Methyl toluene-4-sulphonate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 September 2017 to 07 September 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

OECD Guidelines for Testing of Chemicals, No.:202 (Adopted: 13 April 2004) OECD: Paris.

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Version / remarks:

EPA Health Effects Test Guidelines, OCSPP 850.1010.

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

Commission Regulation (EU) 2017/735 of 14 February 2017 amending, for the purpose of its adaptation to technical progress, the Annex to Regulation (EC) No 440/2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

No further details specified in the study report.

Analytical monitoring:

yes

Details on sampling:

Analytical measurements were performed from the control and at the applied test concentration levels at the beginning and at the end of the renewal periods.

Vehicle:

no

Details on test solutions:

A stock solution with a concentration of 10.0 mg/L (nominal) was prepared with direct addition of the test item, mixed into the test medium (ISO Medium) using ultrasonic bath (approximately 12 minutes). The test solutions were prepared by appropriate dilution of this stock solution just before introduction of the Daphnia (start of the treatments).
Because the test item is not stable over the 48h exposure period (based on the analytical method validation, Study Code: 17/112-316AN) the test was performed under semi-static conditions. The frequency of the water renewal periods was 24 hours. Prior to the treatment, at each of the renewal periods test solution was prepared.

Test organisms (species):

Daphnia magna

Details on test organisms:

pecies and strain: Daphnia magna
Source: István Szent University, 2100 Gödöllő, Páter Károly u. 1, Hungary
Breeding: The Daphnia are bred in Ecotoxicological Laboratory of CiToxLAB Hungary Ltd.
The health of the stock animals is continuously monitored by visual daily checking. Abnormal behaviour or significant decrease of population is recorded.
Justification of strain: Daphnia magna is the standard species of the acute immobilisation test.
Number of animals: There were 20 animals in test group and control group respectively, divided into 4 replicates (5 animals / replicate)
Age of the animals: They were less than 24 h old at the beginning of the test
Acclimatization: There was no acclimatization because the water used was similar to the culture water.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No post exposure observation period specified in the study report.

Hardness:

The reconstituted water (ISO medium) had a total hardness of 246 mg/L (as CaCO3).

Test temperature:

The water temperature was measured at the start and at the end of the renewal periods in each test vessel. The test temperature was in the range of 20.2– 20.7°C measured in the test vessels.
The additionally measured temperature in the climate chamber was between 20.0 and 20.9°C.

pH:

The pH of the test solution was not adjusted and not varied by more than 1.5 units in any one test. The pH was measured at the start and at the end of the renewal periods in each test vessel and was in the range of 7.44 – 7.79.

Dissolved oxygen:

The dissolved oxygen concentration was measured in each test vessel at the start and at the end of the renewal periods and was in the range of 7.5 – 8.8 mg/L.

Salinity:

Not specified

Conductivity:

Not specified

Nominal and measured concentrations:

Because significant immobility was observed at the highest examined concentration levels during the preliminary range-finding test, five test concentrations in a geometric series (factor 2.0) and one control were used in the main experiment under semi-static conditions.
The nominal concentrations of test item used in the main experiment were: 0.625, 1.25, 2.5, 5.0 and 10.0 mg/L.
The test concentrations were analytically determined at the beginning and at the end of the renewal periods.
The corresponding measured geometric mean test item concentrations were: 0.58; 1.19; 2.41, 4.80 and 9.47 mg/L.

Details on test conditions:

DESCRIPTION OF THE TEST PROCEDURE
The test duration was 48 hours. Twenty animals, divided into four groups (glass beakers) of five animals each (at least 5 mL test solution/animal) were used at the test concentration and for the control group as well.
The test was performed under semi-static conditions. The animals were not fed during the test.
The choice of the test concentration was made on the basis of the results of the preliminary range-finding test.

OBSERVATIONS
The immobility or mortality of the Daphnia was determined by visual observation 24 and 48 hours after the start of the test. Those animals not able to swim within 15 seconds after gentle agitation of the test beaker are considered to be immobile.
The number of immobilised animals and the percentage of immobility were determined at 24 and 48 hours.
The water temperature, the oxygen concentrations and pH of the controls and the test solution were measured at the beginning and at the end of the renewal periods.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (batch no.: A0345704)

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

2.41 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

4.8 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4.38 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

VALIDITY
There was no immobilization in the control group and the dissolved oxygen concentration at the end of the test in control and test vessels was more than 3 mg/L.
All validity criteria were within acceptable limits and therefore the study can be considered as valid.

CONCENTRATIONS OF THE TEST ITEM
Test concentrations were analytically determined at the beginning and at the end of the renewal periods.
The following nominal concentrations were tested: 0.625, 1.25, 2.5, 5.0 and 10.0 mg/L.
The corresponding measured geometric mean test item concentrations were: 0.58; 1.19; 2.41, 4.80 and 9.47 mg/L.
The biological results are related to the geometric mean of the measured test item concentrations.

IMMOBILISATION
The number of immobilised animals and the percentage of immobility were determined at the 24th and 48th hour.
In addition to immobility, no abnormal behaviour or appearance of test animals was detected.

Results with reference substance (positive control):

For the evaluation of the quality of the Daphnia clone and the experimental conditions, Potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.
The date of the last study (Study Code: 17/058-023DA) with reference item Potassium dichromate (batch no.: A0345704) is: 08 - 09 March 2017.
The 24h EC50: 0.64 mg/L, (95 % confidence limits: 0.59 – 0.68 mg/L)

Reported statistics and error estimates:

The 24 and 48 hours EC50 values of the test item were calculated using Probit analysis by SPSS PC+ software. The 48h EC100 values of the test item were determined directly from the raw data.
For the determination of the LOEC and NOEC, the immobilization at the test concentrations was tested on significant differences to the control values by Dunnett’s Test using TOXSTAT software.

Results of the first Preliminary range-Finding Test

Nominal concentration [mg/L]	Untreated control	0.1	1	10	100
Number of treated / immobilised animals	10 / 0	10 / 0	10 / 0	10 / 10	10 / 10

 

Calculation of exposure concentrations

Nominal concentration (mg/L)	Measured concentrations (mg/L) 1^strenewal period		Measured concentrations (mg/L) 2^ndrenewal period		Geometric mean
	Start	End	Start	End	mg/L
Control	n.d.	n.d.	n.d.	n.d.	-
0.625	0.931	0.575	0.566	0.371	0.58
1.25	1.86	1.19	1.16	0.779	1.19
2.5	3.72	2.40	2.36	1.59	2.41
5.0	7.37	4.85	4.69	3.17	4.80
10.0	14.6	9.56	9.25	6.23	9.47

n.d. – not detected

 

Number and percentage of immobilised animals

Concentration		Number of treated animals	Immobilised animals
Nominal (mg/L)	Measured (mg/L)		24 hours		48 hours
			Number	Percent	Number	Percent
Control	0.0	20	0	0	0	0
0.625	0.58	20	0	0	0	0
1.25	1.19	20	0	0	0	0
2.5	2.41	20	0	0	0	0
5.0	4.80	20	2	10	13	65*
10.0	9.47	20	10	50*	20	100*

*: statistically significant different compared to the control values (Dunnett’s Test; α = 0.05)

 

Temperature measured in the test vessels (°C)

Concentration (mg/L)		Replicate	Measuring time
Nominal	Measured		0 h (fresh media)	24 h (old media)	24 h (fresh media)	48 h (old media)
Control	0.0	1 2 3 4	20.6 20.6 20.6 20.6	20.3 20.3 20.3 20.3	20.5 20.5 20.5 20.5	20.2 20.2 20.2 20.2
0.625	0.58	1 2 3 4	20.6 20.6 20.6 20.6	20.3 20.3 20.3 20.3	20.5 20.5 20.5 20.5	20.2 20.2 20.2 20.2
1.25	1.19	1 2 3 4	20.6 20.6 20.6 20.6	20.3 20.3 20.3 20.3	20.5 20.5 20.5 20.5	20.2 20.2 20.2 20.2
2.5	2.41	1 2 3 4	20.6 20.6 20.6 20.6	20.3 20.3 20.3 20.3	20.5 20.5 20.5 20.5	20.2 20.2 20.2 20.2
5.0	4.80	1 2 3 4	20.6 20.6 20.7 20.7	20.3 20.3 20.3 20.4	20.5 20.5 20.5 20.6	20.2 20.3 20.3 20.3
10.0	9.47	1 2 3 4	20.7 20.7 20.7 20.7	20.4 20.4 20.4 20.4	20.6 20.6 20.6 20.6	20.3 20.3 20.3 20.3

 

Oxygen concentration measured in the test vessels (mg/L)

Concentration (mg/L)		Replicate	Measuring time
Nominal	Measured		0 h (fresh media)	24 h (old media)	24 h (fresh media)	48 h (old media)
Control	0.0	1 2 3 4	8.6 8.6 8.6 8.6	8.5 8.5 8.5 8.5	8.4 8.4 8.4 8.4	8.7 8.7 8.7 8.8
0.625	0.58	1 2 3 4	8.4 8.4 8.4 8.4	8.4 8.4 8.4 8.4	8.3 8.3 8.3 8.3	8.2 8.2 8.2 8.2
1.25	1.19	1 2 3 4	8.3 8.3 8.3 8.3	8.4 8.4 8.4 8.4	8.2 8.2 8.2 8.2	8.2 8.2 8.2 8.2
2.5	2.41	1 2 3 4	8.2 8.2 8.2 8.2	8.4 8.4 8.4 8.4	8.2 8.2 8.2 8.2	8.2 8.3 8.2 8.2
5.0	4.80	1 2 3 4	8.2 8.2 8.2 8.2	8.4 8.4 8.4 8.4	8.1 8.1 8.1 8.1	8.0 8.2 8.2 8.1
10.0	9.47	1 2 3 4	7.7 7.7 7.7 7.7	8.3 8.3 8.3 8.3	7.5 7.5 7.5 7.5	8.2 8.3 8.2 8.2

 

pH measured in the test vessels

Concentration (mg/L)		Replicate	Measuring time
Nominal	Measured		0 h (fresh media)	24 h (old media)	24 h (fresh media)	48 h (old media)
Control	0.0	1 2 3 4	7.58 7.58 7.58 7.58	7.69 7.71 7.72 7.72	7.63 7.63 7.63 7.63	7.44 7.47 7.49 7.51
0.625	0.58	1 2 3 4	7.62 7.62 7.62 7.62	7.74 7.75 7.76 7.76	7.67 7.67 7.67 7.67	7.57 7.59 7.60 7.61
1.25	1.19	1 2 3 4	7.65 7.65 7.65 7.65	7.76 7.76 7.77 7.78	7.70 7.70 7.70 7.70	7.63 7.64 7.64 7.66
2.5	2.41	1 2 3 4	7.68 7.68 7.68 7.68	7.78 7.79 7.79 7.79	7.72 7.72 7.72 7.72	7.69 7.69 7.69 7.70
5.0	4.80	1 2 3 4	7.70 7.70 7.70 7.70	7.79 7.79 7.79 7.79	7.73 7.73 7.73 7.73	7.68 7.68 7.68 7.68
10.0	9.47	1 2 3 4	7.70 7.70 7.70 7.70	7.79 7.79 7.79 7.79	7.72 7.72 7.72 7.72	7.68 7.67 7.68 7.69

 

Immobilisation of the test animals

Concentration (mg/L)		Replicate	Number of treated animals	Number of immobilised animals
Nominal	Measured			24 h	48 h
Control	0.0	1 2 3 4	5 5 5 5	0 0 0 0	0 0 0 0
0.625	0.58	1 2 3 4	5 5 5 5	0 0 0 0	0 0 0 0
1.25	1.19	1 2 3 4	5 5 5 5	0 0 0 0	0 0 0 0
2.5	2.41	1 2 3 4	5 5 5 5	0 0 0 0	0 0 0 0
5.0	4.80	1 2 3 4	5 5 5 5	0 0 2 0	3 3 5 2
10.0	9.47	1 2 3 4	5 5 5 5	2 2 3 3	5 5 5 5

 

Validity criteria fulfilled:

yes

Conclusions:

Acute toxicity of PTSM was assessed with Acute immobilisation test on Daphnia magna, over an exposure period of 48 hours in a semi-static system.
All validity criteria were met during this study.
Under the conditions of this Daphnia magna acute immobilisation study the observed endpoints for the effect of PTSM were the followings:
The 24h EC50 value: 9.44 mg/L (measured) (95 % conf. limits: 7.53 – 15.29 mg/L)
The 48h EC50 value: 4.38 mg/L (measured) (95 % conf. limits: 3.69 – 5.06 mg/L)
The 48h EC100 value: 9.47 mg/L (measured)
The 48h No-Observed Effect Concentration (NOEC): 2.41 mg/L (measured)
The 48h Lowest Observed Effect Concentration (LOEC): 4.80 mg/L (measured)

Executive summary:

Acute toxicity of PTSM on Daphnia magna was assessed in an acute immobilisation test, over an exposure period of 48 hours in a semi-static test system.

 

Because significant immobility was observed at the highest examined concentration level during the preliminary range-finding test, five test concentrations in a geometric series (factor 2.0) and one control group were tested in the definitive test under semi-static conditions. The frequency of the water renewal periods was 24 hours.

 

The test concentrations were analytically determined at the beginning and at the end of the renewal periods.

The nominal concentrations of test item used in the main experiment were: 0.625, 1.25, 2.5, 5.0 and 10.0 mg/L. The corresponding measured geometric mean test item concentrations were: 0.58; 1.19; 2.41; 4.80 and 9.47 mg/L.

 

As the measured concentrations deviated more than 20 per cent from the nominal in most cases, biological results are based on the measured geometric mean test item concentrations.

 

Twenty animals, divided into four groups (glass beaker) of five animals each were used at the test concentrations and for the control as well.

 

The 24 and 48 hours EC50 values of the test item were calculated using Probit analysis by SPSS PC+ software. The 48h EC100 values of the test item were determined directly from the raw data.

For the determination of the LOEC and NOEC, the immobilization at the test concentrations was tested on significant differences to the control values by Dunnett’s Test using TOXSTAT software.

 

All validity criteria were met during this study.

 

Under the conditions of this Daphnia magna acute immobilisation study the observed endpoints for the effect of PTSM were the followings:

The 24h EC50 value: 9.44 mg/L (measured) (95 % conf. limits: 7.53 – 15.29 mg/L)

The 48h EC50 value: 4.38 mg/L (measured) (95 % conf. limits: 3.69 – 5.06 mg/L)

The 48h EC100 value: 9.47 mg/L (measured)

The 48h No-Observed Effect Concentration (NOEC): 2.41 mg/L (measured)

The 48h Lowest Observed Effect Concentration (LOEC): 4.80 mg/L (measured)

Description of key information

The 24h EC50 value: 9.44 mg/L (measured) (95 % conf. limits: 7.53 – 15.29 mg/L)

The 48h EC50 value: 4.38 mg/L (measured) (95 % conf. limits: 3.69 – 5.06 mg/L)

The 48h EC100 value: 9.47 mg/L (measured)

The 48h No-Observed Effect Concentration (NOEC): 2.41 mg/L (measured)

The 48h Lowest Observed Effect Concentration (LOEC): 4.80 mg/L (measured)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

4.38 mg/L

Additional information

Acute toxicity of PTSM on Daphnia magna was assessed in an acute immobilisation test, over an exposure period of 48 hours in a semi-static test system.

 

Because significant immobility was observed at the highest examined concentration level during the preliminary range-finding test, five test concentrations in a geometric series (factor 2.0) and one control group were tested in the definitive test under semi-static conditions. The frequency of the water renewal periods was 24 hours.

 

The test concentrations were analytically determined at the beginning and at the end of the renewal periods.

The nominal concentrations of test item used in the main experiment were: 0.625, 1.25, 2.5, 5.0 and 10.0 mg/L. The corresponding measured geometric mean test item concentrations were: 0.58; 1.19; 2.41; 4.80 and 9.47 mg/L.

 

As the measured concentrations deviated more than 20 per cent from the nominal in most cases, biological results are based on the measured geometric mean test item concentrations.

 

Twenty animals, divided into four groups (glass beaker) of five animals each were used at the test concentrations and for the control as well.

 

Under the conditions of this Daphnia magna acute immobilisation study the observed endpoints for the effect of PTSM were the followings:

The 24h EC50 value: 9.44 mg/L (measured) (95 % conf. limits: 7.53 – 15.29 mg/L)

The 48h EC50 value: 4.38 mg/L (measured) (95 % conf. limits: 3.69 – 5.06 mg/L)

The 48h EC100 value: 9.47 mg/L (measured)

The 48h No-Observed Effect Concentration (NOEC): 2.41 mg/L (measured)

The 48h Lowest Observed Effect Concentration (LOEC): 4.80 mg/L (measured)