Potassium 3-sulphopropyl methacrylate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms, other

Remarks:

toxicity towards activated sludge, determined within a OECD 302B biodegradation study

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

16 - 30 January 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: OECD 302B

Deviations:

not specified

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

activated sludge

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: Belebtschlamm aus Kläranlage Birsfelden
- Initial biomass concentration: Concentration inoculum: 0.2 g TS/l

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

14 d

Details on test conditions:

TEST SYSTEM
- Sludge concentration (weight of dry solids per volume): 0.2 g TS/L
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : DOC
TEST CONCENTRATIONS
- Test concentrations: 167 mg/L

Reference substance (positive control):

yes

Remarks:

functional control ethylene glycol

Key result

Duration:

7 d

Dose descriptor:

other: 99% biodegradation

Effect conc.:

167 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: DOC determination

Remarks on result:

other:

Remarks:

167 mg/L of the test item were degraded to 99% after 7 days, indicating a relative non-toxicity of SPM

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none stated
- Effect concentrations exceeding solubility of substance in test medium: none stated
- Adsorption (e.g. of test material to the walls of the test container): none stated

Validity criteria fulfilled:

not applicable

Conclusions:

The biodegradability of the test substance was investigated according to OECD guideline 302 B. After 7 days (14 days total) incubation >99 % degradation had occurred. Due to this result SPM can be considered as inherently biodegradable. Further, as such a fast and non-hindered biodegradation could be observed, it can reasonably be concluded that the test item at a concentration of 167 mg/L was relatively non-toxic towards activated sludge.

Executive summary:

The biodegradability of the test substance was investigated according to OECD guideline 302 B. The degradation parameter was the DOC removal in the samples. After 7 days (14 days total) incubation >99 % degradation had occurred. Due to this result SPM can be considered as inherently biodegradable. It was concluded that, based on the fast degradation, SPM at a concentration of 167 mg/L can also be considered as non-toxic towards activated sludge.

Reference 2

Endpoint:

toxicity to microorganisms

Type of information:

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

Adequacy of study:

weight of evidence

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 and environmental fate.


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, also for bacteria / microorganisms, 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.
In consequence, a similar behaviour can be expected in microorganisms. SPA is non-toxic to microorganisms, in a OECD 301D no toxicity was observed at a concentration of 5 mg/l, so the NOEC was set to 5 mg/l. Data on the toxicity control of SPM in a OECD 302B is not given, however, a biodegradation >99% degradation of 167 mg/l SPM was observed within 14 days, which allows the conclusion that the test item is relatively non-toxic towards microorganisms, and a NOAEC can be set to 167 mg/l. In consequence, the value of 5 mg/l as shown on SPA 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 and environmental fate 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 NOEC > 5 mg/l, too.


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 mg/l
Biodegradation not readily biodegradable; inherently biodegradable, not fulfilling specific criteria (OECD 301D) Inherently biodegradable(OECD 301B) / Readily biodegradable (Conclusions / BIOWIN estimation
Toxicity to microorganisms NOEC = 5 mg/l (OECD 301D) NOAEC 167 mg/l (>99% degradation in 14d observed, conclusion: non-toxic; OECD 302B)
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

Remarks:

link to source record

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)- Method: 100 mg test substance were directly added to the culture medium (according to OECD 301D) and dissolved with the aid of ultrasonication (5 min). The volume was adjusted to 100 mL to give a 1000 mg/L stock solution which was inverted several times to ensure adequate mixing and homogeneity. An aliquot of 30 mL was dispersed into the final volume of 6 L to give a concentration of 5 mg/L. 1 drop inoculum per litre was added to each test flask.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source of inoculum/activated sludge: Final effluent of Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, United Kingdom, obtained on 17 Aug 2001- Pretreatment: The effluent was filtered through coarse filter paper, while approx. the first 200 mL were discarded. The filtrate was maintained on continuous aeration in a temperature controlled room at 21 °C.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

14 d

Test temperature:

20°C

Nominal and measured concentrations:

5 mg/L (nominal)

Details on test conditions:

TEST CONDITIONS- Composition of medium: 100 mg test substance were directly added to the culture medium (according to OECD 301D) and dissolved with the aid of ultrasonication (5 min). The volume was adjusted to 100 mL to give a 1000 mg/L stock solution which was inverted several times to ensure adequate mixing and homogeneity. An aliquot of 30 mL was dispersed into the final volume of 6 L to give a concentration of 5 mg/L. 1 drop inoculum per litre was added to each test flask. - Test temperature: 20 °C- pH adjusted: noTEST SYSTEM- Culturing apparatus: 250 - 300 mL darkened glass bottles (BOD bottles), stoppered - Number of culture flasks/concentration: 2- Measuring equipment: Yellow Springs oxygen meter and BOD Probe SAMPLING- Sampling frequency: after 0. 3, 6, 9, 12, 15, 18, 21, 24 and 28 dCONTROL AND BLANK SYSTEM- Inoculum blank: yes- Abiotic sterile control: -- Toxicity control: yes, containing 5 mg/L test substance and 1.5 mg/L reference substance

Reference substance (positive control):

yes

Remarks:

Benzoic acid, sodium salt

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Result of toxicity control from ready biodegradability test

Results with reference substance (positive control):

The reference substance is degraded by 74% within the 14-day window, confirming the inoculum and the test set-up to be appropriate.

Validity criteria fulfilled:

not applicable

Conclusions:

The study was conducted under GLP according to OECD TG 301D on SPA, which is a scientifically reasonable method, and the test report is sufficiently documented. As given in ECHA's guidance documents, the toxicity control of the biodegradation test may be used to cover this endpoint. The test item concentration in the toxicity control of 5 mg/L can hence be used as NOEC value for the toxicity to aquatic microorganisms, as the test substance is not considered to be inhibitory to the inoculum. As outlined in the read-across justification, there is no reason to believe that this result is not relevant for SPM, too.

Executive summary:

The toxicity control of 5 mg/L in a OECD 301D biodegradation test was used to cover this endpoint. The test substance SPA is not considered to be inhibitory to the inoculum, hence, the NOEC was determined as 5 mg/L, which is applicable for the target substance SPM, too.

Reference 3

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

17 Aug - 14 Sep 2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data based on the inhibition control of a ready biodegradability study. This approach is in accordance with the Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance, ECHA 2014).

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 record

Qualifier:

according to guideline

Guideline:

other: OECD 301D

GLP compliance:

yes

Remarks:

The Department of health of the Government of the United Kingdom

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)- Method: 100 mg test substance were directly added to the culture medium (according to OECD 301D) and dissolved with the aid of ultrasonication (5 min). The volume was adjusted to 100 mL to give a 1000 mg/L stock solution which was inverted several times to ensure adequate mixing and homogeneity. An aliquot of 30 mL was dispersed into the final volume of 6 L to give a concentration of 5 mg/L. 1 drop inoculum per litre was added to each test flask.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source of inoculum/activated sludge: Final effluent of Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, United Kingdom, obtained on 17 Aug 2001- Pretreatment: The effluent was filtered through coarse filter paper, while approx. the first 200 mL were discarded. The filtrate was maintained on continuous aeration in a temperature controlled room at 21 °C.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

14 d

Test temperature:

20°C

Nominal and measured concentrations:

5 mg/L (nominal)

Details on test conditions:

TEST CONDITIONS- Composition of medium: 100 mg test substance were directly added to the culture medium (according to OECD 301D) and dissolved with the aid of ultrasonication (5 min). The volume was adjusted to 100 mL to give a 1000 mg/L stock solution which was inverted several times to ensure adequate mixing and homogeneity. An aliquot of 30 mL was dispersed into the final volume of 6 L to give a concentration of 5 mg/L. 1 drop inoculum per litre was added to each test flask. - Test temperature: 20 °C- pH adjusted: noTEST SYSTEM- Culturing apparatus: 250 - 300 mL darkened glass bottles (BOD bottles), stoppered - Number of culture flasks/concentration: 2- Measuring equipment: Yellow Springs oxygen meter and BOD Probe SAMPLING- Sampling frequency: after 0. 3, 6, 9, 12, 15, 18, 21, 24 and 28 dCONTROL AND BLANK SYSTEM- Inoculum blank: yes- Abiotic sterile control: -- Toxicity control: yes, containing 5 mg/L test substance and 1.5 mg/L reference substance

Reference substance (positive control):

yes

Remarks:

Benzoic acid, sodium salt

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Result of toxicity control from ready biodegradability test

Results with reference substance (positive control):

The reference substance is degraded by 74% within the 14-day window, confirming the inoculum and the test set-up to be appropriate.

Validity criteria fulfilled:

not applicable

Conclusions:

The study was conducted under GLP according to OECD TG 301D, which is a scientifically reasonable method, and the test report is sufficiently documented. As given in ECHA's guidance documents, the toxicity control of the biodegradation test may be used to cover this endpoint. The test item concentration in the toxicity control of 5 mg/L can hence be used as NOEC value for the toxicity to aquatic microorganisms, as the test substance is not considered to be inhibitory to the inoculum.

Executive summary:

The toxicity control of 5 mg/L in a OECD 301D biodegradation test was used to cover this endpoint. The test substance SPA is not considered to be inhibitory to the inoculum, hence, the NOEC was determined as 5 mg/L.

Description of key information

Toxicity to microorganisms: NOEC = 5 mg/L (SPA, CAS 31098-20-1, OECD 301D, GLP)

Toxicity to microorganisms: NOAEC 167 mg/L (>99% degradation in 7d observed, conclusion: non-toxic) (SPM, CAS 31098-21-2, OECD 302B)

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

5 mg/L