378
O. Kruger et al.
Schkopau in the period of time between 1990 and 1992. Among them were three
chlor-alkali production works (hereafter denoted L66, 154 and H56), one factory
still producing chlor-alkali (denoted P159) and one acetaldehyde factory (denoted
F44). In these factories, mercury was used as an electrode for chlorine and
sodium hydroxide production and as a catalyst for acetaldehyde production. All
production sites consist of partly removed buildings or buildings with openings.
Since these buildings are continuing to release gaseous mercury into the
surrounding atmosphere, presently, the main problem related to mercury at BSL
Werk Schkopau is the redevelopment of this contaminated area. Furthermore,
the variations of mercury concentrations in the surrounding air and the potential
danger this posed for human health were unknown. Therefore, in order to obtain
an implication about the amount of mercury in air an important task was to
estimate the quantity of mercury emissions originating from specified sources at
the factory premises.
This chapter focuses on the actual situation in 1994 at the industrial site BSL
Werk Schkopau located near Halle!Saale. Emission source strength estimations
based on measurements and model calculations are presented. The following
section describes the measurement method and the quantities of atmospheric
gaseous mercury measured at the BSL Werk Schkopau. After a brief description
of the local dispersion modelling, an inverse modelling procedure which was
applied to estimate source strengths of mercury emissions is explained. Model
experiments due to the applicability of the inverse modelling method at the
individual site BSL Werk Schkopau are discussed, and the results of the source
strengths of gaseous mercury emissions are presented. The conclusions are
outlined in the final section.
2
Measurements of Gaseous Mercury at the BSL Werk Schkopau
In order to determine mercury concentrations in air at the BSL Werk Schkopau,
the analytical methods described in Ebinghaus et al. (1995) were applied. During
the field campaigns total gaseous mercury (TGM) was collected on gold-coated
glass beads. Figure 1 depicts the method of sampling. Basically, two quartz tubes
of 0.4 cm internal diameter were packed with glass beads (100 mesh) to a length
of approximately 1.5 cm, which results in an active sampling surface of 15-20 cm
2
per trap. To prevent contamination, a third tube which was fitted with a gold!
platinum gauze was placed between the adsorber tubes and the pump. The
ambient air was drawn through a 0.5-cm quartz wool plug before passing
through the adsorber tubes. Approximately 10 I of air was collected at a flow rate
of 20-30 lIh. After sampling, the tubes were closed with plastic caps and stored in
a firmly sealed glass container. To prevent contamination during storage, 1 g of
silver wool was kept in the container to trap gaseous mercury diffusing into it.
All samples were analyzed using cold vapour atomic fluorescence spectroscopy
(CYAFS) with the two-step amalgamation technique (Fitzgerald and Gill 1976).
O. Kruger et al.
Schkopau in the period of time between 1990 and 1992. Among them were three
chlor-alkali production works (hereafter denoted L66, 154 and H56), one factory
still producing chlor-alkali (denoted P159) and one acetaldehyde factory (denoted
F44). In these factories, mercury was used as an electrode for chlorine and
sodium hydroxide production and as a catalyst for acetaldehyde production. All
production sites consist of partly removed buildings or buildings with openings.
Since these buildings are continuing to release gaseous mercury into the
surrounding atmosphere, presently, the main problem related to mercury at BSL
Werk Schkopau is the redevelopment of this contaminated area. Furthermore,
the variations of mercury concentrations in the surrounding air and the potential
danger this posed for human health were unknown. Therefore, in order to obtain
an implication about the amount of mercury in air an important task was to
estimate the quantity of mercury emissions originating from specified sources at
the factory premises.
This chapter focuses on the actual situation in 1994 at the industrial site BSL
Werk Schkopau located near Halle!Saale. Emission source strength estimations
based on measurements and model calculations are presented. The following
section describes the measurement method and the quantities of atmospheric
gaseous mercury measured at the BSL Werk Schkopau. After a brief description
of the local dispersion modelling, an inverse modelling procedure which was
applied to estimate source strengths of mercury emissions is explained. Model
experiments due to the applicability of the inverse modelling method at the
individual site BSL Werk Schkopau are discussed, and the results of the source
strengths of gaseous mercury emissions are presented. The conclusions are
outlined in the final section.
2
Measurements of Gaseous Mercury at the BSL Werk Schkopau
In order to determine mercury concentrations in air at the BSL Werk Schkopau,
the analytical methods described in Ebinghaus et al. (1995) were applied. During
the field campaigns total gaseous mercury (TGM) was collected on gold-coated
glass beads. Figure 1 depicts the method of sampling. Basically, two quartz tubes
of 0.4 cm internal diameter were packed with glass beads (100 mesh) to a length
of approximately 1.5 cm, which results in an active sampling surface of 15-20 cm
2
per trap. To prevent contamination, a third tube which was fitted with a gold!
platinum gauze was placed between the adsorber tubes and the pump. The
ambient air was drawn through a 0.5-cm quartz wool plug before passing
through the adsorber tubes. Approximately 10 I of air was collected at a flow rate
of 20-30 lIh. After sampling, the tubes were closed with plastic caps and stored in
a firmly sealed glass container. To prevent contamination during storage, 1 g of
silver wool was kept in the container to trap gaseous mercury diffusing into it.
All samples were analyzed using cold vapour atomic fluorescence spectroscopy
(CYAFS) with the two-step amalgamation technique (Fitzgerald and Gill 1976).