Triisooctyl 2,2',2''-[(octylstannylidyne)tris(thio)]triacetate

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

Reason / purpose for cross-reference:

other: read-across target

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- 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 the test material 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 material has been satisfactorily maintained within 20 percent of nominal concentration

Vehicle:

yes

Remarks:

DMSO

Details on test solutions:

Test Vehicle
- Based on the in house dissolution test the test material was miscible in DMSO (100 µL/L) and reconstituted water. Hence DMSO (100 µL/L) and reconstituted water were selected as the vehicle for preparation of test material formulation.

Test Medium Preparation
- The test medium was prepared by serial dilution of the stock solution. The stock solution was prepared by dissolving the required quantity of test material in DMSO (100 µL/L) and making up to voulme with reconstituted water (Dilution water). The prepared test formulation was kept on magnetic stirrer to maintain the homogeneity.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: In house maintained Daphnia magna procured, from Environmental and Molecular Toxicology Division, Department of Zoology, Karnataka University, Karnataka, India.
- Age: Young Daphnids less than 24 h old were used (Derived from healthy stock showing no signs of stress, such as high mortality rate, discoloured daphnids, presence of male and ephippia, delay in the production of the first brood).
- Feeding during test: no

ACCLIMATION
- Acclimation period: 25 gravid female Daphinds were acclimatised in the reconstituted water for 48 h prior to test (similar for range finding and main study).
- Acclimation conditions: During acclimatisation dissolved oxygen, temperature, pH were measured at beginning and at end. Dissolved oxygen during acclimatisation was between 7.32 to 7.38 mg/L, temperature of 20.1 and 20.2 °C, pH of 6.32 to 6.39 and hardness of 216 and 220 mg CaCO3/L was observed during the range finding and main study.
- Type and amount of food: Daphnids were fed with live algal cells (Pseudokirchneriella subcapitata) of 2 mL per litre at the beginning and on Day 2 of acclimatisation.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

216 to 220 mg/L (as CaCO3)

Test temperature:

20.0 to 20.5 °C

pH:

6.26 to 6.75

Dissolved oxygen:

7.23 to 7.51 mg/L

Nominal and measured concentrations:

- Nominal: 0.9, 2.0, 4.0, 9.0, 20.0 and 40 mg/L
- Measured: 0.99, 1.89, 4.05, 8.79, 20.44 and 38.68 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Thoroughly cleaned rectangular glass beakers having the water holding capacity of 100 mL
- Material, size, headspace, fill volume: 20 mL of test solution was provided for each daphnid (i.e. a volume of 100 mL for five Daphnids per test vessel)
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water was used for holding the Daphnids and as diluent medium during acclimatization and exposure periods.
- Composition of reconstituted water:
The following were added to 1 litre of water:
11.76 g Calcium chloride (CaCl2.2H2O)
4.93 g Potassium chloride (KCl)
2.59 g Magnesium sulfate (MgSO4.7H2O)
0.23 g Sodium bicarbonate (NaHCO3)
25 mL of each stock solution was added to 1 litre of water to prepare the medium.
- Culture medium different from test medium: no
- Intervals of water quality measurement: Total hardness of the diluent water (reconstituted water) prior to its use for exposure was analysed. Temperature, pH and dissolved oxygen were recorded at beginning and at end of the test in control and in all the test concentrations.

OTHER TEST CONDITIONS
- Photoperiod: 16 hour light and 8 hour darkness

EFFECT PARAMETERS MEASURED:
- Each test vessel was observed for immobilised Daphnids at 24 and 48 hours after the beginning of the test, in addition any abnormal behaviour or appearance was recorded.

VEHICLE CONTROL PERFORMED: yes

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 was used along with control to find out the range of the lethal concentration.
- Based on results of the range finding study the main study was conducted at the scattered concentrations of 0.9, 2.0, 4.0, 9.0, 20.0 and 40 mg/L as specified by sponsor, (rationale of concentration spaced is not as per geometric factor specified in guideline, OECD 203 Daphnia sp., Acute Immobilisation 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

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

RANGE-FINDING STUDY
Immobility of 0.0, 0.0, 0.0, 0.0, 10.0, 20.0, 100.0 and 100.0% were observed in the controls (negative and solvent) and at the tested concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L of test material, respectively. Clinical signs of daphnids on the bottom of container were observed at tested concentrations above 1.0 mg/L. No clinical signs or immobility were observed in control groups (negative and solvent) and in the tested concentrations 0.01 and 0.1 mg/L during the 48 hours of observation period.

MAIN TEST
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 of 0.9, 2.0, 4.0, 9.0, 20.0 and 40.0 mg/L, repectively. Clinical signs of lethargy were observed in the tested concentration 2.0 mg/L, however clinical signs of lethargy and daphnia 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 were observed in control groups (negative and solvent) and at tested concentration 0.9 mg/L during the 48 hour of exposure period.

VALIDITY CRITERIA OF THE TEST
- Immobilisation in the control group was 0 % at the termination of the test during main study (validity criterion: should not exceed 10%).
- Dissolved oxygen concentration in the control at the end of the test was 7.32 mg/L in control and 7.23 mg/L in test vessels (Validity of criterion: should be ≥ 3 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 EC50 of 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.

Reported statistics and error estimates:

The EC50 of MOTE at 48 h was calculated using the Probit analysis method (Finney, 1971). The 48 h EC50 of MOTE with 95 % fiducial limits and regression equation established using Probit mortality versus log concentration.

Table 1: Test Concentration Analysis in the Range-finding Study

Group	Nominal Concentration	% Recovery
	(mg/L)
G1	0.0	-
G2	0.0	-
G3	0.01	100
G4	0.1	100
G5	1.0	93
G6	10.0	99.30
G7	50.0	98.60
G8	100.0	101.11

Table 2: Test Concentration Analysis in the Main Study

Group	Nominal Concentration	% Recovery
	(mg/L)
G1	0.0	-
G2	0.0	-
G3	0.9	110.2
G4	2.0	94.5
G5	4.0	101.2
G6	9.0	97.7
G7	20.0	102.2
G8	40.0	96.7

Table 3: Summary of Clinical Signs and Immobility in the Main Study

Group & Concentration (mg/L)	R	No. of Daphnids per replicate at start 0h	Signs of toxicity and immobility of Daphnids observed at
			24 h		48 h
			Toxic signs	I	Toxic signs	I
G1 0.00	R1	05	N(5)	0	N(5)	0
	R2	05	N(5)	0	N(5)	0
	R3	05	N(5)	0	N(5)	0
	R4	05	N(5)	0	N(5)	0
*G2 0.0	R1	05	N(5)	0	N(5)	0
	R2	05	N(5)	0	N(5)	0
	R3	05	N(5)	0	N(5)	0
	R4	05	N(5)	0	N(5)	0
G3 0.9	R1	05	N(5)	0	N(5)	0
	R2	05	N(5)	0	N(5)	0
	R3	05	N(5)	0	N(5)	0
	R4	05	N(5)	0	N(5)	0
G4 2.0	R1	05	N(5)	0	N(5)	0
	R2	05	N(5)	0	N(5)	0
	R3	05	N(5)	0	N(4), L(1)	0
	R4	05	N(5)	0	N(3), L(1)	1
G5 4.0	R1	05	N(4), B(1)	0	N(3), B(1)	1
	R2	05	N(3), L(1)	1	N(3), L(1)	0
	R3	05	N(4), B(1)	0	N(4), B(1)	0
	R4	05	N(3), L(1)	1	N(3), L(1)	0
G6 9.0	R1	05	N(2), B(1), L(1)	1	N(2), B(1)	1
	R2	05	N(3), B(1)	1	N(2), B(1)	1
	R3	05	N(4), B(1)	0	N(3), B(1)	1
	R4	05	N(3), L(1)	1	N(3), L(1)	0
G7 20.0	R1	05	N(2), B(1), L(1)	1	B(2), L(1)	1
	R2	05	B(2), L(1)	2	B(2), L(1)	0
	R3	05	N(1), B(2), L(1)	1	B(2), L(1)	1
	R4	05	B(2), L(1)	2	B(2), L(1)	0
G8 40.0	R1	05	B(1), L(1)	3	-	2
	R2	05	B(2), L(1)	2		3
	R3	05	B(2)	3	-	2
	R4	05	B(2), L(1)	2		3

*: Solvent control; R: Replicate; R1 to R4: Replicates 1 to 4; h: hour; I: Immobility; N: Normal; L: Lethargic; B: on Bottom(localised on the bottom of container); -: Not applicable; The alphabetical outside and values inside the parentheses represent the clinical symptom code and number of daphnids exhibiting that particular symptom, respectively.

Table 4: Summary of Immobility as Different Time Points of Post Exposure in the Main Study

Group	Concentration (mg/L)	Initial No. of Daphnids	Immobility (No.) of Daphnids		Cumulative No. on	% of Cumulative Immobility
			24 h	48 h	48h	24 h	48 h
G1	0.0	20	0	0	0	0.0	0.0
*G2	0.0	20	0	0	0	0.0	0.0
G3	0.9	20	0	0	0	0.0	0.0
G4	2.0	20	0	1	1	0.0	5.0
G5	4.0	20	2	1	3	10.0	15.0
G6	9.0	20	3	3	6	15.0	30.0
G7	20.0	20	6	2	8	30.0	40.0
G8	40.0	20	10	10	20	50.0	100.0

 h: hour; *: Solvent control

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of this study, it can be concluded that the 48 hour acute median effective concentration (EC50) of the test material on Daphnia, is 25.80 mg/L. The No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) over the 48 hour exposure period were 0.9 and 2.0 mg/L, respectively.

Executive summary:

The acute toxicity of the test material to aquatic invertebrates was investigated in accordance with the standardised guideline OECD 202, under GLP conditions.

During the study, daphnids were exposed to test material under static conditions and were observed for signs of toxicity and immobility for a period of 48 hours.

For the range finding study daphnids were exposed to test concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L. Cumulative immobility of 0.0, 0.0, 10.0, 20.0, 100.0 and 100.0 %, respectively, was observed. Based on the results of the range finding study, the main study was conducted at concentrations of 0.9, 2.0, 4.0, 9.0, 20.0 and 40.0 mg/L. Cumulative immobility at these concentrations was of 0.0, 5.0, 15.0, 30.0, 40.0 and 100.0 %, respectively.

Under the conditions of this study, it can be concluded that the 48 hour acute median effective concentration (EC50) of the test material on Daphnia, is 25.80 mg/L.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted on read-across material

Justification for type of information:

Read Across to Octyltin tris(2-ethylhexylmercaptoacetate) (MOTE) (EC Number 248-227-6 and CAS No 27107-89-7) based on structural similarity and hydrolytical behaviour, see attached justification.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

25.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Description of key information

Read-across to structurally similar substance Octyltin tris(2-ethylhexylmercaptoacetate) (MOTE)(CAS No 27107-89-7) (Sadananda, 2016)

Under the conditions of this study, it can be concluded that the 48 hour acute median effective concentration (EC50) of the test material on Daphnia, is 25.80 mg/L. The No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) over the 48 hour exposure period were 0.9 and 2.0 mg/L, respectively.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

25.8 mg/L

Additional information

Read-across to structurally similar substance Octyltin tris(2-ethylhexylmercaptoacetate) (MOTE)(CAS No 27107-89-7)

(Sadananda, 2016)

The acute toxicity of the test material to aquatic invertebrates was investigated in accordance with the standardised guideline OECD 202, under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

During the study, daphnids were exposed to test material under static conditions and were observed for signs of toxicity and immobility for a period of 48 hours.

For the range finding study daphnids were exposed to test concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L. Cumulative immobility of 0.0, 0.0, 10.0, 20.0, 100.0 and 100.0 %, respectively, was observed. Based on the results of the range finding study, the main study was conducted at concentrations of 0.9, 2.0, 4.0, 9.0, 20.0 and 40.0 mg/L. Cumulative immobility at these concentrations was of 0.0, 5.0, 15.0, 30.0, 40.0 and 100.0 %, respectively.

Under the conditions of this study, it can be concluded that the 48 hour acute median effective concentration (EC50) of the test material on Daphnia, is 25.80 mg/L.

(Bouwman, 2010)

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 and the OECD series on testing and assessment number 23, 2000. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

The batch of test material 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 material 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 the test material.

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.

The test material 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.