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Environmental fate & pathways

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Delta-damascone was determined to be hydrolytically stable under acidic conditions, but to hydrolyse under neutral and basic conditions. At pH 4 less than 10% hydrolysis had occurred after 120 hours, equivalent to a half-life of greater than 1 year at 25°C. At pH 7 and pH 9, respectively, half-lives of 332 and 41 days were observed (Huntingdon Life Sciences, 2009a). The half-life at 25°C and pH 7 of 332 days will be used in the assessment.

No further tests are available for abiotic degradation of delta-damascone.

Under aerobic conditions delta-damascone was not found to be ready biodegradable in a screening test (OECD guideline 301C); 16% biodegradation of the test substance was found after 28 days (Kurume Laboratory, 2007a).

No biodegradation simulation tests in water, sediment and/or soil are available for delta-damascone.

The degradation rate constants used in the assessment of delta-damascone are:

 

Degradation rate constant for hydrolysis

7.38E-04 d-1

Degradation rate constant for photolysis

6.93E-07 d-1

Degradation rate constant in air

0 d-1

Degradation rate in the STP

0 d-1

Degradation rate in water

7.39E-04 d-1

Degradation rate in sediment

6.93E-07 d-1

Degradation rate in soil

6.93E-07 d-1

Whole-body steady state bioconcentration factors (BCF) ranged from 49.4 to 297 L/kg for Japanese carp exposed to 0.5 µg/L of delta-damascone and from 31.3 to 310 L/kg at a concentration of 5 µg/L of delta-damascone in a flow-through system at 25 ºC (Kurume Laboratory, 2007b). The BCF indicate a low potential for bioconcentration. A weighted average BCF of 58.3 L/kg is used in the assessment.

Delta-damascone was determined to have a log Koc value of 3.1 (equivalent Koc = 1,259 L/kg) using the HPLC Method (GLP study according to OECD 121) (Huntingdon Life Sciences, 2008a).

Data on volatilisation and distribution among compartments is not available.