2-tetradecyloxirane, reaction products with boric acid

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-tetradecyloxirane, reaction products with boric acid

EC Number:

701-392-2

IUPAC Name:

2-tetradecyloxirane, reaction products with boric acid

Details on test material:

- Physical state: Light coloured liquid
- Analytical purity: Considered to be 100% pure
- Storage condition of test material: In the dark
- Other: MSDS and sample receipt indicate the sample recieved as a solid.

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

Not applicable for this type of study.

Test solutions

Vehicle:

no

Details on test solutions:

The test material was added directly to each test vessel using glass microscopic cover slips. Nominal test material concentrations of 1, 10, 100, 1000 and 10000 mg/L corresponding to 0.0005, 0.005, 0.05, 0.5 and 5 g of test material were used.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- On day or collection and arrival, sludge aerated with low-pressure, oil free air and fed with synthetic feed at a rate of 50 mL /L
- Triplicate 4 mL samples were dried at 100°C to a constant weight, then diluted to produce a dryweight per unit volume concentration of 4 g/L

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Post exposure observation period:

Not applicable

Test conditions

Hardness:

Not applicable

Test temperature:

20°C

pH:

Not applicable

Dissolved oxygen:

Not applicable

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal test material concentrations of 1, 10, 100, 1000 and 10000 mg/L corresponding to 0.0005, 0.005, 0.05, 0.5 and 5 g of test material were used.

Details on test conditions:

TEST SYSTEM
- Test vessel: 1L flint glass bottles
- Total fill volume: 500 mL
- Type : closed
- Aeration: yes, low pressure oil free air by glass pipet
- No. of vessels per concentration (replicates): 1 concentration
- No. of vessels per control (replicates): 2 x reference substance concentration + 1 blank control
- Biomass loading rate: 200 mL sludge

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: softened and dechlorinated tap water
- Culture medium different from test medium: No

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: maintained in dark (24h)

EFFECT PARAMETERS MEASURED :
Oxygen consumption

Reference substance (positive control):

yes

Remarks:

3, 5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

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

Effect concentrations 2

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: The NOEC value is assigned on the basis of the low discriminatory power of the statistical analysis and is not an experimentally determined value

Effect concentrations 3

Duration:

3 h

Dose descriptor:

IC10

Effect conc.:

2.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 95% CI = 0.1 - 5.4 mg/L

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels:
40 mg/L - respiration rate = 0.8 mg/L, (86.6% inhibition)
20 mg/L - respiration rate = 22.1 mg/L (62.9% inhibition)
10 mg/L - respiration rate = 45.8 mg/L (23.0% inhibition)
The EC50 for the reference substance was calculated to be 17.0 mg/L
- Other:

Any other information on results incl. tables

Results:

Test concentration (mg/L)	Change in O2(mg/L)	Change in time (mins)	O2consumption (mg/L*hr)	% inhibition
1	2.2	2 5/6	46.6	21.7
10	2.8	3 2/6	50.5	15.1
100	2.1	2 5/6	44.5	25.2
1000	1.9	2 4/6	42.7	28.2
10000	2.0	3	40.0	32.8

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC 50 (3h) for sewage sludge respiration inhibition is > 10000 mg/L

Executive summary:

Test Guidance

OECD Guideline 209

Method

The study assessed the potential for the test substance to inhibit aerobic microbial metabolism, as indicted by the consumption of oxygen. The test duration was a three-hour exposure period to the test material at five nominal dose concentrations (1, 10 , 100, 1000 and 10000 mg/L) followed by up to ten minutes for the measurement of oxygen consumption. A duplicate control group and a positive control using a reference toxicant, 3,5 -dichlorophenol were run simultaneously with the test group.

Results

The quality control criteria for the test were acceptable. The EC50 for the reference substance was 17 mg/L and the two control replicants produced oxygen consumption rates that were within 15% of each other. The EC50 was calculated to be greater than 10000 mg/L. The statistically derived NOEC is 1 mg/L but the calculation is not sufficently robust.

Conclusion

The test material is not harmful to sewage sludge micro-organisms