BACKGROUND: It is known that mercury (Hg) has a nephrotoxic effect in exposed workers. This effect is evident when there is advanced damage of kidney tissue. METHODS: A random morning urine sample was collected from each participant for measuring urinary concentrations of total protein (UTP), retinol-binding protein (URBP), creatinine (UCr), Hg (UHg), and the activities of leucine-aminopeptidase (ULAP) and glutathione S-transferase (UGST) as well as N-acetyl-beta-D-glucosaminidase (UNAG). RESULTS: Urinary excretion of the measured parameters was significantly increased among Hg-exposed workers who were smokers and among Hg-exposed workers with work duration >or=11 years than those with <or=10 years work duration. CONCLUSIONS: Results of this investigation demonstrated that these urinary parameters of kidney integrity could be used as indicators of nephrotoxic effect of Hg exposure and that cigarette smoking has toxic and synergistic effects with Hg exposure on kidney. Present results additionally suggest reduction in recommended biological threshold limit (50 microg Hg/g Ucr) or biological exposure index (35 microg Hg/g Ucr) of urinary mercury levels because elevated levels of measured parameters were observed at urinary Hg levels of 17.3-28.2 microg Hg/g Ucr.
BACKGROUND: It is known that mercury (Hg) has a nephrotoxic effect in exposed workers. This effect is evident when there is advanced damage of kidney tissue. METHODS: A random morning urine sample was collected from each participant for measuring urinary concentrations of total protein (UTP), retinol-binding protein (URBP), creatinine (UCr), Hg (UHg), and the activities of leucine-aminopeptidase (ULAP) and glutathione S-transferase (UGST) as well as N-acetyl-beta-D-glucosaminidase (UNAG). RESULTS: Urinary excretion of the measured parameters was significantly increased among Hg-exposed workers who were smokers and among Hg-exposed workers with work duration >or=11 years than those with <or=10 years work duration. CONCLUSIONS: Results of this investigation demonstrated that these urinary parameters of kidney integrity could be used as indicators of nephrotoxic effect of Hg exposure and that cigarette smoking has toxic and synergistic effects with Hg exposure on kidney. Present results additionally suggest reduction in recommended biological threshold limit (50 microg Hg/g Ucr) or biological exposure index (35 microg Hg/g Ucr) of urinary mercury levels because elevated levels of measured parameters were observed at urinary Hg levels of 17.3-28.2 microg Hg/g Ucr.