Potassium 3-sulphopropyl methacrylate

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:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientifically acceptable calculation method

Justification for type of information:

QSAR prediction

Guideline:

other: REACH guidance on QSARs Chapter R.6 , May 2008

Principles of method if other than guideline:

The estimation for short-term toxicity to green algae of the test material was performed with US-EPA software ECOSAR v1.11. ECOSAR is currently programmed to identify over 120 chemical classes. For those classes, there are a more than 600 QSARs based on publicly available experimental data and confidential studies collected under the EPA New Chemicals Program. For each class, a standard EPA New Chemicals Program aquatic toxicity profile will be created using available QSARs and/or alternate QSAR approaches and professional judgment.

GLP compliance:

no

Remarks:

(not applicable)

Analytical monitoring:

not required

Details on sampling:

Not applicable

Details on test solutions:

Not applicable

Test organisms (species):

other: Green algae, not further specified

Details on test organisms:

No details available

Test type:

other: QSAR estimation

Water media type:

not specified

Total exposure duration:

96 h

Post exposure observation period:

Not applicable

Hardness:

No details available

Test temperature:

No details available

pH:

No details available

Dissolved oxygen:

No details available

Salinity:

No details available

Nominal and measured concentrations:

No details available

Details on test conditions:

No details available

Reference substance (positive control):

not required

Remarks:

(not applicable)

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

21.553 mg/L

Remarks on result:

other: calculated value ECOSAR Class : Methacrylates-acid

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

8 057.697 mg/L

Remarks on result:

other: calculated value ECOSAR CLASS : Neutral Organic SAR (Baseline Toxicity)

Details on results:

No details available

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Not applicable

Validity criteria fulfilled:

yes

Remarks:

(Scientifically accepted calculation method.)

Conclusions:

The study report describes a scientifically accepted calculation method for the prediction of short-term toxicity to green algae using the US-EPA software ECOSAR v1.11.No GLP criteria are applicable for the usage of this tool and the QSAR estimation is easily repeatable.

Executive summary:

The prediction for short-term toxicity to green algae of the test substance was determined by the computer program ECOSAR v1.11 by US-EPA .ECOSAR is currently programmed to identify over 120 chemical classes. For those classes, there are a more than 600 QSARs based on publicly available experimental data and confidential studies collected under the EPA New Chemicals Program. For each class, a standard EPA New Chemicals Program aquatic toxicity profile will be created using available QSARs and/or alternate QSAR approaches and professional judgment.

Metal [Na] has been removed for proper estimation.

The prediction for ECOSAR Class Methacrylates-acid resulting in a value for green algae EC50(96h) of 21.553 mg/L .

The predicted value for green algae EC50(96h) of 8057.697 mg/L use the Neutral Organics QSAR equations which represent baseline toxicity potential (minimum toxicity) assuming a simple non-polar narcosis model.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2006-04-05 - 2006-09-07

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

GLP - Guideline study with acceptable restrictions Data on pH and temperature of the test solutions and reference substance (concentrations, EC50) are missing. No analytics were conducte

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
see target record

Reason / purpose for cross-reference:

read-across source

Remarks:

link to target

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution was prepared one day before test start by adding 125 mg test substance to 800 mL distilled water and 24 h treatment with a magnetic stirrer. Afterwards 200 mL distilled water were added. Each test concentration is 200 mL, consisting of stock solution, 20 mL nutrient solution, 20 mL inoculum and bidistilled water if dilution is necessary. The final volume of each test concentration is 200 mL.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: chordat 86.81
- Age of inoculum (at test initiation): 3 days
- Method of cultivation: A 7 day old strain is diluted with aqua bidest to a cell concentration of 10E5 cells/mL and than filled up to 1 L with 100 mL nutrient solution and deionised water. 50 mL of this solution is filled into 300 mL Erlenmeyer flasks and put into a breeding room at 23 ± 2°C for 3 days. The flasks are homogenised by daily swaying per hand. The different precultures were united again after 3 days. For inoculum the algae were diluted to 10E5 cell/mL again.

ACCLIMATION
- Culturing media and conditions: same as test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23 ± 2 °C

pH:

no data

Nominal and measured concentrations:

nominal: 0, 1, 5, 10, 25, 50, 75, 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flask
- Type: closed with steel caps
- Size, fill volume: 300 mL flasks filled with 50 mL test solution
- Aeration: none
- Initial cells density: 10E5 cells/mL
- Control cells growth rate: 1.36
- No. of vessels per concentration (replicates): 4 replicates, 3 to measure cell density (via extinction during test period), 1 for measurement of extinction and pH at test start; furthermore 1 replicate with blank test concentrations (without inoculum)
- No. of vessels per control (replicates): 6
- No. of vessels per reference control (replicates): 4
- Homogenisation of algae suspension: by daily swaying per hand only once
- Growth medium: standard medium used

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: not stated
- Light intensity and quality: 85 µE/ m^2 s with neon tube (Osram L36W/ 25 universal white)

EFFECT PARAMETERS MEASURED: Cell density at test start and after 24, 48 and 72 h.
- Determination of cell concentrations: spectrophotometric (measurement of extinction at 578 nm)

Reference substance (positive control):

yes

Remarks:

Potassiumdichromate (K2Cr2O7)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

25.72 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 19.408 - 33.836, taken from raw data

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.613 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 0.614 - 2.957, taken from raw data

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

4.39 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% CL: 1.813 - 7.395 taken from raw data

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.908 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% CL: 0.042 - 2.063, taken from raw data

Details on results:

- Exponential growth in the control: yes, growth rate 1.36/d (corresponding to a 59.9-fold growth)

Results with reference substance (positive control):

- Results with reference substance valid? Yes, inhibition of cell growth 62.4%.

Validity criteria fulfilled:

yes

Conclusions:

The study was conducted under GLP according to OECD TG 202, which is a scientifically reasonable method, and the test report is sufficiently documented. Hence, there is no reason to question the reliability of the results. The test item "Kalium-3-sulfonatopropylacrylat" has a toxic effect on the green algae Desmodesmus subspicatus. The EbC50 was determined as ca. 4.4 mg/L, the ErC50 to ca. 25.7 mg/L. For the classification of the test item SPA the fact that it is not readily biodegradable is considered, too, and the more relevant (acc. CLP) inhibition of growth rate ErC50 will be considered, which is in the range of 10 - 100 mg/L. Accordingly, SPA should be classified as aquatic chronic Cat. 3.

Executive summary:

In a 72h hour acute toxicity study, the cultures of Desmodesmus subspicatus, strain chordat 86.81, were exposed to potassium 3-(acryloyloxy)propane-1-sulfonate at nominal concentrations of 0, 1, 5, 10, 25, 50, 75, 100 mg/L under static conditions in accordance with the OECD TG 201 and EU method C.3. The NOEC or EC₀₅ could not be determined due to mathematical reasons, the EC₅₀ values based on biomass and growth were EbC50 = 4.39 mg/L and ErC50 = 25.72 mg/L, respectively.

There were no compound related abnormalities noted.

This toxicity study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study in aquatic algae.

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

GLP - Guideline study with acceptable restrictions Data on pH and temperature of the test solutions and reference substance (concentrations, EC50) are missing. No analytics were conducted, study was performed on read-across substance

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
[Please provide information for all of the points below. Indicate if further information is included as attachment to the same record, or elsewhere in the dataset (insert links in 'Cross-reference' table)]


1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The rational for the analogue approach is the high structural similarity between the source and the target substance. 2-Propenoic acid, 3-sulfopropyl ester, potassium salt (source) and 2-Propenoic acid, 2-methyl-,3-sulfopropylester, potassium salt (target) are structurally identical except an additional methyl group on position 2 of the target substance. Despite the fact that a methyl group may alter the toxicological behaviour of a substance, this effect is considered very minor as there are three common groups in the molecules which are considered more relevant for their toxicological behaviour, i.e. the sulfo-group, the ester and the Michael-acceptor system. Due to the similarities in structure, similar physico-chemical properties of the substances are to be expected, which would result in a similar toxicokinetic behaviour and most likely also in very similar ecotoxicological behaviour.


2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

Source Chemical: 2-Propenoic acid, 3-sulfopropyl ester, potassium salt, CAS 31098-20-1, EC 250-465-0, SMILES [K+].[O-]S(=O)(=O)CCCOC(=O)C=C, MW 232.30

Target Chemical: 2-Propenoic acid, 2-methyl-,3-sulfopropylester, potassium salt, CAS 31098-21-2, EC 250-466-6, SMILES [K+].CC(=C)C(=O)OCCCS(=O)(=O)O, MW 247.33

Both substances do not contain impurities to an extent which is expected to alter the outcome of the experimental results or read-across approach.


3. ANALOGUE APPROACH JUSTIFICATION
Comparing the actually available information on the substances with regard to their physico-chemical properties, the minor influence of the additional methyl group of the target chemical becomes obvious. So the molecular weight is in the same range, i.e. approx. 240 g/mol, indicating per se the potential for absorption. Both substances are solids which either do not melt or decompose at or above 300°C. Both compounds are very soluble in water, and their logPow is in a negative range, < -3.
In general, absorption of a chemical is possible, if the substance crosses biological membranes. In case where no transport mechanisms are involved, this process requires a substance to be soluble, both in lipid and in water, and is also dependent on its molecular weight. Substances with a molecular weight below 100 are favourable for penetration through the skin and substances above 500 are normally not able to penetrate. Hence, with a similar molecular weight and logPow, their potential for absorption can be considered very similar or even identical.
Besides the common physico-chemical and toxicokinetic properties, they exhibit a similar ecotoxicological behaviour. Both substances are relatively non-toxic towards fish, both LC50(96h) are > 100 mg/L. The experimentally determined EC50 of SPA is > 100 mg/L (NOEC ≥ 100 mg/L) for daphnids over 48h, ECOSAR estimation gives 48h EC50 values of 32 resp. 33 g/L for SPM. The 72h EC50 of SPA for algae was 25.72 mg/L, ECOSAR estimation gives 96h EC50 of SPM as 21 mg/l (ECOSA class Methacrylates-acid) resp. 8 g/L (ECOSAR class Neutral Organic SAR (Baseline Toxicity)). Hence, the assumption of a similar ecotoxicity profile is justified.
Further, SPM is inherently biodegradable as shown in a OECD 302B study, and as a >99% biodegradation after 14 days was observed, it can be concluded that SPM is easily biodegradable, which is supported by QSAR estimation indicating that the substance is readily biodegradable. SPA however is not readily biodegradable but inherently biodegradable, not fulfilling specific criteria (OECD 301D). So it can be assumed that due to the facilitated biodegradation of SPM, all values used for read-across can be considered as a worst case, clearly not underestimating a potential hazard of SPM.
Hence, due to the above-mentioned similarities of the source and target chemical, with regard to their structure, functional groups, toxicokinetic and ecotoxicological behaviour, it can be reasonably concluded that a similar behaviour of the target chemical regarding its ecotoxicological properties compared to the source chemical can be expected. In summary, the target chemical 2-Propenoic acid, 2-methyl-,3-sulfopropylester, potassium salt, is expected to have a similar EC50 values for aquatic algae, too. However, for classification, the difference in biodegradation behaviour needs to be regarded.


4. DATA MATRIX
The following table shows the available data relevant to justify the read-across from the source to the target chemical for the endpoint toxicity towards aquatic algae:

Endpoint Source: SPA Target: SPM
Molecular weight 232.30 g/mol 247.33 g/mol
Physical state solid solid
Partition coefficient logPow = -3.63 logPow = -3.1 (EpiSuite estimation)
Water solubility 3329 g/L 2570 g/L
Biodegradation not readily biodegradable; inherently biodegradable, not fulfilling specific criteria (OECD 301D) Inherently biodegradable(OECD 301B) /
Readily biodegradable (Conclusions / BIOWIN estimation
Hydrolysis Hydrolytically stable, half-life 10.6 a at pH 7 (HYDROWIN v2.00, EpiSuite estimation) Possible degradation into Methacrylic acid (non-validated method)
Short-term toxicity to fish LC50(96 h) > 100 mg/L (OECD 203) LC50(96 h) > 2000 mg/l
NOEC(96 h) = 1000 mg/l
(OECD 203)
Short-term toxicity to aquatic invertebrates 24&48h NOEC ≥ 100 mg/L
24&48h EC50 > 100 mg/L (OECD 202) 48h EC50 = 32 resp. 33 g/L (ECOSAR estimation)
Short-term toxicity to aquatic algae 72h EC50 = 25.72 mg/L
72h EC10 = 1.613 mg/L
(growth rate, OECD 201) 96h EC50 = 21 mg/l resp. 8 g/L (ECOSAR estimation)

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes

pH:

no data

Reference substance (positive control):

yes

Remarks:

Potassiumdichromate (K2Cr2O7)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

25.72 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 19.408 - 33.836, taken from raw data

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.613 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 0.614 - 2.957, taken from raw data

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

4.39 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% CL: 1.813 - 7.395 taken from raw data

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.908 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% CL: 0.042 - 2.063, taken from raw data

Details on results:

- Exponential growth in the control: yes, growth rate 1.36/d (corresponding to a 59.9-fold growth)

Results with reference substance (positive control):

- Results with reference substance valid? Yes, inhibition of cell growth 62.4%.

Validity criteria fulfilled:

yes

Conclusions:

The study was conducted under GLP according to OECD TG 201, which is a scientifically reasonable method, and the test report is sufficiently documented. Hence, there is no reason to question the reliability of the results. The test item "Kalium-3-sulfonatopropylacrylat" has a toxic effect on the green algae Desmodesmus subspicatus. The EbC50 was determined as ca. 4.4 mg/L, the ErC50 to ca. 25.7 mg/L. For the classification of the test item SPA the fact that it is not readily biodegradable is considered, too, and the more relevant (acc. CLP) inhibition of growth rate ErC50 will be considered, which is in the range of 10 - 100 mg/L. Accordingly, SPA should be classified as aquatic chronic Cat. 3. The registered substance SPM however, is not only inherently but can also be considered as readily biodegradable. Hence, no classification according to Regulation (EC) 1272/2008 is triggered.

Executive summary:

In a 72h hour acute toxicity study, the cultures of Desmodesmus subspicatus, strain chordat 86.81, were exposed to potassium 3-(acryloyloxy)propane-1-sulfonate at nominal concentrations of 0, 1, 5, 10, 25, 50, 75, 100 mg/L under static conditions in accordance with the OECD TG 201 and EU method C.3. The NOEC or EC₀₅ could not be determined due to mathematical reasons, the EC₅₀ values based on biomass and growth were EbC50 = 4.39 mg/L and ErC50 = 25.72 mg/L, respectively.

There were no compound related abnormalities noted.

This toxicity study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study in aquatic algae.

Description of key information

Short-term toxicity to algae: 72h EC50 = 25.72 mg/L, 72h EC10 = 1.613 mg/L for Desmodesmus subspicatus, static (SPA, CAS 31098-20-1, growth rate, OECD 201, GLP)

Short-term toxicity to algae: 96h EC50 = 21 mg/l resp. 8 g/L (ECOSAR class Methacrylates-acid resp. ECOSAR class Neutral Organic SAR (Baseline Toxicity)) (SPM, CAS 31098-21-2, ECOSAR estimation)

Key value for chemical safety assessment

EC50 for freshwater algae:

25.72 mg/L

EC10 or NOEC for freshwater algae:

1.643 mg/L

Additional information

The relevant EC50 and EC10 values are taken from an OECD 201 GLP guideline study on a read-across substance,2-Propenoic acid, 3-sulfopropyl ester, potassium salt (SPA). Read-across is justified as set out in the analogue approach justification in the target record.

For classification, the difference in biodegradation behaviour needs to be regarded. The RA substance SPA has a toxic effect on the green algae Desmodesmus subspicatus. The EbC50 was determined as ca. 4.4 mg/L, the ErC50 to ca. 25.7 mg/L. For the classification of the test item SPA the fact that it is not readily biodegradable is considered, too, and the more relevant (acc. CLP) inhibition of growth rate ErC50 will be considered, which is in the range of 10 - 100 mg/L. Accordingly, SPA should be classified as aquatic chronic Cat. 3. The registered substance SPM however, is not only inherently but can also be considered as readily biodegradable. Hence, no classification according to Regulation (EC) 1272/2008 is triggered.