Benzene, 1,1'-oxybis[methyl-, sulfonated, ammonium salts

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 April - 26 May 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

2006

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

Regulation (EC) No 440/2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch No: INB3209089
Storage: at room temperature, protected from light

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source: Sludge from the aeration tank of the ARA Werdhölzli (CH-8048 Zürich), a municipal biological waste water treatment plant.
- Preparation of inoculum for exposure: The sludge was pre-conditioned for 7 days (aerated but not fed) to reduce the amount of O2 consumed by the blank controls. Therefore, the sludge was washed twice with tap water and once with test medium.
- Pretreatment: The activated sludge was used after sampling from the treatment plant without adaptation.
- Concentration of sludge: 30 mg/L dry matter in the final mixture.

Duration of test (contact time):

28 d

Initial conc.:

104 mg/L

Based on:

other: nominal test item concentration based on 101 mg ThOD/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of test medium: Aerobic mineral salts medium prepared with ultrapure water (conductivity: <1.5 µS/cm; DOC: <0.5 mg/L)
* mineral stock solution A (10mL/L): 8.5 g/L KH2PO4, 28.49 g/L K2HPO4.3H2O, 33.4 g/L Na2HPO4.2H2O, 0.5 g/L NH4Cl, pH 7.4
* mineral stock solution B (1 mL/L): 36.4 g/L CaCl2.2H2O
* mineral stock solution C (1 mL/L): 22.5 g/L MgSO4.7H2O
* mineral stock solution D (1 mL/L): 0.25 g/L FeCl3.6H2O
* Final test medium: 10 mL of solution A and 1 mL of solutions B, C and D per L of test medium
After centrifugation, the sludge was suspended in test medium, at about 2 g/L dry matter. Before the test, this suspension was diluted down to 60 mg/L dry matter, i.e. twice the final concentration, since this suspension was diluted 1:1 (v:v) afterwards.
- Test temperature: 22±2°C, controlled at ± 1°C, in a thermostat cabinet in the dark
- pH: 7.4±0.2°C (measured prior to testing and if necessary adjusted with NaOH or HCl (except in flask C).
- Continuous darkness: yes, test bottles were in a thermostat cabinet.

TEST SYSTEM
- Test flasks: 510 mL glass bottles (tightly closed with manometric BOD measuring devices) containing a total volume of test solution of 200 mL. The bottles were equipped with stirring rods and butyl rubber quivers which contain 2 pellets of sodium hydroxide each to absorb the produced CO2 from the head space.
- Test performed in duplicate (two test flasks)

CONTROL AND BLANK SYSTEM
B: Inoculum blank (two replicates)
R: Procedure control (two replicates): 60.3 mg/L Sodium benzoate (100 mg ThOD/L)
C: Abiotic sterile control (one replicate): 98.0 mg/L test item (95.2 mg ThOD/L)
X: Toxicity control (one replicate): 103 mg/L test item and 60.3 mg/L reference item (total 200 mg oxygen demand/L)

SAMPLING
The test vessels were stirred by an inductive stirring system for a maximum test period of 28 days. During the test the O2 uptake was continuously measured with a manometric BOD measuring device. Temperature was recorded with a data logger.
At the end of the test, the pH was measured in all flasks except the abiotic sterile control (C).
Total elimination was determined in each test vessel (test suspension, blank and procedure control) based on the theoretical carbon content and the analysis of the dissolved organic carbon (DOC) concentrations at the end of the test.

STATISTICAL METHODS:
Values of % degradation were calculated for each test flask and day. The arithmetic mean of % degradation in each test flask on each day was calculated.

Reference substance:

other: Sodium benzoate

Remarks:

CAS 532-32-1

Key result

Parameter:

% degradation (O2 consumption)

Value:

-25

Sampling time:

28 d

Remarks on result:

other: test flask 1 after 28 d: -24.6% test flask 2 after 28 d: -24.6%

Details on results:

No biodegradability of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) based on O2 consumption was observed after 28 days as compared to the theoretical oxygen demand (ThOD). The negative biodegradation values (down to -25%) suggest that the test item is slightly toxic for the activated sludge.

The respective concentrations of dissolved organic carbon at the beginning and at the end of the test (measured value, as mg DOC/l) were, respectively:
27.0 and 11.8 for the test units (mean of two replicates)
<0.5 and 0.731 for the blank control (mean of two replicates)
36.9 and 0.845 for the procedure control (mean of two replicates)

The total elimination calculated based on dissolved organic carbon (DOC) measurements reached 58% for Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) and 100% for sodium benzoate, respectively. This data is higher than the degradation calculated based on O2 consumption and suggests that this observed elimination is rather due to adsorption of the test item to the activated sludge than to biodegradation.
Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) is not biodegradable in the Manometric Respirometry Test 301 F within 28 days.

Results with reference substance:

The procedure control sodium benzoate reached 85% biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.

Toxicity control:

At the applied initial test concentration of 103 mg/L the test item was not judged to have any inhibitory effect on the microbial population, since the biodegradation of the mixture (test item + reference item sodium benzoate) exceeded 25% within 14 days. While this seems to be contradictory with the negative degradation values of the test item tested on its own, it could be explained by a better physiological state of the sludge (in presence of a readily biodegradable substrate like sodium benzoate) or to co-metabolic processes.

Abiotic steril control:

Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) was not abiotically degraded (by processes using O2) during the whole test period of 28 days in the absence of microorganisms as confirmed by the lack of oxygen consumption.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

A 28-d ready biodegradability test (OECD 301F, Manometric Respirometry Test) using activated sludge of a municipal sewage treatment plant indicated that Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) (CAS no. 75314-26-0) is not biodegradable in the Manometric Respirometry Test 301 F within 28 days.

Executive summary:

The biodegradability of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) (CAS no. 75314 -26 -0) exposed to microorganisms derived from activated sludge of a municipal sewage treatment plant was investigated under aerobic static exposure conditions, following the test guideline OECD 301 F.

No biodegradability of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) based on O2 consumption was observed after 28 days as compared to the theoretical oxygen demand (ThOD).

The procedure control sodium benzoate reached 85% biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.

The total elimination calculated based on dissolved organic carbon (DOC) measurements reached 58% for Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) and 99% for sodium benzoate, respectively. This data is higher than the degradation calculated based on O2 consumption and suggests that this observed elimination is rather due to adsorption of the test item to the activated sludge than to biodegradation.

Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) (CAS no. 75314 -26 -0) is not biodegradable in the Manometric Respirometry Test 301 F within 28 days.

All validity criteria were fulfilled.

Reference 2

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

9 November - 7 December 1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study acc. to OECD guideline, not GLP but Good Scientific Practice. Further information on test item is lacking in the report but batch composition is known.

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

Version / remarks:

1992

Deviations:

not specified

GLP compliance:

no

Specific details on test material used for the study:

Batch No: 4420725
Storage conditions: Room temperature

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: ARA Werdhölzli, CH-8048 Zürich (09.11.94;9.30 a.m.)
- Preparation of inoculum for exposure: Prior tothe test the sludge was washed twice with mineral salts solution
- Concentration of sludge: 0.2 g/l dry matter in the final mixture

Duration of test (contact time):

28 d

Initial conc.:

ca. 50 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: Aerobic mineral salts medium prepared with double distilled water (conductivity: <1.5 µS/cm; DOC: <0.3 mg/l)
- Additional substrate: none
- Solubilising agent (type and concentration if used): no
- Test temperature: 22 ± 0.5 °C
- pH: 6.5 - 8
- pH adjusted: yes with NaOH or H2SO4
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 1000 ml closed brown glass bottle containing a total volume of test solution of 500 ml
- Number of culture flasks/concentration: 2 flasks
- Method used to create aerobic conditions: aeration with CO2-free air

MEASUREMENTS
The elimination of the test material was followed by DOC-determinations at regular intervals. First samples were analyzed at the beginning of and 3h after starting the test. The trapped CO2 was determined as inorganic carbon (IC).

CONTROL AND BLANK SYSTEM
- Inoculum blank: contained activated sludge + test medium, 2 Replicates
- Procedure control: contained activated sludge + test medium + aniline as ready biodegradable reference compound, 1 replicate

Reference substance:

aniline

Remarks:

50 mg/l

Test performance:

see details on results

Key result

Parameter:

% degradation (DOC removal)

Value:

50

Sampling time:

28 d

Details on results:

The main degradation process occurred between day 0 and day 8 when 39% of the initial DOC were removed. No significant increase in degradation occurred between day 8 and day 19, after which time again a slight increase of degradation up to 50 % was observed. No significant adaptation period (lag phase) was observed.
No significant elimination of the test substance due to adsorption to ttre activated sludge, on the glass surface or other physico-chemical processes was found as determined by means of DOC measurement 3 h after the start of the test.
However, beside this elimination no significant mineralization of the test substance was observed. During the first 22 days a slightly lower CO2 evolution of the test suspensions than in the inoculum blanks was observed, indicating a slightly toxic effect of the test substance to the activated sludge. At day 28 the CO2 evolution of the test suspensions reached the ones of the inoculum blanks indicating a higher rate of CO2 release in the test suspensions than observed during the first 22 days of incubation.

The positive control, aniline, showed 99% biodegradation after 19 days of incubation thus confirming suitability of inoculum and test conditions. The test was considered valid, since the degradation of the reference compound reached more than 70% within 14 days of incubation.

Based on these results, SANDOGEN CN FL can be termed as inherently biodegradable in the static test, since 50% degradation were attained after 28 days of contact time.

Results with reference substance:

see details on results

Validity criteria fulfilled:

yes

Remarks:

The test was considered valid, since the degradation of the reference compound reached more than 70 % within14 days of incubation.

Interpretation of results:

inherently biodegradable

Conclusions:

Based on the results in this study according to OECD 302B, SANDOGEN CN FL can be termed as inherently biodegradable in the static test, since 50% degradation were attained after 28 days of contact time, which is above the threshold of 20% degradation for inherent biodegradation.

Executive summary:

The biodegradability of SANDOGEN CN FL exposed to activated sludge of a municipal sewage treatment plant was investigated under aerobic static conditions.

SANDOGEN CN FL reached a biodegradation of 50% after 28 days.

The main degradation process occured between day 0 and day 8 when 39% of the initial DOC were removed. No significant increase in degradation occurred between day 8 and day 19, after which time again a slight increase of degradation up to 50% was observed. No significant adaptation period (lag phase) was observed.

However, beside this elimination no significant mineralization of the test substance was observed. During the first 22 days a slightly lower CO2 evolution of the test suspensions than in the inoculum blanks was observed, indicating a slightly toxic effect of the test substance to the activated sludge. At day 28 the CO2 evolution of the test suspensions reached the ones of the inoculum blanks indicating a higher rate of CO2 release in the test suspensions than observed during the first 22 days of incubation.

No significant elimination of the test substance due to adsorption to the activated sludge, on the glass surface or other physico-chemical processes was found as determined by means of DOC measurement 3 h after the start of the test.

Based on these results SANDOGEN CN FL can be termed as inherently biodegradable in the static test, since more than 20% degradation was attained after 28 days of contact time.

Description of key information

Key study (ACH, 2017)

The biodegradability of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) (CAS no. 75314 -26 -0) exposed to microorganisms derived from activated sludge of a municipal sewage treatment plant was investigated under aerobic static exposure conditions, following the test guideline OECD 301 F (ACH, 2017).

No biodegradability of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) based on O2 consumption was observed after 28 days as compared to the theoretical oxygen demand (ThOD).

The procedure control sodium benzoate reached 85% biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.

The total elimination calculated based on dissolved organic carbon (DOC) measurements reached 58% for Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) and 99% for sodium benzoate, respectively. This data is higher than the degradation calculated based on O2 consumption and suggests that this observed elimination is rather due to adsorption of the test item to the activated sludge than to biodegradation.

Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) (CAS no. 75314 -26 -0) is not biodegradable in the Manometric Respirometry Test 301 F within 28 days. All validity criteria were fulfilled. The results of the test can be considered reliable without restriction. The study is used as key study for chemical risk assessement.

Supporting study (MBT, 1994)

Additional information from a supporting Zahn-Wellens test (OECD TG 302B) indicates that the substance can be termed as inherently biodegradable in the static test, since more than 20% degradation was attained after 28 days of contact time. However, specific criteria in order to confirm that the substance does not fulfil the criteria for P are not met (< 70% DOC removal within 7 days, MBT, 1994).

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable, not fulfilling specific criteria

Type of water:

freshwater