This summary information comes from Fass.
Persistence. Montelukast is potentially persistent.
Bioaccumulation. Montelukast has high potential for bioaccumulation.
Toxicity. Montelukast has high chronic toxicity.
Risk. The use of montelukast (sales data Sweden 2018) has been considered to result in insignificant environmental risk.
Fass environmental information for Montelukast Krka (montelukast) from Krka (downloaded 2022-01-17). The environmental information for montelukast is produced by the company MSD for Singulair-AR.
Persistence: "Ready degradability: Test results -8 % degradation in 28 days based on CO2 evolution (i.e., no biodegradation) (OECD 301B). ... Montelukast does not pass the ready biodegradation test but is degradable via hydrolysis, photolysis and in acclimated biological systems and river sediments. However, given that no toxicity data is available for metabolites, the phrase “Montelukast is potentially persistent” is thus chosen."
Bioaccumulation: Log D > 4.3 at 7 (OECD 107).
Chronic toxicy: There are data for 3 trophic levels, most sensitive fish (Pimephales promelas) NOEC 32 days (percent live normal fry, total length and dry weight) = 73 microg/L (OECD 210).
PEC/PNEC is based on sales data in Sweden in year 2018. PEC/PNEC = 0.003 which gives the risk insignificant.
Author: Health and Medical Care Administration, Region Stockholm