INTAKE OF DIFFERENT CHEMICAL-SPECIES OF DIETARY ARSENIC BY THE JAPANESE, AND THEIR BLOOD AND URINARY ARSENIC LEVELS

We calculated the intake of each chemical species of dietary arsenic by typical Japanese, and determined urinary and blood levels of each chemical species of arsenic. The mean total arsenic intake by 35 volunteers was 195 +/- 235 i5.8-1039) mu-g As day-1, composed of 76% trimethylated arsenic (TMA), 17.3% inorganic arsenic (As(i)), 5.8% dimethylated arsenic (DMA), and 0.8% monomethylated arsenic (MA): the intake of TMA was the largest of all the measured species. Intake of As(i) characteristically and invariably occurred in each meal. Of the intake of As(i), 45-75% was methylated in vivo to form MA and DMA, and excreted in these forms into urine. The mean measured urinary total arsenic level in 56 healthy volunteers was 129+/-92.0-mu-g As dm-3, composed of 64.6% TMA, 26.7% DMA, 6.7% As(i) and 2.2% MA. The mean blood total arsenic level in the 56 volunteers was 0.73+/-0.57-mu-g dl-1, composed of 73% TMA, 14% DMA and 9.6% As(i). The urinary TMA levels proved to be significantly correlated with the whole-blood TMA levels (r = 0.376; P < 0.01).