Sodium salicylate

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:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental test result using OECD guideline.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

Storage Conditions
Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Substance is Hygroscopic.

Vehicle:

yes

Details on test solutions:

The test test chemical was prepared by adding 60 mg 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 10E4 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

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24 °C ±2°C.

pH:

6.7 to 7.4

Nominal and measured concentrations:

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 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

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

75.25 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	39 x 10^4	41.5 x 10^4	47 x 10^4
Replicate 2	28 x 10^4	46.5 x 10^4	34 x 10^4
Replicate 3	34 x 10^4	42.5 x 10^4	44 x 10^4
CAS No. 54-21-7
12.5 mg/l
Replicate 1	27 x 10^4	17 x 10^4	19.5 x 10^4
Replicate 2	27.5 x 10^4	20.5 x 10^4	12 x 10^4
25 mg/l
Replicate 1	10.5 x 10^4	16 x 10^4	14.5 x 10^4
Replicate 2	12.5 x 10^4	18.5 x 10^4	15.5 x 10^4
50 mg/l
Replicate 1	28.5 x 10^4	11.5 x 10^4	5.5 x 10^4
Replicate 2	22 x 10^4	12.5 x 10^4	10 x 10^4
100 mg/l
Replicate 1	22.5 x 10^4	3.5 x 10^4	6 x 10^4
Replicate 2	35 x 10^4	6 x 10^4	3.5 x 10^4
200 mg/l
Replicate 1	20 x 10^4	22 x 10^4	2.5 x 10^4
Replicate 2	24.5 x 10^4	22 x 10^4	7 x 10^4

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

	CONTROL		12.5 mg/l		25 mg/l		50 mg/l		100 mg/l		200 mg/l
Average Specific Growth rate (µ )	R1	1.283	R1	0.990	R1	0.891	R1	0.568	R1	0.597	R1	0.305
	R2	1.175	R2	0.828	R2	0.913	R2	0.767	R2	0.417	R2	0.648
	R3	1.261
Mean of Avg. Specific growth rate	1.240		0.909		0.902		0.667		0.507		0.477
Percentage Inhibition (%I)	_		26.69		27.26		46.21		59.11		61.53

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	7.3	7.4
Replicate 2	7.2	7.3
Replicate 3	7.4	7.5
CAS No. 54-21-7
12.5 mg/l
Replicate 1	7.3	7.2
Replicate 2	7.0	7.2
25 mg/l
Replicate 1	7.3	7.4
Replicate 2	7.4	7.3
50 mg/l
Replicate 1	7.2	7.2
Replicate 2	7.1	7.1
100 mg/l
Replicate 1	7.0	7.1
Replicate 2	7.1	7.2
200 mg/l
Replicate 1	7.2	7.1
Replicate 2	7.1	7.1

Validity criteria fulfilled:

yes

Conclusions:

After 72 hours of exposure to test substance to various nominal test concentration, EC50 calculated from probit analysis was observed to be 75.25 mg/L.

Executive summary:

This study was designed to assess the effect of the test substance on the growth of green alga Chlorella vulgaris. The study was conducted in accordance with “OECD guideline for testing of chemicals No. 201 – Alga growth inhibition test”.

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 12.5 mg/l, 25 mg/l, 50 mg/l, 100 mg/l and 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. EC50 calculated from probit analysis was observed to be 75.25 mg/L. As the test chemical is readily biodegradable, it cannot be classfied as per CLP classification category.

Description of key information

This study was designed to assess the effect of the test substance on the growth of green algaChlorella vulgaris. The study was conducted in accordance with “OECD guideline for testing of chemicals No. 201 – Alga growth inhibition test”.

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 12.5 mg/l, 25 mg/l, 50 mg/l, 100 mg/l and 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. EC50 calculated from probit analysis was observed to be 75.25 mg/L. As the test chemical is readily biodegradable, it cannot be classfied as per CLP classification category.

Key value for chemical safety assessment

EC50 for freshwater algae:

75.25 mg/L

Additional information

Various experimental of test chemical and its read across chemicals have been reviewed to determine the toxicity of target to aquatic algae and their results are summarized below.

 

The first Experimental study performed for the target chemical and it was designed to assess the effect of the test substance on the growth of green algaChlorella vulgaris. The study was conducted in accordance with “OECD guideline for testing of chemicals No. 201 – Alga growth inhibition test”.

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 12.5 mg/l, 25 mg/l, 50 mg/l, 100 mg/l and 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. EC50 calculated from probit analysis was observed to be 75.25 mg/L. As the test chemical is readily biodegradable, it cannot be classfied as per CLP classification category.

 

Next experimental study was reviewed from handbook in this the green algae were exposed to the test concentration for a period of 14 days to observe average specific growth rate. On the basis of growth rate EC50 value was determined to be 60 mg/L for 3 hrs and > 10 mg/L for 14 days.

 

 Last experimental study was also reviewed from handbook and this study was designed to assess the effect of the test substance on the growth of green algae Haematococcus pluvialis. The green algae were exposed to the test concentration for a period of 4 hr to observe average specific growth rate. On the basis of growth rate EC10 value was determined to be165 mg/L .

 

By considering results of all the studies mentioned above it is concluded that EC50 value of test chemical is in range from 60 mg/L to 165 mg/L. On the basis of this range value and ready biodegradability test chemical is considered to be non toxic and cannot be classified as per CLP regulation.