Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

A Japanese modified MITI test indicated that biphenyl is readily biodegradable. Other available screening studies on both ready and inherent biodegradability support this finding.

Further, several simulation studies for biodegradation in water and water/sediment systems are available which report reliable information on the biodegradation of biphenyl. These studies indicate that biphenyl is biodegraded in water with half-lives of 2-3 days, and half-lives of 2-10 days in aerobic sediment/water systems. Biodegradation of >70% in 28 days based upon CO2 evolution also support that the substance meets the criteria for rapid degradability. Anaerobic biodegradation can be considered of limited importance for biodegradation of biphenyl in the aquatic environment. Based on the available simulation studies, it is suggested to use 3 days as key half-life for biodegradation in water and 10 days as key half-life for biodegradation in sediment for exposure calculations. These half-lives were the highest half-lives obtained in the respective studies and therefore represent a reasonable worst-case approach.

Although soil simulation studies are not required for this readily biodegradable substance, the available supporting study indicates the potential for soil microorganisms to adapt to, and fully mineralize, the biphenyl substance.