ESTONIAN ENVIRONMENTAL REVIEW 2009

5.2.4. Heavy metals
Heavy metals are chemical elements that in the periodic
table fall between copper and bismuth with a density
greater than 5 g/cm 3 . Almost all of the heavy metals are
toxic starting from a certain level, accumulating in the
body and causing liver and kidney damage. Heavy metals
are usually released into the environment by human
activity, either by fuel combustion, industry or in traffic,
depending on the specific compound.
Pursuant to the Ambient Air Protection Act, lead (Pb),
cadmium (Cd) and mercury (Hg) are the most important
pollutants that must be considered in assessing and testing
ambient air quality.
Lead, cadmium and mercury are mainly released by
combustion in the energy sector and in the production
of energy in industry.
The emissions reduction programme must achieve a
level by the year 2010 where heavy metal emissions do
not exceed the following limits: Pb – 39.12 t; Cd – 0.63 t
and Hg – 0.61 t. By 2015, emissions must be under the following
limits: Pb – 34.63 t; Cd – 0.53 t and Hg – 0.51 t.
In 2007, a total of 40 tonnes of lead was emitted
into Estonia’s ambient air, which is slightly more than
the 2010 target (figure 5.10). The bulk of the lead was
generated in the combustion of fuel in the energy and
transformation industries (about 91%) as well as from
road transport (4.5%). The share contributed by other
sectors in 2007 was low. The greatest polluters are Eesti
and Balti power plants in Ida-Viru County. Compared
to 1990, lead emissions into ambient air have dropped
by 80%. Above all, this is due to modernization of the
cleaning equipment at Narva power plants and the use of
lead-free automotive fuels. In 1990, road transport was
responsible for 36% of lead emissions, but in 2007 the
figure was only 4.5% (figure 5.11). The use of ethylated
petrol was discontinued in Estonia in 2000.
In 2007, a certain increase in lead emissions could be
seen compared to the year before, which can be attributed
to the increase in electricity production volumes at Balti
and Eesti power plants.
In 2007, 680 kg of cadmium was discharged into ambient
air, and 650 kg of mercury, which is within the range
of the target for 2010. The overwhelming majority of both
heavy metals (90% of Cd and 94% of Hg) was released
by combustion of fuel in the energy and transformation
industries (figure 5.13).
Compared to 1990 (figure 5.12), Hg and Cd emissions
into ambient air have dropped by 39% and 88%,
respectively, due to a decrease in electricity and cement
production as well as modernization of cleaning installations.
Similarly to lead emissions, in 2007 a certain
increase in these emissions could be seen compared to
the year before, which can be attributed to the increase
in electricity production volumes at power plants.
250
200
150
100
50
tonnes
0
201
185
121
101
124
84
65
52
46
44
37
34
34
39
38
37
34
40
39.12
34.63
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2010 2015
Figure 5.10. Lead emissions, 1990–2007, and emissions reduction targets for 2010 and 2015. Data: EEIC.
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