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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
September 28 2009 to January 29 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodoological deficiencies, which do not affect the quality of relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Biodegradability Test of Chemical substances by Microorganisms (Yakushokuhatsu No. 1121002, Heisei 15.11.13 Seikyoku No.3, Kanpokihatsu No. 031121004, 21/11/03, revised 04/07/08)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Name of chemical substance: Hatcol 1760
CAs no: 156558-98-4
Purity: 99.2%
Lot number: A25983
Appearance: Colourless, clear, slightly viscous liquid
stability: Avoid high temperature, strong acid, strong base and strong oxidant.

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, adapted
Details on inoculum:
- Source of inoculum/activated sludge: Chemicals Evaluation and Research Institute, Japan

- Laboratory culture: Not applicable

- Method of cultivation: not applicable

- Storage conditions: not stated in report

- Storage length: not stated in report

- Preparation of inoculum for exposure: not stated in report

- Pretreatment: not stated in report

- Concentration of sludge:
Mixed liquor suspended solids: 3900 mg/l (BOD measurement), 3200 mg/l (Recovery test)

- Initial cell/biomass concentration: not stated in report

- Water filtered: not stated in report

- Type and size of filter used, if any: not stated in report
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimationopen allclose all
Parameter followed for biodegradation estimation:
DOC removal
Parameter followed for biodegradation estimation:
other: Biochemical oxygen demand - BOD
Details on study design:
TEST CONDITIONS
- Composition of medium:
Composition of liquids A,B, C and D
Liquid A: Aqueous solution containing 2.175% K2HPO4, 0.85% KH2PO4, 4.46% Na2HPO4.12H2O and 0.17% NH4Cl
Liquid B: Aqueous solution containing 2.25% MgSO4.7H2O
Liquid C: Aqueous solution containing 2.75% CaCl2
Liquid D: Aqueous solution containing 0.025% FeCl2.6H2O

- Additional substrate: not applicable
- Solubilising agent (type and concentration if used): not applicable
- Test temperature: 25 +/- 1°C
- pH: 7.0 =/- 0.04
- pH adjusted: yes - with 1N HCL or 1N NaOH.
- CEC (meq/100 g): not stated in report
- Suspended solids concentration: 3900 mg/l (BOD measurement), 3200 mg/l (Recovery test)
- Continuous darkness: not stated in report


TEST SYSTEM
- Culturing apparatus: closed system oxygen consumption measuring apparatus
- Number of culture flasks/concentration: three
- Method used to create aerobic conditions: not stated in report
- Method used to create anaerobic conditions: not applicable
- Measuring equipment: closed system oxygen consumption measuring apparatus
- Test performed in closed vessels: yes
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: not applicable


SAMPLING
- Sampling frequency: At the start and end of exposure
- Sampling method: not stated in report
- Sterility check if applicable: not applicable
- Sample storage before analysis: not applicable


CONTROL AND BLANK SYSTEM
- Inoculum blank: 2.3 ml of activated sludge was added to the basal medium (The total volume of the basal medium and the sludge was held fixed at 300 ml)
- Abiotic sterile control: To 300 ml of purified water, 30.0 mg of the test substance was added
- Toxicity control/ activity control: To the basal medium, 29.5 µl (30.0 mg) of aniline and 2.3 ml of activated sludge was added


STATISTICAL METHODS:
Equations for calculation of degradability:
1) Degradability based on BOD:
Degradability (%) = ((BODs - BODb)/ThOD) x 100
where
BODs: Oxygen consumption (mg) in activity control and test suspensions
BODb: Oxygen consumption (mg) in inoculum blank
ThOD: Theoretical oxygen demand (mg) of aniline or the test substance ThOD

2) Degradability based on DOC
Degradability (%) = [1-(DOCs - DOCb) / DOCc] x 100
where
DOCs: DOC (mg) in test suspensions
DOCb: DOC (mg) in inoculum blank
DOCc: DOC (mg) in abiotic control

Reference substance
Reference substance:
aniline

Results and discussion

Preliminary study:
No preliminary study described in report.
Test performance:
The biodegradability test was judged valid since the measurement results fulfilled all the validity criteria of the guideline.
% Degradation
Parameter:
other: BOD
Value:
59
Sampling time:
28 d
Remarks on result:
other: The average biodegradability based on BOD.
Details on results:
The test substance is multicomponent esters of pentaerythritol and acids. Pentaerythritol and 3,5,5-trimethylhexanoic acid were detected as the transformation product. . Therefore, it is presumed that most of the ester bonds of the test substance were degraded. Linear carboxylic acids that construct the test substance have easily degradable structures. The average degradability based on BOD was 59%. It is considered that linear carboxylic acid is mineralised by sludge.

BOD5 / COD results

BOD5 / COD
Parameter:
BOD5
Value:
59 other:

Any other information on results incl. tables

The average degradability based on BOD was 59%.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: Ready biodegradable when classified according to the Dangerous Preparations Directive (99/45/EEC)
Conclusions:
The substance did not achieve the required level of biodegradation within 28-days in order for it to be considered as readily biodegradable.
Executive summary:

The study was conducted in accordance with the Test Method Relating to New Chemical Substances <Biodegradability Test of Chemical Substances by Microorganisms> (Yakushokuhatsu No. 1121002, Heisei 15.11.13 Seikyoku No. 2, Kanpokihatsu No. 031121002, November 21, 2003; the latest revision November 20, 2006).

The test substance was exposed to activated sludge in a closed-system oxygen consumption measuring apparatus. the biochemical oxygen demand (BOD) was measured over a 28 -day period. After this period, the amount of dissolved organic carbon (DOC) and the residual amount of test substance were measured. Reverse phase HPLC measurement was performed to confirm the existence of the transformation products, and the amount of assumed transformation products was measured. The biodegradability of the test substance was evaluated from these results.

From the degradability results based on the BOD (av. 59%), it is judged that the test substance is not readily biodegradable.

Although the analysis with the GPC column showed that 11 - 13% of the test substance remained, the test substance was not detected in the reversed phase HPLC measurement. Therefore it is considered that all the test substance disappeared and the component at the same retention time with the test substance was the transformation product.

The test substance is multicomponent esters of pentaerythritol and acids.

The average degradability based on BOD was 59%.

LC/MS was used to estimate the transformation products.

All the test substance disappeared, and 3,5,5 -trimethylhexanoic acid and pentaerythritol remained. It is judged that the test substance is not ready biodegradable.