3-iodo-2-propynyl butylcarbamate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001-06-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 0011-1954

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 1.0, 2.2, 4.6, 10, 22, and 46 µg/L
Sampling:
Just before the start of the test:
- one sample from the freshly prepared stock solution
- duplicate samples from each test medium (without algae)
- duplicate samples from the control (without algae)
After 72 hours (stability samples):
- duplicate samples from each test medium (without algae)
- duplicate samples from the control (without algae)

For the 72-hour stability samples, additional flasks with adequate volumes of the freshly prepared test media of all test concentrations and the control were incubated under the same conditions as in the actual test but without algae.
All samples were deep-frozen (at about -20 °C) immediately after sampling. Based on pre-experiments (without GLP) for investigation of the storage stability the test item is sufficiently stable in the test water under these storage conditions.
The concentrations of the test item were analyzed in the duplicate test media samples from the test concentrations of nominal 4.6 - 46 µg/L from both sampling times (0 and 72 hours). The samples from the test concentrations of nominal 1.0 and 2.2 µg/L were not analyzed, since these concentrations were below the determined 72-hour NOEC. From the control samples, only one of the duplicate samples was analyzed from the corresponding sampling times.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution of nominal 10 mg/L was prepared by dissolving 30 mg of the test item completely in 3000 mL test water by ultrasonic treatment (30 minutes) and intense stirring (30 minutes at room temperature in the dark).
- Controls: no treatment control

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: algae
- Strain: 86.81 SAG
- Source: Sammlung von Algenkulturen (Experimentelle Phykologie und Sammlung von Algenkulturen, Albrecht-von-Haller-lnstitut fur Pflanzenwissenschaften, Universitat Göttingen, D-37073 Gottingen, Germany). The algae had been grown in the RCC laboratories under standardized conditions according to the test guidelines.

ACCLIMATION
- Culturing media and conditions: same as test
- Any deformed or abnormal cells observed: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

0.24 mmol/L (=24mg/L) as CaCO3

Test temperature:

21 °C

pH:

7.9 - 8.2

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL Erlenmeyer flasks
- Type: covered
- No. of organisms per vessel: 10000 algal cells per mL test medium
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: artificial water according to guideline
- Culture medium different from test medium: no
- Intervals of water quality measurement: The pH was measured and recorded in each test concentration and the control at the start and at the end of the test. The water temperature was measured and recorded daily in an Erlenmeyer flask filled with water and incubated under the same conditions as the test flasks. The appearance of the test media was recorded daily.

OTHER TEST CONDITIONS
- Light intensity and quality: mean: 8780 lux; range: 8500 - 9270

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: electronic particle counter; after 24 h; 48 h, and 72 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2
- Range finding study: yes
- Test concentrations: 1.0, 2.2, 4.6, 10, 22, 46 µg/L

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

22 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

5.8 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

> 46 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

4.6 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

10 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

53 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

13 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

> 46 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

4.6 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

10 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control: yes
- Observation of abnormalities: no
- Unusual cell shape: no
- Colour differences: no
- Aggregation of algal cells: no
- Other: The microscopic examination of the algal cells after 72 hours test period showed no difference between the algae growing in the test concentration of nominal 4.6 µg/L and the algal cells in the control. The shape and size of the algal cells growing in test media containing the test item at up to this test concentration were obviously not affected.
- Any stimulation of growth found in any treatment: no
- Any observations that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

not applicable

Validity criteria fulfilled:

yes

Conclusions:

The test item had a statistically significant inhibition effect on the growth (biomass and growth rate) of Scenedesmus subspicatus after the exposure period of 72 hours at concentrations of 10 µg/L (= 72-hour LOEC) and above. EC 50 value for growth rate was determiend to be 53 µg/L.

Executive summary:

The influence of the test item on the growth of the green algal species Scenedesmus subspicatus CHODAT was investigated in a 72-hour static test according to the EU Commission Directive 92/69/EEC, C.3, 1992, and the OECD Guideline No. 201, 1984.

The nominal test concentrations were 1.0, 2.2, 4.6, 10, 22, and 46 µg/L. Additionally, a control was tested in parallel.

The analytically determined test item concentrations in the analyzed test media varied in the range of 76 to 97% of the nominal values. The mean measured concentrations (calculated as the average over all measurements per test concentration) ranged from 82 to 93% of nominal. The test item was sufficiently stable during the test period of 72 hours under the test conditions, and consequently the reported biological results are based on the nominal concentration of the test item.

The test item had a statistically significant inhibition effect on the growth (biomass and growth rate) of Scenedesmus subspicatus after the exposure period of 72 hours at concentrations of 10 µg/L (= 72-hour LOEC: lowest concentration tested with toxic effects) and above. The 72-hour NOEC (highest concentration tested without toxic effects) was determined to be 4.6 µg/L, since up to this test concentration both the mean biomass and the mean growth rate µ of the algae were not statistically significantly lower than in the control.

Description of key information

The test item had a statistically significant inhibition effect on the growth (biomass and growth rate) of Scenedesmus subspicatus after the exposure period of 72 hours at concentrations of 10 µg/L (= 72-hour LOEC) and above. EC50 value for growth rate was determiend to be 53 µg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

53 µg/L

EC10 or NOEC for freshwater algae:

4.6 µg/L

Additional information

Toxicity to algae

The influence of the test item on the growth of the green algal species Scenedesmus subspicatus CHODAT was investigated in a 72-hour static test according to the EU Commission Directive 92/69/EEC, C.3, 1992, and the OECD Guideline No. 201, 1984.

The nominal test concentrations were 1.0, 2.2, 4.6, 10, 22, and 46 µg/L. Additionally, a control was tested in parallel.

The analytically determined test item concentrations in the analyzed test media varied in the range of 76 to 97% of the nominal values. The mean measured concentrations (calculated as the average over all measurements per test concentration) ranged from 82 to 93% of nominal. The test item was sufficiently stable during the test period of 72 hours under the test conditions, and consequently the reported biological results are based on the nominal concentration of the test item.

The test item had a statistically significant inhibition effect on the growth (biomass and growth rate) of Scenedesmus subspicatus after the exposure period of 72 hours at concentrations of 10 µg/L (= 72-hour LOEC: lowest concentration tested with toxic effects) and above. The 72-hour NOEC (highest concentration tested without toxic effects) was determined to be 4.6 µg/L, since up to this test concentration both the mean biomass and the mean growth rate µ of the algae were not statistically significantly lower than in the control.