Castor oil, ester with glycerol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data based on the inhibition control of a ready biodegradability study. This approach is in accordance with the Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance, ECHA 2012).

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: OECD 301F: Ready biodegradability

Version / remarks:

OECD 301F (17.07.92): OECD Guideline For Testing Of Chemicals - Ready Biodegradability, Manometric Respirometry Test

GLP compliance:

yes

Remarks:

Ministerium für Arbeit, Integration und Soziales des Landes Nordrhein-Westfalen, Düsseldorf, Germany

Details on test solutions:

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Measuring equipment: The measurement and recording of the oxygen demand was carried out continuously using a SAPROMAT respirometer (VOITH Inc.).
- Test performed in closed 500 mL glass vessels.
- Details of trap for CO2 and volatile organics if used: Evolved carbon dioxide is absorbed in a suitable absorbent.

SAMPLING
- Sampling frequency: Cumulated consumption (mg O2/L) was measured at each day in the 28 day incubation period.
- Sampling method: The measurement and recording of the oxygen demand was carried out continuously using a SAPROMAT respirometer (VOITH Inc.).

TEST SYSTEM
- Toxicity control: A toxicity control containing test item at 100 mg per liter and reference item at 100 mg per liter mineral test medium (25 mg test item/250 ml and 25 mg reference item/250 ml) was applied.

Test organisms (species):

other: Fresh samples of activated sludge from the sewage treatment plant Ruhrverband Klaranlage, Schmallenberg, Germany, which is mainly fed with municipal wastewater.

Details on inoculum:

- Source of inoculum/activated sludge: Fresh samples of activated sludge were withdrawn from the sewage treatment plant Ruhrverband Kläranlage,Schmallenberg, Germany, which is mainly fed with municipal wastewater.
- Pretreatment: The samples were not washed with mineral medium after the arrival at the laboratory but kept aerobic until use. The sludge was left for settlement for ca. one hour. Subsequently the supernatant was discarded and the concentration of suspended solids was measured in the remaining sludge.
- Concentration of sludge: The concentration was adjusted to 4.8 g/L and verified by dry mass measurement. The concentration used in the test was 29.6 mg dry mass/liter (7.4 mg dry mass/250 ml).
- Water filtered: no

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

14 d

Test temperature:

22 °C ± 1 °C

pH:

7.4 ± 0.2

Details on test conditions:

TEST CONDITIONS
- Composition of medium: Mineral stock solution (a): KH2PO4: 8.50 g/L; K2HPO4: 21.75g/L; Na2HPO4: 26.64 g/L; NH4CI: 0.50 g/L; pH 7.4 +/- 0.2; (b) CaCl2x 2 H2O: 36.40 g/L; (c): MgSO4 X 7 H2O: 22.50 g/L; (d) FeCl3 x 6 H2O: 0.25 g/L
The mineral medium applied in the test contained 10 ml/L of mineral stock solution (a) and 1 ml/L of the mineral stock solution (b)-(d), respectively.
- Test temperature: 22 °C ± 1 °C
- pH: 7.4 ± 0.2
- pH adjusted: yes
- Aeration of dilution water: yes
- Continuous darkness: yes

Reference substance (positive control):

yes

Remarks:

sodium benzoate

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Result of toxicity control from ready biodegradability test

Results with reference substance (positive control):

The reference material (sodium benzoate) attained 86% degradation after 14 days in the absence of the test item.

The toxicity control attained 67% degradation after 14 days of incubation.

Since more than 25% degradation occurred in the toxicity control, the substance is with high probability not toxic to aquatic microorganisms. The test item concentration in the toxicity control of 100 mg/L can be used as NOEC value for the toxicity to aquatic microorganisms.

Description of key information

A NOEC for Toxicity to microorganisms was derived from a ready biodegradability study OECD 301F.

NOEC = 100 mg/L

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

100 mg/L

Additional information

The toxicity control of the available study on ready biodegradability conducted according to OECD 301F is used to derive a NOEC for the toxicity to aquatic microorganisms. If a compound degrades well in a ready biodegradability test, or does not inhibit the degradation of a positive control at a certain concentration, this concentration can be used as a NOEC value. This approach is in accordance with the Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance, ECHA 2017).

A substance can be assumed to be not inhibitory to aquatic microorganisms, if in the toxicity control of a ready biodegradation test, more than 25% degradation based on oxygen demand (BOD/ThOD) occurred within 14 days (OECD guideline 301). For Castor oil, ester with glycerol a biodegradation test according to OECD guideline 301F is available (IOI Oleo, 2017). The test includes a toxicity control, which contains 100 mg/L of the test item, Castor oil, ester with glycerol, and 100 mg/L of the reference material, benzoate. The toxicity control attained 67 % degradation after 14 days of incubation. Hence, the substance is not toxic to aquatic microorganisms in the toxicity control and the test item concentration of 100 mg/L can be used as NOEC.