The T-value in the score for hazard refers to acute toxicity. Underlying data for B, T and risk are from Fass. Expert has assessed the data for P, see below.
Fass environmental information for Madopark (benserazide, levodopa) (downloaded 2018-11-15).
Persistence: "Biotic Degradation - Ready biodegradability: 2% after 28 days of incubation BOD/ThOD (OECD 301 F), 48% after 28 days of incubation DOC/TOC (OECD 301 F), 100% after 28 days of incubation Parent (OECD 301 F). Inherent biodegradability: 84% after 7 days of incubation DOC (OECD 302 B), 93% after 14 days of incubation DOC (OECD 302 B), 93% after 28 days of incubation DOC (OECD 302 B). Other degradation information: ND. Abiotic Degradation - Photodegradation: 58% (120 h, 22 °C, light), Hydrolysis: 52% (120 h, 22 °C, in the dark). Benserazide is not readily degradable, but inherently biodegradable according to OECD 302 B. This justifies the phrase 'Benserazide hydrochloride is slowly degraded in the environment."
Bioaccumulation: log Kow ≤ 0.5 QSAR benserazide, BCF < 10 QSAR benserazide.
Acute toxicity: There is data for 3 trophic levels, lowest for green alga (Desmodesmus subspicatus) 2 660 microg/L.
PEC/PNEC is based on sales data in Sweden in year 2016. PEC/PNEC = 0.021 which gives the risk insignificant.
Based on Fass's environmental information above, benserazide is not considered to be persistent according to expert (Researcher at the Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University 2018-12-05).
Author: Health and Medical Care Administration, Region Stockholm