Determination of Arsenic in Scalp Hair of Children and its Correlation with Drinking Water in Exposed Areas of Sindh Pakistan

This study was focused on the analysis of arsenic (As) levels in scalp hair of children (age, <10 years) collected from two towns of Khairpur, Pakistan, to evaluate the effects of As-contaminated groundwater. For comparative purposes, scalp hair samples of children were also collected from that area having low levels of As (<10 μg/L) in drinking water. Groundwater and scalp hair samples of children were collected and analyzed by electrothermal atomic absorption spectrometry prior to microwave-assisted acid digestion. The average As concentrations in groundwater samples of two towns, Thari Mirwah and Gambat, were found to be 28.5 and 98.3 μg/L, respectively. The range of As concentrations in scalp hair samples of children who belong to Thari Mirwah and Gambat was 1.25-1.61 μg/g and 1.73-3.63 μg/g, respectively. Twenty percent of the total children who belong to Gambat have skin lesions on their hands and feet. A positive correlation coefficient (R = 0.91-0.99) was obtained between As contents in drinking water and scalp hairs of children of both towns.     

Age and Gender-Based Comparison of Nickel Content of Scalp Hair of Edible Oil- and Hydrogenated Oil-Consuming Populations

Nickel concentrations (μ g/g, dry weight) in the scalp hair of vegetable oil– and hydrogenated oil–consuming categories of male and female donors, ages between 1–66 years, were estimated by the atomic absorption method to assess the contribution of nickel as a contaminant in the hydrogenated oil. Comparative estimates of hair Ni content revealed enhanced metal levels for donors consuming hydrogenated oil both for male (29.33 μg/g, dry weight) and female (27.09 μg/g, dry weight) population segments, whereas for oil-consuming donors the corresponding levels were 11.51 μg/g and 13.49 μg/g, respectively. The Ni content of hair of elderly donors consuming hydrogenated oil was found significantly higher than that of younger male/female donors. Hair Ni levels as high as 63.59 μg/g and 68.40 μg/g were estimated for hydrogenated oil–consuming males and females, respectively. The Ni concentrations exhibited strong positive correlation with age for the hydrogenated oil–consuming male (r = 0.713) and female (r = 0.707) categories, whereas negative correlations were found for both oil-consuming categories. The regression relationships linking hair nickel content with the donor age of either sex indicated a negative dependence for oil-consuming donors, whereas strong direct dependence was observed for hydrogenated oil-consuming donors. The overall results evidenced an index of elevated nickel levels in the hair of population segment consuming hydrogenated oil, believed to arise from excessive residual nickel in the hydrogenated oil, present at concentrations surpassing the limit recommended by the World Health Organization for the safe ingestion of nickel in food commodities.     

Arsenic Removal Technologies for Drinking Water Treatment

Arsenic contamination as a consequence of human activities such as mining and pesticide use is affecting the water resource quality worldwide. Because of the high risk of arsenic exposure, specific water treatment processes are required to meet the anticipated more severe water quality standards. Better understanding of presently available processes is necessary to develop economic, efficient and effective methods for arsenic removal. Arsenic could either be coagulated, adsorbed using a wide range of materials both mineral and organic or could be directly rejected by membrane processes such as reverse osmosis and nanofiltration. The recent development of submerged hybrid membrane systems, such as membrane bioreactor in wastewater treatment, offers alternative technologies for arsenic treatment. The membrane in hybrid systems allows a better phase separation between the particles binding the arsenic and the treated water. The effect of pH and contact time, and the existence of other ionic compounds must be taken into account when designing the system for optimum arsenic rejection. Further research on both hydraulic and removal performances of hybrid adsorption/membrane technology is still required to assess the full potential of this technology for arsenic removal.     

Importance of Arsenic Speciation in Populations Exposed to Arsenic in Drinking Water

Total arsenic in urine is often the principal means for assessing chronic exposure to arsenic-contaminated drinking water. This approach ignores many components of the human diet, especially fish and seafood that contain arsenic at significant concentrations. The toxicity differences between the inorganic forms and the dietary forms suggest both should be evaluated when attempting to assess risk from arsenic exposure. Urine biomonitoring for 53 participants was used to confirm reduction in arsenic exposure resulting from well water remediation removing inorganic arsenic from drinking water. Initially, only total arsenic urine assays were performed, but spikes in total arsenic urine concentrations were determined to be diet related and demonstrated the need for analytical methods that differentiate the arsenic species. A secondary analysis was added that quantified inorganic-related arsenic in urine and the dietary forms related to fish and seafood by subtraction from total arsenic. Significant differences were found between the inorganic arsenic component and the total arsenic measured in their urine. On average, approximately 76% of total arsenic in urine was attributed to fish and other organo-arsenic dietary sources, implying a potential significant overestimate of exposure, and demonstrating the need for differentiation of the inorganic-related arsenic from dietary arsenic.     

Assessing Risk of Inorganic Arsenic in Drinking Water in the United States

Limitations of the current EPA risk assessment for inorganic arsenic in drinking water in the U.S. are discussed. An empirical approach is suggested that would sample survey the populations in regions with the highest arsenic levels in drinking water for signs of arsenicism, which has been much more prevalent and appeared much earlier in exposed populations than cancer (e.g., of the skin). Biomarkers of exposure, such as arsenic content in urine, nails, hair, and skin scales, may provide even earlier indications of subpopulations with excessive arsenic exposure and identify individuals at risk. Further study is needed to evaluate fully the potential for use of biomarkers, focusing on the accuracy and reliability of analytical methods, the utility of biomarkers as indicators of short-term and long-term exposure and as precursors to clinical signs of arsenicism, and the use of “normal” ranges of biomarkers for interpretation of field observations.     

Health Risk Assessment Due to Groundwater Arsenic Contamination: Children Are at High Risk

Health risk assessment due to groundwater As contamination was conducted in two As-prone panchayats, Rampur Diara (RD) and Haldichapra (HC) of the Maner block of the Patna district, Bihar (India). All 100% of the water samples surveyed were found to be contaminated with As with a mean value of 52 μg/L (n = 10) in RD and 231 μg/L (n = 10) in HC, both exceeding the World Health Organization (WHO) guideline of 10 μg/L and the Bureau of Indian Standards (BIS) standard of 50 μg/L, respectively. The average calculated per capita consumption of As through drinking water in RD ranged from 120 μg/day for 5–10-year-old children to 320 μg/day for adults older than 41 years, while in HC the average calculated As through consumption ranged from 580 μg/day for 5–10-year-old children to 1470 μg/day for adults older than 41 years. Hazard quotients were calculated to be between 12.1 to 41.6 for the RD population and 58.3 to 192.5 for the HC population, both exceeding the typical toxic risk index 1. In addition, cancer risk of 19 per 1000 was found for RD children and 87 per 1000 for HC children. Visible symptoms of Arsenicosis were also observed in the area.     

Arsenic and selenium in human hair

The selenium (Se) content of the diet and/or selenium supplements might have an ameliorating effect on arsenic (As) toxicity as recently shown by Wang et al. (1), Yang et al. (2), and as reviewed by Spallholz et al. (3). The underlying principles of the ameliorating effect is the complexation of Se with As forming the seleno-bis (S-glutathionyl) arsinium ion (4) excreted in bile and the complexation of Se with As in tissues forming nontoxic insoluble selenides (5,6). Addition protection afforded by Se supplementation from arsenicosis could be the elevation of glutathione peroxidase activity reducing the oxidative stress induced by As (7,8). The present study assessed the status of Se and As in hair by neutron activation analysis (NAA). Human hair samples were collected from the United States, Canada, The People's Republic of China (PRC), Bangladesh, and Nepal, the latter two countries now engaged in a struggle to find relief from human arsenicosis resulting from extensive domestic groundwater contamination by As. No statistically significant differences were observed in the samples between the Se and As content of hair from, Lubbock, Texas (USA) or Winnipeg, Canada. The concentration of As in all hair samples analyzed correlated (r=0.960, p<0.001) with the amount of As in the drinking water. Selenium levels in hair were highest from Nepal. The results demonstrate the viability of hair as a noninvasive biomonitor in assessing aspects of dietary Se and environmental As exposure. The hair data confirmed the known low intake of Se in the Keshan disease area of the PRC, the very high accumulation in hair of As from subjects consuming contaminated ground waters, and an adequate Se status in subjects from North America consuming municipal water of low As content. The high As content of hair from people in Bangladesh is the result of a high As consumption from contaminated water compounded by a less than desirable intake of Se (9). From Nepal, the As content of hair corresponded to the known low and high intake of As from contaminated groundwater. The very high Se content found in all hair samples from Nepal might be the result of the use of henna.     

Status of Selected Heavy Metal Distribution in Scalp Hair of Traffic Control Personnel Exposed to Vehicular Emissions

Scalp hair samples of traffic control personnel (n = 71, ages between 25 to 45 years) were analyzed for 11 selected metals by using an Inductively Coupled Argon Plasma Atomic Emission (ICP-AE) technique using nitric acid–perchloric acid based wet digestion method. The observed order of mean concentrations (μ g/g, dry weight) of the metals, in washed hair samples, was: Ca > Mg > Zn > Fe > Pb > Cu > Ni > Mn > Cr > Cd > Co, with corresponding metal levels at 1042.2, 182.4, 169.7, 13.6, 12.4, 11.1, 2.7, 1.9, 1.9, 0.8, and 0.7 μ g/g, respectively. Most of the unwashed samples exhibited 10–15% higher metal levels compared with those in washed samples. A positive metal-to-metal correlation (p < 0.01) was observed for the metal pairs: Ca-Mg (r = 0.737), Pb-Cr (r = 0.441), and Cu-Zn (0.385). Principal Component Analysis (PCA) extracted 6 factors as metals origin using varimax normalized rotation commutatively representing more than 76% of the total variance. Cluster Analysis (CA) showed five strong clusters of selected metals in the hair of the subjects: Age-Exposure, Ca-Mg, Cd-Fe-Mn, Pb-Cr, and Cu-Zn. The results of the current study were compared with those for two other occupationally exposed groups, metal arc welders and autodrivers, using published literature values. The traffic controllers in our study generally, with the exception of Cu, exhibited lower levels of metals in hair samples than did autodrivers and arc welders.     

Health Risk Assessment and Urinary Excretion of Children Exposed to Arsenic through Drinking Water and Soils in Sonora,Mexico

Biological Trace Element Research - Environmental arsenic exposure is associated with increased risk of non-cancerous chronic diseases and a variety of cancers in humans. The aims of this study...     

Sensitivity Analysis of U.S. EPA's Estimates of Skin Cancer Risk from Inorganic Arsenic in Drinking Water

The current U.S. Environmental Protection Agency's (USEPA's) risk analysis on the Integrated Risk Information System (IRIS) for arsenic in drinking water is based on an epidemiological study of skin cancer in Taiwan. Assumptions used in the USEPA application of the multistage-Weibull model for risk estimation were varied to assess the effect on predicted risk of skin cancer to the U.S. population at arsenic concentrations of 1 to 50?µg/L in drinking water. Among the assumptions tested, the only notable change in risk estimates was a reduction when the arsenic concentration used as representative for Taiwan villages in the low range (<300?µg/L) was increased to the 75th percentile (245?µg/L) in place of the mean used in the USEPA analysis (170?µg/L), but the representative value for Taiwan villages in the high range (≥600?µg/L) was not increased simultaneously to the 75th percentile. Additionally, a simulation study was conducted using records of arsenic measurements in wells from the same period and region of Taiwan as the original study. The exposure-response curve estimated from 60 villages (60 data points) differed only marginally from the outcome when data were summarized into four data points (as in the USEPA skin cancer analysis). Briefly discussed are differences between the study area of Taiwan and the U.S. in nutritional status and consumption of inorganic arsenic in food that might bias predicted U.S. skin cancer risks.     

Evaluation of Calcium and Magnesium in Scalp Hair Samples of Population Consuming Different Drinking Water: Risk of Kidney Stone

The objective of this study was to examine the relationship between calcium (Ca) and magnesium (Mg) in underground water (UGW), bottled mineral water (BMW), and domestic treated water (DTW) with related to risk of kidney stones. The water samples were collected from different areas of Sindh, Pakistan. The scalp hair samples of both genders, age ranged 30–60 years, consuming different types of water, have or have not kidney disorders, were selected. The Ca and Mg concentrations were determined in scalp hair of study subjects and water by flame atomic absorption spectroscopy. The Ca and Mg contents in different types of drinking water, UGW, DTW, and BMW, were found in the range of 79.1–466, 23.7–140, and 45–270 mg/L and 4.43–125, 5.23–39.6, and 7.16–51.3 mg/L, respectively. It was observed that Ca concentration in the scalp hair samples of kidney stone patients consuming different types of drinking water was found to be higher (2,895–4721 μg/g) while Mg level (84.3–101 μg/g) was lower as compare to referents subjects (2,490–2,730 μg/g for Ca, 107–128 μg/g for Mg) in both genders. The positive correlation was found between Ca and Mg levels in water with related to kidney stone formations in population, especially who consumed underground water. A relative risk and odd ratio were calculated; the relative risk had a strong positive association with incidence of kidney stone which depends on types of drinking water.     

How Creditable are Cancer Risk Estimates from the S.W. Taiwan Database for Arsenic in Drinking Water?

A database of cancer mortality and arsenic concentrations in village wells in an arseniasis-endemic area of southwestern Taiwan has been the predominant source of information for risk assessments of U.S. Environmental Protection Agency and two National Research Council reports on arsenic and drinking water. A limitation of the data, however, is that exposure is ecological, that is, cancer mortality cannot be matched with arsenic exposure on an individual basis, just grouped by village. The resultant potential for bias is examined by comparing dose-response analyses of villages divided into two groups, those with well concentrations in a narrow range and the remainder. The narrow range group suggests a flat or downward change in risk in the low dose range, whereas the other group indicates increasing risk. More disturbingly, however, the dose-response data are highly dispersed for both groups and the dose-response curve predicts background bladder/lung cancer levels much higher than a southwestern Taiwan comparison population. This may be due to a large variability between villages of the study area in bladder/lung cancer not directly attributable to arsenic. Including the comparison population in the dose-response analysis artificially anchors the dose-response curve at a background level inconsistent with the study population and likely just biases the slope factor upward.     

Arsenic in Seafood: Speciation Issues for Human Health Risk Assessment

Major sources of arsenic exposure for humans are foods, particularly aquatic organisms, which are called seafood in this report. Although seafood contains a variety of arsenicals, including inorganic arsenic, which is toxic and carcinogenic, and arsenobetaine, which is considered nontoxic, the arsenic content of seafood commonly is reported only as total arsenic. A goal of this literature survey is to determine if generalizable values can be derived for the percentage of total arsenic in seafood that is inorganic arsenic. Generalizable values for percent inorganic arsenic are needed for use as default values in U.S. human health risk assessments of seafood from arsenic-contaminated sites. Data from the worldwide literature indicate the percent of inorganic arsenic in marine/estuarine finfish does not exceed 7.3% and in shellfish can reach 25% in organisms from presumably uncontaminated areas, with few data available for freshwater organisms. However, percentages can be much higher in organisms from contaminated areas and in seaweed. U.S. site-specific data for marine/estuarine finfish and shellfish are similar to the worldwide data, and for freshwater finfish indicate that the average percent inorganic arsenic is generally < 10%, but ranges up to nearly 30%. Derivation of nationwide defaults for percent inorganic arsenic in fish, shellfish, and seaweed collected from arsenic-contaminated areas in the United States is not supported by the surveyed literature.     

Estimation of Dietary Intake of Inorganic Arsenic in U.S. Children

Arsenic is a natural component of the environment and is ubiquitous in soils, water, and the diet. Because dietary intake can be a significant source of background exposure to inorganic arsenic (the most toxicologically significant form), accurate intake estimates are needed to provide a context for risk management of arsenic exposure. Intake of inorganic arsenic by adults is fairly well characterized, but previous estimates of childhood intake were based on inorganic arsenic analyses in a limited number of foods (13 food types). This article estimates dietary intake for U.S. children (1 to 6 years of age) based on reported inorganic arsenic concentrations in 38 foods and in water used in cooking those foods (inorganic arsenic concentration of 0.8 μg/L), and U.S. Department of Agriculture food consumption data. This information is combined using a probabilistic software model to extract food consumption patterns and compute exposure distributions. The mean childhood dietary intake estimate for inorganic arsenic was 3.2 μg/day with a range of 1.6 to 6.2 μg/day for the 10th and 95th percentiles, respectively. For both the mean and 95th percentile inorganic arsenic intake rates, intake was predominantly contributed by grain and grain products, fruits and fruit juices, rice and rice products, and milk.     

Arsenic and Heavy Metal Concentrations in Drinking Water in Pakistan and Risk Assessment: A Case Study

The present study was performed to assess drinking water quality and potential health risk in the Nowshera District, Khyber Pakhtunkhwa, Pakistan. For this purpose drinking water samples were collected from local available sources and analyzed for physico-chemical characteristics, arsenic (As) and heavy metals. Results revealed high levels of toxic heavy metals such as chromium (Cr), nickel (Ni), lead (Pb), cadmium (Cd), and As contaminations in the drinking water. Results were evaluated for chronic risk including average daily intake (ADI) and hazard quotient (HQ). Among heavy metals the HQ values were highest for Cd (5.80) and As (2.00). Therefore, populations in the study area may be at a low level of chronic toxicity and carcinogenic risk. Statistical analyses showed that contribution of different drinking water sources to the mean contaminant levels in the study area was insignificant (p =.53). Correlation analysis further revealed that anthropogenic activities were the main sources of contamination, rather than geogenic. This study strongly recommends the treatment of urban and industrial wastewater in the vicinity of the study area and provision of safe drinking water.     

Evaluation of Toxic Risk Assessment of Arsenic in Male Subjects Through Drinking Water in Southern Sindh Pakistan

The arsenic (As) hazardous quotient was estimated based on concentration of As in drinking water and scalp hair of male subjects of two age groups (n = 360) consuming As contaminated water at different levels and non-contaminated drinking water. The total As concentrations in drinking water of less-exposed (LE) and high-exposed (HE) areas was found to be 3- to 30-fold higher than the permissible limit of the World Health Organization (2004) for drinking water, while the levels of As in drinking water of non-exposed (NE) areas was within the permissible limit. The levels of As in scalp hair samples of male subjects of two age groups belonging to NE, LE, and HE areas ranged from 0.01 to 0.27, 0.11–1.31, and 0.36–6.80 μg/g, respectively. A significant correlation between As contents of drinking water and As concentration in scalp hair was observed in sub-district Gambit (r = 0.825–0.852, p < 0.001) as compared to those subjects belonging to LE sub-district Thari Mirwah. A toxicity risk assessment provides a hazard quotient corresponding to <10 that indicates non-carcinogenic exposure risk of understudy areas.     

Uncertainty Analysis of Pesticide Residues in Drinking Water Risk Assessment

Pesticide residues in drinking water can vary significantly from day to day. However, water quality monitoring performed under the Safe Drinking Water Act (SDWA) at most community water systems (CWSs) is typically limited to four data points per year over a few years. Due to this limited sampling, likely maximum residues may be underestimated in risk assessment. In this work, a statistical methodology is proposed to study two types of uncertainties in observed samples and their propagated effect in risk estimates. The methodology was demonstrated using data from 16 CWSs that have three independent databases of atrazine residue to estimate the uncertainty of risk in infants and children. The results showed that in 85% of the CWSs, chronic risks predicted with the proposed approach may be two- to four-folds higher than that predicted with the current approach, wheras intermediate risks may be two- to three-folds higher in 50% of the CWSs. In 12% of the CWSs, however, the proposed methodology showed a lower intermediate risk. A closed-form solution of propagated uncertainty was developed to demonstrate the number of years (seasons) of data and sampling frequency needed to reduce the uncertainty of risk estimates. In general, this methodology provided good insight into the importance of addressing uncertainty of observed water quality data and the need to predict likely maximum residues in risk assessment.     

Effect of Scalp and Facial Hair on Air Displacement Plethysmography Estimates of Percentage of Body Fat

Objective: The objective of this study was to determine the effect of body hair (scalp and facial) on air displacement plethysmography (BOD POD) estimates of percentage of body fat. Research Methods and Procedures: A total of 25 men (31.4 ± 8.0 years, 83.4 ± 12.2 kg, 181.8 ± 6.9 cm) agreed to grow a beard for 3 weeks to participate in the study. Total body density (g/cm³) and percentage of body fat were evaluated by BOD POD. To observe the effect of trapped isothermal air in body hair, BOD POD measures were performed in four conditions: criterion method (the beard was shaven and a swimcap was worn), facial hair and swimcap, facial hair and no swimcap, and no facial hair and no swimcap_. Results: The presence of only a beard (facial hair and swimcap) resulted in a significant underestimation of percentage of body fat (16.2%, 1.0618 g/cm³) vs. the criterion method (17.1%, 1.0597 g/cm³, p < 0.001). The effect of scalp hair (no swim cap worn) resulted in a significant underestimation in percentage of body fat relative to the criterion method, either with facial hair (facial hair and no swimcap; 14.8%, 1.0649 g/cm³) or without facial hair (no facial hair and no swimcap; 14.8%, 1.0650 g/cm³, p < 0.001 for both). Discussion: A significant underestimation of percentage of body fat was observed with the presence of facial hair (～1%) and scalp hair (～2.3%). This underestimation in percentage of body fat may be caused by the effect of trapped isothermal air in body hair on body‐volume estimates. Thus, excess facial hair should be kept to a minimum and a swimcap should be worn at all times to ensure accurate estimates of body fat when using the BOD POD.