Sensitive Indicators of Inorganic Mercury Toxicity

Abstract

Forty-two workers from a chemical plant producing inorganic mercury compounds were evaluated for neurologic, nephrotic, and ophthalmologic toxicity. Despite elevated blood and urinary mercury levels, routine clinical testing such as physical examination, blood chemistries, and urinalysis were generally normal. These findings from the routine examination are in contrast to the complaints of neuropsychological symptoms, elevated urinary n-acetyl B-D-glucosaminidase (NAG) levels, decreased motor nerve conduction velocities, and the presence of lenticular opacities on slit-lamp examination that were found, when organ systems known to be affected by mercury were targeted. More sensitive but objective indicators of toxicity need to be included in routine medical screening so as to help diagnose the etiology of neuropsychological symptoms and prevent long-term sequelae in workers exposed to mercury.

Occupational exposure to airborne mercury during gold mining operations near El Callao, Venezuela

“…and enzymuria (û-galactosidase, N-acetyl-û-D-glucosaminidase (NAG), û-glucuronidase, etc.) [4,6,11,13,22,28,31,32,34]. These manifestations can diminish the ability of proximal tubule segments to reabsorb water, proteins, and other substances, thus aecting the kidneys' ability to maintain volume and composition of body¯uids within normal limits.…”

Subclinical neurotoxicity of mercury vapor revealed by a multimodality evoked potential study of chloralkali workers

“…The blood mercury level is the best measure of recent exposure but has no good correlations with the clinical features in chronic intoxication. On the contrary, Rosenman et al [1986] reported that neuropsychological symptoms and other toxic manifestations had good correlations with urinary mercury levels or 24-hr urinary mercury outputs. We could not find significant correlations between EP abnormalities and body mercury levels in the present study, but these EP changes were mainly seen in mercury workers with high exposure.…”

“…Relationships between mercury levels and clinical manifestations have been extensively investigated in mercury exposure or intoxication [Rosenman et al, 1986;Ellenhorn and Barceloux, 19881. The blood mercury level is the best measure of recent exposure but has no good correlations with the clinical features in chronic intoxication.…”

Epidemiological surveillance of employees in a mercury thermometer plant: An occupational health study

“…Rosemann et al [26] found positive correlation between HgU levels (100 µg -250 µg/L) and neuropsychological symptoms. In a study conducted by Smith et al, [27] short-term memory was affected in a group of individuals with a mean of 180 µg/ L.…”