Urinary excretion of 5-hydroxyindolacetic acid in occupational exposure to polyvinyl chloride and polyurethane foams.

The effect of plastics as polyurethane foams and polyvinyl chloride on the metabolism of tryptophan was investigated by determining the concentration of 5-hydroxyindoleacetic acid (5-HIAA) as its metabolic end product excreted in the urine. Investigation of persons occupationally exposed to polyurethane and polyvinyl chloride showed that these plastics inhibit the metabolism of tryptophan, causing increased excretion of its easily measurable metabolite 5-HIAA. This fact points to the possibility of practical use of this laboratory test which, together with other biological parameters, could improve methods for early detection of occupational exposure to polyurethanes and polyvinyl chloride.