This summary information comes from Fass.
Persistence. Dienogest is persistent.
Bioaccumulation. Dienogest has low potential for bioaccumulation.
Toxicity. Dienogest has very high acute/chronic toxicity.
Risk. The use of dienogest (sales data Sweden 2018) has been considered to result in low environmental risk.
Fass environmental information for Qlaira (dienogest, estradiol) from Bayer (downloaded 2021-10-27).
Persistence: "The overall disappearance half-life from the system exceeded the threshold of 120d described in the FASS guidance. Therefore, dienogest can be classified as being potentially persistent." The database, Pharmaceuticals and Environment, reference group believes that based on these results, a drug substance is persistent and not potentially persistent, hence the information that dienogest is persistent in the initial summary information.
Bioaccumulation: Log P 1.6 at 7 and 25°C (Shake flask method, OECD 117).
Toxicity: There are data for 3 trophic levels, most sensitive fish (Pimephales promelas) NOEC = 0.044 microg/L.
PEC/PNEC is based on sales data in Sweden in year 2018. PEC/PNEC = 0.24 which gives the risk low.
Author: Health and Medical Care Administration, Region Stockholm