Nephrotoxic effects of mercury exposure and smoking among Egyptian workers in a fluorescent lamp factory

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 greater than or equal to11 years than those with less than or equal to10 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 mug Hg/g Ucr) or biological exposure index (35 mug Hg/g Ucr) of urinary mercury levels because elevated levels of measured parameters were observed at urinary Hg levels of 17.3-28.2 mug Hg/g Ucr. (C) 2003 IMSS. Published by Elsevier Science Inc.