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Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
12 Apr - 13 May 2005
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-Guideline study
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal wastewater treatment plant Breisgauer Bucht- Preparation of inoculum for exposure: washed twice by settling the sludge, decanting the supernatant and resuspending the sludge in aerated tap water- Concentration of sludge: 30 mg dry solids/L
Duration of test (contact time):
28 d
Initial conc.:
20 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS- Composition of medium: according to guideline- Test temperature: 21.0-21.5 °C- Suspended solids concentration: 30 mg/L dry solids- Other: constant stirring using magnetic stirrersTEST SYSTEM- Culturing apparatus: 2L gas wash bottles- Number of culture flasks/concentration: 2- Method used to create aerobic conditions: aerated with CO2-free air at a rate of 50-100 mL/min overnight- Measuring equipment: IC determination- Details of trap for CO2 and volatile organics if used: 0.2M NaOHSAMPLING- Sampling frequency: Day 0, 4, 7, 11, 14, 21 and 28- Sampling method: Absorber flask exchangedCONTROL AND BLANK SYSTEM- Inoculum blank: 2- Toxicity control: 1- Reference control: 1
Reference substance:
benzoic acid, sodium salt
Parameter:
% degradation (CO2 evolution)
Value:
95
Sampling time:
28 d
Parameter:
% degradation (CO2 evolution)
Value:
81.5
Sampling time:
10 d
Details on results:
The 10-day window was fulfilled.The degradation in the toxicity control was 91.2% within 14 days and 95.8% within 28 days.
Results with reference substance:
Sodium benzoate reached the pass levels for ready biodegradability within 4 days.
Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Reason / purpose:
read-across source
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal wastewater treatment plant Breisgauer Bucht- Preparation of inoculum for exposure: washed twice by settling the sludge, decanting the supernatant and resuspending the sludge in aerated tap water- Concentration of sludge: 30 mg dry solids/L
Duration of test (contact time):
28 d
Initial conc.:
20 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS- Composition of medium: according to guideline- Test temperature: 21.0-21.5 °C- Suspended solids concentration: 30 mg/L dry solids- Other: constant stirring using magnetic stirrersTEST SYSTEM- Culturing apparatus: 2L gas wash bottles- Number of culture flasks/concentration: 2- Method used to create aerobic conditions: aerated with CO2-free air at a rate of 50-100 mL/min overnight- Measuring equipment: IC determination- Details of trap for CO2 and volatile organics if used: 0.2M NaOHSAMPLING- Sampling frequency: Day 0, 4, 7, 11, 14, 21 and 28- Sampling method: Absorber flask exchangedCONTROL AND BLANK SYSTEM- Inoculum blank: 2- Toxicity control: 1- Reference control: 1
Reference substance:
benzoic acid, sodium salt
Parameter:
% degradation (CO2 evolution)
Value:
95
Sampling time:
28 d
Parameter:
% degradation (CO2 evolution)
Value:
81.5
Sampling time:
10 d
Details on results:
The 10-day window was fulfilled.The degradation in the toxicity control was 91.2% within 14 days and 95.8% within 28 days.
Results with reference substance:
Sodium benzoate reached the pass levels for ready biodegradability within 4 days.
Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
1984
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study with acceptable restrictions.
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
GLP compliance:
no
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: effluent of the sewage treatment plant Hochdahl which treats predominantly domestic sewage.
Duration of test (contact time):
30 d
Initial conc.:
2 mg/L
Based on:
act. ingr.
Initial conc.:
5 mg/L
Based on:
act. ingr.
Parameter followed for biodegradation estimation:
other: theoretical oxygen demand
Details on study design:
TEST CONDITIONS- Composition of medium: deionised water- Aeration of dilution water: yes, saturation 8-9 mg oxygen/LCONTROL AND BLANK SYSTEM- sodium decyl sulphate was used as a reference substance
Reference substance:
other: C12AS-Na (sodium decyl sulphate) 2 mg/L
Parameter:
other: chemical oxygen demand
Value:
98
Sampling time:
30 d
Remarks on result:
other: at concentration 2 mg/L
Parameter:
other: chemical oxygen demand
Value:
92
Sampling time:
30 d
Remarks on result:
other: at concentration 5 mg/L
Details on results:
Kinetic of test substance (2 mg/L): 63% after 5 days99% after 15 days98% after 30 daysKinetic of test substance (5 mg/L): 69% after 5 days 94% after 15 days92% after 30 daysThe test substance was biodegraded by > 60% within the 10-day time window. Thus, it can be considered as readily biodegradable.
Results with reference substance:
Kinetic of the reference substance:42% after 5 days64% after 15 days63% after 30 days
Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study with acceptable restrictions.
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Qualifier:
according to
Guideline:
OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)
GLP compliance:
no
Oxygen conditions:
aerobic
Duration of test (contact time):
8 d
Initial conc.:
75 mg/L
Based on:
test mat.
Value:
ca. 90
Sampling time:
8 d
Remarks on result:
other: value taken from a graphic
Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-Guideline study
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
no
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
other: effluent of domestic sewage treatment plant
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Sewage treatment plant Hochdahl, municipal treatment plant
Duration of test (contact time):
28 d
Initial conc.:
2 mg/L
Based on:
act. ingr.
Initial conc.:
5 mg/L
Based on:
act. ingr.
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance:
benzoic acid, sodium salt
Parameter:
% degradation (O2 consumption)
Value:
97
Sampling time:
28 d
Remarks on result:
other: 2 mg/L
Parameter:
% degradation (O2 consumption)
Value:
94
Sampling time:
28 d
Remarks on result:
other: 5 mg/L
Results with reference substance:
84% degradation of sodium benzoate after 28 days.
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Reason / purpose:
read-across source
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: effluent of the sewage treatment plant Hochdahl which treats predominantly domestic sewage.
Duration of test (contact time):
30 d
Initial conc.:
2 mg/L
Based on:
act. ingr.
Initial conc.:
5 mg/L
Based on:
act. ingr.
Parameter followed for biodegradation estimation:
other: theoretical oxygen demand
Details on study design:
TEST CONDITIONS- Composition of medium: deionised water- Aeration of dilution water: yes, saturation 8-9 mg oxygen/LCONTROL AND BLANK SYSTEM- sodium decyl sulphate was used as a reference substance
Reference substance:
other: C12AS-Na (sodium decyl sulphate) 2 mg/L
Parameter:
other: chemical oxygen demand
Value:
98
Sampling time:
30 d
Details on results:
Kinetic of test substance (2 mg/L): 63% after 5 days99% after 15 days98% after 30 daysKinetic of test substance (5 mg/L): 69% after 5 days 94% after 15 days92% after 30 daysThe test substance was biodegraded by > 60% within the 10-day time window. Thus, it can be considered as readily biodegradable.
Results with reference substance:
Kinetic of the reference substance:42% after 5 days64% after 15 days63% after 30 days
Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Reason / purpose:
read-across source
Oxygen conditions:
aerobic
Duration of test (contact time):
8 d
Initial conc.:
75 mg/L
Based on:
test mat.
Value:
ca. 90
Sampling time:
8 d
Remarks on result:
other: value taken from a graphic
Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Reason / purpose:
read-across source
Oxygen conditions:
aerobic
Inoculum or test system:
other: effluent of domestic sewage treatment plant
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Sewage treatment plant Hochdahl, municipal treatment plant
Duration of test (contact time):
28 d
Initial conc.:
2 mg/L
Based on:
act. ingr.
Initial conc.:
5 mg/L
Based on:
act. ingr.
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance:
benzoic acid, sodium salt
Parameter:
% degradation (O2 consumption)
Value:
97
Sampling time:
28 d
Remarks on result:
other: 2 mg/L
Parameter:
% degradation (O2 consumption)
Value:
94
Sampling time:
28 d
Remarks on result:
other: 5 mg/L
Results with reference substance:
84% degradation of sodium benzoate after 28 days.
Interpretation of results:
readily biodegradable

Description of key information

Readily biodegradable according to OECD criteria: 95% after 28 days based on CO2 evolution (OECD 301 B).

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Since no reliable ready biodegradability tests are available for C9-12AS Na, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5, a read-across to other structurally related category members was conducted. Read-across data on the following substances were used: C10AS Na (CAS 142-87-0) and C12AS Na (CAS 151-21-3).

The key study with C12AS Na (CAS 151-21-3) was performed according to OECD 301 B and is GLP compliant (Elementis, 2005). Non-adapted activated sludge coming from a municipal wastewater treatment plant was used as inoculum and the initial concentration of the test substance was 20 mg/L as DOC. Biodegradation measured as CO2 evolution reached 95% after 28 days and passed a 10-day window (81.5% after 10 days).

A supporting study with C12AS Na (CAS 151-21-3) was performed according to OECD guideline 301 D and GLP (BASF, 1996). Effluent of domestic sewage treatment plant was used as inoculum and the initial concentrations of the test substance were 2 mg/L and 5 mg/L. Biodegradation after 28 days measured as O2 consumption reached 97% at the concentration of 2 mg/L and 94% at the concentration of 5 mg/L. It can be concluded that C12AS Na (CAS 151-21-3) is ready biodegradable according to OECD criteria.

Two further supporting studies are available for C10AS Na (CAS 142-87-0). One non-GLP study assessing biodegradation of C10AS Na (CAS 142-87-0) was performed according to OECD guideline 301 D (BASF, 2001). Effluent of the sewage treatment plant handling predominantly domestic sewage was used as inoculum. The initial concentrations of the test substance were 2 mg/L and 5 mg/L. Biodegradation of 98% measured as oxygen demand was observed after 30 days at the initial concentration of 2 mg/L and 92% at the concentration of 5 mg/L. The test substance was biodegraded by more than 60% in both cases within five days. Based on these results it can be concluded that C10AS Na (CAS 142-87-0) is readily biodegradable. This result was confirmed by a supporting non-GLP study performed according to OECD guideline 301 E (Sanchez Leal et al., 1991). Biodegradation reached ca. 90% after 8 days of testing.

Due to structural and property similarities with the tested category member these results also apply to C9-12AS Na. This substance is considered to be readily biodegradable according to OECD criteria.