Diamminediisocyanatozinc

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

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:

in accordance with the Commission of European Communities directive 92/69/EEC

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

not specified

Vehicle:

no

Remarks:

medium was used

Test organisms (species):

Scenedesmus sp.

Details on test organisms:

TEST ORGANISM
- Strain: Scenedesmus subspicatus

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

24 °C

pH:

The pH values of the control and test cultures were observed to increase from pH 8.0 - 8.1 at 0 hours to pH 8.6 - 10.3 at 72 hours. (The increase in pH observed over the 72-hour study period followed a concentration dependant pattern with the lower test material concentrations exhibiting a greater increase in pH)

Nominal and measured concentrations:

Nominal: 0.625, 1.25, 2.5, 5.0, 10.0 mg/L

Details on test conditions:

- three replicate flasks per concentration

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: spectrophotometer, daily

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0, 0.625, 1.25, 2.5, 5.0, 10 mg/L

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.625 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

4.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Observation of abnormalities (for algal test): none stated
- Unusual cell shape: none stated
- Colour differences: none stated
- Flocculation: none stated
- Adherence to test vessels: none stated
- Aggregation of algal cells: none stated

Results with reference substance (positive control):

not required

Reported statistics and error estimates:

students test

Cell concentration:

Mean cell density of control at 0 h	3.08x104 cells/mL
Mean cell density of control at 72 h	9.03x10s cells/mL
Mean cell density of solvent control at 0 h	3.08x104 cells/mL
Mean cell density of solvent control at 72 h	9.92x10s cells/mL

show that the cell concentration of the control cultures increased by a factor of 29 and the solvent control cultures by a factor of 32 during the test in line with the OECD Guideline that states the enhancement must be at least by a factor of 16 after 72 hours.

Validity criteria fulfilled:

yes

Conclusions:

The study was performed according to OECD TG 201 with no relevant deviations, the results were so obtained via a scientifically reasonable method. The validity criteria for the study as given by the OECD Guideline 201 were met and the study is therefore considered to be valid. Hence, there is no doubt that the obtained results are not reliable: The toxic effect was investigated by determination of the inhibition of the growth rate of the algae and the yield during the exposure period of 72 hours. The effect of the test item on the growth of Scenedesmus subspicatus has been investigated over a 72-hour period and gave an EbC50 value of 2.7 mg/Land an EfCS0 (24 - 48 h) value of 6.5 mg/L. The No Observed Effect Concentration at 72 hours was 0.625 mg/L.

Based on these results, the test item need to be classified as chronic toxic (3) to the aquatic environment.

Executive summary:

In a 72 hour acute toxicity study, the cultures of algae Scenedesmus subspicatus were exposed to the test item at nominal concentrations of 0, 0.625, 1.25, 2.5, 5.0, 10.0 mg test item/L under static in accordance with the OCED 201 guideline.

All test and control cultures were inspected microscopically at 72 hours. There were no abnormalities detected in any of the control or test cultures at 0.625, 1.25, 2.5 and 5.0 mg/L. However at the test concentration of 10 mg/L the algal cells were observed to be clumped together.

None of the following abnormalities were noted: cell shape, color differences, flocculation, adherence of algae to test vessels, aggregation of algal cell, precipitation in the test solution, or stimulation.  

This toxicity study is classified as acceptable and satisfies the guideline requirements for an algae toxicity study.

Based on these results, the test item need to be classified as chronic toxic (3) to the aquatic environment.

 

Results Synopsis

Test Organism: Algae Scenedesmus subspicatus

Test Type: Static

 

72 hr EC50:  1.6 mg a.i./L                      

24-48 hr EC50:  4.3 mg a.i./L

 

72 hr NOEC: 0.625.mg a.i./L

Description of key information

Acute toxicity to algae: NOEC (72h) = 0.625 mg/L, LC₅₀ (72h) = 1.6 mg/L for Scenedesmus subspicatus (OECD 201, GLP, static)

Key value for chemical safety assessment

EC50 for freshwater algae:

1.6 mg/L

EC10 or NOEC for freshwater algae:

0.625 mg/L

Additional information

Based on these results, the test item need to be classified as chronic toxic (2) to the aquatic environment.