Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

The substance can be considered as biodegradable.

Additional information

No specific experiments conducted on propiophenone are available, thus the biodegradability potential has been investigated by estimation tool and using the available data on similar substance acetophenone. The Read Across approach can be considered appropriate for the assessement of biodegradation. Details can be found in the Read Across justification document attached in section 13 of IUCLID.

Based on the physical-chemical properties and based on the knowledge of its biodegradation pathway, the substance is expected to be biodegradable. In order to support this conclusion the ready biodegradability was evaluated using calculation tools. The QSAR based screening criterion for identifying substances for persistency (P and vP) confirmed that the substance is not expected to be persistent; on the contrary, propiophenone is expected to be ready biodegradable.

The analogue acetophenone was found to be ready biodegradable under aerobic conditions.

The 5-day BOD value has been determined using acclimated inocula of wastewater origin and using the techique according to APHA 1980. The mean 5-day BOD resulted 5.61 (SD: 0.17) mmol BOD/ mmol test chemical. The most probable degradation pathway for ketons has been described involving insertion of an oxygen atom next to the keto group by a ketone monooxygenase, producing an ester that is subsequently hydrolyzed, presumably to products that are easily degraded. The log (% removal) appears to be linearly correlated with log P (Vaishnav et al, 1983).

Urano and Kato (1986) determined the biodegradation of acetophenone over a period of 14 days, using electrolytic respirometer. They indicate that ketones are changed into carboxylic acids and they concluded that acetophenone was completely biodegraded in a short time by general microorganisms.

A further investigation has been conducted under anaerobic condition, by Kemeya et al (1995). The biodegradation of acetophenone was determined in a 28 days experiment, by the standard and low concentration test. Under the experimental condition, acetophenone resulted inhibitory and not biodegraded even in the low concentration test.

An experiment was conducted with acetophenone to measure and compare the degradation of chemical in ground, Lester river and Superior harbor waters by autochthonous micro-organisms. Biodegradation in each water was separately measured by the BOD technique (APHA 1980). Acetophenone biodegraded in all three waters, however the percetage of ThBODs varied among the water types. It was found that test item followed first-order kinetics and thus, chemical half-lives were estimated from the first-order biodegradation rate constants. Variations among chemical biodegradation rates in natural waters can arise from the differences in physicochemical and/or microbial composition of waters (Vaishnav and Babeu, 1987).