Modelling the PCB bioaccumulation in the hake (Merluccius merluccius) from the Gulf of Lions...
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Transcript of Modelling the PCB bioaccumulation in the hake (Merluccius merluccius) from the Gulf of Lions...
Modelling the PCB bioaccumulation in the hake (Merluccius merluccius) from the Gulf of Lions (Mediterranean sea)
X. Bodiguel1, V. Loizeau1, C. Mellon2, F. Ferraton2
1IFREMER, BP 70, 29280 Plouzané, France ; 2IFREMER, B.P. 171, Av. J. Monnet 34203 Sète Cedex France
Objectives To evaluate the PCB contamination in hakes from the Gulf of Lions. To establish the bases of a bioaccumulation model of PCBs in a female hake.
Polychlorinated Biphenyls (PCBs), are characterized by a high persistence in the environment, bioaccumulation by the marine organisms and potentially toxic character. Bioaccumulation depends on physical and chemical properties of the compounds and biological factors like feeding, growth and reproduction. At the top of a complex trophic web, the Mediterranean hake (Merluccius merluccius; L, 1758) is potentially exposed to these contaminants and it is significant to evaluate its contamination level and contamination mechanisms.
Conclusions
• 44 liver analyses (individuals from 10 to 34 cm)
• 17 PCBs congeners (CBs) by GC – ECD.
• Major occurrence of CB153 and CB138
• Important presence of DDE (metabolite of DDT)
Evaluate the fate of PCBs in hakes from the gulf of Lions.
Modelling the PCB bioaccumulation (Dynamic Energy Budget approach)
Introduction
Future model development:
• Taking into account Taking into account bio-transformation. bio-transformation.
• Validation for other PCB congeners and Validation for other PCB congeners and other contaminants (Hg).other contaminants (Hg).
• Extension to male hakesExtension to male hakes..
• Extension to the hakeExtension to the hake population population and and itsits trophic web trophic web..
• Contribution of contamination by water during breathingContribution of contamination by water during breathing..
Quantify the contribution and elimination of CB
153 during all the life of a female hake.
Uptake : food
Losses : excretion, spawning, dilution by growth.
The comparison between growth model outputs
and hake weight and length measurements validates
the growth model during the whole life of a female hake.
The PCB bioaccumulation simulation seems to be
acceptable compared to the few analysis results.
R
esu
lts
P
rin
cip
le
Ob
ject
ive
R
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lts
P
CB
An
alys
is
Study area
Conceptual Conceptual diagramdiagram
PCB chromatogram in a male hake liver of 34 cm.
Mediterranean hakes Mediterranean hakes areare significantly contaminated by PCBssignificantly contaminated by PCBs. This contamination seems . This contamination seems to be to be correlated correlated according to growth, according to growth, probably with probably with thethe diet evolution diet evolution and maturation degree. and maturation degree.
The bioaccumulation model simulateThe bioaccumulation model simulatess rather well the growth and contamination of an immature rather well the growth and contamination of an immature hake female.hake female.
Growth model
• Food contained energy is assimilated proportionally to the hake surface area and stocked in the energy
storage compartment (constant efficiency).
• Stored energy is allocated to the soma and for maturity (for juvenils) or reproduction (for adults).
• Maintenance is proportional to the amount of structure
• Adults spawn one time each year, at a fixed date.
• Starvation during winter
• Initial condition: - Egg energy content
• Forcing variables: - Water temperature - No limiting food
Coupled contaminant model
• PCB allocation is described likely and proportionally to the fixed energy allocation
• PCB food content varying with hake diet
• Stored PCB are allocated to somatic and gonadic compartments, proportionally to the energy flow to biovolume and gonads respectively. PCB mobilisation from reserves is function to the PCB storage concentration.
• PCBs are expulsed during the annual spawning.
• Forcing variable : - PCB prey concentration - Energy prey value.
Evolution of the CB 153 concentration function of the hake length
0
10
20
30
40
50
60
70
0 5 10 15 20 25 30 35 40Length (cm)
CB
153
conc
entr
atio
n (n
g / g
WW
)
Females measurements
Undtermined sex measurements
Model
• CB153 : 230 to 1700 ng.g-1 DW (for a juvenile hake of 11,5 cm and a male adult of 34 cm)
• Concentrations 5 to 8 times higher thanin hakes from the Bay of Biscay
• No influence of the Rhone river between the two studied areas
• High inter-individual variability, probably due to their physiological properties.Assumptions explaining the variations:
• Hake lenght (growth)• Hake sex• Sexual maturation degree• Diet evolution
CB153 concentration in the hake livers function of their length
0
400
800
1200
1600
2000
5 10 15 20 25 30 35 40
Length (cm)
CB
153
con
cent
ratio
n (n
g/g
dry
liver
)
Undetermined sex
Males
Females
Sector1
Hake weight and length function of their age
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 1000 2000 3000 4000 5000Age (d)
Wei
gh
t (g
)
0
10
20
30
40
50
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Le
ng
th (
cm
)
Weight (measurements)Weight (model)Length (measurements)Length (model)
Golfe du LionGolfe du LionGulf of Lion
Sector 2Sector 1
Rhône river
21
21
21
Golfe du LionGolfe du LionGulf of Lions
Sector 2Sector 1
Rhône river
21
21
21
CB 153 concentration in the hake livers
function of their length
4.5> 20 cm
3 to 1410 to 20 cm
3< 10 cm
CB153 prey concentration(ng.g-1 WW)
Hake length
4.5> 20 cm
3 to 1410 to 20 cm
3< 10 cm
CB153 prey concentration(ng.g-1 WW)
Hake length
Gut
Food Faeces
Biovolume
Storage
Gonadicmaintenance
Somaticmaintenance
PCB PCB PCB
PCB
PCB
Energy
EnergyEnergy
Energy
Energy
Energy
Energy
Reproduction(adults)
PCBEnergy
Maturity(juvenils)Energy
PCBEnergy
Eggs
Gut
Food Faeces
Biovolume
Storage
Gonadicmaintenance
Somaticmaintenance
PCB PCB PCB
PCB
PCB
Energy
EnergyEnergy
Energy
Energy
Energy
Energy
Reproduction(adults)
PCBEnergy
Maturity(juvenils)Energy
Reproduction(adults)
PCBEnergy
Maturity(juvenils)Energy
PCBEnergy
Eggs