Automobile traffic: A source of PCBs to the atmosphere

Chemosphere, Vd.23, No.6, Printed in Great Britain

pp 785-788,1991

0045-6535/91 $3.00 + 0.00 Pergamon Press plc

AUTOMOBILE TRAFFIC : A SOURCE OF PCBs TO THE ATNOSPHERE

Laurent GRANIER and Marc CHEVREUIL I n s t i t u t d'Hydrologie et de Climatologie, Laboratoire de Chimie Analytique et d'Hydrologie Gdn6rale, Universit~ Paris 6, 4 place Jussieu, B.P. 122, 75252 Paris Cedex 05, France.

Abstract - Air samples from a road tunnel showed that automobile t r a f f i c could be a source of PCBs in the atmosphere. Contrary to what was observed on ambient a i r samples, the PCBs were mainly on particulates, and showed a characteristic chromatographic pattern. INTRODUCTION - The most commonly reported PCB sources are emission by municipal or industrial incinerators and v o l a t i l i s a t i o n from l a n d f i l l s or s o i l s (W.H.O., 1978). Three clues allowed us to believe that automobile t r a f f i c could be a source of these pollutants : i ) newspapers have reported t r a f f i c

of o i l products contaminated by PCBs in France ( c i t y of Limoges) and between

Canada and the U.S.A. ("Le Monde" 01.14.1989 and 05.14.1989);

ii)

in an area of high t r a f f i c

density, we had measured higher PCB concentrations at 10 meters then at 55 meters height (Chevreuil

and Granier, 1990), i i i )

Mazzone and Nicoud (1987) had established a positive

correlation between the contamination of s o i l s by PCBs and the proximity of roadways. We report here on measurements in a road tunnel,

in order to assess the p o s s i b i l i t y of

automotive emission of PCBs. MATERIALS AND METHODS

Sampling ( F i g . 1) The "Tunnel

of the Tuileries"

i s 800 m long and taken by 50,000 cars per day.

were taken b i m o n t h l y d u r i n g maximum t r a f f i c

Four samples

from mondays t o f r i d a y s between 8 and 10 a,m. and

between 3 and 9 p.m.. Bimonthly samples were taken s i m u l t a n e o u s l y on the t o p o f the S a i n t Jacques Tower (55 m h i g h ) and on the U n i v e r s i t y Campus (15 m h i g h ) .

785

786

Figure 1 :

~

/"/ -

sampling p o i n t s

Analyt ica l procedure

3

~'~'~X~ ! I

2 Uniwms~y~ s 3 ~nnel ~ the ~ i l e r i ~

250 to 400 m3 of a i r are pulled through a glass f i b e r

filter

Whatman GF/F followed by a

cartridge f i l l e d with XAD-2 Amberlite resin. The XAD-2 is soxhlet extracted during 96 hours by a mixture of hexane and d i e t h y l e t h e r 90:10. F i l t e r s are cut in s t r i p s and put to r e f l u x during 12 hours with methylchloride. The extracts are concentrated t o 20 ml and p u r i f i e d with 2-3 ml of fuming HzS04 (7 %). The analysis is performed by HRGC on SPB5 column ( l = 30 m, i . d . = 0.25 mm, f i l m = 0.25 IJm), with an ECD detector. The q u a n t i f i c a t i o n of t o t a l PCBs is made by comparison t o a 1:1:1 mixture of Aroclors 1242, 1254 and 1268. Components I.U.P.A.C. n" 18, 28, 52, 60, 101, 153, 138 and 180 were quantified individually. Detection l i m i t s f o r t o t a l PCBs are 0.2 ng.m-s f o r the vapor phase and 0.05 ng.m-s f o r the p a r t i c u l a t e phase. RESULTS AND DISCUSSION

The results of t o t a l PCBs in the tunnel and in ambient a i r (Saint Jacques Tower and Campus) are displayed in the table I.

Table 1 : PCBconcentrations (ng.m-3) in particulate and vapor phases in the roadway tunnel. Comparisonwith ambient air average concentrations at the Saint Jacques Towerand the University Campus. localization

vapor p h a s e

particulate phase

total

roadway tunnel 03.19-29.1990 04.02-14.1990 04.13-24.1990 05.14-28.1990

1.3 1.9 2.5 2.7

5.9 5.6 5.8 3.7

7.2 7.5 8.3 6.4

mean

2.1

5.2

7.3

S a i n t Jacques Tower (n = 4)

1.6

0.69

2.3

Campus (n = 4)

3.8

1.0

4.8

787

The c o n c e n t r a t i o n s o f the vapor phase are s i m i l a r the e x t e r i o r

air

(mean = 2.7 ng.m-3).

phase in the tunnel

between t h e tunnel

On the c o n t r a r y ,

(mean = 2.1 ng.m-3)

PCB c o n c e n t r a t i o n s o f the p a r t i c u l a t e

are much h i g h e r (mean = 5.2 ng.m- 3 ) than In the ambient a i r

n g . m - 3 ) . They represent 71 ~ o f t o t a l

PCBs, whereas t h e p a r t i c u l a t e

1990).

In t h i s

study, t h e p a r t i c u l a t e

(mean = 0.85

phase In t h e ambient a i r

i s u s u a l l y lower than the vapor phase (see, f o r example, Eisenretch e t a l . , Bouchertall,

and

1981; Duinker and

phase amounts t o 30 % o f the t o t a l

a t the

S a i n t Jacques Tower and 21% at the U n i v e r s i t y . Figure 2 shows t y p i c a l extract.

chromatograms o f an ambient a i r f i l t e r

The p a t t e r n o f the l a t t e r

extract,

i s c l e a r l y s h i f t e d on the l e f t

TUNNEL

and o f a tunnel f i l t e r

towards l i g h t e r

components.

FILTER

F i g u r e 2 : Chromatograms o f the e x t r a c t s o f a filter

from the

Tuileries

roadway

t u n n e l and the S a i n t Jacques Tower.

AMBIENT

AIR

i-"

FILTER =

Table 2 presents the same d i f f e r e n c e under a more q u a n t i t a t i v e relative

composition

between j u l y

of

8 components in the

1989 and j u l y

particulate

aspect by comparing the average

phase o f the

Saint

Jacques Tower

1990 (n = 17) w i t h the mean o f the f o u r tunnel f i l t e r

Table 2 : Comparison between the average r e l a t i v e filters

i

and the t u n n e l f i l t e r s .

extracts.

c o m p o s i t i o n o f ambient a i r

Z o f the c o n t r i b u t i o n

components t o t h e i r

o f 8 PCB

sum.

Z.U.P.A.C. n °

18

28

52

60

101

153

138

180

S a i n t Jacques Tower (n : 18)

0

4

9

13

13

20

22

18

Tunnel (n = 4)

5

11

15

18

17

14

14

7

788

This important q u a l i t a t i v e difference shows that the preponderance of the particulate phase is not caused only by the greater amount of particulate matter in the tunnel than outside (around 200 ng.m-3 versus 50 ng.m-3). Bidleman and Foreman (1987) showed that semi-volatile organic compounds reached rapidly equilibrium between vapor and particulate phases. This could explain why the percentage of the particulate phase is not higher in urban areas. Furthermore, part of the particulate matter can possibly s e t t l e

near the source of emission on the streets,

contributing to the enrichment of street runoff by PCBs. CONCLUSION These results underscore a possible source of PCBs to the atmosphere. We could not quantify i t here with an emission factor, due to the i m p o s s i b i l i t y to evaluate the residence time of the a i r in the tunnel. The PCBs are probably o r i g i n a l l y present in o i l , gasoline or diesel. They could be emitted in vapor phase followed by a rapid adsorption.

ACKNOWLEDGEMENT - This study is part of a larger research funded by the Air Quality Agency (AQA). We are g r a t e f u l l to Mrs Petit-Coviaux, of the Laboratoire d'Hygi~ne de la V i l l e de Paris, for her assistance in the choice of the sampling points. Thierry Mellet greatly helped to improve the english of the manuscript. REFERENCES Bidleman T.F.

and Foreman W.T., 1987.- Vapor - p a r t i c l e p a r t i t i o n i n g of semivolatile organic

compounds. In "Sources and Fates of Aquatic Pollutants" (Hites R.A. and Eisenreich S.J. eds.), Adv. in Chem. Ser., Vol. 216, American Chemical Society, p. 27-56. Chevreuil

M.

and

Granier

L.,

1990.- Etude

de

la

pollution

de

l'air

par

les

polychlorobiph~nyles ~ Paris. Rapport d'~tude ~ l'Agence pour la Qualit~ de l ' A i r , 27 p. Duinker J.C. and Bouchertall F., biphenyl

1989.- On the d i s t r i b u t i o n of atmospheric polychlorinated

congeners between vapor phase, aerosols, and rain.

Environ.

Sci.

Technol.,

23 : 57-62. Eisenreich S.J.,

Looney B.B.

and Thornton J . D . ,

1981.- A i r b o r n e o r g a n i c contaminants in the

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important

trafic

de p r o d u i t s

p~troliers

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1987.- Importance de l ' ~ c h a n t i l l o n n a g e

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Rapport

de

dans l ' ~ t u d e de l a p o l l u t i o n recherche

3j== c y c l e ,

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d'hygi~ne

de

l'environnement

2,

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(Received

i n Germany 15 J u l y

1991;accepted

16 A u g u s t 1 9 9 1 )

Polychlorobiph6nyles

et