Benzyl propionate

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:

comparable to guideline study

Justification for type of information:

Experimental test result performed using standard OECD test guideline.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

The effect of test substance Benzyl propionate, CAS No. 122-63-4 was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga growth inhibition test.

GLP compliance:

no

Specific details on test material used for the study:

- Name of test material: benzyl propionate
- Molecular formula: C10H12O2
- Molecular weight: 164.20 g/mol
- Substance type: Organic
- Physical state: Liquid

Analytical monitoring:

no

Details on test solutions:

The test substance Benzyl propionate, was prepared by adding 106.25 mg of test substance in 250 ml of BBM to get the final concentration of 425 mg/L. The sock solution was ultrasonically agitated for 30 minutes to obtain a homogenous solution for the experiment. The remaining test solutions were prepared by dilution from the above stock solution, under aseptic condition. 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

Total exposure duration:

72 h

Test temperature:

24 °C ±2°C.

pH:

6.7 to 7.4

Nominal and measured concentrations:

4.32mg/l, 10.88 mg/l, 27.2mg/l, 68mg/l, 170mg/l and 425mg/l All the six concentration were in geometric series spaced by a factor of 2.

Details on test conditions:

Light Quality White Fluoroscent Light
Light Intensity 1500Lux
Photoperiod 16 Hour Light Period : 8 Hour Dark Period
RPM Speed 120 Revolutions per minute
Water Deionized Waer
Test vessel size 100ml
Test solution volume 60ml
Dilution water Bold’s Basal Medium
Test concentration Six test concentration were:
Replicates per concentration
Three replicates for Control
Two replicates for each test concentration

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

138.96 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: calculated from equation through probit analysis

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 also no significant changes were observed.

Table 1: Showing the average cell count using Haemocytometer of the experimental flasks at an equal interval of 24hrs, 48hrs and 72hrs

Experimental Flasks and test concentration	24 Hours	48 Hours	72 Hours
Control
Replicate 1	68.5 x 10^4	71.5 x 10^4	11.4 x 10^5
Replicate 2	72 x 10^4	75.5 x 10^5	11 x 10^5
Replicate 3	73 x 10^4	83.5 x 10^4	12.65 x 10^5
CAS No. 122-63-4
4.32mg/l
Replicate 1	60 x 10^4	75.5 x 10^4	83.5 x 10^4
Replicate 2	58.5 x 10^4	73 x 10^4	76 x 10^4
10.88 mg/l
Replicate 1	61.5 x 10^4	64.5 x 10^4	71.5 x 10^4
Replicate 2	60.5 x 10^4	64.5 x 10^4	66.5 x 10^4
27.2mg/l
Replicate 1	63 x 10^4	65.5 x 10^4	53.5 x 10^4
Replicate 2	63 x 10^4	61.5 x 10^4	49.5 x 10^4
68mg/l
Replicate 1	60 x 10^4	59 x 10^4	40.5 x 10^4
Replicate 2	61 x 10^4	57.5 x 10^4	37.5 x 10^4
170mg/l
Replicate 1	57 x 10^4	53.5 x 10^4	11 x 10^4
Replicate 2	56 x 10^4	51 x 10^4	8.5 x 10^4
425mg/l
Replicate 1	60 x 10^4	51 x 10^4	2 x 10^4
Replicate 2	59 x 10^4	47 x 10^4	3 x 10^4

Table 2 : Showing the values of average specific growth rate and percentage inhibition after an interval of 72 hours

	CONTROL		4.32mg/l		10.88 mg/l		27.2mg/l		68mg/l		170mg/l		425mg/l
Average Specific Growth rate (µ )	R1	1.578	R1	1.474	R1	1.423	R1	1.326	R1	1.233	R1	0.799	R1	0.231
	R2	1.566	R2	1.443	R2	1.399	R2	1.300	R2	1.208	R2	0.713	R2	0.366
	R3	1.613
Mean of Avg. Specific growth rate	1.586		1.459		1.411		1.313		1.220		0.756		0.298
Percentage Inhibition (%I)	_		8.009		11.042		17.191		23.033		52.322		81.174

Table 3 : 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	7.2	7.2
Replicate 3	7.1	7.1
CAS No. 122-63-4
4.32mg/l
Replicate 1	7.0	6.7
Replicate 2	7.1	6.7
10.88 mg/l
Replicate 1	7.1	6.7
Replicate 2	7.1	6.9
27.2mg/l
Replicate 1	7.2	6.8
Replicate 2	7.2	6.8
68mg/l
Replicate 1	7.2	6.9
Replicate 2	7.1	6.8
170mg/l
Replicate 1	7.1	6.6
Replicate 2	7.1	6.5
425mg/l
Replicate 1	7.1	6.3
Replicate 2	7.1	6.4

Validity criteria fulfilled:

yes

Conclusions:

After 72 hours of exposure to Benzyl propionate (CAS No. 122-63-4) to various nominal test concentration, EC50 calculated from equation through probit analysis was found to be 138.96 mg/L.

Executive summary:

The effect of test substance Benzyl propionate, CAS No. 122 -63 -4 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 4.32mg/l, 10.88 mg/l, 27.2mg/l, 68mg/l, 170mg/l and 425mg/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. EC50 calculated from equation through probit analysis was observed to be 138.96 mg/L.

Description of key information

After 72 hours of exposure to Benzyl propionate (CAS No. 122-63-4) to various nominal test concentration,EC50 calculated through probit analysis was found to be 138.96 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

138.96 mg/L

Additional information

The effect of test substance Benzyl propionate, CAS No. 122 -63 -4 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 4.32mg/l, 10.88 mg/l, 27.2mg/l, 68mg/l, 170mg/l and 425mg/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. EC50 calculated from equation through probit analysis was observed to be 138.96 mg/L.