Neuropsychological effects of low mercury vapor exposure in chloralkali workers

Neuropsychological effects were examined in 47 mercury vapor exposed male c hloralkali workers with current low concentrations of urinary mercury (mean U-Hg 5.9 nmol/mmol creatinine (Cr)). Their ever-age duration of exposure,v as 13.3 years, and the calculated mean concentration of U-Hg was 9.0 nmol H g/nmol Cr per year (exposure intensity) during their time of exposure. They were compared, with 47 age-matched male referents in a cross-sectional stu dy. The two groups were nor statistically significantly different with resp ect to neuropsychological test performance or number of self-reported subje ctive symptoms. The test results of the Static Steadiness Test, which asses ses tremor were not associated with exposure to mercury vapor: However curr ent smokers had more hand tremor than non-smokers. Statistically significan t associations were found between indices of current exposure (the concentr ation of inorganic mercury in whole blood) and the results of the WAIS Digi t Symbol Test and the Benton Visual Retention Test (number of correct respo nses). This could indicate a small effect of current exposure on visuomotor /psychomotor speed and attention, and immediate visual memory Whether the a ssociation found between the historical exposure intensity and the Digit Sy mbol Test results may represent long-term conseqences of exposure cannot be determined in this study (C) 2001 Elsevier Science Inc. All rights reserve d.