkers of As exposure. Individually, levels of arsenicosis were positively correlated with TDIAs. The relationship between TDIAs and prevalence of arsenicosis concluded that, although As levels in crops and drinking water did not exceed national standards, they still pose a potential threat to human health. It was suggested that the maximum permissible levels of crop As and drinking water As should be re-evaluated for protecting human health.

Associations between post translational histone modifications, myelomeningocele risk, environmental arsenic exposure, and folate deficiency among participants in a case control study in Bangladesh

ABSTRACTArsenic exposure may contribute to disease risk in humans through alterations in the epigenome. Previous studies reported that arsenic exposure is associated with changes in plasma histone concentrations. Posttranslational histone modifications have been found to differ between the brain tissue of human embryos with neural tube defects and that of controls. Our objectives were to investigate the relationships between plasma histone 3 levels, history of having an infant with myelomeningocele, biomarkers of arsenic exposure, and maternal folate deficiency. These studies took place in Bangladesh, a country with high environmental arsenic exposure through contaminated drinking water. We performed ELISA assays to investigate plasma concentration of total histone 3 (H3) and the histone modification H3K27me3. The plasma samples were collected from 85 adult women as part of a case-control study of arsenic and myelomeningocele risk in Bangladesh. We found significant associations between plasma %H3K27me3 levels and risk of myelomeningocele (P<0.05). Mothers with higher %H3K27me3 in their plasma had lower risk of having an infant with myelomeningocele (odds ratio: 0.91, 95% confidence interval: 0.84, 0.98). We also found that arsenic exposure, as estimated by arsenic concentration in toenails, was associated with lower total H3 concentrations in plasma, but only among women with folate deficiency (β = −9.99, standard error = 3.91, P=0.02). Our results suggest that %H3K27me3 in maternal plasma differs between mothers of infants with myelomeningocele and mothers of infants without myelomeningocele, and may be a marker for myelomeningocele risk. Women with folate deficiency may be more susceptible to the epigenetic effects of environmental arsenic exposure.

Assessment of human dietary exposure to arsenic through rice

Rice accumulates 10-fold higher inorganic arsenic (i-As), an established human carcinogen, than other grains. This review summarizes epidemiologic studies that examined the association between rice consumption and biomarkers of arsenic exposure. After reviewing the literature we identified 20 studies, among them included 18 observational and 2 human experimental studies that reported on associations between rice consumption and an arsenic biomarker. Among individuals not exposed to contaminated water, rice is a source of i-As exposure – rice consumption has been consistently related to arsenic biomarkers, and the relationship has been clearly demonstrated in experimental studies. Early-life i-As exposure is of particular concern due to its association with lifelong adverse health outcomes. Maternal rice consumption during pregnancy also has been associated with infant toenail total arsenic concentrations indicating that dietary exposure during pregnancy results in fetal exposure. Thus, the collective evidence indicates that rice is an independent source of arsenic exposure in populations around the world and highlights the importance of investigating its affect on health.

An insight of environmental contamination of arsenic on animal health

Abstract The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. Exposure to arsenic is mainly via intake of food and drinking water, food being the most important source in most populations. Although adverse health effects of heavy metals have been known for a long time, exposure to heavy metals continues and is even increasing in some areas. Long-term exposure to arsenic in drinking-water is mainly related to increased risks of skin cancer, but also some other cancers, as well as other skin lesions such as hyperkeratosis and pigmentation changes. Therefore, measures should be taken to reduce arsenic exposure in the general population in order to minimize the risk of adverse health effects. Animal are being exposed to arsenic through contaminated drinking water, feedstuff, grasses, vegetables and different leaves. Arsenic has been the most common causes of inorganic chemical poisoning in farm animals. Although, sub-chronic and chronic exposure of arsenic do not generally reveal external signs or symptoms in farm animals but arsenic (or metabolites) concentrations in blood, hair, hoofs and urine are remained high in animals of arsenic contaminated zones. So it is assumed that concentration of arsenic in blood, urine, hair or milk have been used as biomarkers of arsenic exposure in field animals.

Prevalence of High Arsenic Concentration in Darbhanga District of Bihar: Health Assessment

Background: Arsenic (As) in the groundwater is widely recognised as a global threat to human health. Millions of people from different countries including India are heavily dependent on groundwater containing elevated levels of arsenic for both drinking and irrigation purposes. Bihar and West Bengal located within the Middle-Gangetic plain (MGP), are the two worst arsenic exposed states in India. Today it is estimated that more than 5 million people in the Bihar state are drinking water with arsenic concentration greater than permissible limit of 10 μg/L recommended by World Health Organisation. In the present study, four villages Paghari, Habidih situated under Baheri block and Parri, Bairampur situated under Biraul block of Darbhanga districts of Bihar was taken up for the groundwater arsenic and blood arsenic estimation. The arsenic causing health related problems were also evaluated in the rural population. Methods: Altogether 48 groundwater samples from Hand Tube Wells (HTWs) of four different villages (12 groundwater samples from each village) were randomly collected for arsenic estimation and 48 blood samples were collected from the subject of the same household for blood arsenic estimation (12 blood samples from each village). Assessment of health related problems due to arsenic poisoning was also carried out in this study. Results: The highest arsenic concentration in groundwater was found to be 911 μg/L in Paghari village of Baheri block while in blood sample it was 252 μg/L observed from the same household in the Paghari village. The typical arsenicosis symptoms like hyperkeratosis in the palm and sole, melanosis of the skin and few cases of cancer were also reported among the population. Conclusions: The present study thus, concludes that there was high arsenic concentration in the groundwater of four villages of Darbhanga district. Presence of arsenic in the blood samples indicates as a biomarker of arsenic exposure. Arsenic poisoning has caused severe health related problems in these population. Therefore, a proper strategy is urgently required to mitigate the groundwater arsenic contamination and minimize the severity of the arsenic poisoning in these villages.

Biomarkers of arsenic exposure and effects in a Canadian rural population exposed through groundwater consumption

Drinking water intake of arsenic (As) from private wells may represent a significant exposure pathway and induce oxidative DNA damage. We measured total As concentrations in hair and nails, and concentrations of the different species of As and its metabolites as well as 8-OHdG in urine of 110 non-smoking adults living in a rural region of the Province of Quebec, Canada. Significant differences in exposure biomarker levels were observed between individuals consuming drinking water with As levels of≤1.0,>1.0 -≤10 and>10 μg/l. Multivariate linear regression analysis also showed a significant relationship between estimated daily drinking water intakes of As and biomarker levels. Conversely, 8-OHdG levels were not significantly related to daily drinking water intakes of As or to hair, nail or urinary exposure biomarker levels, according to multivariate linear regression analysis. Even at the relatively low levels of As found in well water of our participants, water consumption significantly increases their body load of As, as confirmed by multiple matrix measurements, which reflected exposure over different time frames. However, this increased internal As dose was not associated with higher oxidative damage to DNA as reflected by urinary 8-OHdG levels.

Oxidative DNA damage and repair in children exposed to low levels of arsenic in utero and during early childhood: Application of salivary and urinary biomarkers

The present study aimed to assess arsenic exposure and its effect on oxidative DNA damage and repair in young children exposed in utero and continued to live in arsenic-contaminated areas. To address the need for biological specimens that can be acquired with minimal discomfort to children, we used non-invasive urinary and salivary-based assays for assessing arsenic exposure and early biological effects that have potentially serious health implications. Levels of arsenic in nails showed the greatest magnitude of difference between exposed and control groups, followed by arsenic concentrations in saliva and urine. Arsenic levels in saliva showed significant positive correlations with other biomarkers of arsenic exposure, including arsenic accumulation in nails (r=0.56, P<0.001) and arsenic concentration in urine (r=0.50, P<0.05). Exposed children had a significant reduction in arsenic methylation capacity indicated by decreased primary methylation index and secondary methylation index in both urine and saliva samples. Levels of salivary 8-OHdG in exposed children were significantly higher (~4-fold, P<0.01), whereas levels of urinary 8-OHdG excretion and salivary hOGG1 expression were significantly lower in exposed children (~3-fold, P<0.05), suggesting a defect in hOGG1 that resulted in ineffective cleavage of 8-OHdG. Multiple regression analysis results showed that levels of inorganic arsenic (iAs) in saliva and urine had a significant positive association with salivary 8-OHdG and a significant negative association with salivary hOGG1 expression.

Delineating the degree of association between biomarkers of arsenic exposure and type-2 diabetes mellitus

Non-carcinogenic effects in low-level (< 100 μgL(-1)) arsenic (As)-impacted populations, such as the development and progression of type-2 diabetes mellitus (T2DM), are often neglected given the primary emphasis of public health authorities on As carcinogenicity. We gathered studies reporting urinary biomarkers of As exposure (U-As) and biomarkers associated with T2DM and its complications (U-T2DM), such as renal damage, oxidation stress, low-grade inflammation, and endothelial damage. Studied U-T2DM biomarkers were: 8-hydroxy-2'deoxyguanosine, N-acetyl-β-d-glucosaminidase, β2-microglobulin, and albumin. Data was expressed as: either arithmetic means and standard deviations, or geometric means and geometric standard deviations, or correlation coefficients of U-As and U-T2DM. Urinary As concentrations were consistently associated with the aforementioned biomarkers of T2DM pathologic complications. Despite the limited selectivity of the selected T2DM biomarkers, a per unit change in As exposure level was reflected in the corresponding T2DM biomarker urinary concentrations. Our systematic review provides new evidence on the role of environmental As exposures influencing the T2DM disease process. Additional epidemiologic studies onto the association between As and T2DM should incorporate both urinary As and T2DM biomarkers, as suggested in this study, in order to evaluate subclinical effects of low-level As exposures.

Behavioural shift of estuarine mudcrab as biomarker of arsenic exposure in Sundarbans estuary of West Bengal

Mudcrab Scylla serrata (Crustacea: Decapoda) in an ecologically and economically important species of Sundarbans Biosphere Reserve was studied for its behaviour under the exposure of toxic arsenic - a common xenobiotic of this area. The behavioural profile of aquatic animals exposed to diverse toxicants are considered as an index to estimate the degree and nature of stress experienced by the animals both in nature and in experimental conditions. Present investigation involved study of selected behavioural shift of S. serrata under the sublethalconcentrations of 1, 2 and 3 ppm of sodium arsenite for 1, 2, 3 and 4 days in controlled laboratory condition. Exposure to arsenic resulted an appearance of selected abnormal behavioural manifestation including tendency of avoidance, hypersecretion of mucoid element and release of excess excretory products. Toxin induced alteration of studied behaviour is indicative to possible shift in the overall physiological functions and biological activities of this important species in its natural habitat. Chronic exposure to 3 ppm of sodium arsenite for 30 days may lead to decline this economically important species in Sundarbans Biosphere Reserve.

Reliability of spot urine samples in assessing arsenic exposure.

Urinary arsenic concentration is often used as a biomarker of arsenic exposure. First morning void (FMV) and spot urine samples from 131 participants in southeastern Michigan were analyzed using an HPLC-IC-PMS system for six different arsenic species: arsenobetaine (AsB), arsenite (As[III]), arsenate (As[V]), methylarsonous acid MMA[III], methylarsenic acid MMA[V], and dimethylarsenic DMA[V]. Bland-Altman plots, intraclass correlation coefficients (ICCs), and Pearson correlation procedures were used to evaluate the relationship between the arsenic species in FMV and spot urine collections after normalizing the samples by specific gravity. DMA[III] and MMA[III] were not detected in any of the samples. The sum of As[III], As[V], MMA[V], and DMA[V] was designated SumAs. The ICC between SumAs in FMV and SumAs in spot samples was 0.90. The ICC showed that 90% of variation comes from between individuals and not within individuals. A significant correlation (r=0.80 p<0.001) was observed between FMV and spot samples for SumAs. The spot sample were a good predictor of the MMA[V] (r=0.83 p<0.0001), and DMA[V] (r=0.77 p<0.0001) in the FMV sample. These associations suggest that either FMV or spot samples can be used as an adequate bioindicator of arsenic metabolites in human urine. The benefit of using spot urine samples, instead of 24-h or FMV urine samples, is the potential reduction in budgetary and logistic requirements in epidemiological studies.

Association Between Low-Level Environmental Arsenic Exposure and QT Interval Duration in a General Population Study

High-level arsenic exposure is consistently associated with QT prolongation, a risk factor for arrhythmia and sudden cardiac death. Arsenic may act on QT by increasing cardiac calcium currents. The authors hypothesized that low-level arsenic exposure would be associated with QT duration and that this effect would be stronger among persons not using calcium channel blockers. They performed a cross-sectional analysis in elderly men from the Normative Aging Study to analyze associations between toenail arsenic and QT and heart rate-corrected QT (QTc) durations and to examine effect modification by calcium channel blocker use, using linear regression and adjusting for potential confounders. Participants were examined in Boston, Massachusetts, between 2000 and 2002 or in 2006. An interquartile range increase in arsenic concentration was associated with a 3.8-millisecond increase in QT (95% confidence interval: 0.82, 6.8) and a 2.5-millisecond increase in QTc (95% confidence interval: 0.11, 4.9). There was no evidence of effect modification by medication use for either QT (P = 0.93) or QTc (P = 0.58). The authors observed positive associations between a biomarker of arsenic exposure and QT duration but found no evidence of effect modification by calcium channel blocker use, possibly because of modest power.

Levels of arsenic in human hair as biomarkers of arsenic exposure in a mining community in Ghana

Arsenic levels were determined in human hair samples collected from a mining and non-mining community in Ghana. Hair samples were digested and analyzed using inductively coupled plasma atomic emission spectrometer (ICP–AES). Elevated levels of arsenic were found in the samples obtained from the mining community, the mean levels in the hair ranged from 0.0142–0.0515 μg/g, whereas arsenic was not detected in the hair samples from the non-mining community. The values obtained from the mining community were all below background levels set by the Agency for Toxic Substance and Disease Registry (ATSDR). The results therefore indicate that arsenic pollution may indeed be associated with mining, inducing human environmental exposure.

Inorganic arsenic as a developmental toxicant: In utero exposure and alterations in the developing rat lungs

In the present study, we characterize the toxic effects of in utero arsenic exposure on the developing lung. We hypothesize that in utero exposure to inorganic arsenic through maternal drinking water causes altered gene and protein expression in the developing lung, indicative of downstream molecular and functional changes. From conception to embryonic day 18, we exposed pregnant Sprague-Dawley rats to 500 ppb arsenic (as arsenite) via the drinking water. Subtracted cDNA libraries comparing control to arsenic exposed embryonic lungs were generated. In addition, a broad Western blot analysis was performed to identify altered protein expression. A total of 59 genes and 34 proteins were identified as being altered. Pathway mapping and analysis showed that cell motility was the process most affected. The most likely affected pathway was alteration in integrin signaling through the beta-catenin pathway, altering c-myc. The present study shows that arsenic induces alterations in the developing lung. These data may be useful in the elucidation of molecular targets and biomarkers of arsenic exposure during lung development and may aid in understanding the etiology of arsenic induced adult respiratory disease and lung cancers.