Concentrations of arsenic in urine of the general population in Sweden.

The concentration of the sum of the metabolites of inorganic arsenic (inorganic arsenic, methylarsonic acid and dimethylarsinic acid) as well as the concentration of organic arsenic compounds, mainly in the form of arsenobetaine, in the urine of human subjects from two cities in Sweden have been studied. The median concentration of metabolites of inorganic arsenic was approximately 8 micrograms As/g creatinine, independent of place of residence, sex, smoking and consumption of beer and wine. However, subjects who frequently ate flatfish and crustacea had somewhat higher (1.5 times) concentrations than those who very seldom ate such food. Flatfish, mainly in the form of plaice, and crustacea were found to be the main source of organic arsenic compounds. Subjects eating this type of seafood more than once a week had approximately 40 micrograms organic As/g creatinine (median value), compared with about 12 micrograms organic As/g creatinine in subjects who very seldom ate it. Other types of seafish or freshwater fish did not give rise to elevated concentrations of arsenic in the urine. The total range of organic arsenic compounds in urine was less than 1 to 525 micrograms As/g creatinine.