Reaction products of decanoic acid and lauric acid with glycerol and polyglycerol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Remarks:

ready biodegradation test including toxicity control

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

1997; including toxicity control

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge from the aeration basin of a municipal sweage treatment plant (Moers, Germany)
- Storage length: 1 day
- Preparation of inoculum for exposure: After determination of the suspended solids dry weight 1875 mg suspended solids was filtered by means of a water jet pump through a filter paper (Whatman GmbH, black ribbon 589(1)). The sludge was washed twice with mineral medium. Afterwards, it was suspended in 250 mL mineral medium and stirred until it was homogeneous. 4 mL of this suspension were used to inoculate 1 L of mineral medium.
- Concentration of sludge: 30 mg/L suspended solids

Test type:

static

Water media type:

freshwater

Total exposure duration:

28 d

Details on test conditions:

TEST CONDITIONS
- Test temperature: 22 ± 1°C
- pH: 7.4
- pH adjusted: yes, if needed
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 3 x blank control, 2 x Abiotic control, 2 x Reference substance, 3 x Test substance, 2 x Toxicity control
- Measuring equipment: Digital Respirometer System, Sensomat system, Liebherr, Aqualytic, Langen, Germany
- Test performed in closed vessels due to significant volatility of test substance: closed system due to the parameter measured (oxygen consumption)
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: trapped by sodium hydroxide
- Other: As inhibitor of nitrogen oxidation 15 drops of N-allylthiourea were added to each test vessel.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 3 vessels
- Abiotic sterile control: 2 vessels
- Toxicity control: 2 vessels

Reference substance (positive control):

no

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Conclusions:

The substance was not inhibitory to microorganisms at 100 mg/L (75% degradation in the toxicity control after 14 d).

Executive summary:

Polyglycerin caprylate/caprinatewas tested in a manometric respirometry test according to the OECD Guideline for Testing of Chemicals, No. 301 F, for 28 days to determine whether the test substance is readily biodegradable.

The oxygen uptake by a stirred preparation of the test substance in a concentration of 100 mg/L in a mineral medium, inoculated with unadapted microorganisms, was measured automatically over a period of 28 days in a darkened, enclosed respirometer at 22 ± 1°C. Biodegradation is expressed as percentage oxygen uptake (corrected for blank uptake) of the Theoretical Oxygen Demand (ThODNH4) calculated for the test substance.

Activated sludge from a municipal sewage treatment plant (Moers, Germany) was used as inoculum. As reference substance (procedure control) sodium benzoate in a concentration of 100 mg/L was

used. After 14 days the reference substance was sufficiently degraded to 89 % of the ThODNH4, thus confirming the suitability of the used activated sludge inoculum and fulfilling the validity criteria

mentioned in the relevant test guideline. The reference substance was degraded to 93 % of the ThODNH4 after 28 days.

At the end of the exposure period a degradation rate of 86 % of the ThODNH4 of the test substance was measured. 62 % was the degradation rate at the end of the 10-days window.

The test substance showed no toxicity towards microorganisms of the activated sludge because 75 % degradation (based on ThOD) was recorded within 14 days in the toxicity control preparations containing both the test substance and the positive control substance in the same concentrations.

Description of key information

14 d NOAEC = 10 mg/L (OECD TG 301 F; RL1; GLP)

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

100 mg/L

Additional information

Polyglycerin caprylate/caprinatewas tested in a manometric respirometry test according to the OECD Guideline for Testing of Chemicals, No. 301 F, for 28 days to determine whether the test substance is readily biodegradable.

The oxygen uptake by a stirred preparation of the test substance in a concentration of 100 mg/L in a mineral medium, inoculated with unadapted microorganisms, was measured automatically over a period of 28 days in a darkened, enclosed respirometer at 22 ± 1°C. Biodegradation is expressed as percentage oxygen uptake (corrected for blank uptake) of the Theoretical Oxygen Demand (ThODNH4) calculated for the test substance.

Activated sludge from a municipal sewage treatment plant (Moers, Germany) was used as inoculum. As reference substance (procedure control) sodium benzoate in a concentration of 100 mg/L was

used. After 14 days the reference substance was sufficiently degraded to 89 % of the ThODNH4, thus confirming the suitability of the used activated sludge inoculum and fulfilling the validity criteria

mentioned in the relevant test guideline. The reference substance was degraded to 93 % of the ThODNH4 after 28 days.

At the end of the exposure period a degradation rate of 86 % of the ThODNH4 of the test substance was measured. 62 % was the degradation rate at the end of the 10-days window.

The test substance showed no toxicity towards microorganisms of the activated sludge because 75 % degradation (based on ThOD) was recorded within 14 days in the toxicity control preparations containing both the test substance and the positive control substance in the same concentrations.