Bis[(2-ethyl-1-oxohexyl)oxy]dioctylstannane

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 February 1988 to 8 March 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Reason / purpose for cross-reference:

other: read-across target

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

no

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 10, 18, 32, 58 and 100 % of saturated solution, sampled at 0 and 72 hours measured as Sn content

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 300 mg of the test substance was added to 1500 mL water and stirred for 48 h then filtered first through a glass filter D4 then through a membrance filter (Millipore Type HA 0.45 µm)
- Controls: A blank was included as a control

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: Cambridge 276/20
- Method of cultivation: In accordance with OECD No. 201

ACCLIMATION
- Culturing media and conditions: 3 days under test conditions

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24 ± 2 °C

pH:

7.8 - 9.2

Nominal and measured concentrations:

Nominal: 0 (blank), 10, 18, 32, 58 and 100 of saturated solution %
Measured: 0, 0.00023, 0.00032, 0.00053, 0.00097 and 0.0018 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks
- Type : closed, stoppered with aluminium caps
- Material, size, headspace, fill volume: 100 mL
- Initial cells density: 1.2 E4 cells/mL
- Control end cells density: 1.95 E5
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes, as detailed in OECD 201 (1984)

OTHER TEST CONDITIONS
- Photoperiod: Continuous illumination
- Light intensity and quality: 120 µE/m2sec ± 20 % (approx. 8000 Lux) cold white fluorescent light

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: Daily on TOA cell counter.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.002 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Equivalent to 100 % saturated solution

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.002 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.001 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
Figure 1 depicts the growth rate.
- Results with test substance: Slight to no effects were noted on the algal growth during the course of the study.
- Concentration of the test substance: Test concentrations were not maintained during the study, results are expressed as initial measured concentration.

Reported statistics and error estimates:

Comparisons for area under growth curve were performed in accordance with the guidance provided in the guideline.

Table 1: Cell density after 24 hours

Conc. (initial) mg/L	Relative cell densities						Mean Relative Density	Dilution Factor 1:	Mean Density N24h cells/mL*1000
	1	2	3	4	5	6
Blank	50	53	48	53	54	63	54	10	8.1
0.00023	59	58	55				57	10	8.6
0.00032	60	56	68				61	10	9.2
0.00053	60	59	55				58	10	8.7
0.00097	51	57	50				53	10	8.0
0.0018	52	55	64				57	10	8.6

 

Table 2: Cell density after 48 hours

Conc. (initial) mg/L	Relative cell densities						Mean Relative Density	Dilution Factor 1:	Mean Density N48h cells/mL*1000
	1	2	3	4	5	6
Blank	154	204	200	262	231	271	220	10	33.0
0.00023	215	194	207				205	10	30.8
0.00032	154	233	227				205	10	30.8
0.00053	203	180	157				180	10	27.0
0.00097	244	229	258				244	10	36.6
0.0018	238	271	312				274	10	41.1

 

Table 3: Cell density after 72 hours

Conc. (initial) mg/L	Relative cell densities						Mean Relative Density	Dilution Factor 1:	Mean Density N72h cells/mL*1000
	1	2	3	4	5	6
Blank	118	128	128	133	127	146	130	100	195
0.00023	125	139	141				135	100	203
0.00032	132	130	161				141	100	212
0.00053	140	144	146				143	100	215
0.00097	135	130	144				136	100	204
0.0018	67	71	81				73	100	110

Multiplication Factor N72h/N0h = 163

 

Table 4: Percentage inhibition

Conc. (initial) mg/L	Areas under growth curve				% Inhibition (IA 0-72h)
	A0-24h	A24-48h	A48-72h	A0-72h
Blank	83	464	2707	3254	0
0.00023	89	444	2777	3310	0*
0.00032	96	451	2885	3432	0*
0.00053	90	400	2875	3365	0*
0.00097	82	506	2858	3446	0*
0.0018	89	568	1784	2441	25
* promotion of algal growth in regard to Blank-Control denoted as: 0

 

Table 5: pH and analytical concentrations

Conc. in % of saturated solution	Measured concentrations*		pH
	0 h mg/L	72 h mg/L	0 h	72 h
Blank			8.1	9.2
0.00023	0.00023	<0.00021	7.8	8.9
0.00032	0.00032	<0.00021	7.8	9.0
0.00053	0.00053	0.00027	7.8	9.0
0.00097	0.00097**	0.00044	7.8	9.1
0.0018	0.0018	0.00079	7.8	9.1
* analytically determined values multiplied by a factor of 100/32.87; Sn content of test substance: 32.87 % ** value of only one sample considered, all others are mean of two samples

Validity criteria fulfilled:

not specified

Conclusions:

Under the conditions of the test, the test substance exhibited little or no difference on the growth rate of the algae Desmodesmus subspicatus (reported as Scenedesmus subspicatus) when tested up to a 100 % saturated solution. The ErC50 of the test substance is greater than the water solubility of the test substance.

Executive summary:

The toxicity of the test substance to aquatic plants was determined in a study conducted to OECD 201, using the algal species Desmodesmus subspicatus (reported as Scenedesmus subspicatus). The study was conducted using a range of concentrations, tested up to the water solubility of the test substance. The concentrations of the test substance were not maintained in the solutions throughout the entire 72 hour test period, results were expressed as the initial concentration. Under the conditions of the test, the test substance exhibited little or no difference on the growth rate of the algae, the ErC50 of the test substance is considered to be greater than the water solubility of the test substance.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

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 structurally similar substance dioctyltin oxide (Public name: DOTO, CAS: 870-08-6, EC: 212-791-1), see attached justification.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.002 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Equivalent to 100 % saturated solution

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.002 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.001 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Description of key information

Read-across to structurally similar substance DOTO (Dioctyltin oxide), CAS 870-08-6

Under the conditions of the test, the test substance exhibited little or no difference on the growth rate of the algae, the ErC50 (and the NOEC) of the test substance is considered to be greater than the water solubility of the test substance.

Additional information

Read-across to structurally similar substance DOTO (Dioctyltin oxide), CAS 870-08-6

The toxicity of the test substance to aquatic plants was determined in a study conducted to OECD 201, using the algal species Desmodesmus subspicatus (reported as Scenedesmus subspicatus). The study was conducted using a range of concentrations, tested up to the water solubility of the test substance. The concentrations of the test substance were not maintained in the solutions throughout the entire 72 hour test period, results were expressed as the initial concentration.

Under the conditions of the test, the test substance exhibited little or no difference on the growth rate of the algae, the ErC50 (and the NOEC) of the test substance is considered to be greater than the water solubility of the test substance.