A new dispersive liquid-liquid microextraction using ionic liquid based microemulsion coupled with cloud point extraction for determination of copper in serum and water samples.

A simple and rapid dispersive liquid-liquid microextraction procedure based on ionic liquid assisted microemulsion (IL-µE-DLLME) combined with cloud point extraction has been developed for preconcentration copper (Cu(2+)) in drinking water and serum samples of adolescent female hepatitits C (HCV) patients. In this method a ternary system was developed to form microemulsion (µE) by phase inversion method (PIM), using ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) and nonionic surfactant, TX-100 (as a stabilizer in aqueous media). The Ionic liquid microemulsion (IL-µE) was evaluated through visual assessment, optical light microscope and spectrophotometrically. The Cu(2+) in real water and aqueous acid digested serum samples were complexed with 8-hydroxyquinoline (oxine) and extracted into IL-µE medium. The phase separation of stable IL-µE was carried out by the micellar cloud point extraction approach. The influence of of different parameters such as pH, oxine concentration, centrifugation time and rate were investigated. At optimized experimental conditions, the limit of detection and enhancement factor were found to be 0.132 µg/L and 70 respectively, with relative standard deviation <5%. In order to validate the developed method, certified reference materials (SLRS-4 Riverine water) and human serum (Sero-M10181) were analyzed. The resulting data indicated a non-significant difference in obtained and certified values of Cu(2+). The developed procedure was successfully applied for the preconcentration and determination of trace levels of Cu(2+) in environmental and biological samples.

Correlation of cadmium and aluminum in blood samples of kidney disorder patients with drinking water and tobacco smoking: related health risk.

The combined exposure to aluminum (Al) and cadmium (Cd) causes more pronounced adverse health effects on humans. The kidneys are the main organs affected by internal exposure to Cd and Al via food and non-food items. The objective of present study was to measure the Al and Cd concentrations in cigarettes tobacco (branded and non-branded) and drinking water (domestic treated, ground and lake water) samples in southern part of Pakistan, to assess the risk due to ingestion of water and inhalation of cigarettes smoke containing high concentrations of both elements. The study population (kidney disorder and healthy) divided into two group based on consuming lake and ground water, while smoking non-branded cigarette as exposed, while drinking domestic treated water and smoking branded cigarette as non-exposed. Electrothermal atomic absorption spectrometry was used to determined Cd and Al concentrations in tobacco, drinking water and blood samples. The resulted data indicated that the levels of Al and Cd in lake and underground water were higher than the permissible limit in drinking water recommended by the World Health Organization. The biochemical parameters of exposed and referent patients, especially urinary N-acetyl-h-glucosaminidase, were used as a biomarkers of kidney disorder. Exposed kidney disorder patients have higher levels of Cd and Al than the exposed referents subjects, while difference was significant when compared to resulted data of non-exposed patients and referents (p = 0.01-0.001). The pearson correlation showed positive correlation between both toxic element concentrations in water, cigarettes versus blood samples of exposed subjects (r = 0.20-0.67 and 0.71-0.82), while lower values were observed for non-exposed subjects (r = 0.123-0.423 and 0.331-0.425), respectively.

Scalp hair and blood cadmium levels in association with chewing gutkha, mainpuri, and snuff, among patients with oral cancer in Pakistan.

BACKGROUND: It has been reported that smokeless tobacco (SLT) chewing can lead to caners of oral cavity. In this study, the relationship between cadmium exposure via consumption of different SLT products by patients with oral cancer with related to referents belongs to different cities of Pakistan are investigated. METHODS: The cadmium in different types of SLT products (gutkha, mainpuri and snuff) consumed by studied population and biological samples (scalp hair and blood) of cancerous and healthy subjects were analyzed. Both referents and patients with cancer have same age group (ranged 30-60 years), socioeconomic status, localities, and dietary habits. The concentrations of cadmium in SLT products and biological samples were measured by electrothermal atomic absorption spectrophotometer after microwave-assisted acid digestion. The validity and accuracy of the methodology were checked by certified reference materials. RESULTS: It was estimated that 10 g intake of different types of gutkha, mainpuri, and snuff could contribute, 18-40%, 15.7-33.6%, and 14-68% of the provisional maximum tolerable daily intake of cadmium, respectively for adults (60 kg). The results of present study showed that the mean value of cadmium was significantly higher in scalp hair and blood samples of patients with oral cancer as compared to those results obtained for referents (P < 0.001). CONCLUSIONS: The high exposure of cadmium due to consuming different SLT products may have synergistic effects with other risk factors associated for oral cancer.

Comparative evaluation of essential and toxic elements in the blood of kidney failure patients and healthy referents.

The aim of the present study was to evaluate the comparative distribution, correlation, and apportionment of selected elements-aluminum (Al), calcium (Ca), cadmium (Cd), potassium (K), magnesium (Mg), sodium (Na), and lead (Pb)-in the blood samples of male kidney failure patients (KFP) and healthy subjects of age ranged 30-60 years. The blood samples were digested with nitric acid and perchloric acid mixture (2:1), followed by the quantification of elements by atomic absorption spectrometry. The concentration of essential elements in blood samples of KFP were found in the range of Ca (97-125), Mg (18-36), Na (2971-3685), and K (177-270) mg/L while, the levels of Al, Cd, and Pb were found in the range of (475-1275), (0.9-9.9), and (211-623) µg/L, respectively. In the healthy referents, concentration of electrolytes in blood samples was lower than KFP, but difference was not significant (p > 0.05). While the levels of toxic elements in blood samples of referents were three- to sixfold lower than KFP (p < 0.01). Principal component analysis (PCA) and cluster analysis (CA) of the element data manifested diverse apportionment of the selected elements in the blood sample of the KFP compared with the healthy counterparts.

Preconcentration and determination of lead and cadmium levels in blood samples of adolescent workers consuming smokeless tobacco products in Pakistan.

The present study was aimed to evaluate the cadmium (Cd) and lead (Pb) levels in the blood samples of adolescent boys, chewing different smokeless tobacco (SLT) products in Pakistan. For comparative purpose, boys of the same age group (12-15 years), not consumed any SLT products were selected as referents. To determine trace levels of Cd and Pb in blood samples, a preconcentration method, vortex-assisted liquid-liquid microextraction (VLLME) has been developed, prior to analysis by flame atomic absorption spectrometry. The hydrophobic chelates of Cd and Pb with ammonium pyrrolidinedithiocarbamate were extracted into the fine droplets of ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate, while nonionic surfactant, Triton X-114 was used as a dispersing medium. The main factors affecting the recoveries of Cd and Pb, such as concentration of APDC, centrifugation time, volume of IL and TX-114, were investigated in detail. It was also observed that adolescent boys who consumed different SLT products have 2- to 3-fold higher levels of Cd and Pb in their blood samples as compared to referent boys (p < 0.001).

Assessment of selenium and mercury in biological samples of normal and night blindness children of age groups (3-7) and (8-12) years.

The causes of night blindness in children are multifactorial and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence biological sample composition. This study was designed to compare the levels of selenium (Se) and mercury (Hg) in scalp hair, blood, and urine of night blindness children age ranged (3-7) and (8-12) years of both genders, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment for the determination of Se and Hg in biological samples of night blindness children. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The Se and Hg in biological samples were measured by electrothermal atomic absorption spectrometry and cold vapor atomic absorption spectrometry, prior to microwave acid digestion, respectively. The concentration of Se was decreased in scalp hair and blood samples of male and female night blindness children while Hg was higher in all biological samples as compared to referent subjects. The Se concentration was inversely associated with the risk of night blindness in both genders. These results add to an increasing body of evidence that Se is a protecting element for night blindness. These data present guidance to clinicians and other professional investigating deficiency of essential micronutrients in biological samples (scalp hair and blood) of night blindness children.

Distribution of potassium, calcium, magnesium, and sodium levels in biological samples of Pakistani hypertensive patients and control subjects.

BACKGROUND: The abnormal metabolism of metal ions plays an important role in health and disease conditions, and studies about them have been attracting significant interest. The aim of our study was to assess the essential minerals (calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na)) in biological samples (scalp hair, blood, urine) of 387 hypertensive males and females, age 30-60 years, in an urban population together with 439 non-hypertensive subjects of same age group and residential areas. METHODS: The element concentrations were measured by means of an atomic absorption spectrophotometer after microwave-induced acid digestion. The validity and accuracy was checked by conventional wet acid digestion method and using certified reference materials. The overall recoveries of all elements were found in the range of 99.1-99.9% of certified values. RESULTS: The results indicated significantly lower levels of Ca, Mg, and K in the biological samples (blood and scalp hair) of hypertensive patients, when compared to controls of both genders. The level of Na was found to be high in biological samples of hypertensive patients as compared to controls. CONCLUSIONS: The deficiency of Ca, Mg, and K may be synergistic with risk factors associated with hypertension. These data present guidance to clinicians and other professionals who will be investigating the deficiency of essential micronutrients in biological samples (scalp hair and blood) of hypertensive patients.

Distribution of arsenic, cadmium, lead, and nickel levels in biological samples of Pakistani hypertensive patients and control subjects.

BACKGROUND: The abnormal metabolism of metal ions plays an important role in health and disease conditions, and studies about them have been attracting significant interest. The aim of our study was to assess the toxic elements arsenic (As), cadmium (Cd), nickel (Ni), and lead (Pb) in biological samples (scalp hair, blood, urine) of 387 hypertensive males and females, aged between 30 and 60 years, from an urban population together with 439 non-hypertensive subjects, of the same age group and residential areas. METHODS: The element concentrations were measured by means of an electrothermal atomic absorption spectrophotometer after microwave-induced acid digestion. The validity and accuracy was checked by conventional wet acid digestion method and using certified reference materials. The overall recoveries of all elements were found in the range of 96.8 - 99.4% of certified values. RESULTS: The results indicated significantly higher levels of As, Cd, Ni, and Pb in the biological samples (scalp hair, blood and urine) of hypertensive patients, when related to controls of both genders. CONCLUSIONS: The high exposure of toxic elements may be synergistic with risk factors associated with hypertension. These data present guidance to clinicians and other professionals who will be investigating the toxicity of heavy elements in biological samples (scalp hair and blood) of hypertensive patients.

Evaluation of chromium and manganese in biological samples (scalp hair, blood and urine) of tuberculosis and diarrhea male human immunodeficiency virus patients.

BACKGROUND: The consequence of trace elements deficiency has been associated with an increased risk of human immunodeficiency virus type 1 (HIV-1) disease progression and mortality. This study examined the association between high concentrations of chromium (Cr) and manganese (Mn) in scalp hair, blood, and urine and opportunistic infections in hospitalized patients with the acquired immune deficiency syndrome (AIDS). METHODS: The study was performed on 62 male HIV+ patients (HIV-1) from different cities of Pakistan. The patients were divided in two groups according to secondary infections (tuberculosis, diarrhea, or high fever). The biological samples (scalp hair, blood and urine) were collected from AIDS patients, and for comparative study 120 healthy subjects (males) of same age group (31 - 45 years), socio-economic status, localities, and dietary habits were also included. The elements in the biological samples were analyzed by electrothermal atomic absorption spectrophotometry after microwave-assisted acid digestion. The validity and accuracy of the methodology was checked by using certified reference materials (CRMs) and with the values obtained by conventional wet acid digestion method on the same CRMs. RESULTS: The results indicated significantly lower concentrations of Cr and Mn in the biological samples (scalp hair, blood, and urine) of male HIV-1 patients, compared with control subjects. It was observed that the lower levels of these trace elements may be predictors for secondary infections in HIV-1 patients. There was a significant decrease in mean values of Cr and Mn in whole blood and scalp hair, whilst higher concentrations were observed in urine samples of the three groups of AIDS patients as compared to a controlled healthy male group (p < 0.001). CONCLUSIONS: Low Cr and Mn levels may be due to increased Cr and Mn losses. These data present guidance to clinicians and other professional investigating deficiencies of Cr and Mn in biological samples of AIDS patients.

Evaluation of fresh and stored rainwater quality in fluoride and arsenic endemic area of Thar Desert, Pakistan.

In the current study, the chemistry of fresh and stored rainwater of Thar Desert, Pakistan, was estimated during two consecutive monsoon periods. The present research deals with the variation in physicochemical parameters, total arsenic (As(t)), inorganic arsenic species (As(i), As(V), As(III)), and fluoride (F(-)) in stored rainwater (SRW) at different time intervals (1 week to 3 months). The pH of fresh rainwater (FRW) samples showed slightly acidic to neutral in nature (6.08-7.06) which were inconsistent with the reference pH value (5.6) of rainwater. The resulted data indicated that As(t) and F(-) levels in SRW were enhanced with time duration. The levels of As(t) and F(-) in SRW after different time intervals were found in the range of 194-683 µg/L and 10-35.4 mg/L, respectively. The values of As(t) and F(-) were 20-70 and 7-24 times higher than those of WHO permissible limits, 10 µg/L and 1.5 mg/L, respectively. The As(III) was dominant species in SRW, which corresponds to >60 % of As(i). The characteristics of the SRW revealed an unacceptable quality to consume for drinking and agricultural purposes in the studied area.

Simultaneous preconcentration of toxic elements in artificial saliva extract of smokeless tobacco product, mainpuri by cloud point extraction method.

It has been extensively investigated that smokeless tobacco chewing can lead mainly to inflammation of oral cavity. In present study, the total and artificial saliva extracted toxic elements, arsenic, cadmium, nickel and lead were estimated in smokeless tobacco product, mainpuri. Cloud point extraction has been used for the preconcentration of arsenic, cadmium, nickel and lead in artificial saliva extract, using complexing reagent, ammonium pyrrolidinedithiocarbamate. Total and extractable toxic elements were measured by electrothermal atomic absorption spectrometry. The chemical variables of cloud point extraction were optimized. The validity of methodology was tested by simultaneously analyzing certified reference material (Virginia tobacco leaves) and spike recovery test. The artificial saliva extractable levels of arsenic, cadmium, nickel and lead ranged from 15-22, 45-70, 35-58, and 18-32%, respectively, of total elemental contents in mainpuri samples. It was estimated that intake of 10g of different brands of mainpuri contributing the 5.88, 55.0, 45.0 and 40.3% of the provisional maximum tolerable daily intake for arsenic, cadmium, nickel and lead, respectively for adults of ~60kg.

Deep eutectic solvent based advance microextraction method for determination of aluminum in water and food samples: Multivariate study.

Preconcentration of aluminum Al3+ was carried out by a novel deep eutectic solvent based ultrasound-assisted liquid phase microextraction (DES-UALPME) method. The deep eutectic solvents (DESs), a green solvent was first time used for enrichment and quantification of very low concentration of Al3+ in water and food samples, prior to analysed by electrothermal atomic absorption spectrometry (ETAAS). In present method it was observed that % recovery of Al-8-hydroxyquinoline chelates efficiently extracted by DES solvent. Pre-enrichment factor and limit of detection were observed to be 50, and 0.032µgL-1, respectively. Developed procedure was validated with the CRM (SLRS-5 river water) of Al and a good agreement was observed in results of measured value to the certified value. The RSD was calculated as 3.3%. The presented procedure was successfully carried out to different water and food samples.

Choline Chloride-Oxalic Acid as a Deep Eutectic Solvent-Based Innovative Digestion Method for the Determination of Selenium and Arsenic in Fish Samples.

An innovative and effective digestion method based on choline chloride (ChCl)-oxalic acid (Ox) deep eutectic solvent (DES) was proposed for the determination of Se and As in fish samples via electrothermal atomic absorption spectrometry (ETAAS). The impacts of different variables, including the composition and volume of ChCl-Ox, temperature, and acid addition, on analyte recovery were studied for optimization. In this procedure, an 80 mg sample was dissolved in a 1:2 molar ratio of ChCl-Ox at 105°C for 40 min, with the subsequent addition of 4.0 mL HNO3 (1.0 M) and further heating at the same temperature for about 5 min. Next, centrifugation was applied, and the supernatant solution was filtered, diluted to a known volume, and measured by ETAAS. The accuracy of the developed method was tested using a Standard Reference Material (NIST SRM 1946 Lake Superior Fish Tissue). The proposed DES-based digestion method was successfully applied to the simultaneous extraction of Se and As from fish samples.

Solid phase microextraction method using a novel polystyrene oleic acid imidazole polymer in micropipette tip of syringe system for speciation and determination of antimony in environmental and food samples.

A simple, rapid and sensitive solid phase microextraction method was used for the speciation of inorganic antimony (Sb) by using a novel synthesized polymeric material in micropipette tip of syringe system. In present methodology, the specie of Sb (III) made hydrophobic complex with diethyl dithiocarbamate (DDTC) at pH 5.5 and subsequently adsorbed on polystyrene oleic acid imidazole polymer (POIP), whereas Sb(V) did not made complex and adsorbed on the polymer, remained in aqueous solutions. The strategy of multivariate was carried out to screen out the different variables and assessed the optimum values of their experimental values for the extraction efficiency of analyte. Then the analyte was sorbed on the polymer in micropipette tip of syringe system was quantitatively eluted by different types of acids at different levels for 2-6 aspirating/dispensing cycles. The extracted Sb(III) ions with modifiers were directed into the graphite furnace atomic absorption spectrometry for analysis. The limit of detection (LOD), limit of quantification (LOQ) and preconcentration factor (PF) for Sb(III) was found to be 6 ng L-1, 20 ng L-1 and 100. The RSD value was found to be 4.2%. The standard addition method and certified reference materials were checked for accuracy and validity of method. The developed method was effectively applied for the determination of total and inorganic species of Sb(III) and Sb(V) in different types of water samples, whereas only total Sb was determined in acid digested soil, Tuna fish, rice, spinach, black tea, mixed fruit juice and ice tea samples.

Ultrasonic assisted dispersive liquid-liquid microextraction method based on deep eutectic solvent for speciation, preconcentration and determination of selenium species (IV) and (VI) in water and food samples.

A novel ultrasound-assisted liquid phase microextraction (UALPME) based on environmental friendly extractants, deep eutectic solvent (DES) was first time presented for speciation of selenium. In present study, five DES solvents of different composition was prepared and used as efficient extractive medium for hydrophobic chelate of Se(IV) with 3,3'-Diaminobenzidine (DAB). The total inorganic Se species were determined after pre-reduction of Se(VI) to Se(IV), prior to applying developed method. The concentration of Se(VI) was calculated by the difference of Se(IV) values and total selenium contents. The concentration of Se in DES rich phase was measured with electrothermal atomic absorption spectrometer (ETAAS). The effects of different parameters on extraction efficiency of study analyte, including pH, ligand concentration, type and volume of DES, sonication time, volumes tetrahydrofuran and aqueous samples were examined. At the optimum conditions, limit of detection and quantification, preconcentration factor, and relative standard deviation (RSD %) were determined as 4.61ngL-1, 15.4ngL-1, 50% and 4.1%, respectively. The accuracy of the presented method was confirmed by analysis of certified reference material and standard addition method for different water and ice tea samples. The developed method was effectively applied to real water and food samples.

Evaluated the adverse effects of cadmium and aluminum via drinking water to kidney disease patients: Application of a novel solid phase microextraction method.

In present study aluminum (Al) and cadmium (Cd) were determined in ground water samples and assesses human health risks associated with elevated concentrations of toxic metals in dissolved form, using a novel solid phase microextraction (SPµE). Ground water sample (n=200) and biological sample (blood) of patients having chronic kidney disorders (CKD) along with healthy control subjects of same area (southern part of Pakistan) were collected. A simple system, including the micropipette tip packed with modified ionic liquid-activated carbon cloth (IL-ACC) coated with 8-hydroxyqunilone (8-HQ) attached to syringe. The analytes in water and acid digested blood samples were manually drawn for 2-10 cycles (drawing/discharging) at different pH range. The analytes sorbed on coated ACC were then desorbed with 2.0molL(-1) HNO3 in ethanol by drawing/discharging cycles for 1-5 times. The concentration of extracted analytes was determined by electrothermal atomic absorption spectrometer. The influence of different variables on the extraction efficiency of Cd and Al, were optimized. The Al and Cd concentrations in groundwater were found to be elevated than recommended limits by the World Health Organization. The urinary N-acetyl-h-glucosaminidase values were significantly higher in CKD patients as compared to refrent subjects (p<0.001). The significant variation in levels of Cd and Al were observed in blood samples of CKD patients than referents subjects (p<0.01). The strong positive correlation among Al and Cd levels in groundwater versus blood samples of CKD patients (r=0.82-0.85) p<0.01) was observed than those values calculated for referent subjects (r=0.425-0.536).

Development of new portable miniaturize solid phase microextraction of silver-APDC complex using micropipette tip in-syringe system couple with electrothermal atomic absorption spectrometry.

An innovative and simple miniaturized solid phase microextraction (M-SPME) method, was developed for preconcentration and determination of silver(I) in the fresh and waste water samples. For M-SPME, a micropipette tip packed with activated carbon cloth (ACC) as sorbent, in a syringe system. The size, morphology and elemental composition of ACC before and after adsorption of analyte have been characterized by scanning electron microscopy and energy dispersive spectroscopy. The sample solution treated with a complexing reagent, ammonium pyrrolidine dithiocarbamate (APDC), was drawn into the syringe filled with ACC and dispensed manually for 2 to 10 aspirating/dispensing cycle. Then the Ag- complex sorbed on the ACC in micropipette was quantitatively eluted by drawing and dispensing of different concentrations of acids for 2 to 5 aspirating/dispensing cycles. The extracted Ag ions with modifier were injected directly into the electrothermal atomic absorption spectrometry for analysis. The influence of different variables on the extraction efficiency, including the concentration of ligand, pH, sample volume, eluent type, concentration and volume was investigated. Validity and accuracy of the developed method was checked by the standard addition method. Reliability of the proposed methodology was checked by the relative standard deviation (%RSD), which was found to be <5%. Under the optimized experimental variables, the limits of detection (LOD) and enhancement factors (EF), were obtained to be 0.86 ng L(-1) and 120, respectively. The proposed method was successfully applied for the determination of trace levels of silver ions in fresh and waste water samples.

Toxic Risk Assessment of Arsenic in Males Through Drinking Water in Tharparkar Region of Sindh, Pakistan.

Humans are exposed to arsenic (As) through air, drinking water, and food. The arsenic (As) hazardous quotient was calculated on the basis of its concentration in drinking water of different origin and scalp hair of male subjects (n = 313), residents of different exposed and non-exposed areas of Sindh, Pakistan. The total As was determined in water and scalp hair samples, while As species were determined in water samples by advance extraction methodologies. The total As concentrations in drinking water of less-exposed (LE) and high-exposed (HE) areas was found to be 2.63 to 4.46 and 52 to 235, fold higher than the permissible limit, respectively, than recommended by 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 resulted data indicated that the dominant species was As(+5) in groundwater samples. The levels of As in scalp hair samples of male subjects of two age groups (18-30 and 31-50 years), belonging to NE, LE, and HE areas, ranged from 0.26 to 0.69, 0.58 to 1.34, and 15.6 to 60.9 µg/g, respectively. A significant correlation between As levels in drinking water and scalp hair was observed in HE area (r = 0.86-0.90, p < 0.001) as compared to those subjects belonging to LE area. A toxicity risk assessment was calculated as hazard quotient (HQ), which indicates that the study subjects of HE area have significantly higher values of HQ than LE. The population of As exposed areas is at high risk of non-carcinogenic and carcinogenesis effects.

Exposure of children to arsenic in drinking water in the Tharparkar region of Sindh, Pakistan.

Humans can be exposed to arsenic (As) through air, drinking water, and food. The aim of this study was to calculate the hazard quotient (HQ) of As, based on its concentration in drinking water and the scalp hair of children (males) belonging to two age groups (5-10 and 11-14 years) who consumed water contaminated with different concentrations of As. The water samples were collected from As-exposed and nonexposed areas, which were classified as low-exposed (LE), high-exposed (HE), and nonexposed (NE) areas. The total concentration of inorganic As (iAs) and its species (As(III) and As(V)) in water samples of all selected areas was determined by advanced extraction methods. For purposes of comparison, the total As level was also determined in all water samples. The resulting data indicated that the predominant inorganic As species in groundwater samples was arsenate (As(V)). The As concentrations in drinking water of LE and HE areas were found to be 2.6-230-fold higher than the permissible limit for drinking water established by the World Health Organization (2004). However, the As levels in drinking water of the NE area was within the permissible limit (<10 µg/L). The As levels in the scalp hair samples from boys of NE, LE, and HE areas ranged from 0.16 to 0.36, 0.36 to 0.83, and 11.5 to 31.9 mg/kg, respectively. A significant, positive correlation was observed between the As levels in drinking water and scalp hair samples of children from the HE area, compared with the other two groups (p>0.01). The As toxicity risk assessment based on HQ for the NE, LE, and HE areas corresponded to <10, ≥ 10, and >10, respectively. These HQ values indicated the noncarcinogenic, less carcinogenic, and highly carcinogenic exposure risks faced by children from the NE, LE, and HE areas, respectively. It can be concluded that children consuming the groundwater of the LE (Khairpur Mir's) and HE (Tharparkar) areas of Pakistan are at a potential risk of chronic As toxicity.