Monitoring of arsenic exposure with speciated urinary inorganic arsenic metabolites for ion implanter maintenance engineers

Arsenic concentrations, distributions and bioaccessibilities at a UNESCO World Heritage Site (Devon Great Consols, Cornwall and West Devon Mining Landscape)

Devon Great Consols (DGC) is a region in south west England where extensive mining for Cu, Sn and As took place in the nineteenth century. Because of its historical and geological significance, DGC has protected status and is part of the Cornwall and West Devon Mining Landscape UNESCO World Heritage Site. Recently, the region was opened up to the public with the construction or redevelopment of various trails, tracks and facilities for walking, cycling and field visits. We used portable x-ray fluorescence spectrometry to measure, in situ, the concentrations of As in soils and dusts in areas that are accessible to the public. Concentrations ranged from about 140 to 75,000 μg g^-1 (n = 98), and in all but one case exceeded a Category 4 Screening Level for park-type soil of 179 μg g^-1. Samples returned to the laboratory and fractionated to <63 μm were subjected to an in vitro assessment of both oral and inhalable bioaccessibility, with concentrations ranging from <10 to 25,500 μg g^-1 and dependent on the precise nature and origin of the sample and the physiological fluid applied. Concentrations of As in PM₁₀ collected along various transects of the region averaged over 30 ng m^-3 compared with a typical concentration in UK air of <1 ng m^-3. Calculations using default EPA and CLEA estimates and that factor in for bioaccessibility suggest a 6-h visit to the region results in exposure to As well in excess of that of minimum risk. The overall risk is exacerbated for frequent visitors to the region and for workers employed at the site. Based on our observations, we recommend that the remodelling or repurposing of historical mine sites require more stringent management and mitigation measures.

Arsenic Exposure and Methylation Efficiency in Relation to Oxidative Stress in Semiconductor Workers

This study examined associations between oxidative stress and arsenic (As) exposure and methylation efficiency in semiconductor workers. An As-exposed group (n = 427) and a control group (n = 91) were included. The As-exposure group (n = 427) included 149 maintenance staff members and 278 production staff members representing high As exposure and low As exposure, respectively. The control group included 91 administrative staff members with no or minimal As exposure. An occupational exposure assessment was conducted to assess personal As exposure by measuring As concentrations in urine, hair, and fingernails of the subjects. Urinary As(III), As(V), monomethylarsonic (MMA), and dimethylarsinic acid (DMA) were quantified to assess an internal dose of inorganic As. Urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) were measured to asses oxidative DNA damage and lipid peroxidation, respectively. As concentrations in urine, hair, and fingernails significantly increased (p < 0.05) in the As-exposed group in comparison to the control group. Geometric mean urinary concentrations of As, 8-OHdG, and MDA in the As-exposed group significantly exceeded those in the control group. As exposure to As-exposed workers had increased concentrations of 8-OHdG in contrast to those in control subjects. Moreover, urinary 8-OHdG concentrations in the semiconductor workers were positively correlated with urinary total As metabolite (As(III) + As(V) + MMA + DMA) concentrations. Furthermore, urinary excretion of 8-OHdG concentrations in As-exposed workers were positively associated with urinary excretion of MMA concentrations and primary methylation index values (the ration of MMA/inorganic As). However, fingernail and hair samples did not perform as well as urinary samples to measure oxidative stress induced by As exposure. 8-OHdG could serve as a more reliable biomarker for assessing As methylation than MDA did. Occupational exposure to inorganic As was associated with increased oxidative stress among semiconductor workers.

Physiologically-based pharmacokinetic and toxicokinetic models for estimating human exposure to five toxic elements through oral ingestion

Biological monitoring and physiologically-based pharmacokinetic (PBPK) modelling are useful complementary tools in quantifying human exposure to elements in the environment. In this work, we used PBPK models to determine the optimal time for collecting biological samples in a longitudinal study to determine if participants who consumed allotment produce had been exposed to arsenic, cadmium, chromium, nickel or lead. There are a number of PBPK models for these elements published in the literature, which vary in size, complexity and application, given the differences in physiochemical properties of the elements, organs involved in metabolism and exposure pathways affected. We selected PBPK models from the literature to simulate the oral ingestion pathway from consumption of allotment produce. Some models required modification by reducing or removing selected compartments whilst still maintaining their original predictability. The performance of the modified models was evaluated by comparing the predicted urinary and blood elemental levels with experimental data and other model simulations published in the literature. Overall, the model predictions were consistent with literature data (r > 0.7, p < 0.05), and were influential in predicting when samples should be collected. Our results demonstrate the use of mathematical modelling in informing and optimising the design of longitudinal studies.

The factors influencing urinary arsenic excretion and metabolism of workers in steel and iron smelting foundry

In order to evaluate the degree of arsenic (As) exposure and the factors influencing urinary As excretion and metabolism, 192 workers from a steel and iron smelting plant, with different type of work in production such as roller, steel smelting, iron smelting and metallic charge preparation, were recruited. Information about characteristics of each subject was obtained by questionnaire and inorganic As (iAs), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) in urine were determined. The results showed that steel smelters had significantly higher concentrations of DMA and total As (TAs) than rollers and metallic charge preparation workers, and iron and steel smelters had a higher value of primary methylation index and lower proportion of the iAs (iAs%) than rollers and metallic charge preparation workers. In steel smelters, urinary As level exceeded the biological exposure index (BEI) limit for urinary As of 35 μg/l by 65.52%, and higher than metallic charge preparation workers (35.14%). The individuals consumed seafood in recent 3 days had a higher TAs than the individuals without seafood consumption. Multivariate logistic regression analysis showed that different jobs, taken Chinese medicine of bezoar and seafood consumption in recent 3 days were significantly associated with urinary TAs exceeded BEI limit value 35 μg/l. Our results suggest that workers in steel and iron smelting plant had a lower level of As exposure, and seafood consumption and taking Chinese medicine of bezoar also could increase the risk of urinary TAs exceeded BEI limit value.

Levels of arsenic, cadmium, lead, manganese and zinc in biological samples of paralysed steel mill workers with related to controls

The determination of essential trace and toxic elements in the biological samples of human beings is an important clinical screening procedure. This study aimed to assess the possible effects of environmental exposure on paralysed male workers (n = 75) belonging to the production and quality control departments of a steel mill. In this investigation, the concentrations of arsenic, cadmium, lead, manganese and zinc were determined in biological samples (blood, urine and scalp hair samples) of exposed paralysis and non-paralysed steel mill workers. For comparative purposes, unexposed healthy subjects of same age group were selected as referents. The elements in the biological samples were measured by atomic absorption spectrophotometry prior to microwave-assisted acid digestion. The validity of the methodology was checked by the biological certified reference materials. The results indicate that the level understudy elements in all three biological samples were significantly higher in paralysed workers of both groups (quality control and production) as compared to referents (p < 0.01). The possible connection of these elements with the aetiology of disease is discussed. The results also show the need for immediate improvements of workplace ventilation and industrial hygiene practices.

Association of environmental toxic elements in biological samples of myocardial infarction patients at different stages

The exposure of toxic elements may directly or indirectly associate with different pathogenesis of heart diseases. In the present study, the association of arsenic (As), cadmium (Cd), cobalt (Co), lead (Pb), and nickel (Ni) in biological samples (whole blood and urine) and mortality from myocardial infarction (MI) patients at first, second, and third heart attacks was carried out. Both biological samples of 130 MI patients (77 male and 53 female), with ages ranging from 45 to 60 years, and 61 healthy persons (33 male and 28 female) of the same age group were collected. The elements in biological samples were assessed by electrothermal atomic absorption spectrophotometer, prior to microwave-assisted acid digestion. The validity of methodology was checked by the biological certified reference materials. During this study, 78% of 32 patients aged above 50 years, registered after third MI attack, died. In these subjects, the levels of As, Cd, Co, Ni, and Pb in blood samples were higher in MI patients as compared with referents (p < 0.05), while increased by 11.7%, 12.2%, 5.55%, and 7.2%, respectively, in the blood samples of those patients who tolerated the third MI attack (p = 0.12). The high level of understudied toxic elements may play a role in the mortality of MI patients.

Evaluation of arsenic, cobalt, copper and manganese in biological Samples of Steel mill workers by electrothermal atomic absorption Spectrometry

The determination of trace and toxic elements in biological samples (blood, urine and scalp hair samples) of human beings is an important clinical test. The aim of our present study was to determine the concentration of arsenic (As), copper (Cu), cobalt (Co) and manganese (Mn), in biological samples of male production workers (PW) and quality control workers (QW) of steel mill, with aged 25–55 years, to assess the possible influence of environmental exposure. For comparison purpose, the same biological samples of unexposed healthy males of same age group were collected as control subjects. The determination of all elements in biological samples was carried out by electrothermal atomic absorption spectrometry, prior to microwave assisted acid digestion. The accuracy of the As, Cu, Co and Mn measurements was tested by simultaneously analyzing certified reference materials (CRMs) and for comparative purposes conventional wet acid digestion method was used on the same CRMs. No significant differences were observed between the analytical results and the certified values, using both methods (paired t-test at P > 0.05). The results indicate that concentrations of As, Cu, Co and Mn in all three biological samples of the exposed workers (QW and PW) were significantly higher than those of the controls. The possible correlation of these elements with the etiology of different physiological disorders is discussed. The results were also demonstrated the need of attention for improvements in workplace, ventilation and industrial hygiene practices.

Significance of urinary arsenic speciation in assessment of seafood ingestion as the main source of organic and inorganic arsenic in a population resident near a coastal area

In order to characterize the different sources of exposure to arsenic (As), urinary excretion of total As, the sum of inorganic As+MMA+DMA determined by the hydride generation-atomic absorption spectrophotometry technique, and the species As3, As5, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine were determined in 49 workers at a steel foundry, with presumed occupational exposure to As, and 50 subjects from the general population, all males. No evidence of occupational exposure to As resulted from environmental monitoring performed in the foundry, although the analysis of minerals used as raw materials showed the presence of As, particularly in fossils and fine ores. The urinary concentrations of As3, MMA, DMA, the sum of inorganic As+MMA+DMA and total As were not different in the two groups, while arsenobetaine appeared significantly higher in the controls than in the workers. The different species of urinary As were all significantly correlated. Urinary excretion of As3 was associated with the consumption of mineral water and with residence in an industrial zone, while MMA, DMA, arsenobetaine, the sum of inorganic As+MMA+DMA and total As urinary excretion were associated with the consumption of crustaceans and/or shellfish 3 days or less before urine collection. Multiple regression analysis confirmed these results. In conclusion, in populations with a high consumption of seafood, living in areas characterized by coastal/marine As pollution, only speciation of As can identify a prevalent role of environmental sources, like the consumption of seafood contaminated by As, in determining urinary As excretion, and exclude an occupational origin of the exposure.

Shared occupational risks for transitional cell cancer of the bladder and renal pelvis among men and women in Sweden

BACKGROUND

Unlike cancer of the bladder, cancer of the renal pelvis is not considered an occupational cancer and little is known about risks among women.

METHODS

Using the Swedish national census and cancer registry-linked data (1971-1989), we identified transitional cell cancers of the renal pelvis (N = 1,374) and bladder (N = 21,591). Correlation between cancer sites for the standardized incidence ratios (SIR) were determined using Pearson's coefficient of the log SIR. Relative risks of job exposure matrix variables were calculated using Poisson regression.

RESULTS

Both cancer sites were significantly elevated among women and men employed in the machine/electronics industry, sedentary work, and indoor work, and men in the metal industry. The highest proportion of the bladder (12%) and renal pelvis (14%) cancers occurred among men employed in shop and construction metal work. Risks by industry were more correlated among women (r = 0.49, P = 0.002) than men (r = 0.24, P = 0.04). Cancers of the renal pelvis were elevated in several occupational and industry groups for which there was no elevated bladder cancer risk.

CONCLUSION

Cancers of the renal pelvis and bladder share common occupational risk factors that may be more frequent among women. In addition, there may be some jobs that pose an increased risk specifically for cancer of the renal pelvis but not bladder.

Effects of arsenic exposure among semiconductor workers: a cautionary note on urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine

Arsenic is a notorious environmental toxicant and was found to cause oxidative stress in cultured cells and animals. However, little work has been done in human studies, especially for the population occupationally exposed to arsenic. In order to investigate the effect of occupational exposure to arsenic in oxidative stress, we measured urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) from 90 semiconductor workers including 50 exposed and 40 nonexposed subjects. A highly sensitive and specific isotope dilution LC-MS/MS method was used for quantification of 8-oxodGuo. The levels of inorganic arsenic (iAs3+, iAs5+), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in urine were determined by high-performance liquid chromatography-flow injection atomic absorption spectrometry (HPLC-FIAAS). Results showed that the mean urinary concentrations of total arsenic and 8-oxodGuo were significantly higher for exposed workers compared with the nonexposed workers. In addition, elevated urinary 8-oxodGuo concentrations of exposed workers were correlated with urinary levels of MMA (r = 0.44, P < 0.005) and the extent of primary methylation (the ratio of MMA to inorganic arsenic) (r = 0.40, P < 0.005). These findings suggested that occupational exposure to arsenic could result in the induction of oxidative stress. The presence and/or formation of MMA could play an important role in arsenic-involved injuries.

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.

Determination of arsenic species: A critical review of methods and applications, 2000–2003

We review recent research in the field of arsenic speciation analysis with the emphasis on significant advances, novel applications and current uncertainties.