The T-value in the score for hazard refers to chronic toxicity. Underlying data for P, B, T and risk are from Fass.
Fass environmental information for Valtrex (valaciclovir) (downloaded 2019-02-08).
"Valaciclovir is a pro-drug which is fully metabolised to the active pharmaceutical ingredient Aciclovir. As a result this assessment is based on aciclovir."
Persistence: "Hydrolysis: Half-life, pH 7 > 1 year (TAD 3.09). Photolysis: Half-life, pH 7 = 3.5 hours (TAD 3.10). Aciclovir is not readily biodegradable nor inherently biodegradable. The phrase “Aciclovir is potentially persistent” is thus chosen."
Bioaccumulation: Log Pcalc = -1.55.
Toxicity: There are data for 3 trophic levels, most sensitive crustacean (Daphnia magna) NOEC 10 000 microg/L.
PPEC/PNEC is based on sales data in Sweden in year 2016. PEC/PNEC = 0.0019 which gives the risk insignificant.
Author: Department of Strategic Careers, Stockholm County Council.