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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

1,3-Dichlorbenzene can be biodegradated to 2,4-dichlorophenol (30 - 100 %) and 2,5-dichlorophenol (5 - 30 %) which result in catechol 3,5-dichloro (30 - 100 %) and catechol 3,4-dichloro (5 - 30 %). Guidelinetests which would allow calculating half-lives are not available.
Performing of a simulation test is considered not appropriate as 1,3-dichlorbenzene evaporises rapidly from water and sediment. According to the high vapour pressure and the high Henry´s law constant the substance is expected to evaporate rapidly from water and sediment.

Key value for chemical safety assessment

Additional information

According to section 1 of REACH Annex XI, testing is omitted, as it is scientifically unjustified to conduct the study as a consequence of the properties of the substance: With a vapour pressure of 2.33 hPa at ambient temperature, the substance is considered as highly volatile. The distribution modelling predicts the substance to be present by about 98.5 in air, whereas only about 0.2% are expected in sediment. In a test for degradation in a water-sediment system, the substance would therefore be mainly expected to evaporate from the water and sediment compartment. The main degradation pathway is then photochemically induced photolysis in air by hydroxy radicals.