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Short-term toxicity to aquatic invertebrates

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Endpoint:
short-term toxicity to aquatic invertebrates
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
1994-04-27 to 1994-04-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 500 mg/l nominal treatment

- Sampling method: Samples of test media were taken at the start and end of the test

- Sample storage conditions before analysis: Refrigerated
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A 500 mg/l nominal concentration of the test substance was prepared by stirring overnight.

- Controls: Dilution water
Test organisms (species):
Daphnia magna
Details on test organisms:

- Type and amount of food: Chlorella vulgaris at 500000 cells/ml

- Feeding frequency: Daily
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Hardness:
204 mg/l as CaCO3
Test temperature:
20.3 - 21.7ºC
pH:
7.4 - 8.1
Dissolved oxygen:
99 - 100% ASV
Nominal and measured concentrations:
Nominal: 0(Control), 500 mg/l

Measured concentration at start of test: 405 mg/l

Measured concentration at end of test: 436 mg/l

Mean measured concentration: 420 mg/l

Mean measured concentration as a percentage of nominal: 84.1%

The test results are presented and interpreted with reference to nominal concentrations.
Details on test conditions:
TEST SYSTEM

- Test vessel: Conical flasks

- Type: closed

- Material, fill volume: Glass, 150 ml of test medium

- Aeration: none

- No. of organisms per vessel: 5

- No. of vessels per concentration (replicates): 4

- No. of vessels per control (replicates): 4


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Reconstituted freshwater prepared by mixing (1:1) treated mains water and proprietary mineral water (Ashbourne, Still Natural Water (Nestle, UK. Limited).

- Culture medium different from test medium: no

- Chlorine: <0.1 mg/l (Total)

- Alkalinity: 134 mg/l as CaCO3

- Conductivity: 404 μS/cm

OTHER TEST CONDITIONS

- Adjustment of pH: no

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilization after 24 and 48 h
Reference substance (positive control):
no
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 500 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis product
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
>= 500 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mobility
Details on results:
- Mortality of control: 0
Reported statistics and error estimates:
No toxic effects were observed in the test media, the test results were therefore not subject to statistical analysis.
Validity criteria fulfilled:
yes
Conclusions:
A 48-hour EC50 value of >500 mg/l and NOEC of ≥500 mg/l have been determined for the effects of the test substance on mobility of Daphnia magna based on nominal concentration of the substance. However it is likely that the test organisms were primarily exposed to the hydrolysis products of the substance.
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
05 - 07 Aug 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
other: Daphnia sp., Acute Immobilization Test stipulated in the Testing Methods for New Chemical Substances of Japan
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
2004
Qualifier:
according to guideline
Guideline:
other: OECD Guidance Document, No.23, September 2000, Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: silanol form was measured in all test levels at the start and the end of the exposure. Methanol was measured for the 100 mg/L level (with pH adjustment) and methanol control at the start of the exposure. As the test item hydrolyzes in water and forms silanol and methanol, these both components were measured in the test solutions instead of the test item itself.

- Sampling method: 10 mL of the test solution was taken out from the middle layer of the test vessel.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: test item and dilution water were mixed and stirred for 2 h at approx. 20 °C. The suspension was filtered with a glass fiber filter. Filtrate was sitted for 30 min at approx. 20 °C to recover dissolved oxygen concentration. Test solutions were prepared by diluting this stock solution with dilution water (pH unadjusted). Additional test solutions were prepared in the same way with a final adjustment of the pH to the pH of the dilution water.

- Controls: dilution water processing similar to stock solution without the test item

- Methanol controls: prepared at the concentration corresponding to the theoretical methanol concentration contained in 100 mg/L test solution (theoretical mehtanol concentration = concentration of silanol form * 32.04 (methanol molecular weight) * 6/257.40 (silanol form molecular weight))

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM

- Common name: water flea

- Clone: A

- Source: young Daphnids produced by parents that were cultured in the laboratory were used (initial source: University of Sheffield, United Kingdom)

- Age at study initiation (mean and range, SD): less than 24 h

- Feeding during test: no

ACCLIMATION

- Acclimation conditions (same as test or not): same type of water, 20 ± 1 °C, same photoperiod as test

- Type and amount of food: Chlorella vulgaris, 0.1 - 0.2 mg C per day and per Daphnia

- Feeding frequency: once a day
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
30 mg/L as CaCO3
Test temperature:
pH unadjusted: 19.8 - 19.9 °C
pH adjusted: 19.8 - 19.9 °C
pH:
pH unadjusted: 7.7 - 9.2
pH adjusted: 7.8 - 8.0
Dissolved oxygen:
pH unadjusted: 8.8 - 9.0 mg/L
pH adjusted: 8.8 - 9.0 mg/L
Nominal and measured concentrations:
0 (control), 20, 30, 44, 67 and 100 mg/L (nominal, as silanol form, pH unadjusted)
100 mg/L (nominal, as silanol form, pH adjusted)
Details on test conditions:
TEST SYSTEM

- Test vessel: 100 mL glass beaker with a transparent plastic lid

- Fill volume: 100 mL

- Aeration: no

- No. of organisms per vessel: 5

- No. of vessels per concentration (replicates): 4

- No. of vessels per control (replicates): 4

- No. of vessels per methanol control (replicates):4

TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: dechlorinated tap water

- Ca/Mg ratio: 8.5/2.2 mg/L

- Culture medium different from test medium: no

- Intervals of water quality measurement: dissolved oxygen, pH and temperature was measured at the start and at the end of exposure

OTHER TEST CONDITIONS

- Adjustment of pH: highest tested concentration (100 mg/L) was prepared in two parallels, one with and one without pH adjustment

- Photoperiod: 16 h light/8 h dark

- Light intensity: artificial light of white fluorescent lamp

EFFECT PARAMETERS MEASURED: immobility and symptoms of test organisms was recorded at 24 and 48 h of exposure

TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.5

- Preliminary study: was conducted in order to follow hydrolysis of the the test item. 156 mg/L (as test item concentration) were prepared in ultra pure water. Methanol was measured after 0, 0.5, 1 and 2 hours in order to follow the state of hydrolysis. 94.3, 95.2, 98.5 and 102% of the theoretical formed concentration (87.8 mg/L) was measured after 0, 0.5, 1 and 2 h, respectively.

- Range finding test: yes, static regime, 5 test organisms/test vessel, 2 parallels with and without pH adjustment

- Test concentrations: 100 mg/L

- Results used to determine the conditions for the definitive study: 0 - 20% immobility was observed after 48 h at 100 mg test item/L when no pH adjustment took place (pH: 8.2 - 9.3). 0% mortality was observed after 48 h when pH was adjusted to the pH of the dilution water (pH: 7.7 - 7.9). Based on these results, concentrations between 20 and 100 mg/L were tested at the definitive test.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: pH unadjusted
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: pH adjusted
Details on results:
- Mortality of control: no

- Mortality of methanol control: no
Results with reference substance (positive control):
- Results with reference substance valid: yes
- EC50 (48 h): 0.26 mg/L
Validity criteria fulfilled:
yes
Conclusions:
A 48 h EC50 value of > 100 mg/L was determined both when the pH was adjusted or unadjusted. However, NOEC (48 h) was found to be 44 mg/L (nominal) when pH was unadjusted and >= 100 mg/L (nominal) when pH was adjusted to the pH of the dilution water.
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
2004-10-29 to 2004-11-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
other: ISO Standard 14669: Water Quality - Determination of Acute Lethal Toxicity to Marine Copepods (Copepoda, Crustacea), 1999.
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: Control and all concentrations.

- Sampling method: Duplicate samples of at least 50 mL were taken.

- Sample storage conditions before analysis: Stored at -18 to -25ºC prior to analysis
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A 200 mg/L stock solution was prepared in synthetic seawater by stirring for 1 hour. The stock solution was used directly as the test medium. It is likely that the nominal concentration exceeded the solubility of the test substance in the test medium.
Test organisms (species):
other: Acartia tonsa (Dana)
Details on test organisms:
TEST ORGANISM

- Source: From laboratory stock culture at ECT Oekotoxicologie GmbH. The stock culture was originally supplied by the Technical University of Denmark, Lyngby, Denmark.

- Age at study initiation (mean and range, SD): 14-21 days

- Feeding during test: none

ACCLIMATION

- Type and amount of food: algae (Rhodomonas salina)

- Feeding frequency: daily

- Acclimation period in test medium: 9 days
Test type:
static
Water media type:
saltwater
Limit test:
yes
Total exposure duration:
48 h
Hardness:
not reported
Test temperature:
19.7-21.1ºC
pH:
7.6-8.7
Dissolved oxygen:
7.8-8.5 mg/L
Salinity:
30.3 ppt
Nominal and measured concentrations:
Nominal concentrations: 0(Control) and 200 mg/L.

Measured concentrations were 79.3% of nominal at the start of the test and 72.5% of nominal at the end of the test.

The measured concentration at the end of the test was 91.4% of the measured concentration at the start of the test.
Details on test conditions:
TEST SYSTEM

- Test vessel: beakers

- Type: covered byglass lids

- Material, size, headspace, fill volume: glass, 100 mL and containing between 50 and 80 mL of test medium

- Aeration: none

- Renewal rate of test solution (frequency/flow rate): none

- No. of organisms per vessel: 5

- No. of vessels per concentration (replicates): 6

- No. of vessels per control (replicates): 6


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Synthetic seawater prepared in accordance with Kusk and Wollenberger (1999). Fully defined saltwater medium for cultivation of and toxicity testing with marine copepod Acartia tonsa. Env Toxicol Chem 18:1564-1567.

- Intervals of water quality measurement: Daily


OTHER TEST CONDITIONS

- Adjustment of pH: no

- Photoperiod: 16 h light, 8 h dark

- Light intensity: 539 Lux


EFFECT PARAMETERS MEASURED: Mortality after 24 and 48 hours.


TEST CONCENTRATIONS

- Spacing factor for test concentrations: Limit test
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
> 200 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
>= 200 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
> 151.9 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
>= 151.9 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
- Mortality of control: 0
Results with reference substance (positive control):
- Results with reference substance valid?: yes

- 48-h LC50: 0.749 (0.634-0.884) mg/L
Reported statistics and error estimates:
No toxic effects were observed in the test and therefore statistical analysis of the results was not required.

Table 1. Results of analysis of test media 

Nominal test substance concentration (mg/L)

Mean measured concentration in fresh test medium at start of test (mg/L)

Mean measured concentration in old test medium after 48 hours (mg/L)

Mean measured concentration at start of test as percentage of nominal

Mean measured concentration after 48 hours as percentage of nominal

0 (Control)

0.8

1.1

-

-

192

152

139

79

73

 

No toxics effects were observed at the only nominal test concentration of 200 mg/L.

Validity criteria fulfilled:
yes
Conclusions:
A 48-hour LC50 value of >200 mg/L and a NOEC of ≥200 mg/L have been determined for the effects of the test substance on mortality of Acartia tonsa based on nominal concentrations.
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
1993-06-22 to 1993-06-24
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)
Principles of method if other than guideline:
DIN 38412 Part 1; EG Guideline 92/69/EWG
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
The DOC concentration of the filtered stock solution used to prepare the test media was determined.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method:The test substance was added to dilution water to provide a nominal concentration of 1 g/l and stirred for 18 hours. The solution was filtered and the DOC content determined to be 534 mg/L, which is equivalent to 1093 mg/L of the test substance. This solution served as the primary stock solution of the test substance for preparation of the other test concentrations. The test began immediately after preparation of the test solution.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM

- Common name: Daphnia magna

- Strain: Clone 5

- Source: Stock culture

- Age at study initiation (mean and range, SD): <24 h

- Method of breeding: Parthenogenetic reproduction

- Feeding during test: None

ACCLIMATION

- Acclimation conditions (same as test or not): yes

- Type and amount of food: Scenedesmussubspicatus, sufficient to be consumed each day leaving no residue

- Feeding frequency: daily
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
Water hardness was reported  as 2.5mmol/L and alkalinity was reported as 0.8 mmol/L.
Test temperature:
20ºC
pH:
The control pH was 7.5 units and the test vessel pH ranged from 7.5 to 8.7 units. 
Dissolved oxygen:
The control DO was 8.4 mg/L and the test vessel DO ranged from 7.8 to 8.7 mg/L.
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal concentrations (based on measured concentrations in stock solution):  0, 8.7, 16.4, 28.4, 54.7, 94.0, 174.9, 306.0, 546.5, and 983.7 mg/L.
Details on test conditions:
TEST SYSTEM

The test vessels were glass cylinders graduated to 10 ml. Each concentration had 4 replicate vessels and each vessel contained 5 test organisms.  The age of the test organisms was <24 hours and they were not fed during the test.  Vessels were kept in the dark at 20ºC and not aerated during the  test.

The dilution water was synthetic fresh water with a hardness of approximately 294 mg/L as CaCO3
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
94 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
331 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 249-441
Details on results:
- Mortality of control: 0
Results with reference substance (positive control):
24 h EC50 lies between 0.9 and 1.9 mg/L
Reported statistics and error estimates:
EC50 values were calculated by Probit analysis. The NOEC was determined by visual examination of the raw data

Table 1. Test results

 Nominal test concentration (mg/L)  Mean percentage immobilisation after 24 hours   Mean percentage immobilisation after 48 hours
 0 (Control)  0  0
 8.7  0  0
 16.4  5  5
 28.4  0  0
 54.7  0  0
 94.0  5  10
 174.9  19  19
 306.0  45  50
 546.5  40  60
 983.7  62  100
Validity criteria fulfilled:
yes
Conclusions:
A 48-hour EC50 value of 331 mg/L and NOEC of 94 mg/L have been determined for the effects of the test substance on mobility of Daphnia magna. It is likely that the test organisms were exposed to the hydrolysis products of the substance.

Description of key information

Silanol HP-X - read-across from triethoxy(methyl)silane (CAS 2031-67-6): 48 hour EC50: >500 mg/l, mobility of Daphnia magna (Hazleton, 1994);

Silanol HP-Y - read-across from N,N-bis(3-triethoxysilylpropyl)amine (CAS 13497-18-2): 48 hour LC50: >200 mg/l, mortality of Acartia tonsa (Dana) (ECT Oekotoxikologie, 2004);

Silanol HP-Y - read-across from 3-(trimethoxysilyl)-N-[3-(trimethoxysilyl)propyl]-1-propanamine (CAS 82985-35-1): 48 hour EC50: >100 mg/l, mobility of Daphnia magna (Yoshikawa, 2014);

Silanol HP-Z - read across from 3-aminopropyl(triethoxy)silane (CAS 919-30-2): 48 hour EC50: 331 mg/l, mobility of Daphnia magna (Hüls, 1993).

Key value for chemical safety assessment

Additional information

There are no measured data for the registration substance as a whole. However according to REACH Annex XI the short-term invertebrate study does not need to be conducted because the data requirements for this endpoint have been addressed using measured or read-across toxicity data for the constituents of the substance and their hydrolysis products in combination with partitioning theory and the toxic units approach to determine whether a test medium prepared at a nominal loading rate of 100 mg/l would be toxic following short-term exposure. The results of applying this approach indicate that a test medium prepared at a nominal loading rate of 100 mg/l would not be toxic to invertebrates. A more detailed description of the method used is given in the Aquatic toxicity End point summary.

The constituents of the substance hydrolyse rapidly, therefore the environmental aspects of chemical safety assessment are based on the hydrolysis products, which are grouped into three silanol assessment entities Silanol HP-X, Silanol HP-Y and Silanol HP-Z. This is discussed further in the ecotoxicological general discussion. Supporting data for each of the three silanol assessment entities are sourced from:

Silanol HP-X - read-across from triethoxy(methyl)silane (CAS 2031-67-6): 48 hour EC50: >500 mg/l, mobility of Daphnia magna;

Silanol HP-Y - read-across from N,N-bis(3-triethoxysilylpropyl)amine (CAS 13497-18-2): 48 hour LC50: >200 mg/l, mortality of Acartia tonsa (Dana);

Silanol HP-Y - read-across from 3-(trimethoxysilyl)-N-[3-(trimethoxysilyl)propyl]-1-propanamine (CAS 82985-35-1): 48 hour EC50: >100 mg/l, mobility of Daphnia magna;

Silanol HP-Z - read across from 3-aminopropyl(triethoxy)silane (CAS 919-30-2): 48 hour EC50: 331 mg/l, mobility of Daphnia magna.

The short-term EC50 values for these substances are all greater than 100 mg/l and in the case of Silanol HP-X and Silanol HP-Y, are limit values. The basis for read-across is discussed further in the Ecotoxicological information endpoint summary.