dipropyl cyclohexane-1,2-dicarboxylate

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:

11 April 2016 - 06 July 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

Gas chromatograph

Details on sampling:

The test samples were thawed with the aid of sonication. The test samples (100 mL) plus 30 g of sodium chloride were extracted directly with 100 mL of hexane in the same bottle. An aliquot of the hexane layer was taken for analysis.

Vehicle:

not specified

Details on test solutions:

Based on the results of the range-finding test the following test concentrations were assigned to the definitive test: 1.0, 3.2, 10, 32 and 100% v/v saturated solution.

Test organisms (species):

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

Details on test organisms:

freshwater unicellular alga, representative of primary producers found in natural waters and can therefore be considered as an important non-target organism in freshwater ecosystems

Test type:

static

Water media type:

other:

Remarks:

The culture medium was prepared using reverse osmosis purified deionized water and the pH adjusted to 7.5 with 0.1N NaOH or HCl.

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24 ± 1 °C

pH:

pH 7.9 at 0 hours to pH 8.2 at 72 hours

Nominal and measured concentrations:

0 hour : Control; 1.0; 3.2; 10; 32; 100
72 hour : Control; 1.0; 3.2; 10; 32; 100

Details on test conditions:

Pre-culture conditions gave an algal suspension in log phase growth characterized by a cell density of 8.96 x 10E5 cells per mL. Inoculation of 900 mL of test medium with 5.0 mL of this algal suspension gave an initial nominal cell density of 5 x 10E3 cells per mL and had no significant dilution effect on the final test concentration. The flasks were plugged with polyurethane foam bungs and incubated (INFORS Multitron Version 2 incubator) at 24 ± 1 °C under continuous illumination (intensity approximately 7000 lux) provided by warm white lighting (380 – 730 nm) and constantly shaken at approximately 150 rpm for 72 hours.

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

5.4 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

8 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

16 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other:

Remarks:

95% confidence limits 13 - 19 mg/L

Details on results:

There were no statistically significant differences between the control, 0.87 and 2.8 mg/L test concentrations (P≥0.05), however all other test concentrations were significantly different (P<0.05) and, therefore the "No Observed Effect Concentration" (NOEC) based on growth rate was 2.8 mg/L. Correspondingly the "Lowest Observed Effect Concentration" (LOEC) based on growth rate was 8.5 mg/L.

Results with reference substance (positive control):

The results from the positive control with potassium dichromate were within the normal ranges for this reference item.

Validity criteria fulfilled:

yes

Conclusions:

Exposure of Pseudokirchneriella subcapitata to the test item gave the following results based on the 0-Hour measured test concentrations:
Growth Rate: EC50 (mg/L)=16; 95% Confidence Limits (mg/L)=13-19; No Observed Effect Concentration (NOEC) (mg/L)=2.8; Lowest Observed Effect Concentration (LOEC) (mg/L)=8.5
Yield: EC50 (mg/L)=8.1; 95% Confidence Limits (mg/L)=7.8-8.3; No Observed Effect Concentration (NOEC) (mg/L)=2.8; Lowest Observed Effect Concentration (LOEC) (mg/L)=8.5

Description of key information

Exposure of Pseudokirchneriella subcapitata to the test item gave the following results based on the 0-Hour measured test concentrations:

Growth Rate: EC50 (mg/L)=16; 95% Confidence Limits (mg/L)=13-19; No Observed Effect Concentration (NOEC) (mg/L)=2.8; Lowest Observed Effect Concentration (LOEC) (mg/L)=8.5

Yield: EC50 (mg/L)=8.1; 95% Confidence Limits (mg/L)=7.8-8.3; No Observed Effect Concentration (NOEC) (mg/L)=2.8; Lowest Observed Effect Concentration (LOEC) (mg/L)=8.5

Key value for chemical safety assessment

EC50 for freshwater algae:

16 mg/L

EC10 or NOEC for freshwater algae:

2.8 mg/L