Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability:

Data on the stability of quinidine are only available for phototransformation. The calculated phototransformation of quinidine in air, calculated from the hydroxyl radical turn over rate is 160.1943 E-012 cm^3/molecule/s (0.00001384 cm^3/molecule/d). Therefore, we consider phototransformation in air to be negligible. These results are calculated using AOP v1.92, expecting, that phototransformation appears at a constant rate. The EPA recommends that empirical measures provide better results. However, empirical studies have not been done, so that we adapt the prediction.

Biodegradation:

Quinidine hydrochloride was tested in a CO2 Evolution Test according to the OECD Guideline 301 B for 28 days (and 29 days after acidification) to determine whether the test substance is readily biodegradable. After a lag phase of 14 days, the degradation extent started to increase to a final value of 69.2% after 28 days and HCl addition (mean of three replicates). The reference compound sodium benzoate reached the pass levels for ready biodegradability within 4 days. The degradation of the toxicity control after 14 days was 32.5%. Thus, the test item quinidine hydrochloride had no inhibitory effects to the inoculum according to the criterion of the guideline. Quinidine hydrochloride reached the criteria for ready biodegradability (60% ThCO2) within the 10-day time window. Therefore, quinidine hydrochloride can be considered to be readily biodegradable within a test period of 28 days.

Bioaccumulation:

The given BCF, BAF and Biotransformation half-life estimations from the models for quinidine show, that quinidine has a low accumulation potential. Nevertheless, the EPA recommends that EPI Suite is a screening-level tool and should not be used if acceptable measured values are available. However, empirical studies have not been done, so that we consider a BCF of 48 L/kg, BAF of 45 L/kg and Biotransformation half-life of 0.126 days.

Transport and distribution:

The EPI Suite v.4.11. results show that, quinidine adsorbs to carbon and in the environment. The major amount is distributed to soil. The estimated Henrys law constant of quinidine is 8.69E-011 Pa-m3/mole.