Diallyl isophthalate

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

Justification for type of information:

ANALOGUE APPROACH JUSTIFICATION
Please refer to attached document

Qualifier:

according to guideline

Guideline:

other: DIN 38412, Part 9

Deviations:

not specified

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: Scenedesmus subspicatus N° 8681 SAG
- Age of inoculum (at test initiation): 10 day old

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

Measurements at the beginning of the test and after 24, 48, 72 & 96 hr

Nominal and measured concentrations:

Nominal: concentration range 0.63-80 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 ml erlenmeyers flasks
- Type (delete if not applicable): covered with metal caps
- Initial cells density: 10000 cells/ml

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Light intensity and quality: E = 17.0 W/m2

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: measurement of optical density (turbidity) using the Eppendorf digital photometer

Reference substance (positive control):

yes

Remarks:

Potassium dichromate, cadmium chloride

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

5.5 mg/L

Nominal / measured:

nominal

Conc. based on:

dissolved

Basis for effect:

growth rate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

11 mg/L

Nominal / measured:

nominal

Conc. based on:

dissolved

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

3 mg/L

Basis for effect:

growth rate

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

1.9 mg/L

Basis for effect:

growth rate

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

4.5 mg/L

Nominal / measured:

nominal

Conc. based on:

dissolved

Basis for effect:

biomass

Remarks:

based on measurement of turbidity

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.8 mg/L

Nominal / measured:

nominal

Conc. based on:

dissolved

Basis for effect:

biomass

Remarks:

based on measurement of turbidity

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

5.3 mg/L

Nominal / measured:

nominal

Conc. based on:

dissolved

Basis for effect:

biomass

Remarks:

based on measurement of turbidity

Duration:

96 h

Dose descriptor:

EC10

Effect conc.:

2.6 mg/L

Basis for effect:

biomass

Remarks:

based on measurement of turbidity

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.6 mg/L

Basis for effect:

biomass

Remarks:

based on measurement of turbidity

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

1.9 mg/L

Basis for effect:

biomass

Remarks:

based on measurement of turbidity

Details on results:

EC10 values indicate recovery of algal growth during the exposure period probably due to degradation of the test substance.

Results with reference substance (positive control):

Potassium dichromate: 96h-EbC50=0.35 mg/l
Cadmium chloride: 96h-EbC50=0.15 mg/l

Reported statistics and error estimates:

Reference to control growth was based on the average values of different control preparations. Assessment of effects on growth was performed on the basis of logarithmic groth versus time. Algal growth in the controls showed a shift from exponential to stationary phase after 48h. Hence, no values for growth rate could be given after 72h when the stationary phase was already reached. Data were evaluated by establishing the growth curves, calculating the area under the growth curve and calculating the differentiates of the exponential phase to assess growth rates. EC-values were determined by assigning the tested concentrations to the respective inhibition values on probability paper.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the study, diallyl phthalate was found to affect algal growth at concentrations above 1.6 mg/l (EC10 for biomass) with an EC50 for biomass corresponding with 3.8 mg/l (72h).

Description of key information

DAIP read-across from DAP;

Due to the fact that algal growth was exponential during the first 48 h in the controls, the EC-values calculated for that time period are most reliable. However, although growth reached the stationary phase after 72h, the EC10 and EC50 values for this period were lower than those for the 48h period, except the EC10 for growth rate. Therefore, the 72h-EC-values will be used as effect parameters.

Key value for chemical safety assessment

EC50 for freshwater algae:

5.5 mg/L

EC10 or NOEC for freshwater algae:

3 mg/L

Additional information

Reference to control growth was based on the average values of different control preparations. Algal growth in the controls showed a shift from exponential to stationary phase after 48h. Hence, no values for growth rate could be given after 72h when the stationary phase was already reached. In the case of diallyl phthalate, the EC10 and EC50 values correspond with the 72h period as these were lower than those determined for the 48h period. (Bringmann & Kühn, 1980)