Urinary Excretion of Arsenic Species After Exposure to Arsenic Present in Drinking Water

Abstract

The water from some drilled wells in southwest Finland contains high arsenic concentrations (min-max: 17-980 microg/L). We analyzed inorganic arsenic (As-i) and organic arsenic (monomethylarsonate [MMA] and dimethylarsinate [DMA]) species in urine and conducted a clinical examination of current users (n = 35) and ex-users (n = 12) of such wells. Ex-users had ceased to use the water from the wells 2-4 months previously. Urinary arsenic species were also analyzed from persons whose drinking water contained less than 1 microg/L of arsenic (controls, n = 9). The geometric means of the concentrations of total arsenic in urine were 58 microg/L for current users, 17 microg/L for ex-users, and 5 microg/L for controls. The excreted arsenic was associated with the calculated arsenic doses, and on average 63% of the ingested arsenic dose was excreted in urine. The ratios of MMA/DMA and As-i/As-tot (As-tot = As-i + MMA + DMA) in urine tended to be lower among the current users and in the higher exposure levels than in controls, suggesting that As-i was better methylated in current users. However, the differences were mainly explained by age; older persons were better methylators of inorganic arsenic than younger individuals. The arsenic content of hair correlated well with the past and chronic arsenic exposure; an increase of 10 microg/L in the arsenic concentration of the drinking water or an increase of 10-20 microg/day of the arsenic exposure corresponded to a 0.1 mg/kg increase in hair arsenic. The individuals were interviewed and complained of muscle cramps, mainly in the legs, and this was associated with elevated arsenic exposure. The present study demonstrates that arsenic methylation has no threshold at these exposure levels.

Maternal Arsenic Exposure and Impaired Glucose Tolerance during Pregnancy

“…Although nails or hair may best represent cumulative exposure, keratin-bound arsenic is isolated from the body's further metabolic processes and may be less biologically active than blood arsenic. Because of these differences in biomarkers of arsenic exposure, we used hair, in a subset of women with samples available, to provide estimates of longer-term exposures, with every 1 cm of hair representing each month of prior exposure (Kurttio et al 1998). We found similar results, though not statistically significant, to those from our analyses using blood arsenic.…”

Study on arsenic level in ground water of Delhi using hydride generator accessory coupled with atomic absorption spectrophotometer

“…Arsenic contamination of well water in Minnetosa and Taiwan has caused signs and symptoms of arsenic toxicity (22,23). Similar resvlts have been reported from Northern Mexico, Nova Scotia Canada, Finland, Alaska and China (24)(25)(26)(27)(28).…”

Arsenic in the human food chain, biotransformation and toxicology – Review focusing on seafood arsenic

“…For instance, increased presence of MA (III) in urine of a Mexican population chronically exposed to iAs in drinking water was associated with a greater risk of As-induced skin lesions [60]. Studies of populations chronically exposed to iAs from drinking water have shown that the relative proportion of urinary MA may increase with increasing dose of iAs exposure [86,87,170,171]. Higher urinary MA associated with increased exposure of iAs in drinking water, has been proposed to be a result of the inhibition of the second methylation step [172].…”

“…A high proportion of MA in urine may indicate lower methylation capacity. Age, smoking and gender seem to influence the relative distribution of methylated urinary arsenicals [85][86][87].…”