Registration Dossier

Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in water: simulation testing on ultimate degradation in surface water
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Qualifier:
according to
Guideline:
OECD Guideline 309 (Aerobic Mineralisation in Surface Water - Simulation Biodegradation Test)
GLP compliance:
yes
Radiolabelling:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
natural water / sediment: freshwater
Duration of test (contact time):
> 1 - < 28 d
Initial conc.:
ca. 80 <= µg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
radiochem. meas.
Reference substance:
benzoic acid, sodium salt
Key result
Compartment:
natural water / sediment: freshwater
DT50:
ca. 2 d
Type:
(pseudo-)first order (= half-life)
Temp.:
12 °C
Transformation products:
yes
No.:
#1
Evaporation of parent compound:
not specified
Volatile metabolites:
yes
Residues:
not specified
Validity criteria fulfilled:
yes
Conclusions:
AS100 and its hydrolysis degradant are not persisent and are readily biodegradabe.

Description of key information

The screening test was a mimic of the OECD 309 test without sediment, using radiolabelled AS100. However, a further screening test has proven that AS100 does not adsorb onto sediment so the results from the riverwater screening tests also apply to the sediment.

The results from the full OECD 309 test, with suspended sediment, concludes that AS100 is not persistent and that DIXD, the main degradant, is also not persistent. Due to the nature of measuring AS100 and DIXD through radio-labelling it has been demonstrated that both of these materials are readily biodegradable with both of them showing half-lives of between 4 -10 days. This also answers the question regarding persistence and confirms the conclusion that AS100, and its degradant DIXD, are neither vPvB or PBT.

Key value for chemical safety assessment

Half-life in freshwater:
4 d
at the temperature of:
12 °C
Half-life in freshwater sediment:
4 d
at the temperature of:
12 °C

Additional information