Indtrængning af PCB i bygningsdele
Primær, sekundær og tertiær forurening
Møde i PCB netværket d. 16. april 2013
Lars Gunnarsen
Statens Byggeforskningsinstitut, Aalborg Universitet
Polychloreret biphenyl
Damptrykkets temperaturafhængighed
Grundlæggende om PCB’er
Sum 7 congenerer: 28, 52, 101, 118, 138, 153 og 180
De 12 dioxinlignende congenerer: 77, 81, 105, 114, 118, 123, 126, 156, 157, 167,
169, og 189
Alle PCB congenerer akkumuleres i kroppen
105 og 118 har WHO TEF på 0,0001 og for 156 er den 5 gange større
Højest TEF har nr. 126 med 0,1
Damptrykket for PCB 118 ved 25 oC er 0,00119 Pa.
I luft ved 1 atm svarer det til 263 µg/m3
Arbejdstilsynets grænseværdi 10 µg/m3
Sundhedsstyrelsen vejledende aktionsgrænser 3 og 0,3 µg/m3
PCB 126, den dioxinlignende kongener med højest TEF
The purpose of this paper
is to present an approach
to calculate the magnitude
of secondary and tertiary
sources in PCB
contaminated buildings
Methods
Paint and lacquer samples were taken using a knife to scrape small parts off the wall
and floor.
The concrete samples were taken by sawing a small concrete block from a wall
including the line of sealant, breaking the block perpendicular to the sealant and
hammering out concrete samples from the fracture surface using a chisel in order to
avoid heating the concrete when sampling.
At the chemical laboratory the samples were homogenized and Soxhlet extracted
using toluene and purified on columns of silica gel and finally the purified extracts
were analyzed by GC-HRMS.
Concrete samples
Data fra Claus Lundsgaard, SBMI, 2012.
Data fra Helle Vibeke Andersen et al: Kortlægning af eksisterende viden om
indtrængning af PCB fra fuger til beton, Miljøstyrelsen 2013.
C ( x)  k  e
M   l  
x2
x1
 nx
1
C ( x)     xdx
2
x2
1
M    l     k   x  e nx dx
x1
2
x2
  x 1  nx 
1
M    l     k  
 2 e 
2
 n n 
 x1
PCBtot (secondary source) in concrete
Distance from sealant [mm]
62 - ∞
10 - 20
20 - 30
30 - 45
45 - 62
447
278
79
21
2.0
0.1
Fraction [%]
54
33
10
2.6
0.2
0.02
Accumulated [%]
54
88
97
99.7
99.9
100
Mass per length [mg/m]
0 - 10
PCBtot (tertiary source)
in surface materials
Amount
Floor lacquer
Floor wood
Wall and ceiling paint
Wall and ceiling concrete
Sealant
Concrete on both sides of sealant
7 m2
7 m2
31 m2
31 m2
0.2 m2
40 m
Thickness
(mm)
0.2
20
0.6
10
10
62
PCBtot
(g)
0.36
0.39
4.40
6.92
508.08
33.20
PCB whereabouts
After approximately 40 years the primary sources contain 92 % of
the remaining PCB.
6 % of the remaining PCB has diffused into concrete along the
sealants making adjoining concrete an important secondary
source.
The last 2 % of the remaining PCB may be found as tertiary
pollution of the large surfaces of walls and floor.
In the 17.4 m3 model room with an air change rate of 0.5 h-1 and
the recommended highest concentration of 300 ng/m3 in the
room air, the annual PCB removal capacity of ventilation becomes
as low as 0.023 g/year or equal to 1 g after 44 years.
Conclusions
Remove all primary sources when renovating rooms with PCB
containing sealants.
Prioritize also to alleviate emissions from concrete and other
materials that have been in direct contact with primary sources.
The expected few grams deposited in the large area of wall paint
and top layer of concrete is an important emission source.