Health status of workers of a thermal power station exposed for prolonged periods to arsenic and other elements from fuel.

The Nováky Power Station (NPS) has been using since 1953 as fuel coal with a high content of As and with a low content of other metals. This involves a constant risk for the workers as well as pollution of the surroundings. The authors described 16 cases of chronic As intoxication in NPS workers after 22.3 +/- 8.4 years of exposure (especially stokers, maintenance workers, boiler cleaners). Among clinical symptoms prevailed sensory and motor polyneuropathy (13 cases), pseudoneurasthenic syndrome (10 cases), toxic encephalopathy (6 cases) and nasal septum perforation (2 cases). After 1989 the intoxications with As did not occur any more due to technical measures and health protection of the workers. The authors present a review of actual results of clinical, haematological and biochemical investigations and tests for metals (AAS methods) in biological materials of workers at risk in NPS (n = 70), exposed on average for 11.9 +/- 0.5 years, of average age 35.91 +/- 1.7 years (mean +/- SE) and compared the results to a matched control group of blood donors not exposed to metals (n = 29). In NPS workers significantly lower Hb values, higher serum creatinine, higher serum beta 2-microglobulin, higher As content in hair as well as higher serum Mn and Pb concentrations compared with the C-group were found. The exposed group had significantly lower serum Se concentrations (0.64 +/- 0.025 mumol/l (mean +/- SE) compared to Se levels of persons from an adjacent district. The authors stress the necessity of individual evaluation of the metal concentrations in relation to clinical findings. With prolonged exposure the situation can become more urgent not only because of chronic poisoning but also because of the cancerogenic effects of these elements on the human organism.

Content of the selected trace elements (Al, As, Cd, Cu, Fe, Hg, Mn, Ni, Pb, Zn) in blood, urine and hair of blood donors without occupational exposure to these metals.

The trace element content in biological samples from blood donors (BD) has not been studied in detail so far. In everyday practice minimum attention is paid to the occupational history of blood donors from different social strata. In addition to clinical and elementary haematological and biochemical examinations, the authors assessed levels of Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn using atomic absorption spectrophotometry (AAS) in two groups of BD--from the Orava (n = 19) and Prievidza region (n = 29). The examined blood donors were never exposed to the risk of metal exposure. No significant differences were found in age and smoking habits between the groups. In analyses electrothermic atomization (AAS-GTA) was mostly used. Hg in urine was assessed, using the technique of hydride vapour formation (VGA). Comparing the results of both BD groups, using Student's t-test, some significant differences between the two regions were found in As, Pb, Cr, Cd, Mn, Ni levels. The authors discuss the possible influence of artificial metal sources from the plants contaminating the environment of the regions for prolonged periods (power plant using coal containing As, metallurgy plant producing ferrochromium and ferromanganese alloys and lead metallurgy plant. Blood levels of metals in BD compared with control groups of the non-exposed population (data obtained from the literature) were within a similar or often lower range. In BD studied very low values of Hg in urine were found (0.015 +/- 0.004 mumol.l-1, 0.021 +/- 0.001 mumol.l-1 of urine -mean +/- SE) with the maximum recorded value of 1.0 mumol Pb.l-1 of blood.

Levels of selected elements (Fe, As, Cd, Pb, Zn, Mn) in biological samples from ferrochromium workers.

A long-term exposure to metals poses the question of whether the impaired health condition is caused exclusively by the quantitatively dominant exposure metal. In 67 workers exposed to ferrochromium alloys on average 12.5 +/- 1.09 years (mean +/- SE), the subgroups of ferrochromium workers and operators of dust removing equipment, average Cr values in urine were 0.233 +/- 0.032 mumol.l-1 (mean +/- SE). In the control group (K) the average Cr values were 0.034 +/- 0.004 mumol.l-1 of urine (mean +/- SE). The levels of plasmatic Fe were assessed photometrically; the levels of Fe, As, Cd, Pb, Mn and Zn in hair, urine and blood were assessed by atom-absorption spectrophotometry (Varian). The results were compared with the control group not significantly different in age (t-test). All the values were correlated with age, years of exposure and the number of cigarettes smoked during life. The values of the single selected metals in furnace workers and operators of dust removing devices were not higher than the limits set for the groups of workers exposed to metals. But compared to the original biological background, there was observed a significant Cd increase (hair, blood, urine) year by year. Average values of As, Pb, Fe, and Mn in hair of the exposed workers were also higher compared to the group K. As and Mn values in hair were increasing up with the years of exposure (r = 0.465, p < 0.05; r = 0.580, p < 0.001). No expected higher values of plasmatic Fe were found. Zn values in hair were falling down with the years of exposure as well as with age, in all groups including the group K. The authors discuss the possible causes of the quantitative changes in the selected metals in connection with professional exposure and non-professional effects (especially smoking). Higher cancer incidence of the organs affected has not been observed so far in the study plant. (Tab. 2, Fig. 8, Ref. 41.)