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Acknowledgements

Acute Effects Of Single And Mixed Polycyclic Aromatic Hydrocarbons Associated To Oil Spills On The Copepod Oithona Davisae . Carlos Barata 1 , Albert Calbet 2 , Enric Sainz 2 , Laura Ortíz 3 , Josep Maria Bayona 3 . 1 Laboratory of Environmental Chemistry, UPC, Terrassa

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Acknowledgements

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  1. Acute Effects Of Single And Mixed Polycyclic Aromatic Hydrocarbons Associated To Oil Spills On The Copepod Oithona Davisae . Carlos Barata1, Albert Calbet 2, Enric Sainz 2, Laura Ortíz 3, Josep Maria Bayona 3. 1 Laboratory of Environmental Chemistry, UPC, Terrassa 2 Dept. Biologia Marina i Oceanografia, CMIMA, CSIC, Barcelona 3 Dept of Environmental Chemistry, IIQAB-CSIC, Barcelona

  2. Acknowledgements • Financial Support: • MEC Spanish project PETROZOO (VEM2003-20037). • MEC R y C contract to Carlos Barata and Albert Calbet

  3. Objectives Develop a modelling framework to predict the toxicity of mixture combinations of petrogenic PAHs in copepod species

  4. Overview – in brief Effects of crude oil spills in marine planktonic food webs??? zooplankton species constitute the major food source for larval fish

  5. Environmental fate 1. Most toxic and persistent components of class 2 fuel oils (Prestige) 2. Occur in complex mixtures Toxicity by non-polar narcosis 1.Toxicity = F (1/log Kow) Toxicity – EC50 2.Toxicity complex mixtures is additive Log Kow Effect PAHs Overview – in brief Polycyclic aromatic hydrocarbons (PAHs)

  6. Test Species: Oithona davisae Methods Chemicals: Naphthalene, 1-methylnaphthalene, 1,2-Dimethylnaphthalene Phenanthrene,1-methylphenanthrene,3,6-dimethylphenanthrene Fluorene, Dibenzothiophene, Pyrene Analysis: SP -HPLC-UV Measured variables: Lethal , Narcosis– after 48 h (%)

  7. Experimental design Exposure scenarios Individual exposures 10 PAHs Mixture combination of only 9 PAHs using an equitox ratio Ci = EC50j / n ; n= 9; Cj = 1/9 TUj Experimental conditions: No food supply, filtered sea water (38 0/00) 20 oC

  8. 100 50 0 Data analysis Modeling % responses: Allosteric decay function i EC = ´ % Mobile mobile 50 control [ ] i i + EC PAH 50 Survival PAHs (mmol/L)

  9. Single - Quantitative Structure Activity Relationship (QSAR) 1 = ´ + Log a log K b owj EC 50 EC50 j Mixture - Concentration Addition model Kow n c å = j 1, For cj = EC 50j /n; 1 = 50% ECx = j 1 j Data analysis Modelling single and mixture toxicities (EC50) of PAHj:

  10. Results- Single solutions Naphthalenes (% mobile vs Control) Narcosis, survival N N1 100 50 0 0 10 20 30 40 0 20 40 60 80 N2 100 50 0 0 5 10 15 PAHs (mmol/L)

  11. Results- Single solutions Phenanthrenes (% mobile vs control) Narcosis, survival P 100 50 0 0 3 6 9 P1 100 50 0 0 1 2 3 PAHs (mmol/L)

  12. Results- Single solutions Rest of PAHs (% mobile vs control) Narcosis, survival F DBT 100 50 0 0 2 4 6 8 10 0 2 4 Ft Py 100 50 0 0.0 0.2 0.4 0.6 0.0 0.3 0.6 0.9 PAHs (mmol/L)

  13. Results- QSAR Survival Narcotization Ft 1 0.5 = ´ - Log 1 log K 5 Py owj EC 50 j 1.0 DBT 2.0 N2 P1 EC 50( mmol/L) P F 5.0 N1 N 20.0 R2 =0.9 60.0 3.0 3.5 4.0 4.5 5.0 5.5 Log K ow

  14. Results- Mixtures Mixture of 9 PAHs at their EC50/9 Narcotization Survival 125 EC 50 = 1.1 (0.9-1.3) 100 75 (% mobile vs control 50 25 0 0 1 2 3 9 å EC50 j Toxic Units = 1 = 9 = j 1

  15. Conclusions 1. Allosteric decay function predicted accurately acute responses 2. Acute responses were inversely related to log Kow QSAR 9 PAH = Daphnia magna QSAR >100 non polar narcotics 3. Mixture toxicity of PAHs was additive following the CA model.

  16. Risk Assessment Implications Naphthalene Alkylated Naphthalenes 1000 Highest 100 Prestige EC 50 (m g/L) 10 1 Background 0.1 1 10 100 1000 Number Mixture components

  17. Derive QSAR models for sublethal responses Clearance rates (feeding) N2 14 Prestige 1 mg/L 50 = ´ - Log 0.9 log K 2.9 owj EC 50 N j 182 3 4 5 6 Kow Future Work 2 . How toxicity of real samples (elutriates or water –accommodated fractions of fuel Oil) can be predicted from Chemical analysis using QSAR models

  18. END Thanks Environmental Toxicology and Chemistry. Volume 24, No. 11, November 2005.   

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