Analysis of PCBs in emission samples: non ortho, mono-ortho and homolog totals by level of chlorination

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Analysis of PCBs in emission samples: non ortho, mono-ortho and homolog totals by level of
chlorination
Werner Tirler
1
, Giulio Voto
1
, Massimo Donegà
1
, Gerhard Kahr
2
1
Eco-Research, Via Negrelli 13, 39100 Bolzano, Italy
2
Monitoring Systems, Schloss 2, Kottingbrunn, Austria
Introduction
Polychlorinated biphenyls (PCBs) are one of the most widespread persistent organic pollutants,
identified in every component of the global ecosystem. A production of approximately 2 * 10
9
Kg
technical PCB occurred form 1930 to the late 1970
1
and the total amount released into the
environment is estimated in 370. 000
2
tonnes. Twelve of the possible 209 PCBs are non- and
mono-ortho substituted chlorinated biphenyls. They resemble 2,3,7,8-tetrachloro dibenzo-p-dioxin
(TCDD) in their biological action, bio accumulating through the food chain and causing immuno-,
reproductive and dermal toxicities. Therefore in 1997 the Word Health Organisation (WHO)
extended the concept of toxic equivalency (TEQs)
3
also to these group of “dioxinlike” PCBs.
At the moment a fraction of the produced PCBs is collected with the household waste and burned in
incinerators. PCBs are evaporated during waste incineration and are partially destroyed during the
incineration process, dependent on residence time/temperature. Catalytic dioxin destruction shall
additionally reduce the emissions of PCBs. Anyway all PCBs left in the flue gas are emitted in the
environment. Some publications present this as an additional source of PCBs
2,4,5,6
.
This work aims to investigate the congeners and homologous group distribution of PCBs in
emission samples of municipal solid waste incinerators and to calculate the WHO-TEQ
PCB
in
relation to the WHO-TEQ
PCDD/F
.
Materials and Methods
The evaluation was conducted on emissions of a municipal solid waste (MSW) incinerator with a
total net capacity of 270 t/day, using roller type combustion grate and energy recovery (electricity
and district heating). Flue gas cleaning is performed by a fabric filter and a wet scrubber, in line
with a final SCR (Selective Catalytic Reduction) unit for NOx and PCDD/F conversion.
Directly on the stack an automatic sampling system wasis installed , capable to perform isokinetic
sampling of . PCDD/F for periods from 6 hours to 6 Weeks. This DioxinMonitoringSystem is using
the dilution method which is described in the EN-1948 Part 1
7
and permits to collect the PCDD/F
as well as PCB on a cartridge containing a dust filter and two dry poly urethane foams
8
. At the end
of sampling the cartridge was transferred to the lab. There the sample was extracted, cleaned and
evaluated using the EN 1948 part 2 and 3. After soxhlet-extraction with toluene the sample extract
was split in two parts:. One for PCDD/F and the other for PCB determination. After sulphuric acid
(98%) pre-treatment an automatic multicolumn system (Dioxin PowerPrep, FMS) clean up has
beenwas used for Dioxins and for PCBs. For PCB analysis carbon
13
C
12
labelled Standards (labeled
“dioxinlike” congeners as well as labeled first and last eluting congener of each chlorination level)
were added according EPA 1668A
9
after sampling. The HRGC- HRMS analysis has beenwas
conducted on a Agilent 6890 gaschromatograph coupled on a Thermofinnigan MAT 95 XP
operating at resolution 10.000. A HT-8 PCB 60 m, 0,25 mm column from SGE was used for PCB
analysis.

Fig. 1: Chromatogram of a Mixture containing all possible 209 PCB congeneres
Fig. 2: Chromatogram of mono, di and trichloro CB in the emission sample

Fig. 3: Chromatogram of tetra, penta and hexa CB in the emission sample
Fig. 4: Chromatogram of hepta, octa, nona and deca CB in the emission sample

Results and Discussion
The chromatogram of a mixture of all possible 209 PCB congeners is shown in Fig1. Especially for
the tetra-, penta- and hexachlorinated biphenyl homologous group quite complex chromatograms
are obtained. Fig. 1 shows, that PCB#126 and PCB#169 are well resolved by the described method,
without interferences.
The chromatograms obtained by the emission sample (Fig. 2, 3 and 4) presents only few of the
possible congeners of each chlorination level at significant concentrations. As table 1 shows
especially PCB#126 (I-TEF = 0,1) and PCB#169 (I-TEF = 0,01) represents 98% of the calculated
WHO-TEQ
PCB
.
Table 1: Concentration of PCBs in an emission sample of a MSW incinerator
ng/Nm3 (dry at 11% O2) Ng/Nm
3 (dry at 11% O2)
PCB #77 0,010 Mono-CB tot 0,01
PCB #126 0,014 Di-CB tot 0,04
PCB #169 0,013 Tri-CB tot 0,11
PCB #81 0,008 Tetra-CB Tot 0,53
PCB #105 0,016 Penta-CB tot 0,23
PCB #114 0,009 Esa-CB tot 0,60
PCB #118 0,025 Epta-CB tot 0,36
PCB #123 0,002 Octa-CB tot 0,15
PCB #156 0,018 Nona-CB tot 0,26
PCB #157 0,010 Deca-CB 0,23
PCB #167 0,009
PCB #189 0,035
WHO-TEQ PCB 0,0016
The WHO-TEQ
PCDD/F
was measured with 0,053 ng /Nm
3
(dry at 11% O2)
. The contribution of the
WHO-TEQ
PCB
to the total toxicity is 3 %.
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