Variation in the concentration of polycyclic aromatic hydrocarbons (PAHs) in mussels (Mytilus galloprovincialis) at the galician coast after the prestige oil
spill.
Ó. NIETO1, J. ABOIGOR1, L. SACO-ÁLVAREZ2 and R. BEIRAS2.
1 Department of Analytical and Food Chemistry
2 Department of Ecology and Animal BiologyFaculty of Marine Sciences
University of VigoE-36310 Vigo, Spain
www.lavozdegalicia.es
LOS HÉROES DEL 13-N. La Voz de Galicia. Jan. 2003. p 12
Sampling stations
M1: Furnas42º 38’ 38” N, 9º 02’ 15” W
M1
M2: Vilar42º 33’ 05” N, 9º 01’ 40” W
M2
M2
Sampling stations
Sampling stations
M3: Aguiño42º 30’ 59” N, 9º 01’ 00” W
M3
M3
Sampling dates
M1 M2 M3
21/11/02 X X -
17/12/02 X X -
3/01/03 X X X
22/01/03 X X X
5/02/03 X X X
4/04/03 X X X
9/06/03 X X X
12/08/03 X X X
27/10/03 X X X
23/12/03 X X X
Condition index
0
2
4
6
8
10
12C
ondi
tion
inde
x (g
m-1 d
.w.)
M1 M2 M3
Sample preparation• The mussels collected are of 40 to 60 mm length• The soft tissue is taken out from the shell and
frozen at -80ºC• Freeze-dry, trituration• Soxhlet extraction:
– solvent n-Hexane : Acetone– 4 cycles per hour
• Solid Phase extraction:– adsorbent: Florisil 10% deactivated– elution with n-Hexane.
• Solvent evaporation and adition of 1 ml acetonitrile
Determination: HPLC with fluorescence detection
• Chromatographic system model alliance 2690 (Waters)
• Fluorimetric detector model 474 (Waters)• Software Millenium 32 (Waters)• Column Vydac 201TP54, 4.6 x 250 mm, 5µm particle
size, Grace Vydac.• Injection volume: 20 µL• Gradient elution with water:methanol• Column temperature: 23,5ºC• Detection by programming the excitation and
emission wavelengths
Sum of PAHs
date
M1 M2 M3
PAH
(103
g K
g-1 d
.w.)
12/02 04/03 08/03 12/03 0,0
1,0
2,0
3,0
4,0
12/02 04/03 08/03 12/03 0,0
2,0
4,0
6,0
8,0
12/02 04/03 08/03 12/03 0,0
0,5
1,0
1,5
2,0
2,5
3,0
Percentage of parent PAHs
Phe Ant Fla
Pyr
BaA Chr
BeP BbF BkF
BaP
Bgh
iPD
ahA
Ipy0
5
10
15
20
25
30
35
Phe Ant Fla
Pyr
BaA Chr
BeP
BbF BkF
BaP
Bgh
iPD
ahA
Ipy
Phe Ant Fla
Pyr
BaA Chr
BeP
BbF BkF
BaP
Bgh
iPD
ahA
Ipy
Phe Ant Fla
Pyr
BaA Chr
BeP
BbF BkF
BaP
Bgh
iPD
ahA
Ipy0
10
20
30
40
50
Phe Ant Fla
Pyr
BaA Chr
BeP
BbF BkF
BaP
Bgh
iPD
ahA
Ipy
Phe Ant Fla
Pyr
BaA Chr
BeP
BbF BkF
BaP
Bgh
iPD
ahA
Ipy
% P
AH
November 2002 – April 2003
June - December 2003
M1 M2 M3
M1 M2 M3
Parent PAHs ratio
LPAH /HPAH0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6
PA
H (1
03 g
Kg-1
d.w
.)
0,0
1,0
2,0
3,0
4,0
5,0
6,0
7,0
ΣLPAH = Nap + Ace + Flu + Phe + Ant ΣHPAH = Fla + Pyr + BaA + Chr + BbF + BkF + BeP + BaP + BghiP + DahA + Ipy
12/02 04/03 08/03 12/03 0,0
0,2
0,4
0,6
0,8
12/02 04/03 08/03 12/03 0,0
0,2
0,4
0,6
0,8
1,0
12/02 04/03 08/03 12/03 0,0
0,4
0,8
1,2
1,6
2,0
2,4
Sum of 6 PAHs 6
PAH
(103
g K
g-1 d
.w.)
date
M1 M2 M3
[BkF] + [BaA] + [BbF] + [BaP] + [DahA] + [Ipy] < 200 ng/g (d.w.)
Depuration rate, r (days-1)
Ct = C0 exp(-rt)
M1 M2 M3
Ant 0.0047 0.0120 / 0.0009 0.0023
Fla 0.0070 0.0019 0.0006
Pyr 0.0099 / 0.0030 0.0006 0.0088 / 0.0003
BaA 0.0121 / 0.0028 0.0218 / 0.0035 0.0162 / 0.0021
Chr 0.0145 / 0.0039 0.0194 / 0.0019 0.0100
BeP 0.0080 / 0.0020 0.0108 / 0.0022 0.0104 / 0.0022
BbF 0.0084 / 0.0027 0.0064 0.0119 / 0.0045
BkF 0.0120 / 0.0021 0.0157 / 0.0001 0.0038
BaP 0.0174 / 0.0018 0.0115 / 0.0026 0.0130 / 0.0011
DahA 0.0139 0.0056 0.0236
Conclusions• Overstated concentrations of PAH are found in
the mussel samples during the following months after the oil spillage– From April-June 2003, these concentrations are
similar to those found in a non polluted area.– Similar percentages of parent PAHs, with a higher
proportion of HPAH with respect to LPAH are found from November 2002 to April 2003.
• The decrease in the PAH concentrations in the mussel samples can be adjusted to the following equation:
– Ct = C0 exp(-rt)– Similar values of r are found for the studied
hydrocarbons.– The results suggest two mechanisms for depuration of
PAHs in mussels.
Acknowledgements
• MCyT (project VEM 2003-20068-C05-02) for financial support
• Dr. Emilio Fernández Suárez and the rest of LEM research group for material support and collaboration in sampling campaings
Thank you very much for your attention