Table 3.
The list of generalized reaction schemes for the combined PFAS environmental and metabolism reaction libraries, examples of the parent PFAS on which the reaction schemes were based, and the associated reaction systems, assigned rankings and references. The studies conducted in environmental systems are highlighted in italics and the studies conducted in biological systems are highlighted in bold
| Reaction scheme | Generalized reaction scheme | Parent PFAS | Reaction system | Half-life/rank (ref.) |
|---|---|---|---|---|
| 1. Conjugation: reduction of alpha-keto glutathione conjugate to alpha-hydroxy glutathione conjugate |
|
|
Rabbit | 1 to 12 h/5 (ref. 47) |
| 2. Conjugation: glutathione–epoxide conjugate formation |
|
|
Rabbit | 1 to 12 h/5 (ref. 47) |
| 3. Conjugation: acetylation of S-Cys-unsaturated fluorotelomer acid conjugate to S-Cys-N-acetyl-unsaturated fluorotelomer acid_PTP |
|
|
Soybean | PTP/3 (ref. 48) |
|
Soybean | PTP, 7 to 60 days/3 (ref. 49) | ||
| 4. Conjugation: gluconerate–fluorotelomer alcohol conjugate formation |
|
|
Carp | 1 to 36 d/4 (ref. 50) |
| Rat | 1 to 10 d/4 (ref. 38) | |||
| Rat hepatocytes | 2 to 4 h/4 (ref. 51) | |||
| Trout | 1.2 h/4 (ref. 26) | |||
| 5. Conjugation: gluconerate–fluorotelomer sec-alcohol conjugate formation |
|
|
Rat liver | Not reported/4 (ref. 38) |
| 6. Conjugation: glutathione–ether conjugate formation |
|
|
Rat liver cytosol | 72 min/6 (ref. 52) |
| 7. Conjugation: glutathione-unsaturated fluorotelomer acid conjugate formation |
|
|
Rat hepatocytes | 2 to 4 h/5 (ref. 51) |
| Trout blood | 9.4 h/5 (ref. 39) | |||
| 8. Conjugation: glutathione-unsaturated fluorotelomer aldehyde conjugate formation |
|
|
Rat hepatocytes | 2 to 4 h/6 (ref. 51) |
| Rat cytosol | 0.5 to 2 h/6 (ref. 26) | |||
| 9. Conjugation: glutathione–vinyl ether conjugate formation |
|
|
Rat cytosol | 27 min/7 (ref. 53) |
| 10. Conjugation: hydrolysis of S-Cys-glycine-unsaturated fluorotelomer alcohol conjugate to S-Cys-unsaturated fluorotelomer alcohol_PTP |
|
|
Soybean | PTP/3 (ref. 48) |
| 11. Conjugation: hydrolysis of glutathione-unsaturated fluorotelomer acid conjugate to S-Cys-glycine-unsaturated acid |
|
|
Rat | Not reported/3 (ref. 38) |
| 12. Conjugation: hydrolysis of glutathione-ether conjugate to cysteine-ether conjugate |
|
|
Rat cytosol | 12 to 24 h/5 (ref. 54) |
| 13. Conjugation: hydrolysis of glutathione-unsaturated fluorotelomer alcohol conjugate to S-CysGly-unsaturated fluorotelomer alcohol_PTP |
|
|
Soybean | PTP/3 (ref. 48) |
| 14. Conjugation: hydrolysis of glutathione-vinyl ether conjugate to cysteine-vinyl ether conjugate |
|
|
Rat cytosol | 12 to 24 h/5 (ref. 54) |
| 15. Conjugation: hydrolysis of sulfide conjugate to carboxylic acid |
|
|
Rat cytosol | 10 to 24 h/5 (ref. 55) |
| 16. Conjugation: hydrolysis of vinyl sulfide conjugate to carboxylic acid |
|
|
Rat cytosol | 10 to 24 h/5 (ref. 55) |
| 17. Conjugation: reduction of glutathione-unsaturated fluorotelomer aldehyde conjugate to glutathione-unsaturated fluorotelomer alcohol conjugate |
|
|
Soybean | Not reported/3 (ref. 48) |
| 18. Conjugation: S-dealkylation of cysteine-ether conjugate to beta thio ether_PTP |
|
|
Rat cytosol | 10 h/5 (ref. 55) |
| 19. Conjugation: S-dealkylation of cysteine–vinyl ether conjugate to beta thio vinyl ether |
|
|
Rat cytosol | 16 h/5 (ref. 55) |
| 20. Conjugation: sulfate-fluorotelomer alcohol conjugate formation |
|
|
Rat | 8 h/5 (ref. 56) |
| Rat | Not reported/5 (ref. 38) | |||
| 21. Conjugation: taurine–fluorotelomer acid conjugate formation |
|
|
Rat hepatocytes | Not possible to estimate half-life/4 (ref. 26) |
| 22. Decarboxylation: alpha carboxy ether to ether |
|
|
Aprotic solvents | 1 to 5 h/1 (ref. 57) |
| 23. Decarboxylation: alpha hydroxy carboxylate to carboxylic acid |
|
|
Aerobic activated sludge | 0.4 d/5 (ref. 29) |
| 24. Decarboxylation: beta carboxy ketone to methyl ketone |
|
|
Activated sludge | PTP/3 (ref. 3) |
| Rat hepatocytes | 30 to 120 min/6 (ref. 6) | |||
| 25. Desulfonation: fluorotelomer sulfonate to fluorotelomer alcohol |
|
|
Bacterial culture | 39 h/4 (ref. 58) |
| Bacterial culture | 120 h/4 (ref. 49) | |||
| Bacterial culture | 160 h/4 (ref. 59) | |||
| 26. Epoxidation: alkene to epoxide_PTP |
|
|
Rabbit | PTP/4 (ref. 60) |
| 27. Hydrolysis: acid fluoride to carboxylic acid |
|
|
Phosphate buffer, pH 7.4 | <1 min/7 (ref. 61) |
|
Rat liver microsomes | Decomposes rapidly/7 (ref. 62) | ||
| 28. Hydrolysis: alpha difluoro alcohol to acid fluoride |
|
|
Rat liver microsomes | Decomposes rapidly/7 (ref. 62) |
| 29. Hydrolysis: alpha fluoro secondary alcohol to ketone |
|
|
Phosphate buffer, pH 7.4 | 0.1 h/7 (ref. 62) |
| Rat and liver microsomes | 0.1 h/7 (ref. 61) | |||
| 30. Hydrolysis: alpha fluoro primary alcohol to aldehyde |
|
|
Aqueous solution | 30 min/7 (ref. 63) |
| Aqueous solution | 30 min/7 (ref. 63) | |||
| 31. Hydrolysis: amide to carboxylic acid |
|
|
Aqueous solution | 0.167 d/5 (ref. 64) |
| Aqueous solution | 0.167 d/5 (ref. 64) | |||
| 32. Hydrolysis: beta hydroxy fluorotelomer iodide to diol_PTP |
|
|
Aerobic soil | PTP/3 (ref. 65) |
| 33. Hydrolysis: carboxylic acid ester to carboxylic acid |
|
|
Aerobic soil | 15 d/3 (ref. 66) |
|
Aerobic soil | 3 to 5 d/3 (ref. 66) | ||
| Trout liver | 1.1 min/7 (ref. 67) | |||
|
Aerobic soil | 10.3 d/3 (ref. 68) | ||
| Aerobic soil | 28 d/3 (ref. 69) | |||
| 34. Hydrolysis: diphosphate ester to monophosphate ester |
|
|
Soil microcosm | 60 d/2 (Lee et al. 2014) |
|
Activated sludge | 84 d/2 (ref. 70) | ||
| Rat serum | 2 to 4 d/4 (ref. 56) | |||
| 35. Hydrolysis: epoxide to diol_PTP |
|
|
Mixed bacterial culture | PTP/3 (ref. 71) |
| 36. Hydrolysis: perfluorinated epoxide to beta keto carboxylic acid |
|
|
Aqueous solution | 13.8 min/7 (ref. 72) |
| Aqueous solution | 13.8 min/7 (ref. 72) | |||
| 37. Hydrolysis: fluorotelomer aldehyde to fluorotelomer unsaturated aldehyde |
|
|
Rat hepatocytes | 30 min/6 (ref. 51) |
| 38. Hydrolysis: fluorotelomer acid to unsaturated telomer acid |
|
|
Aerobic soil | 11 h/4 (ref. 30) |
|
Rat liver microsomes | 2 to 6 h/5 (ref. 73) | ||
| Soybean | 12 to 24 h/5 (ref. 74) | |||
|
Activated sludge | 120 to 480 h/4 (ref. 65) | ||
| 39. Hydrolysis: fluorotelomer iodide to fluorotelomer alcohol |
|
|
Rat liver microsomes | 6 h/5 (ref. 73) |
| Aerobic soil | 10 d/3 (ref. 65) | |||
| 40. Hydrolysis: fluorotelomer urethane to fluorotelomer alcohol |
|
|
Aerobic soil | 3 to 5 months/7 (ref. 75) |
|
Aerobic soil | 16 to 22 months/7 (ref. 75) | ||
| 41. Hydrolysis: hydrodefluorination of PFC chain |
|
|
Activated sludge | 1 to 3 d/4 (ref. 76) |
| 42. Hydrolysis: monophosphate ester to alcohol |
|
|
WWTP microbes | 1 d/4 (ref. 77) |
|
WWTP microbes | 40 d/4 (ref. 41) | ||
|
WWTP microbes | 50 d/4 (ref. 77) | ||
| Trout | 4.4 d/4 | |||
|
Rat | 2.3 d/4 (ref. 78) | ||
| 43. Hydrolysis: diperfluoro-phosphinate to monoperfluoro-phosphonate |
|
|
Aqueous solution | 36 h @ 150 °C/1 (ref. 79) |
|
Trout | 5.5 d/3 (ref. 80) | ||
|
20.4 d/3 (ref. 80) | |||
|
52.7 d/3 (ref. 80) | |||
| 44. Hydrolysis: sulfonamide to sulfonate |
|
|
Earthworm | 9.5 d/3 (ref. 33) |
| Rat | < 10 min/7 (ref. 81) | |||
| 45. Hydrolysis: sulfonyl fluoride to sulfonate |
|
|
Aqueous solution | 0.1 d/3 (ref. 82) |
|
24.3 d/3 (ref. 82) | |||
| 46. Hydroxylation: N-alkyl sulfonamide to N-alkyl sulfonamide alcohol_PTP |
|
|
Marine sediment | PTP/3 (ref. 83) |
| 47. Hydroxylation: unsaturated fluorotelomer acid to alpha hydroxy fluorotelomer acid |
|
|
Rat hepatocytes | PTP/3 (ref. 51) |
| Activated sludge | 3 d/3 (ref. 29) | |||
| 48. Hydroxylation: unsaturated fluorotelomer acid to beta hydroxy fluorotelomer acid |
|
|
Aerobic soil | 63 d/2 (ref. 25) |
| Trout | PTP/3 (ref. 39) | |||
| 49. N-Deacetylation: N-acetyl, N-alkyl sulfonamide to N-alkyl sulfonamide |
|
|
Japanese Medaka | 3.9 d/4 (ref. 84) |
| Marine sediment | 30 to 60 d/3 (ref. 83) | |||
| Aerobic activated sludge | 7.5 d/3 (ref. 85) | |||
| 50. N-Deacetylation: N-acetyl sulfonamide to sulfonamide |
|
|
Earthworms | 5 d/4 (ref. 86) |
| Aerobic activated sludge | 1.9 d/4 (ref. 85) | |||
| 51. N-Dealkylation: N-alkyl sulfonamide to sulfonamide |
|
|
Japanese medaka | 2.5 d/4 (ref. 84) |
| Trout liver microsomes | 1 to 10 d/4 (ref. 87) | |||
| Activated sludge | 0.75 d/5 (ref. 85) | |||
| 52. N-Demethylation: fluorotelomer sulfonamide N-dimethyl-N-acetyl betaine to fluorotelomer sulfonamide N-methyl-N-acetyl betaine |
|
|
Blue mussel | No kinetic data/4 (ref. 88) |
| 53. N-Deacetylation: fluorotelomer sulfonamide N-methyl-N-acetyl-betaine to fluorotelomer sulfonamide N-methyl betaine |
|
|
Blue mussel | No kinetic data/4 (ref. 88) |
| 54. N-Deacetylation: fluorotelomer sulfonamide N-dimethyl-N-acetyl-betaine to fluorotelomer sulfonamide N-dimethyl betaine |
|
|
Blue mussel | No kinetic data/4 (ref. 88) |
| 55. N-Demethylation: fluorotelomer sulfonamide N-methyl betaine to fluorotelomer sulfonamide betaine |
|
|
Blue mussel | No kinetic data/4 (ref. 88) |
| 56. O-Demethylation: alpha difluoro methyl ether to carboxylic acid |
|
|
Rat liver microsomes | 1.5 d/4 (ref. 62) |
| 57. O-Demethylation: fluoromethyl ether to secondary alcohol |
|
|
Human liver microsomes | 2.8 h/6 (ref. 89) |
| 58. Oxidation: alcohol to ketone |
|
|
Aerobic soil | 10 to 30 d/3 (ref. 25) |
| Aerobic soil | 37 d/3 (ref. 30) | |||
| 59. Oxidation: alpha fluoro diol to acid fluoride and carboxylic acid with C–C bond cleavage_PTP |
|
|
Activated sludge | 3 d/3 (ref. 71) |
| Activated sludge | 3 d/3 (ref. 76) | |||
| 60. Oxidation: alpha oxidation of an alpha hydroxy fluorotelomer carboxylic acid to a carboxylic acid |
|
|
Rat hepatocytes | 1 to 2 d/6 (ref. 51) |
| Aerobic activated sludge | 240 to 720 h/3 (ref. 29) | |||
| 61. Oxidation: beta hydroxy fluorotelomer acid to beta keto fluorotelomer acid_PTP |
|
|
Rats | PTP/3 (ref. 38) |
| Aerobic soil | PTP/3 (ref. 30) | |||
| 62. Oxidation: alpha hydroxy fluorotelomer aldehyde to beta hydroxy fluorotelomer carboxylic acid_PTP |
|
|
Aerobic soil | PTP/3 (ref. 65) |
| 63. Oxidation: fluorotelomer diol to beta hydroxy fluorotelomer aldehyde_PTP |
|
|
Aerobic soil | PTP/3 (ref. 65) |
| 64. Oxidation: beta-keto aldehyde to beta-keto acid_PTP |
|
|
Trout | PTP/3 (ref. 39) |
| 65. Oxidation: beta oxidation of beta keto fluorotelomer acid |
|
|
Trout | 1 to 3 d/4 (ref. 90) |
| Aerobic soil | PTP/3 (ref. 30) | |||
| 66. Oxidation: fluorotelomer iodide to alpha beta unsaturated fluorotelomer iodide_PTP |
|
|
Aerobic soil | PTP/3 (ref. 65) |
| Rat liver microsomes | PTP/3 (ref. 73) | |||
| 67. Oxidation: fluorotelomer alcohol to fluorotelomer aldehyde |
|
|
Aerobic sediment | 1.8 d/4 (ref. 91) |
|
Rat hepatocytes | 1 to 2 d/5 (ref. 51) | ||
| Mixed microbial system | 1.2 d/4 (ref. 92) | |||
| Aerobic soil | 1 to 12 d/4 (ref. 25) | |||
| 68. Oxidation: fluorotelomer alcohol to carboxylic acid with loss of methyl group |
|
|
Aerobic soil | 15 d/2 (ref. 25) |
|
Soil | 370 d/2 (ref. 43) | ||
| Aerobic sediment | 97 d/2 (ref. 91) | |||
| Soybean | <1 day/5 (ref. 74) | |||
| 69. Oxidation: fluorotelomer alcohol to fluorotelomer carboxylic acid with loss of CF2 and methyl groups |
|
|
Soybean | <1 day/5 (ref. 74) |
| Aerobic sediment | 97 d/3 (ref. 91) | |||
| Soil | 22 d/3 (ref. 40) | |||
|
Landfill leachate/sediment | 80 to 90 d/3 (ref. 93) | ||
| 70. Oxidation: fluorotelomer aldehyde to fluorotelomer carboxylic acid |
|
|
Pure water, 37 °C | 60 min/6 (ref. 94) |
|
Rat hepatocytes | 30 min/7 (ref. 51) | ||
| Hepatocytes | 30 min/7 (ref. 26) | |||
| 71. Oxidation: fluorotelomer carboxylic acid to 2,3-unsaturated fluorotelomer carboxylic acid |
|
|
Soybean | 4 to 6 d/4 (ref. 74) |
| Aerobic soil | 151 d/2 (ref. 29) | |||
| 72. Oxidation: fluorotelomer polyethoxylate to fluorotelomer ethoxylate aldehyde (PTP) |
|
|
Effluent of waste water treatment plant | 1 d/3 (ref. 95) |
| 73. Oxidation: fluorotelomer ethoxylate aldehyde to fluorotelomer ethoxylate carboxylic acid |
|
|
Effluent of waste water treatment plant | 1 d/3 (ref. 95) |
| 74. Oxidation: fluorotelomer thioether amido sulfonate to fluorotelomer sulfoxide amido sulfonate |
|
|
Soil microcosm | 5 d/4 (ref. 96) |
| 75. Oxidation: fluorotelomer sulfoxide amido sulfonate to fluorotelomer sulfone amido sulfonate |
|
|
Soil microcosm | 35 d/3 (ref. 96) |
| 76. Oxidation: Fluorotelomer sulfonyl amido sulfonate to fluorotelomer sulfonate |
|
|
Soil microcosm | 7 d/3 (ref. 96) |
| 77. Oxidation: hydrodefluorination with alpha oxidation |
|
|
Aerobic soil | 0.35 to 3.5 days/3 (ref. 30) |
| Aerobic soil | 10 to 20 days/3 (ref. 25) | |||
| 78. Oxidation: N-alkyl sulfonamide alcohol to N-alkyl sulfonamide carboxylic acid |
|
|
Anaerobic digestor sludge | 35.8 d/1 (ref. 46) |
|
Japanese medaka | 2.8 d/4 (ref. 84) | ||
| Aerobic sediment | 44 d/1 (ref. 83) | |||
| Anaerobic digestor sludge | 1860 d/1 (ref. 46) | |||
| Aerobic activated sludge | 0.71 d/1 (ref. 85) | |||
| 79. Oxidation: sulfinate to sulfonate |
|
|
Activated sludge | 0.73 d/1 (ref. 85) |
| 80. Reduction: 2,3-unsaturated fluorotelomer carboxylic acid to fluorotelomer carboxylic acid |
|
|
Trout | 1 d/4 (ref. 39) |
| Soybean | 1 to 2 d/4 (ref. 49) | |||
| Aerobic soil | 16 d/3 (ref. 30) | |||
|
Soybean | 1 to 2 d/4 (ref. 74) | ||
|
Bacterial culture | Not possible to estimate half-life/3 (ref. 59) | ||
| Activated sludge | Not possible to estimate half-life/3 (ref. 29) | |||
| 81. Reduction: beta fluoro unsaturated telomer acid to beta H unsaturated telomer acid |
|
|
Aerobic soil | 11.8 d/3 (ref. 30) |
| Soybean | 1 to 2 d/4 (ref. 97) | |||
| Mammalian hepatocytes and microsomes | 0.5 d/4 (ref. 26) | |||
| 82. Reduction: hydrogenolysis of chlorinated perfluorinated ether_PTP |
|
|
Trout | PTP/3 (ref. 98) |
| Soil | PTP/3 (ref. 30) | |||
| 83. Reduction: hydrogenolysis of chlorinated perfluorinated ether sulfonate |
|
|
Trout | 1 to 5 days/4 (ref. 98) |
|
Trout | 24 d/4 (ref. 98) | ||
| Cyano-cobalamin | 1 min/7 (ref. 99) | |||
| 84. Reduction: ketone to alcohol |
|
|
Aerobic activated sludge | 0.5 to 2 h/3 (ref. 29) |
|
Aerobic soil | 1 to 60 days/3 (ref. 30) | ||
| Trout | 2 h/6 (ref. 26) | |||
| 85. Reduction: perfluoroalkyl sulfonyl fluoride to perfluoroalkyl sulfinic acid |
|
|
Glutathione | 1.1 d/4 (ref. 52) |
|
Glutathione | 0.4 d/4 (ref. 52) | ||
|
Glutathione | 1.1 d/4 (ref. 52) | ||
| 86. Reduction: sulfonamide to sulfinic acid |
|
|
Activated sludge | 40 to 80 h/3 (ref. 100) |
|
Digester sludge | 20 to 40 d/3 (ref. 46) | ||
|
Digester sludge | 40 to 80 d/3 (ref. 46) | ||
|
Activated sludge | 9.2 d/3 (ref. 85) | ||
| 87. Reduction: vicinal bis-defluorination of unsaturated carboxylic acid_PTP |
|
|
Aerobic soil | 16 d/3 (ref. 30) |