Human exposure and dose indicators

Human exposure to arsenic has been mainly assessed in the past by the determination of the total arsenic concentration in blood, hair, nails, and urine. In cases of suspected arsenic poisoning gastric juice has also been analyzed. In order to obtain meaningful data, however, it is important to determine the chemical form of arsenic, at least in body fluids. Depending on the source and length of exposure, these indicators have a different meaning and different significance as well (Foa et al., 1987 Vahter, 1988). 

Also arsenic in water used for washing the hair may be bound and give rise to elevated levels. 

For nails the situation is similar to that for hair. Arsenic might be deposited in the nail roots from the blood stream and then migrates distally as the nails grow. The risk of exogenous influences, of course, is also similar and probably even more pronounced. 

Since arsenic is mainiy excreted via the kidneys (see also section Biotransformation and Excretion) the determination of its concentration in urine is by far the predominantly used method to estimate exposure. 

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