Mifepristone
Summary
Persistence. Mifepristone is degraded in the environment.
Bioaccumulation. Mifepristone has low potential for bioaccumulation.
Toxicity. Mifepristone has very high chronic toxicity.
Risk. The use of mifepristone (sales data Sweden 2020) has been considered to result in insignificant environmental risk.
This summary information comes from Fass.
Detailed information
Fass environmental information
Fass environmental information for Mifegyne (mifepristone) from Nordic Drugs (downloaded 2023-06-28).
Hazard
Persistence: The DT50/DT90 values for Mifepristone are 4.5/14.9 days (water phase), 72.1/239.0 days (sediment phase) and 14.3/212.0 days (total system) for sediment system A and 4.1/13.5 days (water phase), 29.6/98.4 days (sediment phase) and 12.7/42.3 days (total system) for sediment system B. DT50 values obtained for the total system for both test systems (A and B) are therefore ≤ 14.3 days, and the substance is degraded in the environment (DT50 ≤ 32 d).
Bioaccumulation: Experimental Log Kow is 4.61, however the estimated bioconcentration factors derived from the Mifepristone bioaccumulation study in fish as per OECD 305 were below 25 L/kg. Mifepristone bioaccumulation potential can therefore be considered to be low (BCF < 500) and the phrase “Mifepristone has low potential for bioaccumulation” is thus chosen.
Chronic toxicity: There are data for 3 trophic levels, most sensitive fish (Danio rerio) NOEC 0.1 microg/L.
Risk
PEC/PNEC is based on sales data in Sweden in year 2020. PEC/PNEC = 0.05686 which gives the risk insignificant.
References
Author: Health and Medical Care Administration, Region Stockholm