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Inorganic arsenic (InAs) is a ubiquitous metalloid that has been shown to exert multiple adverse health outcomes. Urinary InAs and its metabolite concentration has been used as a biomarker of arsenic (As) exposure in some epidemiological studies, however, quantitative relationship between daily InAs exposure and urinary InAs metabolites concentration has not been well characterized. We collected a set of 24-h duplicated diet and spot urine sample of the next morning of diet sampling from 20 male and 19 female subjects in Japan from August 2011 to October 2012. Concentrations of As species in duplicated diet and urine samples were determined by using liquid chromatography-ICP mass spectrometry with a hydride generation system. Sum of the concentrations of urinary InAs and methylarsonic acid (MMA) was used as a measure of InAs exposure. Daily dietary InAs exposure was estimated to be 0.087 µg kg -1 day -1 (Geometric mean, GM), and GM of urinary InAs+MMA concentrations was 3.5 ng mL -1 . Analysis of covariance did not find gender-difference in regression coefficients as significant (P > 0.05). Regression equation Log 10 [urinary InAs+MMA concentration] = 0.570× Log 10 [dietary InAs exposure level per body weight] + 1.15 was obtained for whole data set. This equation would be valuable in converting urinary InAs concentration to daily InAs exposure, which will be important information in risk assessment.

The concentrations of arsenic (As) species in 19 food composites prepared from 159 food items purchased in Shizuoka city, Japan, were determined (1) to estimate total daily intake of inorganic As (InAs) and some organic As species and (2) to determine food contributing to total daily InAs intake. As analysis included extraction of As species with a synthetic gastric juice (0.07 mol/L HCl + 0.01 % pepsin) from food composite and high-performance liquid chromatography-high efficiency photo-oxidation-hydride generation-inductively coupled plasma mass spectrometry. InAs was detected in 9 of 19 food composites at a concentration of 0.423-450 ng As/g fresh-weight. Daily intake of InAs from cereals was greatest (13 μg/person/day) followed by algae (5.7 μg/person/day), and the intake from the two categories constituted 90 % of the total daily InAs intake of adults (21 μg/person/day on a bioaccessible-fraction basis and 24 μg/person/day on a content basis). Analysis of individual food items showed that rice and hijiki contributed virtually 100 % of InAs from cereals and algae, respectively. The present survey indicated that InAs from rice and hijiki consumption contributed to total daily InAs intake and consequently to significant cancer risk of the general Japanese population. Daily intake of some organic forms of As and their contributing food categories was also estimated.

The daily dietary intake of inorganic arsenic (InAs) and some of organic arsenic (OrAs) species of Japanese subjects were estimated by determining the concentrations of As species in two different sets of total diet sample: duplicated diet samples collected from 25 subjects in Japan and a certified reference material with total diet matrix (NIES CRM No. 27 Typical Japanese Diet, TJD). The concentration of InAs and OrAs in diet samples were determined by LC-ICP-MS using a photo-oxidation and hydride generation system. The median intake of InAs for the 25 subjects was 3.8 μg day(-1) (2.0-57 μg day(-1)) and intake of 27 μg day(-1) was estimated from TJD. The median intake of MMA, DMA and TMAsO were <0.18, 1.1 and <0.053 μg day(-1) for the 25 subjects and that of MMA, DMA, AB and TMAsO was estimated to be 3.9, 11, 140 and 5.9 μg day(-1), respectively, based on TJD analysis. On the basis of InAs intakes estimated and the oral slope factor of the US EPA and Health Canada, excess cancer risk was estimated to exceed acceptable level. Cancer risk posed by the dietary InAs of the general Japanese may not be negligible., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The association between oxidative stress and exposure to environmental chemicals was assessed in a group of Japanese preschool children. The concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), 1-hydroxypyrene (1-OHP), inorganic arsenic (iAs) and monomethylarsonic acid (MMA), and cotinine in spot urine samples, collected from 134 children (3-6 yrs) from a kindergarten in Kanagawa, Japan, were measured as biomarkers of oxidative stress or exposure to environmental chemicals. For 76 subjects of the 134, intakes of anti-oxidant nutrients (vitamins A, C, and E, manganese, copper, zinc and selenium (Se)) were estimated from a food consumption survey carried out 2-4 weeks after urine sampling and by urine analysis (Se). The median (min-max) creatinine-corrected concentrations of urinary biomarkers were 4.45 (1.98-12.3), 0.127 (0.04-2.41), 4.78 (1.18-12.7), and 0.62 (<0.6-19.0) μg/g cre for 8-OHdG, 1-OHP, iAs+MMA, and cotinine, respectively. Multiple regression analysis was carried out using 8-OHdG concentration as a dependent variable and urinary biomarkers of exposure and Se intake, intakes of vitamins and biological attributes of the subjects as independent variables. To explain 8-OHdG concentrations, intake of vitamin A and age were significant variables with negative coefficients, while 1-OHP concentration had a positive coefficient. These results indicated that oxidative stress of children is affected by chemical exposure at environmental levels, by nutrient intake and by physiological factors in a complex manner. On the other hand, unstable statistical results due to sub-grouping of subject, based on the availability of food consumption data, were found: the present results should further be validated by future studies with suitable research design., (Copyright © 2011 Elsevier B.V. All rights reserved.)

This paper describes a robust and sensitive method for the determination of arsenic species in seawater by ion-exclusion liquid chromatography (LC) combined with inductively coupled plasma mass spectrometry (ICP-MS) using reaction cell and hydride generation (HG) techniques. A good separation of arsenite, arsenate, and monomethylarsonic acid was achieved using an ion-exclusion column packed with a sulfonated polystyrene resin and a dilute nitric acid at pH 2.0 as the eluent, even when a large volume, i.e. 200 μl, of seawater samples containing a large amount of matrix was repeatedly injected. Separations of the chloride ion due to the matrix and arsenic species were partially performed; however, the extensive peak of ArCl due to high content of Cl− in a sample overlapped peaks of the three arsenic species on 75As measurement by ICP-MS. This ArCl polyatomic interference was efficiently eliminated by collision of ArCl molecules with helium in an octopole reaction cell which was introduced prior to a mass spectrometer. Detection limits of the three arsenic species in a sample containing 2% Cl−, the concentration of which is comparable to that in a seawater sample, by LC–ICP-MS with the octopole reaction system (ORS), ranged from 21 to 25 pg As ml−1; these values were three–six times lower than those by LC–ICP-MS without ORS. As another technique for ArCl interference elimination, HG prior to ICP-MS was also successfully used not only to reduce the interference but also to improve the detection limits to 3.4–4.5 pg As ml−1. The developed LC–ICP–ORS–MS and LC–HG–ICP-MS were validated by analyzing a certified reference material (CRM) of seawater. In addition, no serious decrease in analytical performance of present methods was observed in the experimental periods of half a year for LC–ICP–ORS–MS and 1 year for LC–HG–ICP-MS, respectively. The latter method was successfully applied to characterize seasonal variations of three arsenic species in deep seawater and surface seawater. [Copyright &y& Elsevier]