Persistence. Nomegestrol acetate is potentially persistent.
Bioaccumulation. Nomegestrol acetate has low potential for bioaccumulation.
Toxicity. Nomegestrol acetate has very high chronic toxicity.
Risk. The use of nomegestrol acetate (sales data Sweden 2018) has been considered to result in insignificant environmental risk.
This summary information comes from Fass.
Fass environmental information for Nomegestrol from Zoely (estradiol, nomegestrol acetate) from Theramex Ireland (downloaded 2022-04-11).
Persistence: "Ready Biodegradation (OECD 301B) (Ref. VI): 0% degradation in 28 days. Not readily biodegradable. Since nomegestrol acetate is not readily biodegradable and no other degradation studies are available, the phrase “Nomegestrol acetate is potentially persistent” is chosen."
Bioaccumulation: "Flow through study with zebrafish (Danio rerio) kinetic BCF = 44. Since BCF < 500, nomegestrol acetate has low potential for bioaccumulation."
Toxicity: There are data for 3 trophic levels, most sensitive fish (Danio rerio) NOEC 1.3 microg/L.
PEC/PNEC is based on sales data in Sweden in year 2018. PEC/PNEC = 0.01 which gives the risk insignificant.
Measurements of nomegestrol in the environment are lacking, but the substance binds weakly to both the androgen receptor and SHBG (Sex Hormone Binding Globulin), which gives a low risk profile. The ability of a substance to activate the androgen receptor in fish is believed to contribute to increased risk of environmental impact. Binding to SHBG is believed to contribute to increased bioconcentration (and thus potency) in fish.
Author: Health and Medical Care Administration, Region Stockholm