Arsenic excretion

Inorganic arsenic is eliminated primarily via the kidneys in humans as well as laboratory animals. Studies in adult human males voluntarily ingesting a known amount of either As(III) or As(V) indicate that 45-75 % of the dose is excreted in the urine within a few days to a week (Pomroy et al., 1980 Tam, Char-bonneau and Bryce, 1979 Buchet, Lauwerys and Roels, 1981a Buchet, Lauwerys and Roels, 1981b Lee, 1999). Relatively few studies in volunteers have included the measurement of arsenic in both feces and urine. However, Pomroy et al. (1980) reported that 6% of a single oral dose of arsenic acid was excreted in the feces over a period of seven days compared to 62 % of the dose excreted in urine. No quantitative data are available that directly assess the significance of biliary excretion of As(III) or As(V) in humans. 

Urine is the primary route of elimination for both inorganic As(III) and inorganic As(V) in most common laboratory animals. With the exception of the rat, which exhibits slower overall elimination of arsenic, 50 % or more of a single oral dose of arsenic is usually eliminated in urine within 48 hours. Urine is also the primary route of elimination in species, such as the marmoset, which do not methylate arsenic (Vahter et al., 1982). Comparison of urinary and fecal elimination in mice that have been given the same 

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Charbonneau, S.M., K. Spencer, F. Bryce, and E. Sandi. 1978. Arsenic excretion by monkeys dosed with arsenic-containing fish or with inorganic arsenic. Bull. Environ. Contam. Toxicol. 20 470-477. 

The arsenic concentration in blood were eliminated according to a three-phasic pattern. Arsenic excretion in urine does not seem to be influenced by the varying doses of administered arsenic trioxide. It is shown that 67 % of administrated arsenic trioxide (100 mg/kg) is excreted by kidneys with T0 5 = 3.6 days 74 % is eliminated by urine with T05 = 2.4 days (30 mg/kg) and 68 % is eliminated by urine with T0 5 = 0.8 days (3 mg/kg) ... 

Inhaled arsine is oxidized to form elemental trivalent arsenic (As ) and arsenous oxide (AS2O3), two human carcinogens. Excess cancers from trivalent arsenic and arsenic trioxide have been associated with cumulative lifetime arsenic exposure. Exposure to arsine above 0.004ppm is associated with increased urinary arsenic excretion, indicating exposure to arsenic. Current exposure limits may not prevent potential chronic toxicity. ... 

Human volunteers who drank wine containing inorganic arsenic excreted methylarsonic and cacodylic acids in their urine (96). These two compounds also occur in the urine of copper smelters, the elevated arsenic content presumably coming from copper ores (97). Cacodylate ion forms when H34As04 is administered orally to dogs or hamsters (98-100). A Japanese group reported that various small animals will form methylar-sonate and cacodylate from H3ASO4 (101). On the basis of presently available data, it remains uncertain whether arsenic biomethylation occurs from the bodily processes of the mammals themselves or from microflora of the intestinal tract. 

Concha, G., Vogler, G., Nermell, B. and Vahter, M. (1998b) Low-level arsenic excretion in breast milk of native Andean women exposed to high levels of arsenic in the drinking water. International Archives of Occupational and Environmental Health, 71(1), 42-46. 

X. C. Le, W. R. Cullen, R. J. Reimer, Human urinary arsenic excretion after one-time ingestion of seaweed, crab and shrimp, Clin. Chem., 40 (1994), 617-624. 

Kojima, C., Qu, W., Waalkes, M.P., Himeno, S., Sakurai, T. (2006). Chronic exposure to methylated arsenicals stimulates arsenic excretion pathways and induces arsenic tolerance in rat liver cells. Toxicol. Sci. 91 70-81. 

Pharmacokinetics and metabolism of As(III) in APL 192 patients studied. The intermediate MMA(III) and DMA(III), were detected in most urine samples when diethyldithiocar-bomate, was added to these samples for stabilization of As species. The major urine species As(III), MMA and DMA, accounting for >95% of the total arsenic excreted in urine. On the other hand, these species accounted for 32-65% of the total arsenic, suggesting other pathways of As excretion, such as through the bile, may play an important role in removal of arsenic from the human body when challenged by high levels of As(III)... 

There is no specihc laboratory test for Lewisite. Lfrinary arsenic excretion might be helpful. Hemolytic anemia may be seen in Lewisite exposed patients. 

Arsenic excretion in urine is a linear function of dose for all treatments. Urinary excretion also is independent of time after study day 5, thereby allowing the UEF for each treatment group to be estimated by the slope of the best-tit linear regression line through dose-response data after the fifth day of dosing. 

There is no specific laboratory test for Lewisite. Urinary arsenic excretion might be helpful in identifying possible exposure to Lewisite, however. Patient Management... 

A. Specific levels. In the first 2-3 days after acute symptomatic poisoning, total 24-hour urinary arsenic excretion is typically in excess of several thousand micrograms (spot urine greater than 1000 mcg/L), and depending on the severity of poisoning, may not return to background levels (less than 50 mog in a 24-hour speoimen, or less than 30 mcg/L in a spot urine) for several weeks. Spot urine analyses are usually sufficient for diagnostic purposes. 

Odanaka Y, Matano O, Goto S (1980) Biomethylation of inorganic arsenic by the rat and some laboratory animals. Bull Environ Contam Toxicol 24 452-459 Offergelt JA, Rods H, Buchet JP, Boeckx M, Lauwerys R (1992) Relation between airborne arsenic trioxide and urinary excretion of inorganic arsenic and its methylated metabolites. Br J Ind Med 49 387-393 Overby LR, Frederickson RL (1963) Metabolic stability of radioactive arsanilic acid in chickens. J Agric Food Chem 11 378-381 Overby LR, Frederickson RL (1965) Metabolism of arsanilic acid. II. Localization and type of arsenic excreted and retained by chickens. Toxicol Appl Pharmacol 7 855-867... 

This sulfate ester of arsenorlbosylglycerol accumulates In all aquatic plants. It Is a derivative of an equally universal arsenophosphollpld, an arsenorlbosylphosphatldylglycerol, of all such plants. The steady state concentration of this lipid Is low and varies from one species to another depending on Its rates of removal. It appears to mediate arsenic excretion by oxidative or hydrolytic cleavage from its phospholipid at the outside of the plasma membrane. Arsenical membrane lipids such as this also appear to play a role In the removal of arsenic from some animal systems via the gill membrane (Benson and Summons, 1981). 

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