Reaction products of 2-hydroxyethyl methacrylate and diphosphorous pentoxide and water

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:

from April 26, 2004 to May 28, 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

During the final test singular samples for possible analysis were taken from all test concentrations and the controls.
- Frequency at t=0 h, t=24 h and t=72 h
- Volume 10 mL
- Storage Samples were stored in a freezer until analysis.
Compliance with the Quality criteria regarding maintenance of actual concentrations was demonstrated by running a test vessel at the highest substance concentration but without algae and samples for analysis were taken at the start, after 24 h of exposure and at the end of the test period. Additionally, singular reserve samples of 10 mL were taken for possible analysis. If not used, these samples were stored in a freezer for a maximum of three months after delivery of the draft report, pending on the decision of the sponsor for additional analysis.

Details on test solutions:

Preparation of test solutions:
The standard test procedures required generation of test solutions, which contained completely dissolved test substance concentrations or stable and homogeneous mixtures or dispersions. The testing of concentrations that would disturb the test system were prevented as much as
possible (e.g. film of the test substance on the water surface).

The batch of the substance tested was a slightly yellowish viscous liquid and was completely soluble in test medium at the concentrations tested.
Preparation of test solutions for the range-finding test started with a stock solution of 100 mg/L applying 20 mins of magnetic stirring to accelerate the dissolving of the test substance in the test medium. For the final test a stock solution of 320 mg/L was prepared applying 25 mins of
magnetic stirring followed by a 5-min treatment period with ultrasonic waves. The test concentrations were prepared by subsequent dilutions of the stock in test medium.

The final test solutions were all clear and colourless. Due to the acidic character of the test substance an additional control was prepared in both the range-finding and final test with the same pH level as the highest concentration tested to correct for possible pH-related effects on algal growth.

After preparation, volumes of 50 mL were added to each replicate of the respective test concentration. Subsequently, adequate volumes of an algal suspension were added to each replicate providing a cell density of 10^4 cells/mL.

Test organisms (species):

other: Selenastrum capricornutum, strain: NIVA CHL 1.

Details on test organisms:

TEST ORGANISM
- Species: Selenastrum capricornutum, strain: NIVA CHL 1.
- Source: In-house laboratory culture.
- Reason for selection: This system is an unicellular algal species sensitive to toxic substances in the aquatic ecosystem and has been selected as an internationally accepted species.
- Stock culture: Algae stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar. The suspensions were continuously aerated and exposed to light in a climate room at a temperature of 23±2°C.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

The temperature of the test medium was 22.3°C at the start of the test. During the exposure period the temperature measured in the incubator was maintained between 23.6 and 23.8°C. Temperature remained within the limits prescribed by the protocol (temperature: 21- 25°C, constant within 2°C).

pH:

The pH was generally maintained within the limits prescribed by the protocol (6.0-9.0, preferably not varying by more than 1.5 unit) except at 160 mg/L, which was a consequence of the acidic character of the test substance.

Nominal and measured concentrations:

10, 20, 40, 80 and 160 mg/L (nominal)

Details on test conditions:

- Controls: Test medium without test substance or other additives (blank-control) and one control with pH adjusted to the level of that measured in the highest test concentration (treatment-control).
- Replicates: 3 replicates of each test concentration, 6 replicates of the blank-control, 6 replicates of the treatment-control, 2 replicates of the highest concentration without algae, 1 extra replicate of each test concentration for sampling after 24 hours of exposure.

Test procedures and conditions
- Test duration: 72 h.
- Test type: Static.
- Test vessels: 100 mL, all-glass, containing 50 mL of test medium.
- Medium: M2.
- Cell density: An initial cell density of 1 x 10^4 cells/mL.
- Illumination: Continuously using TLD-lamps of the type ‘Cool-white’ of 30 Watt, with a light intensity within the range of 70 to 102 μE.m-2.s-1.
- Incubation: Vessels were distributed at random in the incubator.
- During incubation the algal cells were kept in suspension by continuous shaking.

Reference substance (positive control):

yes

Remarks:

K2Cr2O7 (Potassium dichromate) in a separate study (NOTOX Project 410658).

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

90 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: Cell growth inhibition

Remarks on result:

other: 59 to 136 mg/L

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

165 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: growth rate reduction

Remarks on result:

other: 130 to 210 mg/L

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

39 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: cell growth inhibition and growth rate

Details on results:

No inhibition of cell growth was observed at nominal test concentrations up to and including 80 mg/L. Algal cell growth was inhibited by 63% at the highest concentration tested, i.e. at 160 mg/L. No statistically significant inhibition of cell growth was found at nominal concentrations of 10 to 80 mg/L (Bonferroni t and Tukey test, = 0.05).
Growth rates were in the range of the blank-control at the concentrations from 10 to 80 mg/L during the 72 h test period, whereas the growth rate of algae exposed to 160 mg/L was significantly reduced, i.e. by 38%. No statistically significant reduction of growth rate was found at nominal concentrations of 10 to 80 mg/L (Bonferroni t and Tukey test, = 0.05).

Results of the analytical investigations:

Analyses showed that the measured concentrations at the start of the test were in agreement with nominal. Analysis was only considered for the nominal concentrations of 40, 80 and 160 mg/L, which were essential for determination of the toxicity parameters. Measured concentrations were 38 mg/L (96%), 73 mg/L (91%) and 149 mg/L (93%) at the expected nominal concentrations of 40, 80 and 160 mg/L, respectively. During the 72 h exposure period the measured concentrations decreased by more than 20% below initial. Based on these results, the Time Weight Average (TWA) exposure concentrations were calculated to correspond to 17, 39 and 114 mg/L, respectively.

RANGE FINDING TEST

Mean cell densities, inhibition of cell growth and reduction of growth rate

The results showed that the EC50 for both cell growth inhibition and growth rate reduction were above nominally 100 mg/L.

Stability of test substance under test conditions

The analytical results showed that measured test substance concentrations in samples taken from 10 and 100 mg/L decreased by more than 20% during the 72 h test period. The measured concentration at 100 mg/L decreased from 76 mg/L to 25 mg/L during the test period, while at 10 mg/L the measured concentration decreased from 8.6 to 0.44 mg/L during the test period.

FINAL TEST

Measured test substance concentrations

At the start of the test, the actual test concentrations were in agreement with nominal. Measured concentrations were 38 mg/L (96%), 73 mg/L (91%) and 149 mg/L (93%) at the expected nominal concentrations of 40, 80 and 160 mg/L. During the 72 h exposure period the measured

concentrations decreased by more than 20% below initial. Based on these results, the Time Weight Average (TWA) exposure concentrations were calculated.

Validity criteria fulfilled:

yes

Conclusions:

The 72 h EC50 for cell growth inhibition and growth rate (based on TWA concentrations) were determined to be 90 and 165 mg/L, respectively, while the NOEC for both the parameters was 39 mg/L.

Executive summary:

A study was conducted to assess the toxicity potential of the test substance to algae according to OECD Guideline 201 and EU Method C.3, in compliance with GLP. In the range-finding test, exponentially growing algal cultures were exposed to test substance concentration range of 0.1 to 100 mg/L increasing by a factor of 10. In addition, a blank and treatment-control (with adjusted pH) were tested. The results showed that the EC50for both cell growth inhibition and growth rate reduction were above nominally 100 mg/L. The project was continued with a final test exposing exponentially growing algal cultures to a blank-control and nominal test substance concentrations of 10, 20, 40, 80 and 160 mg/L. In addition, a treatment-control with pH adjusted to that of the highest test substance concentration was included to correct for possible pH-related effects on algal cell growth at 160 mg/L. The initial algal cell density was 10^4 cells/mL. The total test period was 72 h. Samples for analyses were taken at the start, after 24 h of exposure and at the end of the 72 h test period.

Analyses showed that the measured concentrations at the start of the test were in agreement with nominal. Analysis was only considered for the nominal concentrations of 40, 80 and 160 mg/L, which were essential for determination of the toxicity parameters. Measured concentrations were 38 mg/L (96%), 73 mg/L (91%) and 149 mg/L (93%) at the expected nominal concentrations of 40, 80 and 160 mg/L, respectively. During the 72 h exposure period the measured concentrations decreased by more than 20% below initial. Based on these results, the Time Weight Average (TWA) exposure concentrations were calculated to correspond to 17, 39 and 114 mg/L, respectively. The study met the acceptability criteria prescribed by the protocol and was considered valid.

The 72 h EC50 for cell growth inhibition and growth rate based on TWA concentrations were determined to be 90 and 165 mg/L, respectively, while the NOEC for both the parameters was 39 mg/L (Migchielsen MHJ, 2004).

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Study period:

26-04-2004 to 28-05-2004

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Further information is included in attachment to IUCLID section 13.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The read-across is based on the hypothesis that the source and target substances have common structural features in the same relative positions. The source and target have similar physico-chemical, toxicological properties and because of common metabolism they share common or have similar breakdown products and therefore potential mechanisms of action. Further information is included in attachment to IUCLID section 13.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The source and target chemicals have comparable chemical similarity. Further information is included in attachment to IUCLID section 13

3. ANALOGUE APPROACH JUSTIFICATION
The source substance is a chemically similar substance with common metabolism and common or similar degradants of the target substance. Further information is included in attachment to IUCLID section 13

4. DATA MATRIX
Further information is included in attachment to IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

During the final test singular samples for possible analysis were taken from all test concentrations and the controls.
- Frequency at t=0 h, t=24 h and t=72 h
- Volume 10 mL
- Storage Samples were stored in a freezer until analysis.
Compliance with the Quality criteria regarding maintenance of actual concentrations was demonstrated by running a test vessel at the highest substance concentration but without algae and samples for analysis were taken at the start, after 24 h of exposure and at the end of the test period. Additionally, singular reserve samples of 10 mL were taken for possible analysis. If not used, these samples were stored in a freezer for a maximum of three months after delivery of the draft report, pending on the decision of the sponsor for additional analysis.

Details on test solutions:

Preparation of test solutions:
The standard test procedures required generation of test solutions, which contained completely dissolved test substance concentrations or stable and homogeneous mixtures or dispersions. The testing of concentrations that would disturb the test system were prevented as much as
possible (e.g. film of the test substance on the water surface).

The batch of the substance tested was a slightly yellowish viscous liquid and was completely soluble in test medium at the concentrations tested.
Preparation of test solutions for the range-finding test started with a stock solution of 100 mg/L applying 20 mins of magnetic stirring to accelerate the dissolving of the test substance in the test medium. For the final test a stock solution of 320 mg/L was prepared applying 25 mins of
magnetic stirring followed by a 5-min treatment period with ultrasonic waves. The test concentrations were prepared by subsequent dilutions of the stock in test medium.

The final test solutions were all clear and colourless. Due to the acidic character of the test substance an additional control was prepared in both the range-finding and final test with the same pH level as the highest concentration tested to correct for possible pH-related effects on algal growth.

After preparation, volumes of 50 mL were added to each replicate of the respective test concentration. Subsequently, adequate volumes of an algal suspension were added to each replicate providing a cell density of 10^4 cells/mL.

Test organisms (species):

other: Selenastrum capricornutum, strain: NIVA CHL 1.

Details on test organisms:

TEST ORGANISM
- Species: Selenastrum capricornutum, strain: NIVA CHL 1.
- Source: In-house laboratory culture.
- Reason for selection: This system is an unicellular algal species sensitive to toxic substances in the aquatic ecosystem and has been selected as an internationally accepted species.
- Stock culture: Algae stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar. The suspensions were continuously aerated and exposed to light in a climate room at a temperature of 23±2°C.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

The temperature of the test medium was 22.3°C at the start of the test. During the exposure period the temperature measured in the incubator was maintained between 23.6 and 23.8°C. Temperature remained within the limits prescribed by the protocol (temperature: 21- 25°C, constant within 2°C).

pH:

The pH was generally maintained within the limits prescribed by the protocol (6.0-9.0, preferably not varying by more than 1.5 unit) except at 160 mg/L, which was a consequence of the acidic character of the test substance.

Nominal and measured concentrations:

10, 20, 40, 80 and 160 mg/L (nominal)

Details on test conditions:

- Controls: Test medium without test substance or other additives (blank-control) and one control with pH adjusted to the level of that measured in the highest test concentration (treatment-control).
- Replicates: 3 replicates of each test concentration, 6 replicates of the blank-control, 6 replicates of the treatment-control, 2 replicates of the highest concentration without algae, 1 extra replicate of each test concentration for sampling after 24 hours of exposure.

Test procedures and conditions
- Test duration: 72 h.
- Test type: Static.
- Test vessels: 100 mL, all-glass, containing 50 mL of test medium.
- Medium: M2.
- Cell density: An initial cell density of 1 x 10^4 cells/mL.
- Illumination: Continuously using TLD-lamps of the type ‘Cool-white’ of 30 Watt, with a light intensity within the range of 70 to 102 μE.m-2.s-1.
- Incubation: Vessels were distributed at random in the incubator.
- During incubation the algal cells were kept in suspension by continuous shaking.

Reference substance (positive control):

yes

Remarks:

K2Cr2O7 (Potassium dichromate) in a separate study (NOTOX Project 410658).

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

90 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

i.e. cell growth inhibition

Remarks on result:

other: C.I. 59 to 136 mg/L

Remarks:

Equivalent nominal concentration: 137 (C.I. 105 to 179) mg/L

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

165 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: C.I. 130 to 210 mg/L

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

49 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: C.I. 28 to 60 mg/L

Remarks:

Equivalent nominal concentration: 92 (C.I. 80 to 105) mg/L

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

39 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: cell growth inhibition and growth rate

Remarks on result:

other:

Remarks:

Equivalent nominal concentration: 80 mg/L

Details on results:

No inhibition of cell growth was observed at nominal test concentrations up to and including 80 mg/L. Algal cell growth was inhibited by 63% at the highest concentration tested, i.e. at 160 mg/L. No statistically significant inhibition of cell growth was found at nominal concentrations of 10 to 80 mg/L (Bonferroni t and Tukey test, = 0.05).
Growth rates were in the range of the blank-control at the concentrations from 10 to 80 mg/L during the 72 h test period, whereas the growth rate of algae exposed to 160 mg/L was significantly reduced, i.e. by 38%. No statistically significant reduction of growth rate was found at nominal concentrations of 10 to 80 mg/L (Bonferroni t and Tukey test, = 0.05).

Results of the analytical investigations:

Analyses showed that the measured concentrations at the start of the test were in agreement with nominal. Analysis was only considered for the nominal concentrations of 40, 80 and 160 mg/L, which were essential for determination of the toxicity parameters. Measured concentrations were 38 mg/L (96%), 73 mg/L (91%) and 149 mg/L (93%) at the expected nominal concentrations of 40, 80 and 160 mg/L, respectively. During the 72 h exposure period the measured concentrations decreased by more than 20% below initial. Based on these results, the Time Weight Average (TWA) exposure concentrations were calculated to correspond to 17, 39 and 114 mg/L, respectively.

RANGE FINDING TEST

Mean cell densities, inhibition of cell growth and reduction of growth rate

The results showed that the EC50 for both cell growth inhibition and growth rate reduction were above nominally 100 mg/L.

Stability of test substance under test conditions

The analytical results showed that measured test substance concentrations in samples taken from 10 and 100 mg/L decreased by more than 20% during the 72 h test period. The measured concentration at 100 mg/L decreased from 76 mg/L to 25 mg/L during the test period, while at 10 mg/L the measured concentration decreased from 8.6 to 0.44 mg/L during the test period.

FINAL TEST

Measured test substance concentrations

At the start of the test, the actual test concentrations were in agreement with nominal. Measured concentrations were 38 mg/L (96%), 73 mg/L (91%) and 149 mg/L (93%) at the expected nominal concentrations of 40, 80 and 160 mg/L. During the 72 h exposure period the measured

concentrations decreased by more than 20% below initial. Based on these results, the Time Weight Average (TWA) exposure concentrations were calculated.

Validity criteria fulfilled:

yes

Conclusions:

The target substance is expected to have 72-h ErC50 (aquatic algae; growth rate) > 100 mg/L (or 165 mg/) based on TWA concentrations (and/or > 100 mg/L nominal); 72-h ErC10 (algae; growth rate) = 49 mg/L based on TWA concentrations (or 92 mg/L nominal) and/or 72-h NOErC (algae; growth rate) = 39 mg/L based on TWA concentrations (or 80 mg/L nominal).

Executive summary:

The algal growth inhibition to Pseudokirchneriella subcapitata (previous name: Selenastrum capricornutum) strain: NIVA CHL 1, was carried out on a source substance according to OECD TG 201 Freshwater Alga and Cyanobacteria, Growth Inhibition Test and EU Method C.3 guidelines under GLP. In the preceding range-finding test, exponentially growing algal cultures were exposed to test item concentration range of 0.1 to 100 mg/L nominal loading concentrations). In addition, a blank and treatment-control (with adjusted pH) were tested. The results showed that the EC50 for both cell growth inhibition and growth rate reduction were above 100 mg/L nominal concentrations. A definitive test was conducted exposing algal cultures to a range of test item concentrations : 0 (control), 10, 20, 40, 80 and 160 mg/L nominal loading concentrations. In addition, a treatment-control with pH adjustment was conducted at the highest test item concentration (160 mg/L nominal) to correct for potential pH-related effects on algal cell growth. The initial algal cell density was 1x10^4 cells/mL. The total test period was 72 hours. Samples for analyses were taken at the start, after 24 h of exposure and at the end of the 72 h test period. Analyses showed that the measured concentrations at the start of the test were in agreement with nominal concentrations. Measured concentrations were 38 mg/L (96%), 73 mg/L (91%) and 149 mg/L (93%) at the expected nominal concentrations of 40, 80 and 160 mg/L, respectively. Analysis was only considered for the nominal concentrations of 40, 80 and 160 mg/L, which were essential for determination of the toxicity parameters. During the 72 h exposure period the measured concentrations decreased by > 20% initial concentrations. The equivalent Time Weight Average (TWA) exposure concentrations were calculated to correspond to 17, 39 and 114 mg/L, respectively. The study met the all acceptability criteria and was considered valid. The 72-h EC50 for cell growth inhibition was 90 mg/L. The 72-h EC50 for growth rate inhibition was 165 mg/L based on TWA concentrations. The corresponding 72-h EC10 was 49 mg/L and the NOEC was 39 mg/L based on TWA concentrations.

For the target substance:

72-h ErC50 (aquatic algae; growth rate) > 100 mg/L (or 165 mg/) based on TWA concentrations (and/or > 100 mg/L nominal)

72-h ErC10 (algae; growth rate) = 49 mg/L based on TWA concentrations (or 92 mg/L nominal)

72-h NOErC (algae; growth rate) = 39 mg/L based on TWA concentrations (or 80 mg/L nominal)

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
Estimation Programme Interface (EPI) Suite programme for Microsoft Windows v4.11
Contact EPISuite:
U.S. Environmental Protection Agency
1200 Pennsylvania Ave.
N.W. (Mail Code 7406M)
Washington, DC 20460

2. MODEL (incl. version number)
ECOSAR v1.11 - Algae 96h EC50
19 June 2012 (model development)

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See attached: ‘Aquatic Toxicity Predictions: Reaction products of 2-hydroxyethyl methacrylate and diphosphorous pentoxide and water’ version 1.0; dated 30 May 2018.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Full details of the method are provided in the attached QMRF named ‘QMRF Title: ECOSAR v1.11 Green Algae 96h EC50’ version 1.2; updated 30 May 2018.

5. APPLICABILITY DOMAIN
See ‘any other information on results incl. tables’.
See attached: ‘Aquatic Toxicity Predictions: Reaction products of 2-hydroxyethyl methacrylate and diphosphorous pentoxide and water’ version 1.0; dated 30 May 2018.

6. ADEQUACY OF THE RESULT
1) QSAR model is scientifically valid. 2) The substance falls within the applicability domain of the QSAR model. 3) The prediction is fit for regulatory purpose.
The prediction is adequate for the Classification and Labelling or risk assessment of the substance as indicated in REACH Regulation (EC) 1907/2006: Annex XI Section 1.3. Specifically when combined with further information such as physico-chemistry and environmental fate testing and modelling.

Guideline:

other: REACH Guidance on QSARs R.6, May/July 2008

Guideline:

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

Version / remarks:

This guideline is preferred for the training set but not obligatory

Principles of method if other than guideline:

1. ECOSAR v1.11 - Green Algae 96h EC50
2. Aquatic Toxicity Assessment of UVCB substances using the Additivity Approach
3. Assessment of Degradability for the purpose of Classification and Labelling

Specific details on test material used for the study:

Detailed information on the 'test material identity' is provided in the attached QSAR Prediction Reporting Format (QPRF) document including information on individual constituents according to point '2. Aquatic Toxicity Assessment of UVCB substances using the Additivity Approach' requirements.

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

1.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Additive Endpoint Values calculated in line with Block Method Approach

1. Defined Endpoint:

QMRF 3. Ecotoxic effects

QMRF 3.2. Short-term toxicity to algae (inhibition of the exponential growth rate)

Reference to type of model used and description of results:

ECOSAR v1.11 – Green Algae 96h EC50 ; 19 June 2012

Note: Effect levels for each trophic group derived from the associated ECOSAR v1.11 model classes above are provided here for completeness.

 

2. Description of results and assessment of reliability of the prediction:

The test item ‘Reaction products of 2-hydroxyethyl methacrylate and diphosphorous pentoxide and water’is a substance of Unknown or Variable composition, Complex reaction products or Biological Materials (UVCB). his complex substance falls under the category of substances difficult to test defined in ECHA Guidance on Information Requirements and Chemical Safety Assessment Chapter R7.b: Endpoint Specific Guidance, Appendix R.7.8-1. As the test item is difficult to test and assessment has been conducted using the block method (reference: Redman et al. PETROTOX: An Aquatic Toxicity Model for Petroleum Substances.: Env, Toxicol. Chem. 31: 2487-2506).

 

1) ECOSAR v1.11 – Green Algae 96h EC50

2) Aquatic Toxicity Assessment of UVCB substances using the Additivity Approach

Inputs Used for Test Item: All modelling was based on input of SMILES notation for each constituent of the test item and respective hydrolysis products (presented in the attached Aquatic Toxicity Predictions 30-05-2018 QPRF report), meaning that the process relied on modelled values for Kow and water solubility to define the blocks. This approach is in line with the PETROTOX methodology and ECHA Guidance on Information Requirements and Chemical Safety Assessment Chapter R7.b for hazard assessment of complex mixtures.

Table 1. ECOSAR Output for Consolidated Blocks of Test Item Constituents

Block	Block Identifier	Typical Concentration in Test Item (% (w/w))	Log Kow KOWWIN	Water Solubility (mg/L) WSKOWWIN	Daphnid 48 h EC50 (mg/L)	Algae 96 h EC50 (mg/L)	Fish 96 h LC50 (mg/L)
1	Partially soluble – Ester (phosphates)/ Methacrylates	C.B.I.	2.1995	24.73	0.015	0.633	8.029
2	Soluble -Methacrylates	C.B.I.	-1.72 to 1.06	1124 to 1.37 x10^5	202.88	0.951	269.189
3	Soluble – Esters / phosphine oxides	C.B.I.	-0.7699 to 0.6535	11200 to 5.39 x10^5	9.087	213.229	168.576

Note: Concentration in the test item contributing to the additive endpoint values are presented in the attached Aquatic Toxicity Predictions 30-05-2018 QPRF report.

 

For the purpose of concluding on classification and labelling for this substance the additivity formula from Annex I, Section 4.1.3.5.2 of CLP Regulation (EC) 1272/2008 is applied to data on the known components of the substance. The effect values for the test item for each relevant trophic group are presented in the following table.

 

Table 2. Additive Endpoint Values for the Test Item for each Trophic Group

Trophic Level	Endpoint	Endpoint Value (mg/L)
Daphnid	48 h EC50	0.37
Algae	96 h EC50	1.1
Fish	96h LC50	111.7

 

Substance rapidly degradable: YES (OECD TG 301B, 2018)

Log Kow < 4.0: YES. (Block Method, KOWWIN v1.68, US EPA, 2018

 

3) Assessment of Degradability for the purpose of Classification and Labelling

The following data are considered for conclusion on classification and labelling of the test item:

Aquatic toxicity data availability: Acute

96 h EC50 for Daphnia:                0.37 mg/L

Substance rapidly degradable:       YES

Log Kow:                                       < 4

 

Based on the above considerations, the substance is precautionarily classified as hazardous to the environment under CLP Regulation (EC) 1272/2008: Acute Category 1: H400: Very toxic to aquatic life. Further evidence, generated at a later date may confirm the suggestion that no classification and labelling is warranted. For example: at REACH Regulation (EC) 1907/2006: Annex VIII information requirements.

 

Assessment of the substance within the applicability domain as documented within the corresponding QMRF named ‘QMRF Title: ECOSAR v1.11 Green Algae 96h EC50’ version 1.2; updated 30 May 2018 – section 5;indicates the substance:

(i) Falls within the Log Kow domain of < 5 (general domain for the model; and relevant chemical classes specific cut off);

(ii) Molecular weights of all constituents are < 1000 g/mol and;

(iii) Effect levels are predicted below the water solubility.

 

The ECOSAR QSAR model as detailed is not known to function by specific modes of action associated with the chemical class(es) assigned. Full references to training set data are presented within ECOSAR v1.1 Help System; if not proprietary (in such cases the chemical identification is listed as CBI, but the relevant descriptor data are provided). A summary of this information is presented by the applicant. The substances in the training set are considered analogues to the target substance since they possess relevant chemical groups and log Kow < 5 and MW < 1000 g/mol. The substance and the structural analogues share a common functional group and physico-chemical domains versus a neutral organics class (baseline toxicity). The ECOSAR class is based on similar relationships between toxicity and the various types of pharmacologic properties.

 

3. Uncertainty of the prediction and mechanistic domain:

No external validation set is available for the chemical class used in this prediction.

Consistency of ECOSAR data compared to measured toxicity showed 60-64 % of green algae predictions (all chemical classes assessed) within a tolerance factor of 10, which is comparable to that seen in Hulzebos & Posthumus (2003).

Uncertainty in the prediction relates to:

Limited external validation on the relevant chemical classes Model predictivity could be improved by the assignment of additional chemical categories and expansion of sub-structure rules, in addition further substances addition to the training set and rules for stereochemical effects within the model would improve predictivity. The ECOSAR QSAR model as detailed is not known to function by specific modes of action associated with the chemical class(es) assigned. ECOSAR classes are grouped based on similar relationships between toxicity and the various types of pharmacologic properties. The model does not apply a mechanistic approach to assessment of toxicity other than assignment of chemical classes (to identify potential toxicity in excess of baseline narcosis) using an expert decision tree.

Validity criteria fulfilled:

yes

Conclusions:

The results are adequate for the for the regulatory purpose.

Executive summary:

ECOSAR v1.11 – Fish 96h LC50 ; 19 June 2012

Additive endpoint values: Fish 96-hr LC50 111.7 mg/L

Adequacy of the QSAR:

1) QSAR model is scientifically valid. 2) The substance falls within the applicability domain of the QSAR model. 3) The prediction is fit for regulatory purpose.

The prediction is adequate for the Classification and Labelling or risk assessment of the substance as indicated in REACH Regulation (EC) 1907/2006: Annex XI Section 1.3.

Description of key information

72-h ErC50 (aquatic algae; growth rate): target : Reaction products of 2-hydroxyethyl methacrylate and diphosphorous pentoxide and water : > 100 mg/L (or 165 mg/L) based on TWA concentrations, 72 hour, freshwater, OECD TG 201, 2021

72-h ErC10 (algae; growth rate) : target : Reaction products of 2-hydroxyethyl methacrylate and diphosphorous pentoxide and water : = 49 mg/L based on TWA concentrations, 72 hour, freshwater, OECD TG 201, 2021

72-h NOErC (algae; growth rate): target : Reaction products of 2-hydroxyethyl methacrylate and diphosphorous pentoxide and water : = 39 mg/L based on TWA concentrations, 72 hour, freshwater, OECD TG 201, 2021

Read-Across: source data : Reaction products of 2-hydroxyethyl methacrylate and diphosphorus pentaoxide : 

72-h ErC50 (aquatic algae; growth rate): = 165 mg/L based on TWA concentrations (or > 160 mg/L nominal), 72 hour, freshwater, OECD TG 201, 2004

72 -h ErC10 (aquatic algae; growth rate): = 49 mg/L based on TWA concentrations (or 92 mg/L nominal), 72 hour, freshwater, OECD TG 201, 2004

72-h NOErC (algae; growth rate): = 39 mg/L based on TWA concentrations (or 80 mg/L nominal), 72 hour, freshwater, OECD TG 201, 2004

 

Supporting previous information:

QSAR: Green Algae EC50-96h= 1.1 mg/L (additive endpoint values), ECOSAR v1.11, US EPA, 2018

Key value for chemical safety assessment

EC50 for freshwater algae:

165 mg/L

EC10 or NOEC for freshwater algae:

49 mg/L

Additional information

Key data : OECD TG 201, 2004 : Read-Across SOURCE ( Reaction products of 2-hydroxyethyl methacrylate and diphosphorus pentaoxide ): The algal growth inhibition to Pseudokirchneriella subcapitata (previous name: Selenastrum capricornutum) strain: NIVA CHL 1, was carried out according to OECD TG 201 Freshwater Alga and Cyanobacteria, Growth Inhibition Test and EU Method C.3 guidelines under GLP. In the preceding range-finding test, exponentially growing algal cultures were exposed to test item concentration range of 0.1 to 100 mg/L nominal loading concentrations). In addition, a blank and treatment-control (with adjusted pH) were tested. The results showed that the EC50 for both cell growth inhibition and growth rate reduction were above 100 mg/L nominal concentrations. A definitive test was conducted exposing algal cultures to a range of test item concentrations : 0 (control), 10, 20, 40, 80 and 160 mg/L nominal loading concentrations. In addition, a treatment-control with pH adjustment was conducted at the highest test item concentration (160 mg/L nominal) to correct for potential pH-related effects on algal cell growth. The initial algal cell density was 1x10^4 cells/mL. The total test period was 72 hours. Samples for analyses were taken at the start, after 24 h of exposure and at the end of the 72 h test period. Analyses showed that the measured concentrations at the start of the test were in agreement with nominal concentrations. Measured concentrations were 38 mg/L (96%), 73 mg/L (91%) and 149 mg/L (93%) at the expected nominal concentrations of 40, 80 and 160 mg/L, respectively. Analysis was only considered for the nominal concentrations of 40, 80 and 160 mg/L, which were essential for determination of the toxicity parameters. During the 72 h exposure period the measured concentrations decreased by > 20% initial concentrations. The equivalent Time Weight Average (TWA) exposure concentrations were calculated to correspond to 17, 39 and 114 mg/L, respectively. The study met the all acceptability criteria and was considered valid. The 72-h EC50 for cell growth inhibition was 90 mg/L. The 72-h EC50 for growth rate inhibition was 165 mg/L based on TWA concentrations. The corresponding 72-h EC10 was 49 mg/L and the NOEC was 39 mg/L based on TWA concentrations.

 

Supporting previous information:

QSAR: Green Algae EC50-96h= 1.1 mg/L (additive endpoint values), ECOSAR v1.11, US EPA, 2018