Chromosome Aberrations Induced by Occupational Exposure to Mercury

Abstract

The incidence of chromosome aberrations was studied by peripheral blood incubation (52 hr, the last 4 hr in the presence of Colcemid) using a modification of the Evans' technique in twenty-two men exposed to either vapors of metallic mercury (Group I) or organic mercury (Group II). Mercury concentrations of the work areas frequently exceeded the Maximum Allowable Concentrations in the past. During the year proceding the investigation, mercury values ranged between 0.15 and 0.44 mg/m3. None of the investigated men were poisoned, but all had had repeated increased mercury absorption with urinary eliminations reaching 890 microgram/l and 896 microgram/l for subjects in Groups I and II, respectively. The incidence of chromosome aberrations was significantly higher (P less than .001) in subjects exposed to mercury as compared with a control group (ten subjects) of a similar mean age. There was no statistical difference in the incidence of chromosome aberrations between men belonging to Groups I and II. Although an increase of both chromatid gaps and breaks was noticed in exposed men, the incidence did not significantly differ from controls. No chromatid interchanges were recorded and no difference between exposed and control subjects was noticed concerning the frequency of aneuploid or polyploid cells.

Scientific Opinion on the risk for public health related to the presence of mercury and methylmercury in food

“…Since after inhalation of elemental mercury vapour in the blood elemental mercury is oxidised to mercuric mercury (ATSDR, 1999) the following section summarises genotoxicity in human lymphocytes after exposure towards elemental mercury. In human lymphocytes genetic damage (in terms of chromosome aberrations) has been observed after occupational exposure to elemental and organic mercury (Verschaeve et al, 1976;Popescu et al, 1979;Cebulska-Wasilewska et al, 2005); sister chromatid exchanges (Popescu et al, 1979;Cebulska-Wasilewska et al, 2005) and DNA damage as measured by the alkaline version of the Comet assay (Cebulska-Wasilewska et al, 2005) were not statistically significantly increased in these studies. Repair efficiencies in lymphocytes of 25 workers exposed to elemental mercury vapour were reduced compared with 50 individuals nonoccupationally exposed, as measured by the X-rays challenge assay (Cebulska-Wasilewska et al, 2005).…”

Chromosome aberrations in chloralkali workers previously exposed to mercury vapor.

“…Versc haeve et al (6) observe d an increased prevalence of chromosome aberrat ions in 28 subjects exposed to various mercury compounds, but the resu lts were not confirmed in a later study (7) . Popescu et al (8) found an increa se in chromosome aberrations, but no increase in chromatid-type aberration s in four subjects with repeatedly high urinary mercury concentrations reaching 890 ug . I-I (4450 nmol .…”

“…In human studies, micronucleus assay indicated an accumulation of cytogenetic damage in lymphocytes after exposure to mercury vapor (4) or mercury fulminate (5). Previous studies on humans during ongoing exposure to inorganic mercury compounds showed conflicting results when other cytogenetic methods were used (6)(7)(8)(9).…”

Effects of occupational exposure to mercury vapor on lymphocyte micronuclei.

“…The ability of inorganic mercury to induce gene mutations seems, however, to be low (3,4). Cytogenetic in vivo studies have, in most cases, shown no effects on human chromosomes (6)(7)(8)(9). Only few studies of cancer in animals after exposure to mercury have been reported, and none used the inhalation of mercury vapor as the method of exposure (10,11).…”