Information about P, B and T for metformin is from the assessment report Segluromet (ertugliflozin/metformin hydrochloride) 25 January 2018, EMA/86928/2018, see data below. T refers to chronic toxicity.
Measured levels in Sweden are far below reported concentration of environmental impact. Abroad significant higher levels in wastewater are reported.
Below is Hazard and Risk according to data from the assessment report for Segluromet (ertugliflozin/metformin hydrochloride) 25 January 2018, EMA / 86928/2018.
Persistence: "DT50, sediment (20C) = 14d, DT50, water (12C) = 12-43.3d, DT50, sediment (12C) = 38.8d, % shifting to sediment = 50.8-59.5% AR after 17d. TG218 test. Metformin can be considered persistent in water according to PBT criteria (DT50>40d)."
Bioaccumulation: log Kow -2, "Not B".
Chronic toxicity: There is NOEC for three trophic levels, lowest NOEC for fish 10 mg/L.
The risk, PEC/PNEC, calculated from data in the assessment report from a European perspective:
PEC = 5.0 mikrog/L
PNEC = Lowest NOEC, 10 000 microg/L/10 (Assessment Factor (AF) for three chronic studies) = 1 000 microg/L
PEC/PNEC = 0.005 which gives the risk insignificant.
Risk from Fass environmental information for metformin was developed by Novartis for Eucreas, Icandra, Zomarist (downloaded 2018-05-28). The risk assessment insignificant (PEC/PNEC = 0.021) is calculated on the total amount (kg) of the substance sold in Sweden in 2015 and the substance's toxicity, i.e. consideration has not been taken of measured levels in the environment.
Author: The Pharmaceutical unit of Region Stockholm