PCB CONGENER PROFILE OF
UNINTENTIONAL FORMATION FROM
PIGMENT MANUFACTURING PROCESS
Takeshi Nakano1 and Katsunori Anezaki2
1Osaka University
2Hokkaido Research Organization
PCB CONGENER PROFILE OF
UNINTENTIONAL FORMATION FROM
PIGMENT MANUFACTURING PROCESS
FeCl3
3,3’-dichlorobenzidine
Chlorinated Paraffins
Diphenyl Silane diol
Organic pigment
High Volume Air Sampler
Noise/Vibration absorption rubber
Using chlorinated paraffins containing PCB
PCB CONGENER PROFILE OF
UNINTENTIONAL FORMATION FROM
PIGMENT MANUFACTURING PROCESS
FeCl3
Chlorinated Paraffins
3,3’-dichlorobenzidine
Diphenyl Silane diol
Organic pigment
TCPS
CTPS
DCDPS
D
Cu,Ag
+
Si
Chlorobenzene
Trichlorophenylsilane
PCB-1
Dichlorodiphenylsilane
Chlorotriphenylsilane
PCB-2
PCB-4
PCB-8
PCB-6
PCB-13
PCB-11
PCB-3
MoCBs
PCB-15
DiCBs
dichlorodiphenylsilane
PCBs
Sample
Diphenylsilanediol (DPSDO)
Congener Chlorine
Manuf.
A
G
H
IUPAC #
positions
#1
2-MoCB
0.036
1.1
#2
3-MoCB
0.049
11
#3
4-MoCB
0.036
8.7
#4
2,2¢-DiCB
0.16
#6
2,3¢-DiCB
1.6
#7
2,4-DiCB
#8
2,4¢-DiCB
0.79
#9
2,5-DiCB
0.0071
#11
3,3¢-DiCB
2.1
#13
3,4¢-DiCB
2.8
#15
4,4¢-DiCB
0.98
#28
2,4,4'-TrCB
0.016
MoCBs
0.12
21
DiCBs
8.4
TrCBs
0.016
S PCBs
0.12
30
Blank spaces indicate that none of that component was detected.
0.89
38
33
2.0
13
4.7
11
11
2.3
71
44
120
PCB congeners in diphenylsilanediol (mg/kg)
UNINTENTIONAL FORMATION OF PCB
FROM CHEMICAL
MANUFACTURING PROCESS
FeCl3
3,3’-dichlorobenzidine
Chlorinated Paraffins
Diphenyl Silane diol
Organic pigment
Concentrations and Congener Profiles
of Polychlorinated Biphenyls,
Pentachlorobenzene, and
Hexachlorobenzene
in Commercial Pigments
-A report from the Japan Dyestuff and Industrial
Chemicals Association (JDICA) revealed that
some organic pigments contained a trace of
polychlorinated biphenyl (PCB) unintentionally
generated in their manufacturing process.
- In response to the report, the Ministry of
Economy, Trade and Industry (METI) decided to
immediately carry out an investigation into the
actual situation and, as an urgent measure for
the time being, instruct entrepreneurs to stop
manufacture, import or shipment of organic
pigments found to contain PCB over the
international standard (50ppm).
Table 1 List of PCBs, PeCBz and HxCBz
standards
Congener IUPAC #
Recovery
Homologue
1)
Surrogate
standards1)
PCBs
MoCBs
DiCBs
TrCBs
TeCBs
PeCBs
HxCBs
HpCBs
OcCBs
NoCBs
DeCB
#3
#15
#28
#60
#101
#141
#178
#194
#208
#209
#8
#32
#70
#97
#153
#180
#205
#206
Chlorobenzenes
PeCBz
HxCBz
1) denote
13
#32
#32
C12 labeled standards
Results
PCB congener profiles of
azo pigment
NaNO2, HCl
3,3’-dichloro
benzidine
diazonium
Ｎ－acetoacetyl
aniline
diazonium
pigment production
disazo
NaNO2, HCl
(CuCl2)
CB-52(25-25)
CB-101(245-25)
2,2’,5,5’- tetrachloro benzidine
Sandmeyer reaction
Ar-N+≡N + CuX → Ar-X + Cu+ + N2↑
CB-153(245-245)
Compound View
JEOL DioK V4.02 2011/05/31 15:04:30 Page 1
DqData: rh (), Injection= P115 (UNK)
Original: rh_T-PCB-110420.mfl, InjectionNo= 22, Sample= P115, Date= <Date>
(341082) D2CB / Average
100
#11 (3-3)
Intensity
80
60
40
20
0
12
14
16
18
20
22
Retention Time (min)
24
26
28
30
24
26
28
30
(16777200) T4CB / Average
100
#52(25-25)
Intensity
80
60
40
20
0
2,2’,5,5 ’- tetrachloro
benzidine
12
14
16
18
(225850) P5CB / Average
100
#101(245-25)
80
Intensity
20
22
Retention Time (min)
60
40
20
0
12
14
16
18
20
22
Retention Time (min)
24
(180016) H6CB / Average
100
28
30
#153(245-245)
80
Intensity
26
60
40
20
0
12
14
16
18
20
22
Retention Time (min)
24
26
28
30
PCB congeners in pigment (disazo)
permanent yellow lemon; PY81;
azo-type pigment
CH3
CO
CH3
H 3C
CH3
CH
HNOC
CO
Cl
N=N
N=N
CH3
Cl
CH3
CONH
CH
Pigment yellow12
（benzidine yellow）
Cl
raw material
Cl
H2 N
NH2
#11
Cl
Cl
3,3’-dichlorobenzidine
Cl
Cl
Cl
Cl
Cl
Cl
#35
Cl
#77
azo-type pigment
CH3
CH3
H 3C
HNOC
CH3
CO
CH
Cl
CO
Cl
N=N
N=N
Pigment yellow81
（benzidine yellow）
raw material
Cl
H2 N
CH3
CONH
CH
Cl
Cl
CH3
Cl
Cl
Cl
NH2
Cl
Cl
#52
Cl
Cl
2,2’,5,5’-tetrachlorobenzidine
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
#101
Cl
Cl
#153
Cl
azo-type pigment
#11
#52
100
ratio(%)
80
60
40
#35
#77
20
0
A
A
A
A
A
A A
a1 a2 a3
a4 a5 a6
a7
A
a8
A
A
A
A
A
#11
#35
#52
#77
#99
B
B
a9 a10
a11 a12
a13 a14
a15
PCB congener profiles of azo pigment
Results
PCB congener profiles of
phthalocyanine pigment
phthalocyanine-type pigment
By-product
raw material
Cl
phthalic anhydride
urea
copper chloride
Cl
Cl
Cl Cl
Cl
Cl
HCB
Cl
Cl
Cl
Cl Cl
#209
Cl
Cl
Cl
Cl
Cl
Cl
chlorination
D
pigment green 7
Cl
Cl
PeCBz
pigment blue 15
(phthalocyanine blue)
pigment green 7
(phthalocyanine green)
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl Cl
#208
Cl
highly chlorinated PCBs
phthalocyanine-type pigment
pigment green 7
100
ratio(%)
80
pigment blue 15
60
40
#209
#208
#207
#206
#202
#11
20
0
A
p1
A
p2
A
A
p3
B
p4
p5
PCB congener profiles of phthalocyanine pigment
100
80
60
Pigment yellow81
#52
40
20
#101
0
#153
100
80
60
40
#11
#35
#77
pyrazolone ogange
20
0
#209
100
80
60
40
phthalocyanine green
20
0
10
8
6
4
KC400
2
0
Congener pattern
PCB congener profiles of
diketo-pyrrolo-pyrrole pigments
PCB congener profiles of
dioxazine violet pigments
PV23
o-DCB + Chloranil
o-DCB + 3-amino
N-ethyl-carbazole
o-DCB only
o-DCB + Chloranil
+ 3-amino Nethylcarbazole
trace
PCB- 40
PCB- 56
PCB- 77
23- 23
23- 34
34- 34
trace
PCB- 40
PCB- 56
PCB- 77
23- 23
23- 34
34- 34
150 C
o-DCB + V-70L
40min
Radical initiator
o-DCB + V-70L
20min
Radical initiator
V-70L : rac-2,2'-Azobis[(2R*)-2,4-dimethyl-4-methoxypentanenitrile]
PCB FORMATION FROM PCBz
via different PCBz radicals
Only one PCB isomer Formation
from one PCBz radical
one PCB isomer formation
Δ
V-70L
CB-52 (25-25)
p-dichlorobenzene
Δ
V-70L
CB155 (246-246)
1,3,5-trichlorobenzene
3 PCB isomers Formation
from 2 PCBz radicals
CB-56 > CB-77 > CB-40
11
5
CB-5 (23-)
CB-56 (23-34)
5
3
CB-12 (34-)
CB-77 (34-34)
V-70L
2
Δ
CB-40 (23-23)
o-dichlorobenzene
CB-157 > CB-128 > CB-169
CB128 (234-234)
Δ
V-70L
CB-157 (234-345)
CB-169 (345-345)
1,2,3-trichlorobenzene
CB-157 > CB-128 > CB-169
MCounts
124-TCBz-V70L-40mL-.XMS 360.0>290.0 [-35.0V] Filtered
360.0>290.0 [-35.0V]
15
10
124-TCBz ->HxCB
5
0
MCounts
135-TCBz-V70L-40mL-.XMS 360.0>290.0 [-35.0V] Filtered
360.0>290.0 [-35.0V]
1.25
1.00
135-TCBz ->HxCB
0.75
0.50
CB-157
(234-345)
#155 (246-246)
0.25
0.00
kCounts
123-TCBz-V70L-40mL-.XMS 360.0>290.0 [-35.0V] Filtered
360.0>290.0 [-35.0V]
150
123-TCBz ->HxCB
100
CB-169 (345-345)
CB128
(234-234)
50
0
MCounts
WINDOW-PCB.XMS 360.0>290.0 [-35.0V] Filtered
360.0>290.0 [-35.0V]
200
CB-169 (345-345)
CB155 (246-246)
150
Window-PCB
100
50
0
20
25
30
35
trichlorobenzene  HxCB
40
45
minutes
6 PCB isomers Formation
from 3 PCBz radicals
CB-6 > CB-8 > CB-11, CB-13 > CB-4 > CB-15
CB-4 (2-2)
CB-6 (2-3)
CB-11 (3-3)
CB-8 (2-4)
CB-15 (4-4)
V-70L
Δ
CB-13 (3-4)
chlorobenzene  DiCB
CB-6 > CB-8 > CB-11, CB-13 > CB-4 > CB-15
MCounts
MCBz-V70L-40mL-001.XMS 222.0>152.0 [-30.0V] Filtered
222.0>152.0 [-30.0V]
150
125
#6 (2-3)
100
#13 (3-4)
#8 (2-4)
#11 (3-3)
75
50
#4 (2-2)
#15 (4-4)
25
0
MCounts
EC-5433_0.01ppm_611.XMS 222.0>152.0 [-30.0V] Filtered
222.0>152.0 [-30.0V]
#10
(26-)
100
75
#4
(2-2)
#9
(25-)
#8
(2-4)
#11
(3-3)
#12
(34-)
#15
(4-4)
50
25
0
9
10
11
12
13
chlorobenzene  DiCB
14
15
minutes
CB-68 > CB-47 > CB-73, CB-51 > CB-80 > CB-54
CB-54 (26-26)
CB-51 (24-26)
CB-73 (26-35)
V-70L
Δ
CB-68 (24-35)
CB-80 (35-35)
CB-47 (24-24)
m-dichlorobenzene
#68
#47
kCounts
m-DCB-2.74g.xms 292.0>222.0 [-35.0V] Filtered
292.0>222.0 [-35.0V]
80
#51
70
#73
60
50
40
30
20
10
#80
#54
0
kCounts
750
EC-5433_STD_0.01ppm.xms 292.0>222.0 [-35.0V] Filtered
292.0>222.0 [-35.0V]
#54
#49
#52
#44
#57
#74 #70
500
#78
#66
#81
250
#77
#79
0
15.0
17.5
20.0
22.5
25.0
m-DCBz  TeCB
27.5
30.0
minutes
CB-157 > CB-128 > CB-169
CB128 (234-234)
Δ
V-70L
CB-157 (234-345)
CB-169 (345-345)
1,2,3-trichlorobenzene
CB-157 > CB-128 > CB-169
MCounts
124-TCBz-V70L-40mL-.XMS 360.0>290.0 [-35.0V] Filtered
360.0>290.0 [-35.0V]
15
10
124-TCBz ->HxCB
5
0
MCounts
135-TCBz-V70L-40mL-.XMS 360.0>290.0 [-35.0V] Filtered
360.0>290.0 [-35.0V]
1.25
1.00
135-TCBz ->HxCB
0.75
0.50
CB-157
(234-345)
#155 (246-246)
0.25
0.00
kCounts
123-TCBz-V70L-40mL-.XMS 360.0>290.0 [-35.0V] Filtered
360.0>290.0 [-35.0V]
150
123-TCBz ->HxCB
100
CB-169 (345-345)
CB128
(234-234)
50
0
MCounts
WINDOW-PCB.XMS 360.0>290.0 [-35.0V] Filtered
360.0>290.0 [-35.0V]
200
CB-169 (345-345)
CB155 (246-246)
150
Window-PCB
100
50
0
20
25
30
35
trichlorobenzene  HxCB
40
45
minutes
CB-146, CB-149, CB-135 > CB-153, CB-136, CB-133
CB133 (235-235)
CB-135 (235-236)
CB-136 (236-236)
CB146 (235-245)
V-70L
Δ
CB-149 (236-245)
CB-153 (245-245)
1,2,4-trichlorobenzene
MCounts
124-TCBz-V70L-40mL-.xms 360.0>290.0 [-35.0V] Filtered
360.0>290.0 [-35.0V]
CB-149
(236-245)
15
CB146
(235-245)
CB-135
(235-236)
10
CB-136
(236-236)
CB133
(235-235)
CB-153
(245-245)
5
0
25.0
27.5
30.0
1,2,4-TrCBz  HxCB
32.5
minutes
- Results
- pigment from 3,3’-dichlorobenzidine
contain #11, #35, #77
- pigment from 2,2’,5,5’-tetrachlorobenzidine
contain #52, #101, #153
- pigment from o-chlorobenzene as solvent
contain #40, #56, #77
- phthalocyanine-type pigment
contain #209, PeCBz, HCBz
- Results
Seasonal variations of PCBs,
DiCBs, and #11 in ambient air
( Sapporo city, Japan)
April 2005 ~ March 2011
50
40
Temp.
#11
DiCBs
PCBs
1400
1200
1000
800
30
600
20
400
PCBs Conc. (pg/m3)
Temperature(oC), DiCBs、#11Conc. (pg/m3)
60
10
200
0
-10
0
-200
Seasonal variations of PCBs, DiCBs, and #11 in ambient air
( Sapporo city : April 2005 ~ March 2011)
PCBs: 69-1200 pg/m3, ave:361 pg/m3 #11: 2.4-37 pg/m3, ave:11.4 pg/m3
Jan-11
Oct-10
Jul-10
Apr-10
Jan-10
Oct-09
Jul-09
Apr-09
Jan-09
Oct-08
Jul-08
Apr-08
Jan-08
Oct-07
Jul-07
Apr-07
Jan-07
Oct-06
Jul-06
Apr-06
Jan-06
Oct-05
Jul-05
Apr-05
Ratio (%)
Jan-11
Oct-10
Jul-10
Apr-10
Jan-10
Oct-09
Jul-09
Apr-09
Jan-09
Oct-08
Jul-08
Apr-08
Jan-08
Oct-07
Jul-07
Apr-07
Jan-07
Oct-06
Jul-06
Apr-06
Jan-06
Oct-05
Jul-05
Apr-05
Ratio (%)
14
12
Sapporo
10
#11 / ΣPCBs
8
6
4
#52 / ΣPCBs
2
0
20
Muroran
16
12
#11 / ΣPCBs
8
4
#52 / ΣPCBs
0
Anezaki, Nakano :ESPR (2013)
Jan-11
Oct-10
Jul-10
Apr-10
Jan-10
Oct-09
Jul-09
Apr-09
Jan-09
Oct-08
Jul-08
Apr-08
Jan-08
Oct-07
Jul-07
Apr-07
Jan-07
Oct-06
Jul-06
Apr-06
Jan-06
Oct-05
Jul-05
Apr-05
Ratio (%)
Jan-11
Oct-10
Jul-10
Apr-10
Jan-10
Oct-09
Jul-09
Apr-09
Jan-09
Oct-08
Jul-08
Apr-08
Jan-08
Oct-07
Jul-07
Apr-07
Jan-07
Oct-06
Jul-06
Apr-06
Jan-06
Oct-05
Jul-05
Apr-05
Ratio (%)
100
Sapporo
80
60
#11 / DiCBs
40
20
#52 / TeCBs
0
100
Muroran
80
60
#11 / DiCBs
40
20
0
#52 / TeCBs
Anezaki, Nakano :ESPR (2013)
- Conclusion
use
BAT (Best Available Techniques)
BEP (Best Environmental Practices)
to reduce emissions and human risk.
organic pigment product 22,510t (2010)
cosmetics
- Conclusion
organic pigment product 22,510t (2010)
use
BAT (Best Available Techniques)
BEP (Best Environmental Practices)
to reduce emissions and human risk.
paint ink plastic
ICAEC2014
Nov. 24-26, 2014
Chulabhorn Institute
Bangkok
http://www.j-ec.or.jp/icaec/
http://ee-net.ne.jp/dioxin/
感谢您的关注
Thank you for your attention
Chemical class
C.I. name
dominant
dependent
dioxin toxicity
dis-azo
pyrazolone
PY12, PY13, PY14, PY17,
PY55, PY83, PY152, PO13,
PO16
#11
#35,#77
yes
dis-azo
phthalocyanine
dioxazine
diketopyrrolopyrrole
naphthol AS
naphthol AS
PY81
PG7,PG36
PV23,PV37
PR254,PR255
PR9
PR112
#52
#209
#5,#12,#40,#56,#77
#6,#13,#15
#52
#146,#149,#153
#101,#153
#206,#207,#208, etc
#1,#16,#20/33, etc
#4,#8,#11, etc
#18,#31,#101, etc
#67,#48,#74,#101,#109,#118 etc
no
no
yes
no
no
yes
- Results
- pigment from 3,3’-dichlorobenzidine
contain #11, #35, #77
- pigment from 2,2’,5,5’-tetrachlorobenzidine
contain #52, #101, #153
- pigment from o-chlorobenzene as solvent
contain #40, #56, #77
- phthalocyanine-type pigment
contain #209, PeCBz, HCBz
3,3’-ジクロロベンジジン
（ジアゾニウム塩）
3,3’-ジクロロビフェニル（PCB-11)
3,3’-ジクロロビフェニル（PCB-11)
3,3’,4-トリクロロビフェニル（PCB-35)
3,3’,4,4’-テトラクロロビフェニル（PCB-77)
- Conclusion
use
BAT (Best Available Techniques)
BEP (Best Environmental Practices)
to reduce POPs emissions.
顔料由来の異性体と
環境試料中のPCB
50
KC300-60
40
PCB製品
0
30
20
10
0
60
Sediment
50
40
底質
30
20
10
PCB-11
0
50
Water
40
水質
30
20
10
0
40
35
30
25
20
15
10
5
0
#37
#35
#33/#20
#31/#28
#25
#26
#16/#32
#18/#17
#15
#12/#13
#11
Air (gas phase)
#4
大気
Rain
#8/#5
雨水
80
70
60
50
40
30
20
10
0
図 PCB製品および環境試料中のDi-TrCB異性体分布 #10/(2,6-)#4(2,2'-), #8(2,4-)/#5(2,3-), #11(3,3'-), #12(3,4-)/#13(3,4'), #15(4,4'-),
#18(2,2',5-)/#17(2,2',4-), #16(2,2',3-)/#32(2,4',6-), #26(2,3',5-), #25(2,3',4-),#31(2,4',5-)/#28(2,4,4'-),#33(2',3,4-)/#20(2,3,3'-),#35(3,3',4-), #37(3,4,4'-)
中野ら, 環境化学討論会要旨集 P-281 (2001)
中野武 50才
Simon Litten
50
KC300-60
40
PCB製品
0
30
20
10
0
60
Sediment
50
40
底質
30
20
10
PCB-11
0
50
Water
40
水質
30
20
10
0
40
35
30
25
20
15
10
5
0
#37
#35
#33/#20
#31/#28
#25
#26
#16/#32
#18/#17
#15
#12/#13
#11
Air (gas phase)
#4
大気
Rain
#8/#5
雨水
80
70
60
50
40
30
20
10
0
図 PCB製品および環境試料中のDi-TrCB異性体分布 #10/(2,6-)#4(2,2'-), #8(2,4-)/#5(2,3-), #11(3,3'-), #12(3,4-)/#13(3,4'), #15(4,4'-),
#18(2,2',5-)/#17(2,2',4-), #16(2,2',3-)/#32(2,4',6-), #26(2,3',5-), #25(2,3',4-),#31(2,4',5-)/#28(2,4,4'-),#33(2',3,4-)/#20(2,3,3'-),#35(3,3',4-), #37(3,4,4'-)
中野ら, 環境化学討論会要旨集 P-281 (2001)
底質
底質
河川水
河川水
図 底質、表層水中の2塩素化ﾋﾞﾌｪﾆｰﾙのSIMｸﾛﾏﾄｸﾞﾗﾑ
#10/(2,6-)#4(2,2'-), #8(2,4-)/#5(2,3-), #11(3,3'-), #12(3,4-)/#13(3,4'), #15(4,4'-)
角谷ら, 環境化学討論会要旨集 P-281 (2001)
Identification of a novel PCB source through analysis
of 209 PCB congeners by US EPA modified method 1668
Simon Litten et al, Chemosphere, 46, 1457-1459(2002)
PISCES survey, 7/27/00–8/2/00 to locate sources of PCB congeners (ng/l)
Total PCB PCB-11
Pigment discharge
4200
3600
WPCF influent
520
490
Trunk1
18
0.07
Trunk2
12
0.4
Trunk3
12
0.6
Trunk4
3
0.08
Trunk5
1
0.2
PCB-35
380
2.3
0
0.02
0.03
0.04
0.02
PCB-77 PCB-126 TEQ(fg/L)
190
1.6
18000
2.5
0.01
150
0
<0.001
15
0.01
<0.0004
13
0.01
<0.001
8
0.05
<0.001
2
0.04
0.001
1
人工水路3　12ng/L
顔料 排出水　4200ng/L
0.06
0.05
0.04
1
0.8
0.6
0.03
0.02
0.01
0
0.4
0.2
0
PCB-11
PCB-35
PCB-77
PCB-11
PCB-126
PCB-35
PCB-77
PCB-126
人工水路4　3ng/L
排水処理場流入水　520ng/L
0.03
0.025
1
0.8
0.6
0.02
0.015
0.01
人口水路１ 18ng/L
0.4
0.2
0.005
0
0
PCB-11
PCB-35
PCB-77
PCB-126
PCB-11
PCB-35
PCB-77
PCB-126
人工水路5　1ng/L
人口水路２　12ng/L
0.25
0.035
0.03
0.025
0.02
0.015
0.01
0.005
0
0.2
0.15
0.1
0.05
0
PCB-11
PCB-35
PCB-77
PCB-126
PCB-11
PCB-35
Simon Litten et al, Chemosphere, 46, 1457-1459(2002)
PCB-77
PCB-126
安藤良ら, 名古屋市環境科学研究所所報第38号 31-40(2008)
底質中のPCB分析
表 #11の測定値比較
分析方法
#11(μg/kg)
加圧流体抽出法
0.13
ソックスレー抽出法
0.1
加熱アルカリ分解法(乾泥)
0.3
加熱アルカリ分解法(湿泥)
16
松木司ら, 広島市衛生研究所年報第24号 (2005)
PCB-11
加圧流体抽出法
ソックスレー抽出法
加熱アルカリ分解法(乾泥)
加熱アルカリ分解法(湿泥)
PCB STD
松木司ら, 広島市衛生研究所年報第24号 (2005)
Evidence for Unique and Ubiquitous Environmental Sources of 3,3′Dichlorobiphenyl (PCB 11)
Lisa A.Rodenburg, Jia Guo, Songyan Du, and Gregory J.Cavallo
Environ. Sci. Technol. 2010, 44, 2816–2821
Inadvertent Polychlorinated Biphenyls in Commercial Paint Pigments
Dingfei Hu and Keri C. Hornbuckle
Environ. Sci. Technol. 2010, 44, 2822–2827
顔料由来の異性体と
環境大気中のPCB
Discovery of non-aroclor PCB (3,3'-dichlorobiphenyl) in Chicago air.
Hu D, Martinez A, Hornbuckle KC
Environ Sci Technol. 2008 Nov 1; 42(21):7873-7.
Fig. 3 Seasonal variations of PCBs, DiCBs and #11 congener in Sapporo city
Anezaki et al, organohalogen compounds 74,1433-1436 (2012)