1. Ecotoxicology Toxicology Uptake and distribution of xenobiotics

2. pH = 6.4 [conc. 4] Ca ++ + + + - - - - pH=7.4 [conc. 2] Functions of the biological membrane Maintain homeostasis Selective uptake and excretion Excitability

3. The biological membrane

4. The lipophilic route

5. Phospholipid

6. Passage of chemicals through the membrane depends on: Size Fat solubility Resemblance with endogenous molecules The passage takes place through: Passive diffusion through the phospholipids Through water and ion channels Active transport through channels Endocytosis Passive diffusion most important toxicologically

7. The diffusion rate increases with the water-octanol distribution coefficient (Kow) n-octanol Water K ow 1 >>1 1:5 1:1 5:1 21:1 ][ octanol][ conc Kow  water

8. 110 2 3 4 5 6 7 8 9 Solubility in water (nM) 10 2 3 4 5 6 7 n-octanol:water Distribution coefficient 2,2',4,4',5,5'-PCB DDT 2,2',4,5,5'-PCB DDE 4,4'-PCB Parathion Naphtalen Benzen Toluen Chloroform p -dichlorbenzen Chlorbenzen Benzoic acid

9. Kow Diffusion rate O and N increase hydrophilic characteristics Alkyl groups increase lipophilic characteristics mnemonic rule: compound lipophilic if 4 > + ON C

10. Ionization AH A - + H + BOH B + + OH - +-+- +-+- pH dependent Water +-+- +-+- +-+- +-+- +-+- +-+- +-+-

11. The diffusion follows the concentration gradient given by Fick’s law CAP dt dn  P = Permeability constant (mol/cm 2 ) A = Area ΔC = Concentration difference

12. COO - NH 3 + COO - NH 3 + COOH NH 2 COOH NH 2 + H + H + + + H + 1 1 1 1 100 1000 2512 251 Stomach pH 2 COO - NH 3 + COO - NH 3 + COOH NH 2 COOH NH 2 + H + H + + + H + 1 1 1 1 100 10 2512 251 Intestine pH 6 Plasma pH 7.4 Uptake of Benzoic acid og Aniline

13. The hydrophilic route

14. Channel for divalent cation 2+2+ 2+2+ 2+2+ 2+2+ 2+2+ 2+2+ 2+2+

15. Pyrethroides’ effect on excitable membranes

16. Cadmium passes the Ca ++ channel Cd ++ [0,97 Å] Ca ++ [0,99 Å]

17. Endocytosis

18. H + H + lysosome receptor coated vesikel iron - transferrin complex Endocytosis of iron

19. Uptake, distribution and excretion of xenobiotics Alimentary canalRespiratory surfaces Skin Faeces Bile Secretory structures Secretions Lungs/gills Alveoli Air/water Liver Blood and lymph Kidney Bladder Urine Extra-cellular fluid Organs Soft tissue Hard tissue Fat

20. Enterohepatic circulation

21. 1 2 3 4 5 Day no 2.5 2.0 1.5 1.0 0.5 Ppm Hg (Hg++) 1 2 3 4 5 6 7 8 Day no 90 60 30 Ppm Hg (MeHg) 1 2 3 4 5 6 7 8 Day no 120 60 40 Weight (mg) 1 2 3 4 5 6 7 8 Day no 120 60 40 Weight (mg) Mercury uptake in maggots 10 ppm 1.0 ppm 0.1 ppm

22. Air route Alimentary channel Blood / haemolymphe Bronchioler / Tracheoles Bronchi / Trachea Nose and pharynx

23. Hydrofile Lipofile The skin Wet skin: Increases penetration by a factor 3 Soap and other detergents: Increased penetration of hydrophilic compounds Organic solvents: Irreversible degradation of corneum

24. Xenobiotics are distributed in tissue fluids Plasma:4% of body weight Extracell. fluid:13% - Intracell. fluid:41% - Intracellular fluid Extracellular fluid Plasma Lipophilic compounds Hydrophilic compounds

25. Plasma - protein linkage K1K1 K2K2 The organism’s other compartments High K diss loosely bound Low K diss tightly bound Low affinity and high capacity toxicological most important

26. Dose Blood sample Compartment of distribution ”Apparent compartment of distribution” V D V D low: high depositing in organs V D high: low depositing in organs

27. Depositing to organs Conc. Time 1. order Conc. Time 0. order

28. Brodie-Gillette’s box model Bound Free Bound Free Bound Free Metabolites Excretion Absorption Target site Depot Metabolism

29. Excretory organs Nephridia in earthworm Vertebrate kidney

30. Nephridium of an invertebrate

32. Excretion CKonc. Tid 1. order Conc. Tid 0. order

33. 01020304050 Time (days) 30 50 100 % dioxin remaining In body T ½ = 30,5 days eee t0 k 0,693 k ln2 k lnC T½   