SODIUM 2,3-DIMERCAPTOPROPANE-1-SULFONATE CHALLENGE TEST FOR MERCURY IN HUMANS .2. URINARY MERCURY, PORPHYRINS AND NEUROBEHAVIORAL CHANGES OF DENTAL WORKERS IN MONTERREY, MEXICO

The sodium salt of 2,3-dimercaptopropane-1-sulfonic acid (DMPS) challe nge test (300 mg p.o. after an Il-hr fast) was given in Monterrey, Mex ico to dental and nondental personnel. Urine samples were collected an d analyzed for total mercury. The mean mercury urinary excretion (+/- S.E.) for 6 hr before and 6 hr after DMPS administration for 10 dental technicians, who formulate amalgam, was 4.84 mu g +/- 0.742 and 424.0 mu g +/- 84.9; for 5 dentists, who use amalgam in their practice, 3.2 8 mu g +/- 1.11 and 162.0 mu g +/- 51.2; and for 13 nondental personne l, 0.783 mu g +/- 0.189 and 27.3 mu g +/- 3.19. The urinary coproporph yrin revels before DMPS administration, which are indicative of renal mercury content, were quantitatively associated with the urinary mercu ry levels among the three study groups after DMPS administration. This was not so if the urinary mercury level before DMPS administration wa s compared with the urinary coproporphyrin concentration. The urinary mercury level after DMPS administration is a better indicator of expos ure and renal mercury burden than is the mercury level measured in the urine before DMPS is given. Regression analysis showed that the coeff icient of urinary mercury was statistically and adversely associated w ith complex attention (switching task), the perceptual motor task (sym bol-digit substitution), symptoms and mood. The easily performed DMPS- mercury challenge test is useful for monitoring dental personnel For m ercury vapor exposure.