URINARY ALKOXYACETIC ACIDS AND RENAL EFFECTS OF EXPOSURE TO ETHYLENE-GLYCOL ETHERS

Objectives-Ethylene glycol ethers and their acetates are widely used i n industry, because of their hydrophilic and simultaneously lipophilic properties. Ethylene glycol ethers and their acetates are mainly meta bolised to alkoxyacetic acids, but there is also a minor pathway throu gh ethylene glycol to oxalic acid. The main pathway of ethylene glycol ethers is associated with significant clinical or experimental health effects and the minor pathway is also interesting because formation o f urinary stones depends principally upon the urinary concentration of oxalate and calcium. Methods-Excretion of alkoxyacetic and oxalic aci ds was examined among silkscreen printers for an entire working week. The aim of the study was to evaluate alkoxyacetic acids as early indic ators of exposure to glycol ethers and to evaluate their toxicity to k idneys. The load of alkoxyacetic and oxalic acids was compared of pare d with the excretion of calcium, chloride, ammonia, and glycosaminogly cans (GAG). Morning urine was chosen for the main analysis, as the ove rall metabolite, ethoxyacetic acid (EAA), has a long elimination time from the body. Results-The excretion of calcium increased according to the urinary alkoxyacetic acid load. The excretion of ammonia and chlo ride was higher among the exposed workers than among the controls. The highest urinary alkoxyacetic acid load was also associated with incre ased excretion of GAG, which may reflect the toxicity of metabolites o f ethylene glycol ether. The excretion of GAG correlated positively wi th that of calcium in the printers with highest exposure. The tendency to form urinary stones was 2.4-fold higher among silkscreen printers than among office workers. Conclusion-On the basis of renal effects ou r study indicates the need for establishing a new biological exposure limit before a workshift that is clearly below 100 mmol ethoxyacetic a cids per mol creatinine in morning urine of people occupationally expo sed to ethylene glycol ethers.