Aluminum, benzoate C16-18 fatty acids complexes - high aluminium

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Data waiving:

other justification

Justification for data waiving:

the study does not need to be conducted because the substance is readily biodegradable

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

7 August 2012 to 5 September 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant, guideline study, available as an unpublished report.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum: Aeration stage of sewage treatment plant which treats predominantly domestic sewage.
- Storage conditions: Continuously aerated at 21°C
- Storage length: Used on day of collection
- Preparation of inoculum for exposure: Washed twice by settlement and resuspension in mineral medium to remove any excessive amounts of dissolved organic carbon (DOC) that may be present. Test vessels containing 2400 mL mineral medium and 22.5 mL inoculum were aerated with CO2 free air overnight prior to the addition of the test and reference items. The volume in all vessels was finally adjusted to 3 litres.
- Concentration of sludge: 4.0 g suspended solids/L prior to use..

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

other: Total carbon content

Initial conc.:

15.4 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium:OECD guideline mineral medium containing KH2PO4 (0.0850g/L), K2HPO4 (0.2175 g/L), Na2HPO4.2H2O ().3340 g/L), NH4Cl (0.005 g/L), CaCl2 (0.0255 g/L), MgSO4.7H2O (0.0225 g/L) and FeCl3 (0.00025 g/L).
- Test temperature: 21°C
- pH: 7.6 to 7.7
_ pH adjustment: If necessary, the pH was adjusted to 7.4 ± 0.2 using dilute hydrochloric acid or sodium hydroxide solution prior to aeration of the mineral medium
- Aeration of dilution water: Test vessels were sealed and CO2-free air was bubbled through the solutions at rates of 30 to 100 mL/minute/vessel and stirred continuously with a magnetic stirrer. CO2-free air was produced by passing compressed air through a glass column containing self-indicating lime soda.
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 5L test culture vessel
- Number of culture flasks/concentration: Two for test item, inoculate control and reference item. One for toxicity control (test item plus reference item).
- Method used to create aerobic conditions: Continuous aeration with C02-free air.
- Measuring equipment: inorganic carbon (IC) and total carbon (TC) channels of TOC analyser.
- Details of trap for CO2: Two 500 mL Dreschel bottles containing 350 mL of 0.05 M NaOH solutions with purified degassed water.

SAMPLING
- Sampling: 2 mL samples were taken from the first CO2 absorber vessels on days 0, 2, 6, 8, 10, 14, 21, 28 and 29 and analysed for CO2 immediately using IC channel of TOC analyser. Second absorber vessels were sampled on days 0 and 29.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Inoculated mineral medium.
- Procedure control: Reference item (sodium benzoate) in inoculate medium to give a final concentration of 10 mg carbon/L.
- Toxicity control: Test item plus reference item in inoculated mineral medium to give a final concentration of 20 mg carbon/L.

Reference substance:

benzoic acid, sodium salt

Preliminary study:

Not applicable

Test performance:

The results of the inorganic carbon analysis of samples from the first absorber vessels on day 29 showed a decrease in all replicate vessels, which was considered to be due to sampling/analytical variation. Inorganic carbon analysis of samples from the second absorber vessels on day 29 showed no significant carry-over of CO2.

Parameter:

% degradation (CO2 evolution)

Value:

79

Sampling time:

28 d

Details on results:

The test item satisfied the 10-day window validation criterion, whereby 60% degradation must be obtained within 10 days of the degradation exceeding 10%. The test item is therefore considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

The toxicity control attained 64% degradation after 14 days and 87% degradation after 28 days thereby confirming the test item was not toxic to the sewage treatment micro-organisms used in the test.

Results with reference substance:

The reference substance (sodium benzoate) attained 82% degradation after 14 days and 92% degradation after 28 days thereby confirming the suitability of the inoculum and test conditions.

Table 1. Percentage Biodegradation Values

Day	Percentage Biodegradation
	Test item	Sodium Benzoate Procedure Control	Test Item plus Sodium Benzoate Toxicity Control
0	0	0	0
2	21	56	36
6	28	68	46
8	40	70	53
10	52	80	51
14	64	82	64
21	61	83	69
28	75	90	79
29*	79	92	87

*  Day 29 values corrected to include any carry-over of CO₂detected in Absorber 2

Validity criteria fulfilled:

yes

Remarks:

The total CO2 evolution in the inoculum control was < 40 mg/L (actual 27.36 mg/L). The IC content of the test item in the mineral medium at test start was < 5% (actual 2%). The difference in CO2 production at test end between replicates was < 20%.

Interpretation of results:

readily biodegradable

Conclusions:

Aluminum, benzoate C16-18-fatty acids complexes reached 79% degradation after 28 days, meeting the 10 day window, and therefore is considered to be readily biodegradable.

Executive summary:

Aluminum, benzoate C16-18-fatty acids complexes reached 79% degradation after 28 days, meeting the 10 day window, and therefore is considered to be readily biodegradable. The ready biodegradability of the test item was determined in a GLP-compliant CO2 evolution test following OECD guideline 301B (Harlan 2012). The study is considered reliable and relevant for use for this endpoint. Aluminum, benzoate C16-18-fatty acids complexes is not considered to be inhibitory to sewage treatment micro-organisms.