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

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

7 August 2012 to 5 September 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD 301B, CO2 evolution test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Aluminum, benzoate C16-18-fatty acids complexes

EC Number:

303-385-6

EC Name:

Aluminum, benzoate C16-18-fatty acids complexes

Cas Number:

94166-87-7

Molecular formula:

C23H37AlO5, C25H41AlO5

IUPAC Name:

Aluminum, benzoate C16-18-fatty acids complexes

Test material form:

other: solid

Details on test material:

- Physical state: Pale Yellow Solid
- Purity: Not applicable - UVCB
- Substance identity: Aluminum, benzoate C16-18-fatty acids complexes
- Batch number: 11074091 + Benzoic acid
- Carbon Content: 65.1%
- Analysis code: A118
- Date recieved: 07 June 2012
- Expiration date: 01 July 2013
- Storage of test material: Room temperature in the dark

Specific details on test material used for the study:

The substance is the Source of the read-across.

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

Not applicable

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test item (46.2 mg) was dispersed in approximately 400 mL of mineral medium with the aid of high shear mixing (approximately 7500 rpm for 15 minutes) prior to dispersal in inoculated mineral medium. An aliquot (51.4 mL) of sodium benzoate stock solution (1000 mg/L) was also added to the test vessel and the volume adjusted to 3 litres to give a final concentration of 15.4 mg test item/L and 17.1 mg sodium benzoate/L, equivalent to a total of 20 mg carbon/L.
- Controls: Inoculated mineral medium
- Procedure control: Reference item (sodium benzoate) in inoculate medium to give a final concentration of 10 mg carbon/L.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): Slightly cloudy dispersion with very fine particles of test item dispersed throughout and on the surface.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

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: 30 mg suspended solids/L.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

28 d

Post exposure observation period:

No data reported

Test conditions

Hardness:

No data reported

Test temperature:

21°C

pH:

7.5 to 7.7

Dissolved oxygen:

No data reported.

Salinity:

Not applicable

Nominal and measured concentrations:

- Nominal concentration: 15.4 mg test item/L equivalent to 10 mg Carbon/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 5L test culture vessel containing 3L of test solution
- Aeration: 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.
- No. of vessels per concentration (replicates): One
- No. of vessels per control (replicates): Two for both inoculated control and reference item control.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: 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).
- Culture medium different from test medium: No
- Intervals of water quality measurement: pH measured at Days 0 and 28

OTHER TEST CONDITIONS
- Adjustment of pH: : 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
- Photoperiod: Total darkness:

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : CO2 evolution. CO2 trapped in two 500 mL Dreschel bottles containing 350 mL of 0.05 M NaOH solutions in purified degassed water. 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.


TEST CONCENTRATIONS
Limit test with single test item concentration of 15.4 mg/L.

Reference substance (positive control):

yes

Remarks:

Sodium Benzoate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

15.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Carbon content

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

- Results: The toxicity to micro-organisms result was taken from the toxicity control of a ready biodegradability test. At the only concentration tested (15.4 test item/L), the toxicity control (test item plus sodium benzoate) obtained ≥ 25% degradation by Day 14 (actual 64%) and therefore the test item can be considered to be non-inhibitory to the micro-organisms tested.

Results with reference substance (positive control):

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.

Reported statistics and error estimates:

No data reported

Any other information on results incl. tables

Table 1. Percentage Biodegradation Values

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

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

Applicant's summary and conclusion

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%.

Conclusions:

The No Observed Effect Concentration (NOEC) of aluminum, benzoate C16-18-fatty acids complexes to aquatic micro-organisms is 15.4 mg test item/L.

Executive summary:

The No Observed Effect Concentration (NOEC) of aluminum, benzoate C16-18-fatty acids complexes to aquatic micro-organisms is 15.4 mg test item/L. The toxicity of the test item to activated sewage sludge was taken from the toxicity control of a GLP-compliant ready biodegradability CO₂evolution test following OECD guideline 301B (Harlan 2012). The study is considered reliable and relevant for use for this endpoint.