Theory 57/Environmental Chemistry
Persistence Is a Partitioning Ratio
The claim
The environmental persistence of a chemical is set by the ratio of its degradation rate to its partitioning into protected phases, so a compound can persist long after it becomes undetectable in water.
01The mechanism
Chemicals sorbed to organic matter or sediment are shielded from degradation; the ratio of sorbed to dissolved fraction sets the effective half-life.
02Predictions
- P1Persistence should track the ratio.
- P2Water concentration should mispredict long-term fate.
03Refutation
Persistence tracking aqueous degradation would remove the partitioning term.