Reaction mass of divinylbenzene and ethylstyrene

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:

1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

not specified

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

The tested concentrations were measured at the start (0 hour) and the end (72 hours) of the test.

Vehicle:

yes

Details on test solutions:

Vehicle/Solvent and Concentrations: 2-Methoxyethanol and HCO-40 were used as solvents in the tests. The concentrations of 2-Methoxyethanol and HCO-40 in stock solution were 2500 mg/L each. The total final concentrations of the two solvents for the tests were 60 mg/L.

Stock Solutions Preparations and Stability: The test substance (50 mg) was dissolved in 2-Methoxyethanol (250 mg), and HCO-40 (250 mg) was added. The amount of the stock solution was adjusted to 100 mL by medium (test substance 500 mg/L).

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

- Test Organisms:
a) Method of Cultivation: Subculturing in OECD medium until use
b) Stain Number: ATCC22662
c) Supplier/Source: American Type Culture Collection

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

None

Hardness:

No data

Test temperature:

22.5-23.3°C

pH:

start of test: 7.9-8.0
end of test: 8.0-10.5

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

Nominal Concentrations (as mg/L): 0, 0.300, 0.490, 0.810, 1.30, 2.20, 3.60 and 6.00
Measured Concentrations (as mg/L): <0.006 (control), 0.158, 0.274, 0.465, 0.740, 1.23, 2.21 and 3.67 (53 - 61% of nominal concentrations) at 72 hours (the end of the test)

Details on test conditions:

Test Conditions:
a) Medium: OECD medium
b) Exposure Vessel Type: 100 mL Medium in a 500 mL Conical Flask
c) Nominal Concentrations (as mg/L): 0, 0.300, 0.490, 0.810, 1.30, 2.20, 3.60 and 6.00
d) Vehicle/Solvent and Concentrations: 2-Methoxyethanol and HCO-40 were used as solvents in the tests. The concentrations of 2-Methoxyethanol and HCO-40 in stock solution were 2500 mg/L each. The total final concentrations of the two solvents for the tests were 60 mg/L.
e) Stock Solutions Preparations and Stability: The test substance (50 mg) was dissolved in 2-Methoxyethanol (250 mg), and HCO-40 (250 mg) was added. The amount of the stock solution was adjusted to 100 mL by medium (test substance 500 mg/L).
f) Number of Replicates: 3
g) Initial Cell Number: 10000 cells/mL
h) Water Temperature: 22.5 - 23.3°C
i) Light Condition: 4000 - 5000 lux, continuous

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.73 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.81 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

- Mean Cell Concentration of Each Flask at 72 hours (as cells/mL): Control (655600), 0.300 mg/L (589300), 0.490 mg/L (549900), 0.810 mg/L (556900), 1.30 mg/L (478600), 2.20 mg/L (200900), 3.60 mg/L (19300) and 10.0 mg/L (12800)
- Growth Curves: Log phase during the test period

Reported statistics and error estimates:

Data Analysis: Least Squares Method for EC50, Bartlett Method, 1-Way ANOVA and Williams Method for NOEC
Method of Calculating Mean Measured Concentrations (i.e. arithmetic mean, geometric mean, etc.): Not described

Validity criteria fulfilled:

yes

Conclusions:

The 72 hour EC50 for Selenastrum capricornutum following 72 hour exposure to DVB-HP is 1.73 mg/L and the NOEC is 0.81 mg/L.

Executive summary:

The study was conducted in accordance to OECD Guideline 201. The 72 hour EC50 for Selenastrum capricornutum following 72 hour exposure to DVB is 1.73 mg/L and the NOEC is 0.81 mg/L.

Description of key information

A GLP-study according to OECD guideline 201 is available for the reaction mass of divinylbenzene and ethylstyrene. The 72-hour EC50 and NOEC (based on biomass) for DVB-HP (80% divinylbenzene/20% ethylstyrene) was 1.73 and 0.81 mg/L in an exposure with Selenastrum capricornutum.

Key value for chemical safety assessment

EC50 for freshwater algae:

1.73 mg/L

EC10 or NOEC for freshwater algae:

0.81 mg/L

Additional information

One high quality (Klimisch rating 1) chronic toxicity study with Selenastrum capricornutum was performed using DVB-HP (approximately 80% divinylbenzene and 20% ethylstyrene). The 72 -hour NOEC (based on biomass) was 0.81 mg/L. The 72 -hour EC50 (based on biomass) was 1.73 mg/L. Since the toxicity of the reaction mass of divinylbenzene and ethylstyrene increases with increasing divinylbenzene content (based on data from acute toxicity studies with Daphnia magna and freshwater fish), the NOEC for DVB-HP is expected to be a conservative estimate of toxicity for all other grades of the reaction mass of divinylbenzene and ethystyrene with less than 80% divinylbenzene.