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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Available information: 
1,1 -DPE:
The biodegradation of 1,1-DPE was investigated in a CO2 Evolution Test according to OECD Guideline 301B. For 1-Phenylethylbenzene, the 10-day window started on Day 19 with a mean biodegradation of 12.23%, and ended on Day 29 with a mean biodegradation of 20.93%. At 28 days, 1-Phenylethylbenzene achieved a maximum mean biodegradation of 21.83%. Therefore, the test substance is not considered readily biodegradable.
The biodegradation of 1,1 -DPE (Dowtherm Q; 1,1-DPE: 62 - 68%) was investigated in a CO2 Evolution Test similar to OECD 301B. The method consisted of an inoculum adaptation period followed by a 29 day shake flask biodegradation test with a defined medium. 40.6% (+/- 2.9%) of the nominal concentration of the compound was mineralized to CO2.
1,1 -DPE was not readily biodegradable, but inherently biodegaradable under the conditions of the test performed.
The biodegradation of SAS-40 was investigated in a Modified MITI Test according to
EEC Directive 79/831, Annex V, Part C, section 5.2.A
fter a lag-phase of 5 days about 15 % biodegradation of the test substance was achieved within 4 days. Biodegradation stopped until day 17. Then the biodegradation started again. After an incubation time of 45 days a final degradation of 60 % was achieved .
The biodegradation of Phenyl-tolyl-ethane was investigated in a CO2 Evolution Test according to OECD 301B.
Phenyl-tolyl-ethane was not readily biodegradable under the conditions of the modified Sturm test performed.
A biodegradation study according to OECD Test Guideline 301 C was conducted. Based on the BOD analysis no biodegradation was observed in 28 days whilst 6, 5 and 3 % of primary degradation rates were determined by HPLC analysis. Taking into account the above results, it is concluded that the substance is not readily biodegradable. No data on inherent biodegradation test is available.

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable

Additional information

The reported studies for 1,1 -DPE are GLP compliant and have Klimisch score 1 and 2.

Conclusion: The available data on biodegradation clearly indicates that 1,1’-DPE is not readily biodegradable but only inherently biodegradable as is the case for all members of the diphenylmethane category.