Evaluation of Internal Doses of Mercury
at Intermittent Exposure to Elemental Mercury
at the Mine in Idrija
A. KOBAL, E. NANUT, M. HORVAT, P. STEGNAR, and A. SABADIN
Our experience suggested that the urine mercury concentration is not a valid indicator of individual
internal doses received during intermittent type of exposure to elemental mercury. We decided to
define the current internal dose of mercury through the analysis of total blood mercury. Thirty two
miners were observed before and immediately after exposure to elemental mercury. Because the
workers made use of respiratory protection, the residual external exposure was assessed with a
personal sampler in 15 miners. Blood and urine samples of all examined miners were taken before and
immediately after exposure for analysis of total mercury. Total mercury was determined in plasma,
erythrocytes and also in the 18-h urine samples of 20 miners. The mercury concentration in all urine
postshift samples was corrected to a urinary specific gravity of 1.024 and the postexposure 18-h urine
samples of 20 workers was corrected to a urine volume of 1 mllmin. Mercury in the blood, urine and
gold trap was determined by cold vapour atomic absorption spectrometry. A very good correlation
was found between elemental mercury in inhaled air and the postexposure blood mercury
concentration (r = 0.96, P = 0.000). A significant increase (P < 0.001) in blood mercury and urine
mercury was established after exposure. The urine and blood mercury concentration after exposure
was well correlated (r = 0.68, P < 0.001). No correlation was found between the blood mercury
concentration before and after exposure (r = 0.29, P > 0.05). A significant increase (P < 0.01) in
erythrocyte mercury and predominantly in plasma mercury was also established during exposure. The
correlation between plasma and postshift urine mercury was higher (r = 0.82, P = 0.000) than
between erythrocyte and postshift urine mercury (r = 0.70, P = 0.002), if the correction of urine
mercury concentration to a urine volume of 1 ml/min was used. Our results confirm that blood
mercury concentration is a valid and reliable indicator of current or recent individual exposure to
elemental mercury at intermittent type of exposure. At this type and level of exposure, urine mercury
in postshift samples, particularly if adjusted to a urine volume of 1 mllmin, reflect not only the
accumulation of mercury from earlier exposures but partly also the current group level exposure.
1
Introduction
Our practical experience in assessing miners intermittently exposed to elemental
mercury (HgO) in the Idrija Mercury Mine (Kobal 1991) and the experiences of
other authors (Piotrowski et al. 1975; Nakaaki et al. 1975; WHO 1976) suggested
that the urine mercury (U-Hg) concentration is not a valid indicator of individual
internal dose received during exposure. Therefore, we decided to define the
current internal dose of mercury (Hg) through the analysis of total blood
mercury (B-Hg), erythrocyte mercury (E-Hg) and plasma mercury (P-Hg). We
shall also study the relationship between B-Hg and U-Hg concentrations in
postshift urine samples.
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebinghaus et al.l
© Springer-Verlag Berlin Heidelberg 1999
at Intermittent Exposure to Elemental Mercury
at the Mine in Idrija
A. KOBAL, E. NANUT, M. HORVAT, P. STEGNAR, and A. SABADIN
Our experience suggested that the urine mercury concentration is not a valid indicator of individual
internal doses received during intermittent type of exposure to elemental mercury. We decided to
define the current internal dose of mercury through the analysis of total blood mercury. Thirty two
miners were observed before and immediately after exposure to elemental mercury. Because the
workers made use of respiratory protection, the residual external exposure was assessed with a
personal sampler in 15 miners. Blood and urine samples of all examined miners were taken before and
immediately after exposure for analysis of total mercury. Total mercury was determined in plasma,
erythrocytes and also in the 18-h urine samples of 20 miners. The mercury concentration in all urine
postshift samples was corrected to a urinary specific gravity of 1.024 and the postexposure 18-h urine
samples of 20 workers was corrected to a urine volume of 1 mllmin. Mercury in the blood, urine and
gold trap was determined by cold vapour atomic absorption spectrometry. A very good correlation
was found between elemental mercury in inhaled air and the postexposure blood mercury
concentration (r = 0.96, P = 0.000). A significant increase (P < 0.001) in blood mercury and urine
mercury was established after exposure. The urine and blood mercury concentration after exposure
was well correlated (r = 0.68, P < 0.001). No correlation was found between the blood mercury
concentration before and after exposure (r = 0.29, P > 0.05). A significant increase (P < 0.01) in
erythrocyte mercury and predominantly in plasma mercury was also established during exposure. The
correlation between plasma and postshift urine mercury was higher (r = 0.82, P = 0.000) than
between erythrocyte and postshift urine mercury (r = 0.70, P = 0.002), if the correction of urine
mercury concentration to a urine volume of 1 ml/min was used. Our results confirm that blood
mercury concentration is a valid and reliable indicator of current or recent individual exposure to
elemental mercury at intermittent type of exposure. At this type and level of exposure, urine mercury
in postshift samples, particularly if adjusted to a urine volume of 1 mllmin, reflect not only the
accumulation of mercury from earlier exposures but partly also the current group level exposure.
1
Introduction
Our practical experience in assessing miners intermittently exposed to elemental
mercury (HgO) in the Idrija Mercury Mine (Kobal 1991) and the experiences of
other authors (Piotrowski et al. 1975; Nakaaki et al. 1975; WHO 1976) suggested
that the urine mercury (U-Hg) concentration is not a valid indicator of individual
internal dose received during exposure. Therefore, we decided to define the
current internal dose of mercury (Hg) through the analysis of total blood
mercury (B-Hg), erythrocyte mercury (E-Hg) and plasma mercury (P-Hg). We
shall also study the relationship between B-Hg and U-Hg concentrations in
postshift urine samples.
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebinghaus et al.l
© Springer-Verlag Berlin Heidelberg 1999