Diisononyl adipate

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions, no GLP, no analytical monitoring

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

The study was performed according to European standard test guideline, Directive 79/831/EWG, appendix V, part C, stand May 1988.

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A 200 mg/L stock solution was prepared using a solubilizer. The stock solution was diluted to form the desired test concentrations.
- Chemical name of vehicle: Cremophor RH40
- Concentration of vehicle in test medium (stock solution): 40 mg/L

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISMS
- Test organism: Scenedesmus subspicatus CHODAT
- Source (laboratory, culture collection): in-house culture originally obtained from Culture Collection of Algae Goettingen, Germany
- Method of cultivation: temperature: 23°C, photoperiod: permanent lighted, cultivation water was identical to test water, stock culture 10000 cells/mL , cultivation in 250 ml Erlenmeyer flasks

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23 °C

Nominal and measured concentrations:

Nominal: 0.78, 1.56, 3.13, 6.25, 12.5, 25, 50 and 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: test tubes with 8 mL test solution
- Initial cells density: 10000 cells/mL
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic medium
- Culture medium different from test medium: no
- Intervals of water quality measurement: at the beginning and the end of the test

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: continuous light
- Light intensity and quality: 120 E/m*m*2

EFFECT PARAMETERS MEASURED: Number of cells were recorded at the beginning and the end of the exposure time.
- Determination of cell concentrations: counting chamber
- Chlorophyll measurement: In vicvo Chlorophyll a Fluorescence at 685 nm was recorded after 0, 24, 48 and 72h.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

72 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

12.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no

RESULT GROWTH RATE
ErC 10 (72h):    72 mg/l
ErC 50 (72h): > 100 mg/l
ErC 90 (72h): > 100 mg/l

RESULT BIOMASS
EbC 10 (72h):    14 mg/l
EbC 50 (72h): > 100 mg/l
EbC 90 (72h): > 100 mg/l

REMARK
Effect concentration is greater than the solubility of the substance in the test medium.

Validity criteria fulfilled:

yes

Conclusions:

In a toxicity test under static conditions, Desmodesmus subspicatus showed no significant growth rate inhibition to DINA concentrations up to 12.5 mg/L. The 72h-EC50 value is determined to be > 100 mg/L and the 72h-EC10 value is determined to be 72 mg/L.

Description of key information

EC50 (72h) > 100 mg/L, EC10 (72h) = 72 mg/L (nominal, vehicle used) for Desmodesmus subspicatus (similar to OECD 201)

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

72 mg/L

Additional information

One study investigating the toxicity of Diisononyl adipate (DINA) to aquatic algae is available. The study was performed according to European standard test guideline, Directive 79/831/EWG, appendix V, part C, adopted May 1988. (similar to OECD 201) under static conditions using Desmodesmus subspicatus as test organism (BASF 1990). Concentrations between 0.78 and 100 mg/L were tested using a solubilizer (Cremophor RH 40). No significant growth inhibition was observed in the control and treatments up to 12.5 mg/L during the exposure period of 72h. The 72h-EC50 is determined to be > 100 mg/L and the 72h-EC10 is determined to be 72 mg/L based on nominal concentrations.

Further, three studies investigating the toxicity of the structurally similar read-across substance DEHA (CAS 103-23-1) to feshwater algae are available. One study was performed according to DIN guideline 38412, part 9 using Scenedesmus subspicatus as test organism (BASF 1989). A 500 mg/L stock solution was preparted using 200 mg/L Cremophor RH40 as dispersant. After stirring of 17h the test solution was still an emulsion. This emulsion was tested. Nominal test concentrations between 7.8 and 500 mg/L were tested. The 72h-EC50 value is determined to be > 500 mg/L. An 72h-EC20 value is determined to be 398.6 mg/L. Since the effect concentration is greater than the solubility of DEHA in the test medium, it can be concluded that DEHA is not harmful to freshwater algae up to the saturation limit in water.

Result and conclusion is confirmed by two supporting studies, which assessed the acute toxicity of DEHA to Selenastrum capricornutum (Felder et al. 1989) and Scenedesmus subspicatus (Hüls 1996), respectively.

The combined data clearly indicates that DINA is not toxic to aquatic algae up to the saturation concentration.