Relation between airborne arsenic trioxide and urinary excretion of inorganic arsenic and its methylated metabolites.

The relation between exposure to As2O3 fumes and dust, and the urinary excretion of inorganic arsenic metabolites (monomethylarsonic acid, dimethylarsinic acid, unchanged inorganic arsenic) has been studied in 18 workers from a sulphuric acid producing plant. The concentration of arsenic in the breathing zone of each worker was measured during five consecutive days and urine samples were obtained after one shift and before the next. The collection efficiency of the air sampling system exceeded 95%. The time weighted average exposure (TWA) concentrations of As2O3 ranged from 6 to 502 micrograms As/m3 and were log normally distributed. Although exposure probably occurred by ingestion as well as inhalation, statistically significant correlations (log scales) were found between airborne TWA of As2O3 and the inorganic arsenic metabolites in urine collected immediately after the shift, or just before the next shift. For a TWA of 50 micrograms As/m3, the mean concentration of the sum of the three inorganic arsenic metabolites in a postshift urine sample amounted to about 55 micrograms arsenic/g creatinine (95% confidence interval (95% CI) 47-62). Higher estimates of urinary arsenic reported by other authors are probably due either to the influence of dietary organoarsenicals when total arsenic is measured in urine or to a low retention efficiency of the air sampling system for As2O3 in the vapour phase.     

Relation between airborne arsenic trioxide and urinary excretion of inorganic arsenic and its methylated metabolites.

The relation between exposure to As2O3 fumes and dust, and the urinary excretion of inorganic arsenic metabolites (monomethylarsonic acid, dimethylarsinic acid, unchanged inorganic arsenic) has been studied in 18 workers from a sulphuric acid producing plant. The concentration of arsenic in the breathing zone of each worker was measured during five consecutive days and urine samples were obtained after one shift and before the next. The collection efficiency of the air sampling system exceeded 95%. The time weighted average exposure (TWA) concentrations of As2O3 ranged from 6 to 502 micrograms As/m3 and were log normally distributed. Although exposure probably occurred by ingestion as well as inhalation, statistically significant correlations (log scales) were found between airborne TWA of As2O3 and the inorganic arsenic metabolites in urine collected immediately after the shift, or just before the next shift. For a TWA of 50 micrograms As/m3, the mean concentration of the sum of the three inorganic arsenic metabolites in a postshift urine sample amounted to about 55 micrograms arsenic/g creatinine (95% confidence interval (95% CI) 47-62). Higher estimates of urinary arsenic reported by other authors are probably due either to the influence of dietary organoarsenicals when total arsenic is measured in urine or to a low retention efficiency of the air sampling system for As2O3 in the vapour phase.     

Assessment of environmental arsenic levels in Prievidza district

A coal-burning power station in the Nitra Valley in central Slovakia annually emitted large quantities of arsenic (up to 200 tonnes) between 1953 and 1989. Since then, pollution-control measures have reduced arsenic emissions to less than 2 tonnes a year. However, the power station was still a source of airborne arsenic pollution. As part of an EU-funded study on exposure to arsenic and cancer risk in central and Eastern Europe we carried out a study of environmental levels of arsenic in the homes and gardens of residents of the district. Garden soil samples (n=210), house dust samples (n=210) and composite house dust samples (n=109) were collected and analysed using inductively coupled plasma atomic absorption spectroscopy (ICP-AES) at Imperial College. The mean arsenic content of coal and ash in samples taken from the plant was 519 microg/g (n=19) and 863 microg/g (n=22), respectively. The geometric mean (GM) arsenic concentration of garden soils was 26 microg/g (range 8.8-139.0 microg/g), for house dust 11.6 microg/g (range 2.1-170 microg/g) and for composite house dust 9.4 microg/g (range 2.3-61.5 microg/g). The correlation between the arsenic levels in soil and in house dust was 0.3 (P<0.01), in soil and composite house dust 0.4 and house dust and composite house dust 0.4 (P<0.01 for both), i.e., were moderate. Arsenic levels in both house dust and soil decreased with distance from the power station. Overall, levels in both fell by half 5 km from the point source. Weak correlations were seen between the total urinary arsenic concentrations and arsenic concentrations in composite house dust.     

Airborne arsenic and urinary excretion of metabolites of inorganic arsenic among smelter workers

Summary The relationship between airborne concentrations of arsenic and the urinary excretion of inorganic arsenic metabolites (inorganic arsenic + methylarsonic acid + dimethylarsinic acid) have been studied among smelter workers exposed to arsenic trioxide. The urinary concentrations of arsenic metabolites were found to increase steadily during the first day of the working week (after 2–3 d off from work), whereafter they reached a steady state. The concentration in the late evening after a day of exposure was very similar to that in the early morning after. Both were well correlated to the total daily excretion. In the second part of the study, comprising 18 subjects, the first-void morning urine of each participant was collected for 2 to 3 d during the steady-state phase. Total concentration of arsenic in the breathing zones was measured by personal air samplers. Airborne arsenic (8-h values) varied between 1 and 194 g As/m³, and urinary arsenic between 16 and 328 g As/g creatinine. With the urinary arsenic concentrations (mean values of 2–3 d for each subject) plotted against the corresponding airborne arsenic concentrations, the best fit was obtained by a power curve with the equation y = 17 x x^0.56. However, four of the participants were found to excrete far more (105–260%) arsenic in the urine than possibly could have been inhaled, most likely due to oral intake of arsenic via contaminated hands, cigarettes or snuff. If these four were excluded, the best fit was obtained by a straight regression line with the slope 2.0 and the intercept 29 g As/g creatinine (coefficient of correlation 0.92; P < 0.001).     

Monitoring of low level arsenic exposure during maintenance of ion implanters

To delineate potential exposure in ion implanter maintenance, the authors recruited 21 maintenance engineers (exposed group) and 10 computer programmers (controls) at three semiconductor manufacturing facilities. Samples of air, wipes, and urine; used cleaning cloths; and used gloves were collected for the characterization of arsenic exposure. Arsenic levels were very low in environmental samples, but high arsenic levels were found in some wipe samples, used cleaning cloths, and gloves. The average baseline content of urinary arsenic measured for maintenance engineers was 3.6 microg/g creatinine. Maintenance engineers experienced an increase of 1.0-7.8 microg/g creatinine in urinary arsenic levels during ion implanter maintenance. Results of a mixed-model analysis indicated that urinary arsenic levels were associated significantly with time series (p = .0001), and the extent of association was different among the three facilities (p = .0226). The results of this study indicate that arsenic intake via ingestion, rather than through inhalation, might play a significant role in the elevation of urinary arsenic levels. However, a series of urine samples with self-reference continue to be a good approach for the monitoring of low-level arsenic exposure.     

Arsenic drinking water exposure and urinary excretion among adults in the Yaqui Valley, Sonora, Mexico

The objective of this study was to determine arsenic exposure via drinking water and to characterize urinary arsenic excretion among adults in the Yaqui Valley, Sonora, Mexico. A cross-sectional study was conducted from July 2001 to May 2002. Study subjects were from the Yaqui Valley, Sonora, Mexico, residents of four towns with different arsenic concentrations in their drinking water. Arsenic exposure was estimated through water intake over 24 h. Arsenic excretion was assessed in the first morning void urine. Total arsenic concentrations and their species arsenate (As V), arsenite (As III), monomethyl arsenic (MMA), and dimethyl arsenic (DMA) were determined by HPLC/ICP-MS. The town of Esperanza with the highest arsenic concentration in water had the highest daily mean intake of arsenic through drinking water, the mean value was 65.5 microg/day. Positive correlation between total arsenic intake by drinking water/day and the total arsenic concentration in urine (r = 0.50, P < 0.001) was found. Arsenic excreted in urine ranged from 18.9 to 93.8 microg/L. The people from Esperanza had the highest geometric mean value of arsenic in urine, 65.1 microg/L, and it was statistically significantly different from those of the other towns (P < 0.005). DMA was the major arsenic species in urine (47.7-67.1%), followed by inorganic arsenic (16.4-25.4%), and MMA (7.5-15%). In comparison with other reports the DMA and MMA distribution was low, 47.7-55.6% and 7.5-9.7%, respectively, in the urine from the Yaqui Valley population (except the town of Cocorit). The difference in the proportion of urinary arsenic metabolites in those towns may be due to genetic polymorphisms in the As methylating enzymes of these populations.     

Effectiveness of arsenic mitigation program in Bangladesh--relationship between arsenic concentrations in well water and urine

BACKGROUND: Arsenic in drinking water remains a major public problem in Bangladesh, although arsenic mitigation programs began there a decade ago. The purpose of this study was to examine the effectiveness of this program by determining the relationship between current arsenic levels in well water and the high level of urinary arsenic excretion. METHODS: A community-based cross-sectional study was conducted in the Pabna district of Bangladesh between May and July 2005. We included 174 married couples and collected their drinking water from 138 wells. The allowable limit for arsenic in drinking water is 50 microg/L in Bangladesh, while the normal level of urinary arsenic is < or =40 microg x 1.5 L(-1) x day(-1) by Dhaka Community Hospital. RESULTS: Of 348 subjects, 304 exceeded the urinary arsenic level of 40 microg x 1.5 L(-1) x day(-1). Of all wells, 44.2% had arsenic levels >50 microg/L. Multiple-adjusted odds ratios of urinary arsenic level >40 microg x 1.5 L(-1) x day(-1) were 8.90 (95% CI: 3.31-23.93) for the arsenic level in well water of 11-50 microg/L, and 53.07 (11.91-236.46) for that of 51-332 microg/L, compared with < or =10 microg/L. When the Bangladeshi standard arsenic level in drinking water of 50 microg/L was used, the sensitivity in detecting subjects with a urinary arsenic level >40 microg x 1.5 L(-1) x day(-1) was 50%, although when the World Health Organization (WHO) guideline value of 10 microg/L was used, it was 76.3%. CONCLUSIONS: Green marked wells, which the Bangladesh government regards as safe, are not always safe. The mitigation programs should use the WHO guideline arsenic level to determine the safety of well water for drinking.     

Urinary arsenic concentration adjustment factors and malnutrition

This study aims at evaluating the suitability of adjusting urinary concentrations of arsenic, or any other urinary biomarker, for variations in urine dilution by creatinine and specific gravity in a malnourished population. We measured the concentrations of metabolites of inorganic arsenic, creatinine and specific gravity in spot urine samples collected from 1466 individuals, 5-88 years of age, in Matlab, rural Bangladesh, where arsenic-contaminated drinking water and malnutrition are prevalent (about 30% of the adults had body mass index (BMI) below 18.5 kg/m(2)). The urinary concentrations of creatinine were low; on average 0.55 g/L in the adolescents and adults and about 0.35 g/L in the 5-12 years old children. Therefore, adjustment by creatinine gave much higher numerical values for the urinary arsenic concentrations than did the corresponding data expressed as microg/L, adjusted by specific gravity. As evaluated by multiple regression analyses, urinary creatinine, adjusted by specific gravity, was more affected by body size, age, gender and season than was specific gravity. Furthermore, urinary creatinine was found to be significantly associated with urinary arsenic, which further disqualifies the creatinine adjustment.     

Exposure assessment for study of olfactory function in workers exposed to styrene in the reinforced-plastics industry

BACKGROUND: This study was undertaken in conjunction with an evaluation of the olfactory function of 52 persons exposed to styrene vapors to provide quantitative styrene exposure histories of each subject for use in the interpretation of the results of olfactory function testing. METHODS: Current and historic exposures were investigated. Historic exposures were reconstructed from employment records and measurements of styrene exposure made in the subject facilities over the last 15 years. Current exposures were estimated for every exposed subject though personal air sampling and through pre- and post-shift measurements of urinary metabolites of styrene. RESULTS: The study population had been employed in the reinforced-plastics industry for an average of 12.2 +/- 7.4 years. Their mean 8-hr time weighted average (TWA) respirator-corrected annual average styrene exposure was 12.6 +/- 10.4 ppm; mean cumulative exposure was 156 +/- 80 ppm-years. The current respirator-corrected 8-hr TWA average exposure was 15.1 +/- 12.0 ppm. The mean post-shift urinary mandelic and phenylglyoxylic acid (PGA) concentrations were 580 +/- 1,300 and 170 +/- 360 mg/g creatinine, respectively and were highly correlated with air concentrations of styrene. CONCLUSIONS: This quantitative exposure evaluation has provided a well-characterized population, with documented exposure histories stable over time and in the range suitable for the purposes of the associated study of olfactory function.     

Renal and neurologic effects of cadmium, lead, mercury, and arsenic in children: evidence of early effects and multiple interactions at environmental exposure levels

Lead, cadmium, mercury, and arsenic are common environmental pollutants in industrialized countries, but their combined impact on children's health is little known. We studied their effects on two main targets, the renal and dopaminergic systems, in > 800 children during a cross-sectional European survey. Control and exposed children were recruited from those living around historical nonferrous smelters in France, the Czech Republic, and Poland. Children provided blood and urine samples for the determination of the metals and sensitive renal or neurologic biomarkers. Serum concentrations of creatinine, cystatin C, and beta2-microglobulin were negatively correlated with blood lead levels (PbB), suggesting an early renal hyperfiltration that averaged 7% in the upper quartile of PbB levels (> 55 microg/L; mean, 78.4 microg/L). The urinary excretion of retinol-binding protein, Clara cell protein, and N-acetyl-beta-d-glucosaminidase was associated mainly with cadmium levels in blood or urine and with urinary mercury. All four metals influenced the dopaminergic markers serum prolactin and urinary homovanillic acid, with complex interactions brought to light. Heavy metals polluting the environment can cause subtle effects on children's renal and dopaminergic systems without clear evidence of a threshold, which reinforces the need to control and regulate potential sources of contamination by heavy metals. Key words: arsenic, biomarkers, cadmium, dopaminergic, heavy metals, interactions, lead, mercury, renal.     

Airborne crystalline silica concentrations at coal-fired power plants associated with coal fly ash

This study presents measurements of airborne concentrations of respirable crystalline silica in the breathing zone of workers who were anticipated to encounter coal fly ash. Six plants were studied; two were fired with lignite coal, and the remaining four plants used bituminous and subbituminous coals. A total of 108 personal breathing zone respirable dust air samples were collected. Bulk samples were also collected from each plant site and subjected to crystalline silica analysis. Airborne dust particle size analysis was measured where fly ash was routinely encountered. The results from bituminous and subbituminous fired plants revealed that the highest airborne fly ash concentrations are encountered during maintenance activities: 0.008 mg/m3 to 96 mg/m3 (mean of 1.8 mg/m3). This group exceeded the threshold limit values (TLV) in 60% of the air samples. During normal production activities, airborne concentrations of crystalline silica ranged from nondetectable to 0.18 mg/m3 (mean value of 0.048 mg/m3). Air samples collected during these activities exceeded the current and proposed TLVs in approximately 54% and 65% of samples, respectively. Limited amounts of crystalline silica were detected in samples collected from lignite-fired plants, and approximately 20% of these air samples exceeded the current TLV. Particle size analysis in areas where breathing zone air samples were collected revealed mass median diameters typically between 3 microm and 8 microm. Bulk and air samples were analyzed for all of the common crystalline silica polymorphs, and only alpha quartz was detected. As compared with air samples, bulk samples from the same work areas consistently yielded lower relative amounts of quartz. Controls to limit coal fly ash exposures are indicated during some normal plant operations and during episodes of short term, but high concentrations of dust that may be encountered during maintenance activities, especially in areas where ash accumulations are present.     

Inhalation exposure to 1,3-dichloropropene in the Dutch flower-bulb culture. Part II. Biological monitoring by measurement of urinary excretion of two mercapturic acid metabolites

A biological monitoring study was carried out in the Dutch flower-bulb culture to determine the relationship between respiratory occupational exposure to Z- and E-1,3-dichloropropene (Z- and E-DCP) and urinary excretion of two mercapturic acid metabolites, N-acetyl-S-(Z- and E-3-chloropropenyl-2)-L-cysteine (Z- and E-DCP-MA). Urinary excretion of Z- and E-DCP-MA, either based on excretion rates or on creatinine excretion, followed first order elimination kinetics after exposure. Urinary half-lives of elimination were 5.0 ± 1.2 hr for Z-DCP-MA and 4.7 ± 1.3 hr for E-DCP-MA and were not statistically significantly different. Calculated coefficients of variation indicated that the half-lives of elimination of Z- and E-DCP-MA were quite consistent inter- and intra-individually.Strong correlations (r 0.93) were observed between respiratory 8-hr time weighted average (TWA) exposure to Z-and E-DCP and complete cumulative urinary excretion of Z- and E-DCP-MA. Z-DCP yielded three times more mercapturic acid than E-DCP, probably due to differences in metabolism. Z- and E-DCP were excreted 45 and 14% as their respective mercapturic acid metabolites.A respiratory 8-hr TWA exposure to the Dutch occupational exposure limit of 5 mg · m^–3 DCP would result in a complete cumulative excretion of 14.4 mg (95% confidence interval: 11.7–17.0 mg) Z-DCP-MA and 3.2 mg (95% confidence interval: 2.3–4.1 mg) E-DCP-MA.     

Breast-feeding protects against arsenic exposure in Bangladeshi infants

BACKGROUND: Chronic arsenic exposure causes a wide range of health effects, but little is known about critical windows of exposure. Arsenic readily crosses the placenta, but the few available data on postnatal exposure to arsenic via breast milk are not conclusive. AIM: Our goal was to assess the arsenic exposure through breast milk in Bangladeshi infants, living in an area with high prevalence of arsenic-rich tube-well water. METHODS: We analyzed metabolites of inorganic arsenic in breast milk and infant urine at 3 months of age and compared them with detailed information on breast-feeding practices and maternal arsenic exposure, as measured by concentrations in blood, urine, and saliva. RESULTS: Arsenic concentrations in breast-milk samples were low (median, 1 microg/kg; range, 0.25-19 microg/kg), despite high arsenic exposures via drinking water (10-1,100 microg/L in urine and 2-40 microg/L in red blood cells). Accordingly, the arsenic concentrations in urine of infants whose mothers reported exclusive breast-feeding were low (median, 1.1 microg/L; range, 0.3-29 microg/L), whereas concentrations for those whose mothers reported partial breast-feeding ranged from 0.4 to 1,520 microg/L (median 1.9 microg/L). The major part of arsenic in milk was inorganic. Still, the infants had a high fraction (median, 87%) of the dimethylated arsenic metabolite in urine. Arsenic in breast milk was associated with arsenic in maternal blood, urine, and saliva. CONCLUSION: Very little arsenic is excreted in breast milk, even in women with high exposure from drinking water. Thus, exclusive breast-feeding protects the infant from exposure to arsenic.     

Mercury exposures in informal gold miners and relatives in southern Peru

Subjects working in or living near informal gold mining and processing in southern Peru were studied to determine mercury exposures from two tasks: amalgamation and amalgam smelting. The authors collected 17 airborne and 41 urinary mercury levels. The mean urinary levels were 728 (range: 321-1662) and 113 (45-197) microg/L for working in smelters and living near smelters, respectively. A third group working in amalgamation had a mean 18 microg/L (range 8-37). People living in the mining town but with no mining activities had 8 microg/L (5-10), while a control group outside the town had 4 microg/L (2-6). Mean airborne mercury exposure was 2423 microg/m3 (range 530-4430) during smelting, 30.5 microg/m3 (12-55) during amalgamation, and 12 microg/m3 (3-23) in the mining town. Smelters are highly contaminated with mercury, as are the people living around smelters.     

Spatial and temporal variations in arsenic exposure via drinking-water in northern Argentina

This study evaluated the spatial, temporal and inter-individual variations in exposure to arsenic via drinking-water in Northern Argentina, based on measurements of arsenic in water, urine, and hair. Arsenic concentrations in drinking-water varied markedly among locations, from <1 to about 200 microg/L. Over a 10-year period, water from the same source in San Antonio de los Cobres fluctuated within 140 and 220 microg/L, with no trend of decreasing concentration. Arsenic concentrations in women's urine (3-900 microg/L, specific weight 1.018 g/mL) highly correlated with concentrations in water on a group level, but showed marked variations between individuals. Arsenic concentrations in hair (range 20-1,500 microg/kg) rather poorly correlated with urinary arsenic, possibly due to external contamination. Thus, arsenic concentration in urine seems to be a better marker of individual arsenic exposure than concentrations in drinking-water and hair.     

Metabolic profile in workers occupationally exposed to arsenic: role of GST polymorphisms

Arsenic is a well-known human carcinogen with a ubiquitous distribution in the natural environment. Chronic exposure to inorganic arsenic involves a biotransformation process that leds to the main excretion of organic methylated metabolites, such as monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), as well as the parental inorganic species. Interindividual variation in arsenic metabolism has been extensively reported, and polymorphisms in genes involved in such process could be related to changes in the arsenic excretion profile and the response to chronic exposures. Our analysis of the metabolic profiles in three groups of workers exposed to different arsenic exposure levels showed high amounts of inorganic arsenic and MMA in the most-exposed workers versus the least-exposed workers, in whom high amounts of DMA were observed. With respect to the role of different genetic polymorphisms in the glutathione S-transferase (GST) genes in the modulation of the urinary profiles, for the overall population only a tendency was just observed between GSTM1 null and MMA excretion as well as between GSTP1 val/val and DMA excretion.     

A study of factors influencing urinary arsenic excretion in exposed workers

This study was designed to evaluate the influence of occupational and non-occupational factors on urinary arsenic excretion in workers exposed to iAs (inorganic arsenic) in the dismantlement of a factory which once produced fertilisers. We measured iAs and its methylated metabolites in 108 urinary samples of workers exposed to iAs in July 2006. A total of 13.9% of the samples showed levels higher than the Biological Exposure Index (BEI) of 35 μg/l (mean value 23.9 μg/l). After the improvement of working conditions, in August–October 2006 we collected urinary samples from each of the 108 workers enrolled. We also administrated a questionnaire, in order to investigate the influence of occupational and non-occupational factors on the urinary arsenic excretion. A significant difference was observed in relation with seafood consumption and age stratification. We have found a significant reduction of urinary arsenic excretion between the two phases of biological monitoring, probably due to appropriate hygiene work-related interventions.     

Geographical and temporal differences in the urinary excretion of inorganic arsenic: a Belgian population study.

OBJECTIVE: This Belgian study assessed the geographical and temporal differences in the exposure of the population to inorganic arsenic, a known carcinogen. METHODS: In the CadmiBel study (1985-9) the 24 h urinary arsenic excretion was measured, as an index of recent exposure, in industrialised cities (Liège: n = 664, Charleroi: n = 291), in a rural control area (Hechtel-Eksel: n = 397), and in rural districts in which the population had possibly been exposed through the drinking water or the emissions of nonferrous smelters (Wezel: n = 93, Lommel: n = 111, and Pelt: n = 133). In the PheeCad study, in 1991-5, the rural areas (n = 609) were re-examined together with an urban control area (Leuven: n = 152). RESULTS: The CadmiBel results showed that after adjustment for sex, age, and body mass index, the 24 h arsenic excretion was on average low in Liège (91 nmol), Charleroi (155 nmol), Hechtel-Eksel (144 nmol), and Wezel (158 nmol), whereas the highest excretions were found in Lommel (570 nmol) and Pelt (373 nmol). During the PheeCad study, the mean 24 h arsenic excretion in the rural areas ranged from 81 to 111 nmol. This was lower than six years earlier and similar to the excretion in the control town (108 nmol). Longitudinal studies in 529 people living in the rural areas confirmed that their 24 h arsenic excretion had decreased (P < 0.001) from 222 to 100 nmol. As well as the drinking water, industry was likely to be a source of the increased exposure in Lommel and Pelt in 1985-9, because at that time the urinary arsenic excretion did not follow the regional differences in the arsenic content of the drinking water, because the fall in the arsenic excretion over time coincided with the implementation by industry of stricter environmental regulations, because in individual subjects the urinary arsenic excretion was inversely correlated with the distance to the nearest smelter, and because an increased arsenic excretion was only found downwind from the main smelter. The official network that monitors the arsenic concentration in airborne and fall out dust did not detect the high exposure in Lommel and Pelt between 1985 and 1989. CONCLUSION: This study highlights the necessity to validate environmental monitoring programmes by directly estimating the internal exposure of the population.     

Intervention trial to assess arsenic exposure from food crops in Bangladesh

The authors assessed the contribution of food irrigated with arsenic-contaminated water to human exposure to arsenic in Bangladesh. An intervention trial was conducted in a village in the Jessore District of Bangladesh, where irrigation water had been field-tested in March 2000 and was found to contain arsenic with concentrations ranging from 100 to 500 microg/l. In May 2000, a random sample of 63 households was selected from the village, and 1 eligible person from each household was recruited to the study and randomized to an intervention or control group. The intervention group received food purchased from a village where irrigation water was found to contain < 10 microg/l arsenic. The control group received food purchased from markets in the study village, where irrigation water was found to contain > 100 microg/l arsenic. Pre- and postintervention urine samples were collected for urinary arsenic speciation assays. Preintervention, the mean urinary total arsenic concentrations were 139.25 microg/l and 129.15 microg/l for the intervention and control groups, respectively. These concentrations did not change significantly following intervention. Arsenic concentrations in samples of selected raw and cooked foods from the low-contamination area did not contain less arsenic than samples from the high-contamination area. Further studies to investigate the arsenic content of food grown in areas with high and low arsenic contamination of irrigation water are recommended.     

Exposure to inorganic arsenic in drinking water and total urinary arsenic concentration in a Chilean population

The relationship of inorganic arsenic exposure through drinking water and total urinary arsenic excretion in a nonoccupationally exposed population was evaluated in a cross-sectional study in three mayor cities of Chile (Antofagasta, Santiago, and Temuco). A total of 756 individuals in three population strata (elderly, students, and workers) provided first morning void urine specimens the day after exposure and food surveys were administered. Arsenic intake from drinking water was estimated from analysis of tap water samples, plus 24-h dietary recall and food frequency questionnaires. Multilevel analysis was used to evaluate the effects of the age group and city factors adjusted by predictor variables. Arsenic levels in drinking water and urine were significantly higher in Antofagasta compared with the other cities. City-and individual-level factors, 12% and 88%, respectively, accounted for the variability in urinary arsenic concentration. The main predictors of urinary arsenic concentration were total arsenic consumption through water and age. These findings indicate that arsenic concentration in drinking water continues to be the principal contributing factor to exposure to inorganic arsenic in the Chilean population.