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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:
end on 26-JUN-2002
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: the test was performed according to OECD guideline and GLP
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap de Maaskant', 's-Hertogenbosch, the Netherlands
- Method of cultivation: The sludge was kept under continuous aeration until further treatment. The concentration of suspended solids was 4.7 g/l in the concentrated sludge (information obtained from the municipal sewage treatment plant).
- Storage conditions: data not available
- Storage length: data not available
- Preparation of inoculum for exposure: Before use, the sludge was allowed to settle (30-90 minutes) and the liquid decanted for use as inoculum at the amount of 10 ml/l of mineral medium.
- Pretreatment: none
- Concentration of sludge: 4.7 g/l in the concentrated sludge (information obtained from the municipal sewage treatment plant)
- Initial cell/biomass concentration: data not available
- Water filtered: data not available
Duration of test (contact time):
ca. 28 d
Initial conc.:
ca. 12 mg/L
Based on:
other: TOC
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium:
> Milli-RO / Milli-Q water: Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon and ionexchange cartridges (Milli-Q) (Millipore Corp., Bedford, Mass., USA).
> Stock solutions of mineral components:
* A) 8.50 g KHpP04, 21.75 g K2HP04, 67.20 g Na2HP04.12 H20, 0.50 g NH4Cl dissolved in 1 I Milli-Q water, pH 7.4 + 0.2
* B) 22.50 g MgS04.7H20 dissolved in 1 I Milli-Q water
* C) 36.40 g CaCI2.2H20 dissolved in 1 I Milli-Q water
* D) 0.25 g FeCI3.6H20 dissolved in 1 I Milli-Q water
> Mineral medium: 1 I mineral medium contains: 10 ml of solution (A), 1 ml of solutions (B) to (D) and Milli-RO water.

- Additional substrate: none
- Solubilising agent: none
- Test temperature: The temperature recorded in a vessel with water in the same room varied between 22 and 22.5°C
- pH: between 7.2 and 7.5
- pH adjusted: no
- Aeration of dilution water: yes (with CO2-free air)
- Continuous darkness: data not available


TEST SYSTEM
- Culturing apparatus: 2 litre all-glass brown coloured bottles
- Number of culture flasks/concentration:
> Test suspension: containing test substance and inoculum (2 bottles)
> lnoculum blank: containing only inoculum (2 bottles)
> Positive control: containing reference substance and inoculum (1 bottle)
> Toxicity control: containing test substance, reference substance and inoculum (1 bottle)
- Method used to create aerobic conditions: aeration
- Measuring equipment: data not available
- Test performed in closed vessels due to significant volatility of test substance: data not available


SAMPLING
Titrations were made every second or third day during the first 10 days, and thereafter at least every fifth day until the 28th day.


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: yes


STATISTICAL METHODS: not applicable
Parameter:
% degradation (CO2 evolution)
Value:
ca. 80
Sampling time:
28 d
Details on results:
The relative degradation values calculated from the measurements performed during the test period revealed 78 and 82% degradation of ALDOLASE (IUB 4.1.2.4), % for A and B respectively.
Furthermore, biodegradation of ALDOLASE (IUB 4.1.2.4) of at least 60% was reached within 10 days of biodegradation exceeding 10%. Thus, the criterion for ready biodegradability was met.
In the toxicity control more than 25% degradation occurred within 14 days (based on ThCO2). Therefore, the test substance was assumed to be not inhibitory on microbial activity.
Results with reference substance:
The positive control substance was degraded at least 60% within 7 days.
Validity criteria fulfilled:
yes
Remarks:
The positive control substance was degraded at least 60% within 7 days. The total C02 release in the blank reached a total value.of 59 mg C02 per 2 litres of medium. The difference of duplicate values for %-degradation of ALDOLASE was always less than 20.
Interpretation of results:
readily biodegradable
Conclusions:
ALDOLASE (IUB 4.1.2.4) was readily biodegradable under the conditions of the modified Sturm test presently performed.
Executive summary:

ALDOLASE (IUB 4.1.2.4) was tested for its ready biodegradability in the carbon dioxide (CO2) evolution test (modified Sturm test). The study procedure was based on EEC directive 92/69, C.4-C, December 1992, and OECD guideline No. 301 B July 17, 1992.

ALDOLASE (IUB 4.1.2.4) is well soluble in water. Since calculation of the theoretical TOC value was not possible this value was determined by analysis. Prior to the biodegradation study a weighed amount of 5.0436 g of ALDOLASE (IUB 4.1.2.4) was added to a volumetric flask and dissolved in 500 mL milli-RO water. The stock was a homogeneous, slight turbid solution. The TOC concentration of this solution was determined. The TOC concentration of the 10 g/L ALDOLASE (IUB 4.1.2.4) solution was 379.6 +:- 10.09 ppm. Based on the TOC concentration the Theoretical CO2 production (ThCO2) of the ALDOLASE (IUB 4.1.2.4) solution was calculated to be 1.39 mg CO2/mg (= mg CO2/mL stock solution). In the modified Sturm test 63 mL of the ALDOLASE (IUB 4.1.2.4) solution was tested in 2 litres test medium, corresponding to 12 mg TOC/L.

The relative degradation values calculated from the measurements performed during the test period revealed 78 and 82% degradation of ALDOLASE (IUB 4.1.2.4), % for A and B respectively. Furthermore, biodegradation of ALDOLASE (IUB 4.1.2.4) of at least 60% was reached within 10 days of biodegradation exceeding 10%. Thus, the criterion for ready biodegradability was met. In the toxicity control ALDOLASE (IUB 4.1.2.4) was found to be not inhibitory on microbial activity.

Since all acceptability criteria prescribed by the protocol were met, this study was considered to be valid.

In conclusion, ALDOLASE (IUB 4.1.2.4) was readily biodegradable under the conditions of the modified Sturm test presently performed.

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:
Please refer to the analogue justification attached to IUCLID section 13.
Reason / purpose:
read-across source
Specific details on test material used for the study:
Composition of biodegradable enzyme material is similar and from the same production strain.
Parameter:
% degradation (CO2 evolution)
Value:
ca. 80
Sampling time:
28 d
Conclusions:
The key values retained for the assessment of the biodegradation in water of the target substance is ca. 80% degradation based on CO2 evolution (OECD 301B, activated sludge, RA to CAS 9026-97-5).
Executive summary:

Experimental data on the toxicity of Penicillin Amidohydrolase) IUB 3.5.1.11 (CAS 9014-06-6) on biodegradation in water are not available. The toxicity was assessed using read across data from the analogue substance Aldolase enzyme concentrate; deoxyribose-phosphate aldolase IUB 4.1.2.4 (CAS 9026-97-5). This read-across is in accordance with Regulation (EC) No. 1907/2006 Annex XI, 1.5. Details on the read across justification are provided in section 13 of the IUCLID dossier.

 

The source substance ALDOLASE (IUB 4.1.2.4) was tested for its ready biodegradability in the carbon dioxide (CO2) evolution test (modified Sturm test). The study procedure was based on EEC directive 92/69, C.4-C, December 1992, and OECD guideline No. 301 B July 17, 1992.

ALDOLASE (IUB 4.1.2.4) is well soluble in water. Since calculation of the theoretical TOC value was not possible this value was determined by analysis. Prior to the biodegradation study a weighed amount of 5.0436 g of ALDOLASE (IUB 4.1.2.4) was added to a volumetric flask and dissolved in 500 mL milli-RO water. The stock was a homogeneous, slight turbid solution. The TOC concentration of this solution was determined. The TOC concentration of the 10 g/L ALDOLASE (IUB 4.1.2.4) solution was 379.6 +:- 10.09 ppm. Based on the TOC concentration the Theoretical CO2 production (ThCO2) of the ALDOLASE (IUB 4.1.2.4) solution was calculated to be 1.39 mg CO2/mg (= mg CO2/mLstock solution). In the modified Sturm test 63 mL of the ALDOLASE (IUB 4.1.2.4) solution was tested in 2 litres test medium, corresponding to 12 mg TOC/L.

The relative degradation values calculated from the measurements performed during the test period revealed 78 and 82% degradation of ALDOLASE (IUB 4.1.2.4), % for A and B respectively. Furthermore, biodegradation of ALDOLASE (IUB 4.1.2.4) of at least 60% was reached within 10 days of biodegradation exceeding 10%. Thus, the criterion for ready biodegradability was met. In the toxicity control ALDOLASE (IUB 4.1.2.4) was found to be not inhibitory on microbial activity.

Since all acceptability criteria prescribed by the protocol were met, this study was considered to be valid. ALDOLASE (IUB 4.1.2.4) was readily biodegradable under the conditions of the modified Sturm test presently performed.

In conclusion, the target substance Penicillin Amidohydrolase IUB 3.5.1.11 (CAS 9014-06-6) is considered readily biodegradable, too, based on the read-across conducted.

Description of key information

Penicillin Amidohydrolase IUB 3.5.1.11 (CAS 9014-06-6) is readily biodegradable (ca. 80% degradation) (activated sludge, OECD 301B, read-across from CAS 9026-97-5)

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

Experimental data on the toxicity of Penicillin Amidohydrolase IUB 3.5.1.11 (CAS 9014-06-6) on biodegradation in water are not available. The toxicity was assessed using read across data from the analogue substance Aldolase enzyme concentrate; deoxyribose-phosphate aldolase IUB 4.1.2.4 (CAS 9026-97-5). This read-across is in accordance with Regulation (EC) No. 1907/2006 Annex XI, 1.5. Details on the read across justification are provided in section 13 of the IUCLID dossier.

 

ALDOLASE (IUB 4.1.2.4) was tested for its ready biodegradability in the carbon dioxide (CO2) evolution test (modified Sturm test). The study procedure was based on EEC directive 92/69, C.4-C, December 1992, and OECD guideline No. 301 B July 17, 1992.

ALDOLASE (IUB 4.1.2.4) is well soluble in water. Since calculation of the theoretical TOC value was not possible this value was determined by analysis. Prior to the biodegradation study a weighed amount of 5.0436 g of ALDOLASE (IUB 4.1.2.4) was added to a volumetric flask and dissolved in 500 mL milli-RO water. The stock was a homogeneous, slight turbid solution. The TOC concentration of this solution was determined. The TOC concentration of the 10 g/L ALDOLASE (IUB 4.1.2.4) solution was 379.6 +:- 10.09 ppm. Based on the TOC concentration the Theoretical CO2 production (ThCO2) of the ALDOLASE (IUB 4.1.2.4) solution was calculated to be 1.39 mg CO2/mg (= mg CO2/mL stock solution). In the modified Sturm test 63 mL of the ALDOLASE (IUB 4.1.2.4) solution was tested in 2 litres test medium, corresponding to 12 mg TOC/L.

The relative degradation values calculated from the measurements performed during the test period revealed 78 and 82% degradation of ALDOLASE (IUB 4.1.2.4), % for A and B respectively. Furthermore, biodegradation of ALDOLASE (IUB 4.1.2.4) of at least 60% was reached within 10 days of biodegradation exceeding 10%. Thus, the criterion for ready biodegradability was met. In the toxicity control ALDOLASE (IUB 4.1.2.4) was found to be not inhibitory on microbial activity.

Since all acceptability criteria prescribed by the protocol were met, this study was considered to be valid. ALDOLASE (IUB 4.1.2.4) was readily biodegradable under the conditions of the modified Sturm test presently performed.

In conclusion, Penicillin Amidohydrolase IUB 3.5.1.11 (CAS 9014-06-6) is considered readily biodegradable, too, based on the read-across conducted.