1. Programme INTERREG III : STARDUST
Spatial and Temporal Assessment of high Resolution Depth profiles
Using novel Sampling Technologies
                                  
                         
Vlaams Institute voor de Zee
Université des Sciences et Technologies de Lille
Vrije Universiteit Brussel
Study of organic contaminants in river sediments
Adeline CHARRIAU, Laurent BODINEAU, Baghdad OUDDANE
Herhaling titel van presentatie
Lille, march 28th 2008

2. Context of the study  Compounds of interest: hydrophobic contaminants
Cl x
Polychlorobiphenyles (PCB)
- proven toxicity
- persistence in the aquatic ecosystems
- bioaccumulative character
Polycyclic Aromatic Hydrocarbons (PAH)
n-alkanes
Contamination levels and potential toxicity
Source apportionment (biologic, petrogenic, pyrolytic)
 River sediments: acted as a sink for contaminants but can represent a threat in case of a release to the overlying water column 1

3. Optimisation of analytical tools and procedures
 Optimisation of extraction conditions for aliphatic and aromatic hydrocarbons
Analysis of polychlorobiphenyls by mass spectrometry
- good preliminary results in the SIS mode
- validation of the analytical procedure in progress for the Tandem mode
Time saving
Higher reproducibility
Higher sensitivity for planar PCB 2

4. Organic contaminants in river sediments [1]
Sampling area
Yser canal
Superficial sediments
 Lys canal
Escaut canal
Espierre canal
Superficial sediments and sediment cores 3

5. Organic contaminants in river sediments [2]
Yser canal
n-alkanes
- Total concentrations range: 2.9 – 16.2 mg/kg
- Absence of unresolved complex mixture
- Major hydrocarbons coming from biogenic sources (higher plant waxes)
- High amounts of low molecular weight n­alkanes for sediments 1 to 6
PAH
- Total concentrations range: 0.5 – 4.2 mg/kg
Predominance of high molecular weight PAH
Strong pyrolitic fingerprint
Lower concentrations in the upstream part of the river 4

6. Organic contaminants in river sediments [3]
Prospecting campaign
Espierre I.1
Espierre I.2
Helkijn II.1
Helkijn II.2
Helkijn II.3
Helkijn II.4
Bleharies III.1
Wervik IV.1
Wervik IV.2
Wervik IV.3
PAH
n-Alkanes
n-alkanes
- Total concentrations range: 6.4 – 55.7 mg/kg
High and homogeneous contamination for Wervik sediments
Lower concentrations in the Escaut canal
Scheldt
PAH
- Total concentrations range: 1.5 – 33.9 mg/kg
- Higher heterogeneity
Lower concentrations in the confluence with the Scheldt canal
Evaluation of accessibility, presence of muddy sediments and contamination levels 5

7. Organic contaminants in sediment cores [1]
Molecular fingerprint
Petroleum
Petroleum combustion
Biomass and coal combustion
Combustion
Mixed
Bordery lines based on Yunker et al., 2002
PAH
molecular indices consistent with combustion process
presence of alkyl homologues
Major pyrolitic origin and minor part from petrogenic process
n-alkanes
presence of a broad and large UCM
major n-alkanes of biogenic origins (C27, C29, C31)
UCM 28 27 29 30 31 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 32 33 34
Phy
Pri
Terrestrial inputs and biodegraded oil residues 6

8. Organic contaminants in sediment cores [2]
Risk assessment
ERL
Sediment Quality Guidelines
- ERL value exceeded for Helkijn and Wervik sediments
- ERM value exceeded for Espierre sediments
ERM
Global threshold value of the European legislation (8.649 mg.kg –1)
- exceeded for all Espierre sediments (more than 6 times
the recommended value)
- exceeded for surface and bottom sediments of Wervik 7

9. Conclusions
High contamination levels for Helkijn, Wervik and especially Espierre sediments: potential threat for the aquatic ecosystems
Strong historical contamination in the Espierre canal (PAH and degraded oil residues)
Strong pyrolytic inputs for PAH
 Trans-boarder benefits: joint samplings and comparison with Calux results 8