N-(2-aminoethyl)-N'-[3-(trimethoxysilyl)propyl]ethylenediamine

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:

2002-01-24 to 2002-02-01

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions. The study was conducted under GLP, however exposure concentrations were not measured.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II) (January 2012)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A 50 mg/L stock solution was prepared by placing 0.049 ml (density of 1.028 g/ml) of aminosilane in a 1000 mL volumetric flask and diluting to volume with sterile AAP medium containing 0.10 mL of dimethylformamide (DMF, CAS No. 68-12-2). The resulting stock solution was observed to be clear and colourless with no visible undissolved test substance. Nominal concentrations were prepared by dilution of the 50 mg/L stock solution. A solvent control was prepared with AAP medium containg 0.1 mL/L of DMF. A blank control comprising only of AAP medium was also prepared.

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM

- Strain: 1648

- Source (laboratory, culture collection): The alga was obtained from Carolina Biological Supply Co., Burlington, North Carolina, and was maintained in stock culture at Springborn Smithers. 

- Culture conditions: The stock cultures were maintained within the following conditions:  a shaking rate of 100 ± 10 rpm, a temperature of 24 ± 1 °C and continuous illumination at the surface of the medium with an intensity of approximately 300 to 500 footcandles (3200 to 5400 lux).  Lighting was supplied by Duro-Test® Vita-Lite® fluorescent bulbs.  Culture flasks were agitated continuously on an orbital shaker.

- Growth/test medium:  The culture medium used was Algal Assay Procedure (AAP) medium prepared with sterile, deionized water.  

- Culture vessesl: Stock cultures were grown in 250 ml glass flasks, each containing 100 ml of culture medium. The flasks were closed with stainless steel caps that permitted gas exchange.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

No data but conductivity measured at start and end of test ranged between 75 and 90 µmhos/cm

Test temperature:

23 to 24 °C

pH:

7.2-8.7 at start of test

7.8-8.2 at end of test

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

Nominal test concentrations: 0 (Control), 0 (Solvent control), 1.6, 3.1, 6.3, 13, 25 and 50 mg/l

Details on test conditions:

TEST SYSTEM

- Growth/test medium:  The culture medium used was Algal Assay Procedure (AAP) medium prepared with sterile, deionized water.  

- Exposure vessel type: The test was conducted in sterile 250-ml Erlenmeyer flasks containing  100-ml of test solution.  All test vessels were fitted with stainless steel caps which permit gas exchange.  

- Culture medium:  The culture mediumused was Algal assay Procedure (AAP) medium prepared with sterile deionised water. The TOC concentration of a sample collected in January 2002 was 0.47 mg/l.

- Light levels and quality during exposure:  320 - 420 footcandles (3400 - 4500 lux).  The photosynthetically-active radiation (PAR) of the test area measured at test initiation ranged from 50 to 69 µE/m2/s.

- Test Design:  Approximately 30 minutes after the test solutions were added to the test flasks (100 ml per flask), a 0.323-ml inoculum of Pseudokirchneriella subcapitata cells, at a density of approximately 310 x 10E4 cells/ml, was aseptically introduced into each flask.  This inoculum provided the required initial (0 hour) cell density of approximately 1.0 x 104 cells/ml.  Three replicate test vessels were established for each treatment level, the dilution water control and the solvent control.

- Determination of cell concentrations: At the start of the test and at each subsequent 24 observation period, cell counts were made on each three replicates of each treatment using a hemacytometer (Neubauer improved).

- Range finding test: The test concentrations were set on the basis of the results of a range finding test conducted at concentyrations of 0.00095, 0.0095, 0.095 and 0.95 mg/l and a second test conducted at concentrations of 60, 130, 240, 480 and 960 mg/l. No effects were observed in the first test and effects at all treatment levels were observed in the second test.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

3.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

8.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

growth rate

Remarks on result:

other: 95% CI: 2.3-34 mg/L

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

5.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

biomass

Remarks on result:

other: 95% CI: 1.8-17 mg/L

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

biomass

Remarks on result:

other: determined empiracally as the highest concentration with <10% inhibition

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

11 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

other: cell density

Remarks on result:

other: 95% CI: 2.2-61 mg/L

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

6.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

other: cell density

Details on results:

- Exponential growth in the control (for algal test): yes

- Control cell density at end of test: 1580000 cells/ml (Control), 1360000 cells/ml (Solvent control), 1470000 cells/ml (Pooled control)

Reported statistics and error estimates:

The EC50 values were determined by linear regression using the method of inverse regression.

The NOECs were determined by either Williams' test (if the data sets passed the test homogeneity and normality) or the Kruskal-Wallis'test if they did not. If the statistical analyses did not yield a reasonable NOEC it was selected empiracally as the highest treatment level that resulted in <10% inhibition.

All statistical determinations were made at 95% level of certainty.

Table 1. Test results

Nominal concentration (mg/l)	Mean cell concentration after 24 hours (cells/ml)	Mean cell concentration after 48 hours (cells/ml)	Mean cell concentration after 72 hours (cells/ml)	Mean cell concentration after 96 hours (cells/ml)	Percentage reduction in cell concentration at end of the test*	Percentage reduction in biomass at end of the test*	Percentage reduction in 0 -72 -hour growth rate*
0 (Control)	24200	75000	435000	1580000	-	-	-
0 (Solvent control)	21700	75000	408000	1360000	-	-	-
0 (Pooled control)	20000	80000	420000	1470000	-	-	-
1.6	17500	75800	390000	1420000	3	7.0	2.0
3.1	10800	52500	413000	1590000	-8	14	1.0
6.3	7500	35800	256000	1220000	17	48	15**
13	800	10000	87000	860000	41**	89	44**
25	800	800	3000	10000	99**	108**	128**
50	800	5000	3000	0	100**	106	128**

*A negative sign (-) indicates that biomass or growth rate was higher than in the Control.

** Significantly different compared with pooled control

Validity criteria fulfilled:

yes

Conclusions:

A 72-hour EC50 value of 8.8 mg/l and NOEC of 3.1 mg/l have been determined for the effects of the test substance on growth rate of Pseudokirchnerella subcapitata. The results are expressed relative to nominal concentrations of the test substance. However the substance is subject to rapid hydrolysis and under the test conditions it is therefore likely that exposure will have been to its hydrolysis products (methanol and trisilanols).

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1994-11-29 to 1994-12-02

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

Cited as Directive 92/69/EEC, C.3

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

The Dissolved Organic Carbon (DOC) concentration of the stock solution used to prepare the test media and the test media was determined at the start and end of the test

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: The test substance was added to the dilution medium at 1 g/l and stirred for 18 hours. After that the solution was filtered and the DOC determined. The stock solution was used to prepare the treatments by dilution.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM

- Strain: 86.81.SAG

- Source (laboratory, culture collection): Institute for Water, Ground and Air Hygiene, Berlin (Germany)

- Age of inoculum (at test initiation): 3 days

- Method of cultivation: A pre-culture is produced from an original culture by super-inoculation three days before the test begins. From this culture the test cultures are inoculated at a density of about 20000 cells/ml.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

No data

Test temperature:

24 +/-1ºC

pH:

6.9-8.4 at start of test

8.6-9.5 at end of test

Dissolved oxygen:

Not reported

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal test concentrations (based on measured DOC concentration in stock solution converted to the equivalent test substance concentration): 0 (Control), 4.4, 9.1, 20, 44, 91, 200 and 436 mg/l.

The measured concentrations at the start and end of the test were with 20% of the nominal values and therefore the test results are interpreted with reference to nominal concentrations.

Details on test conditions:

TEST SYSTEM

- Test vessel:

- Type: open Erlenmeyer flasks

- Material: glass

- Aeration: none

- Initial cells density: 20000 cells/ml

- Control end cells density: 660000 cells/ml

- No. of vessels per concentration (replicates): 5

- No. of vessels per control (replicates): 8

GROWTH MEDIUM

- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS

- Culture medium different from test medium: no

- Intervals of water quality measurement: start and end of test

OTHER TEST CONDITIONS

- Sterile test conditions: yes

- Adjustment of pH: no

- Photoperiod: continuous

- Light intensity and quality: 8000 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Algal cell counts were made photometrically at 0, 24, 48 and 72 hrs.

- Determination of cell concentrations: spectrophotometer (absorption at 685 nm)

TEST CONCENTRATIONS

- Spacing factor for test concentrations: 2.1-2.2

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

352 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

59 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

other: biomass and growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

26 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

126 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

biomass

Details on results:

- Exponential growth in the control (for algal test): yes

Reported statistics and error estimates:

EC50 values were determined by Probit Analysis

Table 1. Test results

Nominal concentration (mg/l)	Nominal cell concentration at start of test (cells/ml)	Mean cell concentration after 24 hours (cells/ml)	Mean cell concentration after 48 hours (cells/ml)	Mean cell concentration after 72 hours (cells/ml)	Percentage reduction in biomass at end of the test*	Percentage reduction in 0 -72 -hour growth rate*
0 (Control)	20000	80000	230000	660000	-	-
4.4	20000	60000	170000	740000	6.8	-3.3
9.1	20000	70000	210000	850000	-11.0	-7.2
20	20000	60000	200000	900000	-3.4	-5.5
44	20000	70000	170000	540000	22.0	5.7
91	20000	70000	130000	310000	48.3	21.6
200	20000	60000	100000	180000	66.1	37.2
436	20000	60000	60000	110000	78.8	51.3

*A negative sign (-) indicates that biomass or growth rate was higher than in the Control.

Validity criteria fulfilled:

yes

Conclusions:

A 72-hour EC50 value of 352 mg/l and NOEC of 20 mg/l have been determined for the effects of the test substance on growth rate of Scenedesmus subspicatus (new name: Desmodesmus subspicatus). The results are expressed relative to nominal concentrations of the test substance. However the substance is subject to rapid hydrolysis and under the test conditions it is therefore likely that exposure will have been to its hydrolysis products (methanol and trisilanols).

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Please refer to the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

8.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

growth rate

Remarks on result:

other: 2.3-34 mg/L

Remarks:

Source: Springborn Smithers 2002

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

3.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other:

Remarks:

Source: Springborn Smithers 2002

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

352 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other:

Remarks:

Source: Hüls 1994

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

59 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

growth rate

Remarks on result:

other:

Remarks:

Source: Hüls 1994

Conclusions:

Two studies are available for the source substance CAS 1760-24-3. 72 hour EC50 values of 8.8 and 352 mg/l as well as 72 hour NOEC values of 3.1 and 59 mg/L have been determined for the effects of the test substance on the growth rate of green algae. The more sensitive values were used as key values. As detailed in the attached justification, similar effects are expected by the target substance.

Description of key information

ErC50 (72 h) = 8.8 mg/L and NOErC (72 h) = 3.1 mg/L (nominal, Pseudokirchneriella subcapitata, OECD 201) based on read across from CAS 1760-24-3.

Key value for chemical safety assessment

EC50 for freshwater algae:

8.8 mg/L

EC10 or NOEC for freshwater algae:

3.1 mg/L

Additional information

Experimental data on the toxicity of N-(2-aminoethyl)-N’-[3-(trimethoxysilyl)propyl]ethylenediamine (CAS 35141-30-1) towards algae are not available. Therefore, in accordance with the Regulation (EC) No. 1907/2006 Annex XI, 1.5 “Grouping of substances and read across” and the read across assessment framework (RAAF, ECHA 2017) a read across from the analogue substance N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (CAS 1760-24-3) has been performed. Details on the read-across justification can be found in the attached justification in the respective target entry and in the overall justification for grouping of substances attached in IUCLID Section 13.

The influence of the analogue substance N-(2 -aminoethyl)-3 -aminopropyltrimethoxysilane (CAS 1760 -24 -3) on the growth of the green algal species Pseudokirchneriella subcapitata was investigated in a 96-hour static test according to the OECD guideline 201 and GLP standards (2002). The nominal test item concentrations used were 1.6, 3.1, 6.3, 13, 25 and 50 mg/L as well as a control and a solvent control. Dimethylformamide was used as a solvent in a concentration of 0.10 mL/L. Analytical monitoring was not performed. However the substance is stable in terms of DOC in the test medium during the test, as the second available study (1994) including analytics revealed. The study resulted in an ErC50 (72 h) of = 8.8 mg/L and a NOErC (72 h) of 3.1 mg/L (nominal, based on growth rate).

A further study (supporting) is available testing the toxicity of the analogue substance to algae according to EU Method C.3 and GLP (1994). Desmodesmus subspicatus was exposed to nominal test item concentrations of 4.4, 9.1, 20, 44, 91, 200 and 436 mg/L and a control for 72 h. The Dissolved Organic Carbon (DOC) concentration of the stock solution and of the treatments was determined at the start and end of the test. The test item was stable in terms of dissolved organic carbon (DOC) during the test with a recovery of > 80% and thus the effect concentrations were expressed in terms of nominal values. The study resulted in an ErC50 (72 h) of 352 mg/L and an ErC10 (72 h) of 59 mg/L (nominal, based on growth rate).    

Since static conditions were used for both tests and the hydrolysis of the substance at neutral pH is rapid (half-life = 4.3 h at pH 7), it is assumed that the tested organisms were exposed to both the parent compound and the hydrolysis products.

Based on the results of the analogue substance and the attached read across justification, similar effects are expected by the target substance N-(2-aminoethyl)-N’-[3-(trimethoxysilyl)propyl]ethylenediamine (CAS 35141-30-1).