This summary information on persistence, biockumulation and toxicity comes from Fass. The risk comes from the Goodpoint report.
Persistence. It cannot be excluded that topiramate is persistent, due to the lack of data.
Bioaccumulation. Topiramate has low potential for bioaccumulation.
Toxicity. Topiramate has moderate acute toxicity.
Risk. No obvious environmental risk from a Swedish perspective.
Fass environmental information
Fass environmental information for Topimax (topiramate) from Janssen (downloaded 2021-04-14).
Persistence: "The potential for persistence of topiramate cannot be excluded due to lack of data."
Bioaccumulation: Log Kow = 0.5 (pH = 6.0).
Toxicity: There are data for 3 trophic levels, most sensitive algae (Pseudokirchneriella subcapitata) 93 000 microg/L.
PEC/PNEC is based on sales data in Sweden in year 2019. PEC/PNEC = 0.000453012 which gives the risk insignificant.
Report Goodpoint 2020
Comparative assessment of environmental risk when using antiepileptics: lamotrigine, levetiracetam, oxcarbazepine, topiramate and zonisamide from a Swedish perspective.
Although lamotrigine is linked to a slightly higher risk than other substances (based on higher fat solubility), there is no obvious environmental risk for any of the substances. Therefore, no exchanges from an environmental risk point of view are recommended. Measurements of lamotrigine in Swedish wastewater/biota are recommended.
Author: Health and Medical Care Administration, Region Stockholm