Civil Engineering Reference
In-Depth Information
Table 6 Typical and maximum activity concentrations in common building materials and
industrial by-products used for building materials in Europe (Kovler et al.
2002
; Kovler
2009
)
Material
Typical activity concentration
(Bq/kg)
Maximum activity concentration
(Bq/kg)
226
Ra
232
Th
40
K
226
Ra
232
Th
40
K
Construction materials
Concrete
40
30
400
240
190
1,600
Lightweight concrete
60
40
430
2,600
190
1,600
Ceramic bricks
50
50
670
200
200
2,000
Concrete blocks
10
10
330
25
30
700
Natural stone
60
60
640
500
310
4,000
Natural gypsum
10
10
80
70
100
200
Industrial by-products
Phosphogypsum
390
20
60
1,100
160
300
Blast furnace slag
270
70
240
2,100
340
1,000
Coal fly ash
180
100
650
1,100
300
1,500
concrete with a lower concentration but with a more porous structure and therefore
with a higher exhalation rate (Keller et al.
2001
).
Taylor-Lange et al. (
2012
) show that concrete floors made with 25 wt% fly ash
resulted in 90 % of the simulated homes having double the dose compared to the
control concrete (2.3 Bq/m
3
). This is not only a problem for new buildings but also
in the refurbishment context that often includes the replacement of wood floors by
concrete-based slabs. Recent studies (Trevisi et al.
2012b
) based on 2,727 concrete
specimens from 23 European countries show very different radon concentrations
and some as high as 1,450 Bq/kg for the radionuclide
40
K in Portugal, thus
meaning that some countries should have a special attention to this subject.
6 Conclusions
Radon constitutes the second cause of lung cancer in the general population, the
first being smoking. In the past, it was accepted that only radon concentrations
above 400 Bq/m
3
could constitute a health risk; however, recent epidemiological
findings demonstrate lung cancer risk from exposure to indoor radon at levels in
the order of 100 Bq/m
3
. It is estimated that millions of residents in Europe live in
homes which have radon concentrations above 200 Bq/m
3
; however, the majority
of the public seems to consider the health risks involved from exposure to radon as
being negligible. Still recent regulation continues to allow high indoor radon
concentrations. The recent agenda on building energy efficiency refurbishment can
provide the right context in order to raise the radon problem once again. Using
post-construction, remediation like SDS seems to be more cost-effective than the
use
of
protection
measures
installed
during
construction
like
radon-barrier
