2-ethylhexyl 10-ethyl-4-[[2-[(2-ethylhexyl)oxy]-2-oxoethyl]thio]-4-octyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecanoate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 August 2016 to 31 August 2016

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:

13 April 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Test concentration analysis was done at Auriga Research Ltd, Unit-III, No. 136, 6th Cross, 2nd Stage, Yeshwanthpur industrial suburb, Bangalore-560022.
During range finding study and main study, samples from all the test concentrations was collected at 0 hour on day 0 for the analysis of test concentration and at 48 hour on day 2 for stability analysis. The samples were collected from the central point of the test vessel. The validated analytical method for determination of test concentrations analysis of DOTE was used for analytics.
The test concentration samples were collected in duplicates (2 x 10 mL) for each test concentrations including vehicle control and transferred at ambient condition for test concentration confirmation analysis to Auriga Research Ltd, Unit-III, No. 136, 6th Cross, 2nd Stage, Yeshwanthpur industrial suburb, Bangalore-560022. Results are based on measured concentration, the concentration of test substance has been satisfactorily maintained within 20 percent of nominal concentration.

Vehicle:

yes

Details on test solutions:

Based on the in house dissolution test MOTE was miscible in DMSO (100 µL/L) and reconstituted water. Hence DMSO (100µL/L) and reconstituted water will be selected as the vehicle for preparation of test item formulation.

Test organisms (species):

Daphnia magna

Details on test organisms:

In house maintained Daphnia magna procured, from Environmental and Molecular Toxicology Division, Department of Zoology, Karnataka University, Karnataka, India.
Young daphnids less than 24 h old. (Derived from healthy stock showing no signs of stress, such as high mortality rate, discolored daphnids, presence of male and ephippia, delay in the production of the first brood).

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Remarks on exposure duration:

Duration of the experiment was 48 hour. Experiment was conducted in static condition i.e., the test media was not renewed until completion of the exposure period of 48 hour

Hardness:

216-220 mg CaCO3/L

Test temperature:

20.2-20.3 °C

pH:

6.29-7.75

Dissolved oxygen:

7.23-7.51 mg/L

Nominal and measured concentrations:

Range Finding Study
A range finding (RF) study with 6 concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L of MOTE was used along with controls (negative and solvent) to find out the range of the lethal concentrations.

Main Study
Based on results of the range finding study, the main study was conducted at the scattered concentrations of 0.05, 0.1, 1.0, 5.0, 20.0 and 40 mg/L specified by the sponsor (rationale of concentration spaced is not as per geometric factor specified in guideline, OECD 203 Daphnia sp., Acute Immobilization Test) along with the control groups (negative and solvent groups).

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

25.8 mg/L

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 0.9 mg/L

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

ca. 2 mg/L

Results with reference substance (positive control):

The 48 hours acute median effective concentration (EC50) of Potassium dichromate on Daphnia is 0.90 mg/L (BIO-ET 051). This 48 hour EC50of Potassium dichromate lie in the validity criteria acceptance range (0.60 to 2.12 mg/L) towards test system response and test procedure followed. Hence this test with reference standard establishes the acceptability of test system response and test procedure followed.

Validity criteria fulfilled:

yes

Conclusions:

Based on the above results of the experiment and under experimental conditions employed, it can be concluded that the 48 hour acute median effective concentration (EC50) of MOTE on Daphnia, is 25.80 mg/L.

Executive summary:

The test item MOTE, was evaluated for 48-hour acute toxicity on Daphnia magna, in accordance with OECD Guideline No. 202, “Daphina sp., Acute Immobilisation Test”.

During the study, Daphnids were exposed for the test item under static condition. Daphnids were observed at 24 and 48 hours for signs of toxicity and immobility during exposure.

For the range finding study duplicate containers of 5 daphnids at each concentration plus control groups (negative and solvent) were used. Daphnids were exposed to test concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L of MOTE. Cumulative immobility of 10.0, 10.0, 20.0, 40.0 and 100.0%, respectively, was observed within the MOTE test groups. There were recorded observations of daphnids localized on the bottom of the container at the tested concentration of 1.0 mg/L. Lethargy in addition to daphnids localized on the bottom of container were observed at the tested concentrations of 10.0, 50.0 and 100.0 mg/L of MOTE during the 48 hours of observation period. No clinical signs or immobility were observed in negative or solvent controls during the 48 hour exposure period.

Based on the results of the range finding study and the main study was conducted at the concentration of 0.9, 2.0, 4.0, 9.0, 20.0 and 40.0 mg/L of MOTE of test medium along with control groups (negative and solvent).

Immobility of 0.0,0.0,0.0, 5.0, 15.0, 30.0, 40.0 and 100.0% were observed at control (negative and solvent) and in the tested concentrtions 0.9, 2.0, 4.0, 9.0, 20.0and 40.0 mg/L, repectively. Clinical signs of lethargy observed in the tested concentration 2.0 mg/L, however clinical signs of lethargy and localized on the bottom of container were observed at the tested concentrations of 4.0, 9.0, 20.0 and 40.0 mg/L, no clinical signs or immobility observed in control groups (negative and solvent) and at tested concentration 0.9 mg/L of MOTE during the 48 hour of exposure period.

Based on the above results of the experiment and under experimental conditions employed, it can be concluded that the 48 hour acute median effective concentration (EC50) of MOTE on Daphnia, is 25.80 mg/L.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

March 15 to April 16, 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

The test material only contained 70% MOTE and in addition the substance tested is believed to contain EHTG as an impurity, which is more soluble than the registered substance and known to be more hazardous. This technical grade of the material is not considered to be the most representative of MOTE itself and therefore the effects noted are not considered to be representative of the registered substance.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

During the final test duplicate samples for analysis were taken from all test concentrations and the control according to the schedule below. In addition, the filter used for preparation of the WSF was retained for possible analysis of the residue. The method of analysis is described in the appended Analytical Report.

Frequency at t=0 h and t=48 h
Volume 25 ml
Storage Not applicable, samples were analysed on the day of sampling.

At the end of the exposure period, the replicates were pooled at each concentration before sampling.

Vehicle:

no

Details on test solutions:

The standard test procedures required generation of test solutions, which should contain completely dissolved test substance concentrations or stable and homogeneous mixtures or dispersions. The testing of concentrations that disturb the test system should be prevented (e.g. film of the test substance on the water surface).

The batch of Octyltintris(2-ethylhexyl mercaptoacetate) tested was a clear colourless to light yellow liquid with a purity of 98.00% and the substance was not completely soluble in test medium at the initial loading rate prepared.

Preparation of test solutions started with a loading rate of 100 mg/l applying one day of magnetic stirring followed by a one day stabilisation period to reach maximum solubility of the test substance in the test medium. The slightly hazy and colourless Water Soluble Fraction (WSF) was filtered through glass wool for the combined limit range-finding test and through a glass fibre filter for the final test. The WSF filtered through glass wool was stil) slightly hazy, white the WSF filtered through a glass fibre filter was clear and colourless. These WSF's were used as the highest test concentration in the respective tests. The lower test concentrations were prepared by subsequent dilutions of the WSFs in test medium. These lower test concentrations were all clear and colourless.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions.
Source: In-house laboratory culture with a known history.
Validity of batch: Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animais and there was no delay in the production of the first brood.

Characteristics: For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

180 mg/I expressed as CaCO3

Test temperature:

The temperature of the test medium was 19.7°C at the start of the test. The temperature continuously measured in a temperature control vesse) varied between 19.1 and 19.7°C during the test, and complied with the requirements as laid down in the protocol (18-22°C, constant within 2°C).

pH:

6.0-8.5, not varying by more than 1.5 unit

Dissolved oxygen:

oxygen: >_3 mg/l at the end of the test

Salinity:

not applicable

Nominal and measured concentrations:

10, 18, 32, 56 and 100% of a WSF prepared at a loading rate of 100 mg/I

Details on test conditions:

Test duration: 48 hours
Test type: static
Test vessels: 100 ml, all-glass
Medium: Adjusted ISO medium
Number of daphnids: 20 per concentration
Loading: 5 per vessel containing 80 ml of test solution
Light: 16 hours photoperiod
Feeding: No feeding
Aeration: No aeration of the test solutions
Introduction of daphnids: Within 40 minutes after preparation of the test solutions

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

>= 18 - <= 32 other: % WSF

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

18 other: %WSF

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

The measured concentration of octyltin species in the duplicate samples taken from the undiluted WSF showed initial concentrations of 112 and 142 µg/L. The three highest test concentrations remained stable during the test period (89-114% of initial), while the two lower test concentrations slightly decreased (62-70% of initial). Given these results, the effect parameters were expressed in terms of both % of WSF (Octyltintris(2-ethylhexyl mercaptoacetate)) and the average concentrations (octyltin species). The average concentrations were calculated to be 19, 29, 49, 75 and 124 µg/L.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study Octyltintris(2-ethylhexyl mercaptoacetate) did not induce acute immobilisation of Daphnia magna exposed to the concentration obtained in 18% of a WSF prepared at a loading rate of 100 mg/l (NOEC).

The 48h-EC50 was between the concentrations obtained in 18 and 32% of a WSF prepared at a loading rate of 100 mg/l.

Executive summary:

The study procedures described in this report were based on the OECD guideline No. 202, 2004. In addition, the procedures were designed to meet the test methods of the Commission Regulation (EC) No 440/2008, Part C.2, 2008, the ISO International Standard 6341, 1996 andthe OECD series on testing and assessment number 23, 2000.

The batch of Octyltintris(2-ethylhexyl mercaptoacetate) tested was a clear colourless to light yellow liquid with a purity of 98.00% and the substance was not completely soluble in test medium at the initial loading rate prepared.

Based on the results of a combined limit/range-finding test, a final test was performed. Preparation of test solutions started with a loading rate of 100 mg/L applying one day of magnetic stirring followed by a one day stabilisation period to reach maximum solubility of the test substance in the test medium. The slightly hazy and colourless Water Soluble Fraction(WSF) was filtered through a glass fibre filter and the clear and colourless solution was used as the highest test concentration. The lower test concentrations were prepared by subsequent dilutions of the WSF in test medium.

Twenty daphnids per concentration (four replicates, five daphnids per replicate) were exposed to 10, 18, 32, 56 and 100% of the WSF prepared at a loading rate of 100 mg/L and to a control group. The total test period was 48 hours and duplicate samples for analytical confirmation of actual exposure concentrations were taken at the start and the end of the test.

Analysis was performed on the octyltin species in Octyltintris(2-ethylhexyl mercaptoacetate).

The measured concentration of octyltin species in the duplicate samples taken from the undiluted WSF showed a mean initial concentration of 127 µg/L. Lower test concentrations contained 19, 28, 41 and 56% of the undiluted WSF. The three highest test concentrations remained stable during the test period (89-114% of initial), while the two lower test concentrations slightly decreased (62-70% of initial).

The study met the acceptability criteria prescribed by the protocol and was considered valid.

Octyltintris(2-ethylhexyl mercaptoacetate) did not induce acute immobilisation of Daphnia magna exposed to the concentration obtained in 18% of a WSF prepared at a loading rate of 100 mg/L (NOEC).

The 48h-EC50 was between the concentrations obtained in 18 and 32% of a WSF prepared at a loading rate of 100 mg/L.

Description of key information

Sadananda (2016) - Key Study

Under the experimental conditions employed, it can be concluded that the 48 hour acute median effective concentration (EC50) of MOTE on Daphnia, is 25.80 mg/L.

Bouwman (2010) - Supporting Study

Under the conditions of the study Octyltintris(2-ethylhexyl mercaptoacetate) did not induce acute immobilisation of Daphnia magna exposed to the concentration obtained in 18% of a WSF prepared at a loading rate of 100 mg/L (NOEC).

The 48h-EC50 was between the concentrations obtained in 18 and 32% of a WSF prepared at a loading rate of 100 mg/L (equivalent to average concentrations of 29 to 49 µg/L).

Despite the concerns for the reliability of this study, the value for chemical safety assessment is taken from the results of the Bouwman study since it provides the most conservative estimate of toxicity of the substance.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

39 µg/L

Additional information

Two relevant studies are available, as follows:

Sadananda (2016) - Key Study

The test item MOTE, was evaluated for 48-hour acute toxicity on Daphnia magna, in accordance with OECD Guideline No. 202, “Daphina sp., Acute Immobilisation Test”.

During the study, Daphnids were exposed for the test item under static condition. Daphnids were observed at 24 and 48 hours for signs of toxicity and immobility during exposure.

For the range finding study duplicate containers of 5 daphnids at each concentration plus control groups (negative and solvent) were used. Daphnids were exposed to test concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L of MOTE. Cumulative immobility of 10.0, 10.0, 20.0, 40.0 and 100.0%, respectively, was observed within the MOTE test groups. There were recorded observations of daphnids localized on the bottom of the container at the tested concentration of 1.0 mg/L. Lethargy in addition to daphnids localized on the bottom of container were observed at the tested concentrations of 10.0, 50.0 and 100.0 mg/L of MOTE during the 48 hours of observation period. No clinical signs or immobility were observed in negative or solvent controls during the 48 hour exposure period.

Based on the results of the range finding study and the main study was conducted at the concentration of 0.9, 2.0, 4.0, 9.0, 20.0 and 40.0 mg/L of MOTE of test medium along with control groups (negative and solvent).

Immobility of 0.0,0.0,0.0, 5.0, 15.0, 30.0, 40.0 and 100.0% were observed at control (negative and solvent) and in the tested concentrtions 0.9, 2.0, 4.0, 9.0, 20.0and 40.0 mg/L, repectively. Clinical signs of lethargy observed in the tested concentration 2.0 mg/L, however clinical signs of lethargy and localized on the bottom of container were observed at the tested concentrations of 4.0, 9.0, 20.0 and 40.0 mg/L, no clinical signs or immobility observed in control groups (negative and solvent) and at tested concentration 0.9 mg/L of MOTE during the 48 hour of exposure period.

Based on the above results of the experiment and under experimental conditions employed, it can be concluded that the 48 hour acute median effective concentration (EC50) of MOTE on Daphnia, is 25.80 mg/L.

Bouwman (2010) - Supporting Study

The study procedures described in this report were based on the OECD guideline No. 202, 2004. In addition, the procedures were designed to meet the test methods of the Commission Regulation (EC) No 440/2008, Part C.2, 2008, the ISO International Standard 6341, 1996 andthe OECD series on testing and assessment number 23, 2000.

The batch of Octyltintris(2-ethylhexyl mercaptoacetate) tested was a clear colourless to light yellow liquid with a purity of 98.00% and the substance was not completely soluble in test medium at the initial loading rate prepared.

Based on the results of a combined limit/range-finding test, a final test was performed. Preparation of test solutions started with a loading rate of 100 mg/L applying one day of magnetic stirring followed by a one day stabilisation period to reach maximum solubility of the test substance in the test medium. The slightly hazy and colourless Water Soluble Fraction(WSF) was filtered through a glass fibre filter and the clear and colourless solution was used as the highest test concentration. The lower test concentrations were prepared by subsequent dilutions of the WSF in test medium.

Twenty daphnids per concentration (four replicates, five daphnids per replicate) were exposed to 10, 18, 32, 56 and 100% of the WSF prepared at a loading rate of 100 mg/L and to a control group. The total test period was 48 hours and duplicate samples for analytical confirmation of actual exposure concentrations were taken at the start and the end of the test.

Analysis was performed on the octyltin species in Octyltintris(2-ethylhexyl mercaptoacetate).

The measured concentration of octyltin species in the duplicate samples taken from the undiluted WSF showed a mean initial concentration of 127 µg/L. Lower test concentrations contained 19, 28, 41 and 56% of the undiluted WSF. The three highest test concentrations remained stable during the test period (89-114% of initial), while the two lower test concentrations slightly decreased (62-70% of initial).

The study met the acceptability criteria prescribed by the protocol and was considered valid.

Octyltintris(2-ethylhexyl mercaptoacetate) did not induce acute immobilisation of Daphnia magna exposed to the concentration obtained in 18% of a WSF prepared at a loading rate of 100 mg/L (NOEC).

The 48h-EC50 was between the concentrations obtained in 18 and 32% of a WSF prepared at a loading rate of 100 mg/L.