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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Data is from NTRL report.
Justification for type of information:
Data is from NTRL report.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Principles of method if other than guideline:
Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance Nonylphenol ethoxylates. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)).
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material (as cited in study report): Nonylphenol ethoxylates
- Molecular formula : C17H28O2
- Molecular weight : 264.409 g/mol
- Substance type:Organic
- Physical state: Liquid
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Concentration of sludge: 30 mg/l
Duration of test (contact time):
28 d
Based on:
not specified
Parameter followed for biodegradation estimation:
DOC removal
Key result
Parameter:
% degradation (DOC removal)
Value:
81
Sampling time:
28 d
Remarks on result:
other: Other details not known
Details on results:
Test substance undergoes 81% degradation by DOC removal parameter in 28 days.
Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
The percentage degradation of test substance was determined to be 81% by DOC removal parameter in 28 days. Thus, based on percentage degradation, Nonylphenol ethoxylates is considered to be readily biodegradable in water.
Executive summary:

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance Nonylphenol ethoxylates (CAS no. 127087 -87 -0). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). Concentration of inoculum i.e, sludge used was 30 mg/l. During the 28 day period the biological oxygen demand is measured and at the end of the 28 day period the level of organic carbon remaining in the aqueous phase is also measured. The percentage degradation of test substance was determined to be 81% by DOC removal parameter in 28 days. Thus, based on percentage degradation, Nonylphenol ethoxylates is considered to be readily biodegradable in nature.

Description of key information

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance Nonylphenol ethoxylates (CAS no. 127087 -87 -0) (NTRL report no. OTS0558989, 1997). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). Concentration of inoculum i.e, sludge used was 30 mg/l. During the 28 day period the biological oxygen demand is measured and at the end of the 28 day period the level of organic carbon remaining in the aqueous phase is also measured. The percentage degradation of test substance was determined to be 81% by DOC removal parameter in 28 days. Thus, based on percentage degradation, Nonylphenol ethoxylates is considered to be readily biodegradable in nature.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

1 experimental study for the target compound Polyethylene glycol mono(branched p-nonylphenyl) ether(CAS No. 127087-87-0) which is supported further by the 2 weight of evidence studies (from peer reviewed journal and authoritative database) for its closest read across substance with logKow as the primary descriptor were reviewed for the biodegradation end point which are summarized as below:

 

In a weight of evidence study for target chemical Polyethylene glycol mono(branched p-nonylphenyl) ether(CAS No. 127087-87-0), biodegradation experiment was conducted for 28 days (NTRL report no. OTS0558989, 1997). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). Concentration of inoculum i.e, sludge used was 30 mg/l. During the 28 day period the biological oxygen demand is measured and at the end of the 28 day period the level of organic carbon remaining in the aqueous phase is also measured. The percentage degradation of test substance was determined to be 81% by DOC removal parameter in 28 days. Thus, based on percentage degradation, Nonylphenol ethoxylates is considered to be readily biodegradable in nature.

Another weight of evidence study of biodegradation for read across substance Triethylene glycol ethyl ether (CAS no. 112 -50 -5) (having a 50 -60% similarity with the target chemical Polyethylene glycol mono(branched p-nonylphenyl) ether) was carried out for 20 days for evaluating the percentage biodegradability of chemical Triethylene glycol ethyl ether (Kenneth S. Price et. al; 1974) . Initial test substance conc. used in the study was 3, 7 and 10 mg/l, respectively. Domestic wastewater was used as a test inoculum.The BOD bottles were half filled with aerated dilution water containing the specified minerals and buffer. Small aliquots of the test chemicals were added to these bottles from 0.1% stock solutions yielding conc. of 3, 7 and 10 mg/l. At least two of these concentrations were tested in duplicate. These concentrations gave a potential oxygen demand of 3 to 30 mg/l over the 20 days duration of test. Dissolved oxygen was monitored periodically in the individual bottles through the use of a commercial DO meter filled with an agitated probe. The bottles were opened for sampling and DO measurements about five times during the course of the 20 day test.The percentage degradation of test substance was determined to be8, 47, 63 and 71% degradation in 5, 10, 15 and 20 days, respectively.Thus, based on percentage degradation,Triethylene glycol ethyl etheris considered to be readily biodegradable in nature.

For the same read across chemical Triethylene glycol ethyl ether (CAS no. 112 -50 -5) from authoritative database (J-CHECK, 2016), biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substanceTriethylene glycol ethyl ether (CAS no. 112 -50 -5). Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of test substance was determined to103, 99 and 100% by BOD, TOC removal and GC parameter in 28 days. Thus, based on percentage degradation,Triethylene glycol ethyl ether is considered to be readily biodegradable in nature

On the basis of above results for target chemicalPolyethylene glycol mono(branched p-nonylphenyl) ether(from NTRL report) and for its read across substance (from peer reviewed journal and authoritative database J-CHECK) , it can be concluded that the test substance Polyethylene glycol mono(branched p-nonylphenyl) ether can be expected to be readily biodegradable in nature.