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Environmental fate & pathways

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The half-life for indirect phototransformation of biphenyl in air through reaction with hydroxyl radicals has been determined to be 16 h, based on experimental second-order rate constant (Atkinson et al., 1984) and assumed hydroxyl radical concentrationof 1.5 million molecules/cm3. No other reliable information was identified with regard to abiotic transformation of biphenyl in the environment. However, the available information indicates that direct phototransformation in air and water are most likely not processes significantly contributing to degradation of biphenyl in the environment. No information was available on hydrolysis but because biphenyl does not contain any water-reactive or hydrolysable groups, hydrolysis is not considered an important degradation process either. No further testing is needed on abiotic degradation pathways, as biodegradation of this (readily biodegradable) substance will serve as the dominant fate process in aquatic, benthic, and terrestrial environments.