3-iodo-2-propynyl butylcarbamate

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:

from 2000-08-28 to 2000-10-20

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

- Batch No.: 147-270300-1

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Controls: 2 controls, one on each end of the test system

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Laboratory culture: n.a.
- Name and location of sewage treatment plant where inoculum was collected: aeration tank of a waste water treatment plant treating predominantly domestic sewage (Wupper area water authority)
- Method of cultivation: not specified
- Preparation of inoculum for exposure: according to quideline
- Pretreatment: aeration of activated sludge; daily feed with synthetic medium
- Initial biomass concentration: 400 mg/L suspended solids

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

21.1 – 21.63 °C

pH:

7.8 – 8.0

Dissolved oxygen:

2.9 - 7.5 mg/L

Salinity:

NA

Nominal and measured concentrations:

Nominal concentrations: 10, 18, 32, 56 and 100 mg/L
No measured concentrations

Details on test conditions:

TEST SYSTEM
- Aeration: permanent aeration during incubation time
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Sludge concentration: 400 mg/L suspended solids

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Test concentrations: 10, 18, 32, 56 and 100 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorphenol

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

6 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:

EC50

Effect conc.:

44 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Reported statistics and error estimates:

The EC values was determined by probit analysis.

The test item showed 73.8 % respiration inhibition of activated sludge at a test substance concentration of 100 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

The respiration inhibition of the test item was determined to be 73.8 % at concentration level of 100 mg/L. The EC50 and EC10 were calculated with Probit analysis method to be 44 and 6.0 mg/L, respectively.

Executive summary:

A test was conducted according to EU Commission Directive 88/302/EEC, Part C.11. The test organisms were activated sludge from an aeration tank of a waste water treatment plant treating predominantly domestic sewage. A concentration series of the test item was tested (nominal concentrations: 10, 18, 32, 56 and 100 mg/L). After exposure period of 3 hours, the test item showed 73.8 % respiration inhibition of the activated sludge at a test concentration of 100 mg/L. The Probit analysis method was used. The EC50 was calculated to be 44 mg/L and the EC10 - 6.0 mg/L, respectively.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2001-11-12 to 2002-03-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1988

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 0004-1545

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature at about 20 °C, away from direct sunlight

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Based on the results of a pre-test and the information of the sponsor, no stock solution could be prepared due to the insufficient water solubility of the test item.
Therefore, test item amounts of 5.23, 16.02, 50.41, 160.61 and 502.62 mg were directly weighed (by means of an analytical balance) into the respective test flasks with 284 mL of tap water. The test item was mixed into the tap water by ultrasonic treatment for ten minutes and intense stirring for 24 hours at room temperature in the dark to dissolve a maximum amount of the test item and/or disperse it as homogeneously as possible. Then, 16 mL of synthetic wastewater and 200 mL of the activated sludge inoculum were added.

- Controls: Additionally, two controls (tap water, synthetic wastewater and activated sludge inoculum, without test item) and the reference item 3,5-dichlorophenol (positive control) at nominal concentrations of 5, 16 and 50 mg/L were tested in parallel under otherwise identical test conditions.

- Evidence of undissolved material: Based on the physical appearance of the test solutions/suspensions, at least part of the test item was not homogeneously distributed in the test water under the test conditions down to the lowest test item concentration of 10 mg/L.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: ARA Ergolz II, Fullinsdorf, Switzerland
- Preparation of inoculum for exposure: The sludge was washed once with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated.

- Pretreatment: Based on this ratio, an aliquot of washed sludge was suspended in tap water to obtain a concentration equivalent to 3 g dry material per liter. During holding, the sludge was fed three times with 50 mL synthetic wastewater per liter. On the fourth day of holding immediately prior to use, the sludge was fed once again with 25 mL synthetic wastewater per liter. During the entire holding period, the sludge was kept at room temperature under continuous aeration. Immediately before use, the dry weight of the activated sludge was measured again in the inoculum used for the test. The pH of the activated sludge inoculum was adjusted from 8.1 to 6.9 with a diluted sulfuric acid solution.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 °C

pH:

7.7 - 8.6

Nominal and measured concentrations:

nominal concentrations: 10, 32, 100, 320, 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 1000 mL glass flasks
- Aeration: yes
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Sludge concentration: 3 g dry material per litre

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic waste water:
16 g peptone
11 g meat extract
3 g urea
0.7 g NaCI
0.4 g CaCI2 • 2H20
0.2 g MgS04 • 7H20
2.8 g K2HP04
filled up to a final volume of 1 liter with deionized water

EFFECT PARAMETERS MEASURED: dissolved oxygen measurement after 3 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- range-finding study: yes

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

45 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Key result

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

57 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

160 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Key result

Duration:

3 h

Dose descriptor:

other: EC 80

Effect conc.:

447 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:
Based on the physical appearance of the test solutions/suspensions, at least part of the test item was not homogeneously distributed in the test water under the test conditions down to the lowest test item concentration of 10 mg/L

Results with reference substance (positive control):

- Results with reference substance valid: yes
- Relevant effect levels: The 3-hour EC50 of the reference item 3,5-dichlorophenol (positive control) was calculated to be 20 mg/L with 95% confidence limits from 12 to 33 mg/L. The 3-hour EC50 is within the guideline-recommended range of 5-30 mg/L, confirming suitability of the activated sludge used.

Validity criteria fulfilled:

yes

Conclusions:

The inhibitory effect of the test item on the respiration rate of aerobic wastewater microorganisms of activated sludge was investigated in a 3-hour respiration inhibition test. NOEC was determined to be 45 mg/L.

Executive summary:

The inhibitory effect of the test item on the respiration rate of aerobic wastewater microorganisms of activated sludge was investigated in a 3-hour respiration inhibition test according to the EU Commission Directive 87/302/EEC, and the OECD Guideline for Testing of Chemicals, No. 209.
The following nominal concentrations were tested: 10, 32, 100, 320 and 1000 mg/L. Concentrations exceeding 1000 mg/L were not tested.
In addition, two controls and three different concentrations of the reference item 3,5-dichlorophenol (5, 16 and 50 mg/L) were tested in parallel. The results of these treatments confirmed suitability of the activated sludge and the method used.
Based on the physical appearance of the test solutions/suspensions, at least part of the test item was not homogeneously distributed in the test water under the test conditions down to the lowest test item concentration of 10 mg/L.
Up to and including the concentration of 32 mg/L the test item had no significant inhibitory effect (<15%) on the respiration rate of activated sludge after the incubation period of three hours. At the next higher test item concentrations of 100, 320 and 1000 mg/L the test item showed significant inhibitory effects of 49, 77 and 87%, respectively on the respiration rate of the activated sludge.
The calculated 3-hour EC-values were as follows:

NOEC (determined as the calculated 3-hour EC15): 45 mg/L

EC20: 57 mg/L

EC50: 160 mg/L

EC80: 447 mg/L

Description of key information

In the key study an EC50 of 44 mg/L was determined. The EC10 was determined to be 6.0 mg/L.

In a supporting study the inhibitory effect of the test item on the respiration rate of aerobic wastewater microorganisms of activated sludge was investigated in a 3-hour respiration inhibition test. NOEC was determined to be 45 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

44 mg/L

EC10 or NOEC for microorganisms:

6 mg/L

Additional information

Key study:

A test was conducted according to EU Commission Directive 88/302/EEC, Part C.11. The test organisms were activated sludge from an aeration tank of a waste water treatment plant treating predominantly domestic sewage. A concentration series of the test item was tested (nominal concentrations: 10, 18, 32, 56 and 100 mg/L). 3,5-dichlorophenol was tested as a reference substance. After exposure period of 3 hours, the test item showed 73.8 % respiration inhibition of the activated sludge at a test concentration of 100 mg/L. The Probit analysis method was used. The EC50 was calculated to be 44 mg/L and the EC10 = 6.0 mg/L, respectively.

Supporting study:

The inhibitory effect of the test item on the respiration rate of aerobic wastewater microorganisms of activated sludge was investigated in a 3-hour respiration inhibition test according to the EU Commission Directive 87/302/EEC, and the OECD Guideline for Testing of Chemicals, No. 209.
The following nominal concentrations were tested: 10, 32, 100, 320 and 1000 mg/L. Concentrations exceeding 1000 mg/L were not tested.
In addition, two controls and three different concentrations of the reference item 3,5-dichlorophenol (5, 16 and 50 mg/L) were tested in parallel. The results of these treatments confirmed suitability of the activated sludge and the method used.
Based on the physical appearance of the test solutions/suspensions, at least part of the test item was not homogeneously distributed in the test water under the test conditions down to the lowest test item concentration of 10 mg/L.
Up to and including the concentration of 32 mg/L the test item had no significant inhibitory effect (<15%) on the respiration rate of activated sludge after the incubation period of three hours. At the next higher test item concentrations of 100, 320 and 1000 mg/L the test item showed significant inhibitory effects of 49, 77 and 87%, respectively on the respiration rate of the activated sludge.
The calculated 3-hour EC-values were as follows:

NOEC (determined as the calculated 3-hour EC15): 45 mg/L

EC20: 57 mg/L

EC50: 160 mg/L

EC80: 447 mg/L