Decanoic acid, mixed esters with heptanoic acid, octanoic acid and pentaerythritol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 May 1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study with acceptable restrictions: No analytical purity is given. , no analytical monitoring)

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Test substanz was emulsified using Ultra-Turrax.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Laboratory culture: Activated sludge from sewage plant Bempflingen, Germany
- Preparation of inoculum for exposure: Activated sludge was washed with tap water twice, afterwards centrifuged and the dry residue was
determined. The amount of the sludge was weighed per liter, which was corresponded to 4 g dry mass.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Hardness:

not stated

Test temperature:

20 ± 2 °C

pH:

not stated

Dissolved oxygen:

> 6.5 mg/L

Nominal and measured concentrations:

Nominal: 10000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Material: glass; Size: 1 L; Fill volume: 500 mL
- Aeration: continously to reach an oxygen content > 6.5 mg/L
- No. of vessels per concentration: 1
- No. of vessels per control: 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated tap water

EFFECT PARAMETERS MEASURED: Respiration inhibition by decrease of oxygen content was measured in 15-minutes-pulses over a test period of 3 h using an OXI-meter.

Reference substance (positive control):

yes

Remarks:

3,5 dichlorphenol

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

- Results with reference substance valid? Yes, result is in the range of 5 to 30 mg/L
- Relevant effect levels: EC50 = 5 mg/L

An increase about 43% of respiration rate could be observed at the nominal tested concentration of 10000 mg/L in comparison to the control.

Table 1: Respiration rate of control, reference and test substance and inhibition of the respiration rate of test and reference substance (*A negative sign means an increase of the respiration)

	Replicates	Concentration [mg/L]	Respiration rate [mg O2/L x h]	Inhibition [%]
Control	1		24.0 25.0	-
Referenz	1 2 3	2.5 10 30	22.0 11.0 5.0	10.2 55.1 79.6
Test substance	1	10000	35.0	-43.0*

 *: negative value indicate an increase of respiration

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

The substance is a member of a group of pentaerythritol and a mixture of alkyl carboxylic acids which share similar characteristics across the group. Please see attached justification for read across.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: CAS 11138-60-6

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: CAS 11138-60-6

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: CAS 70693-33-3

Conclusions:

The substance, CAS 68441-67-8, is analogous to the substances to be read across to, in terms of basic form, and the degree of substitution of functional groups is not considered to effect the proposed read across for the endpoint of toxicity to microorganisms. The substance is considered to be not toxic to microogranisms for the defined endpoints on the basis of read across. This will be confirmed by appropriate study data as soon as this is available.

Executive summary:

The substance, CAS 68441-67-8, is analogous to the substances to be read across to, in terms of basic form, and the degree of substitution of functional groups is not considered to effect the proposed read across for the endpoint of toxicity to microorganisms. The substance is considered to be not toxic to microogranisms for the defined endpoints on the basis of read across. This will be confirmed by appropriate study data as soon as this is available.

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

22 November 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed in accordance with OECD & EU test guidelines in compliance with GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

Since HATCOL 5236 was hardly soluble in water, the test substance was quantiatively added to the test vessels. A nominal concentrtion of 100 mg/l was tested in duplicate.

Vehicle:

no

Details on test solutions:

Since HATCOL 5236 was hardly soluble in water, the test substance was quantiatively added to the test vessels. A nominal concentrtion of 100 mg/L was tested in duplicate.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Test System: Micro-organisms in activated sludge.
Source: Municipal sewage treatment plant: 'Waterschap de Maaskant', 's-Hertogenbosch, the Netherlands.
Number of micro-organisms: Number of micro-organisms was determined as the amount of Mixed Liquor Suspended Solids (MLSS) per litre test medium.
Preparation of the sludge: The sludge was coarsely sieved, washed and diluted with tap-water. A small amount of the sludge was weighed and dried at ca. 105°C to determine the amount of suspended solids (2.5 g/l of sludge, as used for the test). Before use the pH was checked (measured value: 7.6).
The batch of sludge was used on the subsequent day, therefore 50 ml of synthetic sewage feed was added to each lire of activated sludge at the end of each working day. The sludge was kept aerated at test temperature until use.
Rationale: Recognized by international guidelines as the recommended test system.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

30 min

Post exposure observation period:

No post exposure observation period specified in the study report.

Hardness:

Not specified in the study report.

Test temperature:

The temperature of the test medIum was 21.6°C.

pH:

7.8 - 8.1

Dissolved oxygen:

Not applicable - respiration inhibition study

Salinity:

Not applicable - freshwater study

Nominal and measured concentrations:

Nominal concentrations.

Details on test conditions:

TEST PROCEDURE AND CONDITIONS
Contact time: 30 minutes, during which aeration and stirring took place.
Vessels: All glass, 300 ml oxygen bottles and 1 L test bottles.
Milli-RO / Milli-Q water: Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon and ¡on-exchange cartridges (Milli-Q) (Millipore Corp., Bedford, Mass., USA).
Synthetic sewage feed: 16 g peptone; 11 g meat extract; 3 g urea; 0.7 g NaCI; 0.4 g CaCI2.2H20; 0.2 g MgSO4 .7H2O; 2.8 g K2HPO4. Dissolved in 1 L Milli-Q water and filtered. The pH was 7.1.
Air supply: Clean, oil-free air.
Oxygen meter: WTW inolab Oxi Level 2 supplied with a WT CellOx 325 oxygen electrode, electrolyte type ELY/G.
Recorder: Flatbed recorder SE 102 (Kipp & Zonen).
Performance of the test: The synthetic sewage feed (16 ml) and an adequate amount of the test substance were mixed and made up to 300 ml with Milli-RO water. Activated sludge (200 ml) was added and the mixture was aerated in a 1 L bottle during the contact time, using a pipette as an aeration device.
Then a well mixed sample of the contents was poured Into a 300 ml oxygen bottle, and the flask was sealed with an oxygen electrode connected to a recorder, forcing the air out of the vessel. Oxygen consumption was measured and recorded for approximately 10 minutes. During measurement, the sample was not aerated but continuously stirred on a magnetic stirrer. The pH was determined In the remaining part of the reaction mixture.
This procedure was repeated for the duplicate concentration. In each test series two controls without test substance were tested, one at the start and one at the end.
Each batch of activated sludge was checked for sensitivity by testing the reference substance 3.5-dichlorophenol.
The flasks were filled up to 500 ml final volume.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol.

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

Toxicity of HATCOL 5236
No inhibition of respiration rate of the sludge was recorded at 100 mg HATCOL 5236 per litre.
The duplicate measurement confirmed the result of the first measurement.
Therefore no further testing was needed.

Experimental conditions
The temperature of the test medium was 21.6°C.

Acceptability of the test
The mean respiration rate of control 1 and 2 was 31 mg O2/l/hr. The difference between the controls was 3%.

Since all criteria for acceptability of the test were met, this study was considered to be valid.

Results with reference substance (positive control):

The EC50 of 3,5-dichlorophenol was 12 mg/l (regression line: Y = 56.01 X -1 0.87, Y = % inhibition and X = log concentration (mg/l)).

Reported statistics and error estimates:

Not specified in the study report.

pH, oxygen concentration at the start of measurement and the influence of 3,5-dichlorophenol and HATCOL 5236 on the oxygen consumption of microbes in activated sludge and percentage inhibition of respiration rate

Flask	Concentration reference/test substance (mg/l)	Oxygen conc. at the start (= mg O2/l)	Oxygen consumption mg O2/l/hr	Inhibition %	pH
C1	-	8.3	30	-	8.1
C2	-	8.2	31	-	8.1
Mean C1 + C2			31 (∆3%)
R1	3.2	8.0	25	18	8.1
R2	10	8.4	17	44	8.1
R3	32	8.5	8	74	8.1
T1	100	7.0	33	-8^1	7.8
T2	100	6.5	33	-8^1	7.9

C: Control; R: Reference substance; 3,5-dichlorophenol; T: Test substance, HATCOL 5236;¹: Negative values indicate simulation of respiration rate of the sludge. These values are considered as not significant.

 

Determination of the EC50-value for 3,5-dichlorophenol

Parameter: % inhibition

Concentration (mg/l)	X Log conc. (mg/l)	Y Inhibition (%)
3.2	0.505	18
10	1.000	44
32	1.505	74

 

Prediction of X values based on known Y values

Known Y Inhibition (%)	10^Xreg(mg/l)	10^X95%(mg/l)	10^X95%+(mg/l)
50	12.2	5.2	28.5

 

Validity criteria fulfilled:

yes

Conclusions:

In conclusion. under the conditions of the test, HATCOL 5236 was not toxic to waste water (activated sludge) bacteria at a concentration of 100 mg/l.

Executive summary:

The Influence of HATCOL 5236 on the respiration rate of activated sludge was investigated after a contact time of 30 minutes.

The study procedure was based on OECD Guideline No. 209, adopted April4, 1984 and EEC Directive 67/548 amended November 18,1987 (87/302), Part C, Publication No. L133, adopted May 30, 1988.

Since HATCOL 5236 was hardly soluble in water, the test substance was quantitatively added to the test vessels. A nominal concentration of 100 mg/l was tested in duplicate. The concentration was approved by the study director in the study files.

No Inhibition of respiration rate of the sludge was recorded at 100 mg HATCOL 5236 per lire.

The duplicate measurement confirmed the result of the first measurement. Therefore no further testing was needed.

The respiration rates of the controls were within 15% of each other.

The EC50 of the reference substance, 3,5 dichlorophenol. was 12 mg/l.

Therefore, the test was considered to be valid.

In conclusion under the conditions of this present test, HATCOL 5236 was not toxic to waste water (activated sludge) bacteria at a concentration of 100 mg/l.

Description of key information

Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate (CAS-No. 11138-60-6) is not harmful to microorganisms.

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L

Additional information

One study, investigating the toxicity to microorganisms, was available for Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate (CAS-No. 11138-60-6). This respiration inhibition test (Kuttler, 1998) with activated sludge (domestic) according to OECD 209 showed an increase about 43% of respiration rate at the nominal tested concentration of 10000 mg/L in comparison to the control. No inhibition of respiration rate was observed. Therefore the EC50 and EC10 (3h) can be stated as > 10000 mg/L (nominal). Furthermore, the biodegradation tests exhibit the readily biodegradability of the test substance. Thus, a disturbance in the biodegradation process of a sewage treatment plant is not anticipated.

The Influence of HATCOL 5236 on the respiration rate of activated sludge was investigated after a contact time of 30 minutes.

Since HATCOL 5236 was hardly soluble in water, the test substance was quantitatively added to the test vessels. A nominal concentration of

100 mg/l was tested in duplicate. The concentration was approved by the study director in the study files.

No Inhibition of respiration rate of the sludge was recorded at 100 mg HATCOL 5236 per lire.

The duplicate measurement confirmed the result of the first measurement. Therefore no further testing was needed. The respiration rates of the controls were within 15% of each other.

The EC50 of the reference substance, 3,5 dichlorophenol was 12 mg/l.

Therefore, the test was considered to be valid.

In conclusion under the conditions of this present test, HATCOL 5236 was not toxic to waste water (activated sludge) bacteria at a concentration of 100 mg/l.