2'-[2,4-dichloro-5-(1-methylethoxy)phenyl]-2,2-dimethylpropionohydrazide

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 18 July 2003 (beginning of the study) to 21 July 2003 (end of the study)

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This test was performed according to international guidelines without GLP statement. All validity criteria were fulfilled (corresponding to the version of the guidelines used). However, this study corresponds to a screening test.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

, 7th June 1984

Deviations:

yes

Remarks:

, only a screening test was performed.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

, 31 st July 1992

Deviations:

yes

Remarks:

, only a screening test was performed.

Principles of method if other than guideline:

Not applicable

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

2'-[2,4-dichloro-5-(1-methylethoxy)phenyl]-2,2-dimethylpropionohydrazide

EC Number:

257-027-8

EC Name:

2'-[2,4-dichloro-5-(1-methylethoxy)phenyl]-2,2-dimethylpropionohydrazide

Cas Number:

51167-18-1

Molecular formula:

C14H20Cl2N2O2

IUPAC Name:

N'-(2,4-dichloro-5-isopropoxyphenyl)-2,2-dimethylpropanehydrazide

Test material form:

other: solid

Details on test material:

- Name of test material (as cited in study report): HTMA [1-TRIMETHYLACETYL-2-(2,4-DICHLORO-5-ISOPROPOXYPHENYL)-HYDRAZINE]
- Molecular weight: 319 mg/L
- Substance type: brown orange-colored pieces
PHYSICO-CHEMICAL PROPERTIES
- Water solubility: 40 ppm
- Density: 1.25
- Physical state: solid
- Stability under test conditions: no data
- Storage condition of test material: no data

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

Not applicable

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test solutions were prepared by further dilution of the stock solution with water or directly from the test item. A solution containing a maximum of 100 mg/L of the test item plus two other range-finding concentrations were prepared. Test vessels were filled directly from the test solution containers immediately after preparation.
- Eluate: reconstituted water
- Control: yes
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): not applicable
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no data

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Scenedesmus subspicatus
- Strain: CCAP 276/20
- Source (laboratory, culture collection): Culture Collection of Algae and Protozoa, Institute of Freshwater Ecology, Far Sawrey, Ambleside, Cumbria, LA22 OLP, UK.
- Age of inoculum (at test initiation): no data
- Method of cultivation: The algae are cultured under sterile conditions and maintained at exponential growth rate by adding weekly aliquots of algal culture to fresh reconstituted water samples.

ACCLIMATION
- Acclimation period: no data

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

None

Test conditions

Hardness:

No data

Test temperature:

24 - 25°C

pH:

7.65 - 7.87

Dissolved oxygen:

No data

Salinity:

Not applicable

Nominal and measured concentrations:

Screening test:
- Nominal concentrations: 0, 1, 10 and 100 mg/L (loading rates)

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL conical flasks
- Aeration: no
- Initial cells density: 10 000 cells/mL
- Control end cells density: mean of 835 000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of vessels per vehicle control (replicates): not applicable

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Prepared using deionized water with a conductivity less than 10µS/cm. The final solution after autoclaving has a pH of 7.5 +/- 0.3.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: not necessary
- Photoperiod: constant illumination
- Light intensity and quality: 7000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable)
- Determination of cell concentrations: counting chamber (at T72 hours only)
- Chlorophyll measurement: no
- Other: none

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and biomass

Details on results:

See tables in "Any other information on results incl. tables" section.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Not relevant.

Any other information on results incl. tables

Table 6.1.5/1: T 72 hours, number of cells and calculation of the specific growth rate at each concentration

Nominal loading rate (mg/L)	Replicate	Total No. of cells at 72 h (104/mL)	Ln No. of cells	Mean Ln No of cells	Specific growth rate	Inhibition of growth rate (%)
0	1 2 3	95.0 81.5 74.0	13.76 13.61 13.51	13.63	0.06	-
1	1 2 3	1.8 1.6 1.9	9.80 9.68 9.85	9.78	0.01	87.18
10	1 2 3	1.0 1.0 1.0	9.21 9.21 9.21	9.21	0.00	100.00
100	1 2 3	1.0 1.0 1.0	9.21 9.21 9.21	9.21	0.00	100.00

Table 6.1.5/2: T 72 hours, number of cells at each observation time and calculation of the area under the growth curve (biomass) at each concentration

Nominal loading rate (mg/L)	Replicate	Total No. of cells at 72 h (104/mL)	Growth 0 to 72 hours	Average (0-72 hours)	Inhibition of growth (%)
0	1 2 3	95.0 81.5 74.0	3384.0 2898.0 2628.0	2970.0	-
1	1 2 3	1.8 1.6 1.9	28.8 21.6 32.4	27.6	99.07
10	1 2 3	1.0 1.0 1.0	0.0 0.0 0.0	0.0	100.00
100	1 2 3	1.0 1.0 1.0	0.0 0.0 0.0	0.0	100.00

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

OECD validity criteria of the testing guideline 201 (version of 1984) : the cell concentration in the control cultures have increased by a factor of more than 16 within 3 days.

Conclusions:

The highest concentration without effect on growth (NOEC) at 72 hours was lower than 1 mg/L based on growth rate and biomass data. The 72h-ErC50 and EbC50 were lower than 1 mg/L.

Executive summary:

This test was performed according to international guidelines without GLP statement.

The objective of this screening test is to assess the effects of the test substance on the growth of an unicellular green alga species Scenedesmus subspicatus, in a 72 hour static test.

3 nominal loading rates concentrations (1, 10 and 100 mg/L) were used plus one control. No analytical monitoring was performed and the number of cells was counted at 72 hours.

At the first nominal loading rate of 1 mg/L, 87.18% and 99.07% of inhibition of growth rate and biomass, respectively, were observed. At the other nominal loading rates (10 and 100 mg/L), 100% of inhibition of growth rate and biomass were observed .

Based on these results, the highest concentration without effect on growth (NOEC) at 72 hours was lower than 1 mg/L based on growth rate and biomass data. The 72h-ErC50 and EbC50 were lower than 1 mg/L.

All validity criteria were fulfilled, corresponding to the version of the guidelines used. However, this study corresponds to a screening test and no specific endpoint values were determined.