Diisopropyl 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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental study according to guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

The objective of the test was to determine the effects of test chemical on the growth of freshwater microalgae Chlorella vulgaris. The algae were exposed to various concentrations of the test item under static conditions over a period of 72h. The growth rate relative to the control in a 72 h test was taken as a parameter to observe the algal growth inhibition

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The test substance Diisopropyl adipate was prepared by adding 60 µl of test substance in 300 ml of BBM to get the final concentration of 200 mg/L. The remaining test solutions were prepared by dilution from the above stock solution. To have a better growth and visibility of cells, the initial cell density of the culture was kept 1 X 104 cells/ml. Care was taken to have a homogeneous solution for the experiment.

Test organisms (species):

Chlorella vulgaris

Details on test organisms:

The fresh water green alga Chlorella vulgaris, was used as the test organism. Sterile, unicellular, liquid cultures of algae.
The culture was examined under the microscope to confirm that it was unicellular, healthy and not contaminated.
The medium to be used for the growth of algae was Bold’s Basal Medium (BBM). It is a medium composed of macronutrients, micronutrients, alkaline EDTA solution and Iron solution. Stock solution of each of these was prepared separately and then a complete medium was prepared and sterilized. De-ionized water was used to prepare the BBM.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24°C ±2°C.

pH:

6.4-7

Nominal and measured concentrations:

Nominal concentration: 6.25 mg/l, 12.5 mg/l, 25 mg/l, 50 mg/l, 100 mg/l and 200 mg/l

Details on test conditions:

Light Quality White Fluoroscent Light
Light Intensity: 1500Lux
Photoperiod: 16 Hour Light Period : 6 Hour Dark Period
RPM Speed: 120 Revolutions per minute
Water: Deionized Water
Test vessel size: 100ml
Test volume 60ml
Dilution water: Bold’s Basal Medium
Test concentration: Six test concentration were: 6.25 mg/l, 12.5 mg/l, 25 mg/l, 50 mg/l, 100 mg/l and 200 mg/l
Replicates per concentration:
• Three replicates for Control
• Two replicates for each test concentration

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

3.78 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: other details not known

Duration:

72 h

Dose descriptor:

other: EC30

Effect conc.:

15.93 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Other details not known

Details on results:

The microscopic observations were also noted in each of the experimental flasks. All the cells appeared healthy, round and green throughout the test duration in the control and in the experimental flask slight reduction in the cell growth at higher concentration was observed

Table : Depicting pH values at test initiation (0 Hours) and test termination ( 72 Hours)

 

Experimental Flasks and test concentration	0 Hours	72 Hours
CONTROL
Replicate 1	7.2	7.1
Replicate 2	7.3	7.0
Replicate 3	7.2	7.1
Test chemical
6.25 mg/l
Replicate 1	7.2	7.2
Replicate 2	7.2	7.1
12.5 mg/l
Replicate 1	7.0	7.1
Replicate 2	7.1	7.1
25 mg/l
Replicate 1	7.0	7.0
Replicate 2	7.0	7.1
50 mg/l
Replicate 1	7.1	7.0
Replicate 2	7.1	7.2
100 mg/l
Replicate 1	7.2	7.0
Replicate 2	7.2	7.1
200 mg/l
Replicate 1	7.0	7.1
Replicate 2	7.2	7.1

Validity criteria fulfilled:

yes

Conclusions:

After 72 hours of test chemical exposure to various nominal test concentration, EC30 and EC10 was determined to be 15.93 and 3.78 mg/L, respectively.

Executive summary:

The effect of test substance was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga growth inhibition test. The test concentration chosen for the study were 6.25 mg/L, 12.5 mg/L, 25 mg/L, 50 mg/L, 100 mg/L & 200 mg/L were prepared using stock solution of the test substance using de-ionized water. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of test substance. EC10 calculated from probit analysis was determined to be 3.78 mg/L. As the test chemical is readily biodegradable, it cannont be classified as per CLP criteria.

Description of key information

The effect of test substance was studied on the growth of fresh water green algaChlorella vulgaris.The study was conducted following OECD guideline 201- Alga growth inhibition test. The test concentration chosen for the study were 6.25 mg/L, 12.5 mg/L, 25 mg/L, 50 mg/L, 100 mg/L & 200 mg/L were prepared using stock solution of the test substance using de-ionized water. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of test substance. EC10 calculated from probit analysis was determined to be 3.78 mg/L. As the test chemical is readily biodegradable, it cannont be classified as per CLP criteria.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

3.78 mg/L

Additional information

The effect of test substance was studied on the growth of fresh water green algaChlorella vulgaris.The study was conducted following OECD guideline 201- Alga growth inhibition test. The test concentration chosen for the study were 6.25 mg/L, 12.5 mg/L, 25 mg/L, 50 mg/L, 100 mg/L & 200 mg/L were prepared using stock solution of the test substance using de-ionized water. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of test substance. EC10 calculated from probit analysis was determined to be 3.78 mg/L. As the test chemical is readily biodegradable, it cannont be classified as per CLP criteria.