Succinonitrile

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:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

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: DSM Engineering Plastics B.V. lotnumber SN0620140520
- Expiration date of the lot/batch: 2016.07.01
- Purity test date: 99.93%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store in a cool area (IO-20°C). Containers that have been opened must be filled with dry nitrogen for at least 1min and then sealed. Be careful not to import any water or impurities during the filling and sealing course.
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: Easily soluble in cold water


FORM AS APPLIED IN THE TEST white waxy solid

Analytical monitoring:

yes

Details on test solutions:

nitial biomass concentration: 0.5><104 cell/m1;

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Desmodesmus subspicatus, fi'eshwater alga species,
- Source Institute of Hydrobiology, Chinese Academy of Sciences and cultured continually in the facility. The test alga batch number was Desmodesmus subspicatus 20151030.
The stock alga was originally introduced from Institute of Hydrobiology, Chinese Academy of Sciences and cultured continually in the facility.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

November 04, 2015- November 06, 2015

Hardness:

10 to 250 mg/L (as CaC03)

Test temperature:

21-24 °C

pH:

7.74 - 8.13

Dissolved oxygen:

9.01 — 9.44 mg/L

Nominal and measured concentrations:

nominal concentration 100 mg/l
Measured concentration 86.5 mg/l

Details on test conditions:

Illumination: The continuous light was used; the measured light intensity was 4726-5109 lux for cool white light at the beginning and the end of the test. The light intensity was in the range of ~5.0% ~ 2.7% from the average light intensity, i.e. 4976 lux over the incubation area
( Section 15 Table 4).
All test vessels were capped with air-permeable membrane.

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Details on results:

During the 72-hour test duration, there was no any abnormal appearance of the algae
observed in control and test replicates. After 72 hours exposure, there were no apparent
inhibition effects upon growth at the test concentration comparing with the control group.
Student’s T-test showed that there were no statistically significant differences (p>0.05)
between the control growth and the growth in treatment group.

Results with reference substance (positive control):

The results showed that for the nominal test item concentration of 100 mg/L, the mean
measured concentration was 84.5 mg/L at the beginning and 88.5 mg/L at the end, the overall
mean concentration was 86.5 mg/L. The determined concentration was 86.5% of the nominal
concentration and met the criteria of 80 — 120%.
Results are shown in Appendix 1 Table 5. (see attached document under the chapter background information)

13.1 Results of pH determination and observation

The results of daily cell counting were presented in Section 15 Table 6. The results of percent inhibition in average specific growth rate (1,) and percent inhibition of yield (1,) were listed in Section 15 Table 7. The growth curves of alga during 72 hours exposure period see Section 15 Figure 1.

13.2 Verification of Test Concentration in the Definitive Test

Conclusions:

According to the results, the 72-hour median effect concentration of average specific growth rate (Ercso) and yield (Eycso) of Succinonitrile to Desmodesmus subspz‘catus was greater than 100 mg/L (nominal concentration). The 72-hour no observed effect concentration (NOEC) was 100 mg/L (nominal concentration).

Executive summary:

An alga growth inhibition study of Succinonitrile was conducted for a period of 72 hours.

The test was designed to be compatible with OECD Guidelines for the Testing of Chemicals No. 201 “Freshwater Alga and Cyanobacteria, Growth Inhibition Test”. According to the results, the 72-hour median effect concentration of average specific growth rate (Ercso) and yield (Eycso) of Succinonitrile to Desmodesmus subspicatus was greater than 100 mg/L (nominal concentration). The 72-hour no observed effect concentration (NOEC) was 100 mg/L (nominal concentration).

Description of key information

The 72-hour no observed effect concentration (NOEC) was 100 mg/L (nominal concentration).

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L