3-aminophenol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From August 06, 2013 to January 15, 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental test performed using standard test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Biodegradability of test chemical was determined by uisng standard test guideine 301 F

GLP compliance:

yes (incl. QA statement)

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): aerobic activated sludge, microorganisms from a domestic waste water treatment plant was supplied by the sewage plant Roßdorf, Germany
- Storage conditions: no data
- Preparation of inoculum for exposure:The aerobic activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in tap water and centrifuged again. This procedure was done three times. The sediment was re-suspended in test water and aerated overnight. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 3.5 g dry material per litre were mixed with test water. This suspension was used for the experiment.
- Concentration of sludge: 3.5 g dry material per litre

Duration of test (contact time):

28 d

Initial conc.:

102 mg/L

Based on:

test mat.

Initial conc.:

195 mg/L

Based on:

other: ThOD NH4

Initial conc.:

255 mg/L

Based on:

other: ThOD NO3

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Reconstituted Test Water:
Analytical grade salts were added to deionised water to prepare
the following stock solutions:
a) 8.5 g KH2PO4, 21.75 g K2HPO4, 33.4 g Na2HPO4 x 2 H2O, 0.5 g NH4Cl filled up with deionised water to 1000 mL volume
b) 22.5 g MgSO4 x 7 H2O filled up with deionised water to 1000 mL volume
c) 36.4 g CaCl2 x 2 H2O filled up with deionised water to 1000 mL volume
d) 0.25 g FeCl3 x 6 H2O filled up with deionised water to 1000 mL volume
In order to avoid precipitation of iron hydroxide in the stock solution d) after storage and before use, one drop of concentrated HCl per litre was added.
50 mL of stock solution a) and 5 mL of the stock solutions b) to d) were combined and filled up to a final volume of 5000 mL with deionised water. The pH-value was 7.5 and therefore no adjustment was necessary.
- Additional substrate: no
- Solubilising agent (type and concentration if used): No emulsifiers or solvents were used
- Test temperature: 21 - 22 °C
- pH: 7.6 (measured at the start of the test), 7.5–7.9 (measured at the end of the test)
- pH adjusted: no
- Aeration of dilution water: no data
- Suspended solids concentration: 3.5 g dry material per litre
- Continuous darkness: yes
- Other:

TEST SYSTEM
- Culturing apparatus: test flasks containing a volume of approximately 500 mL
- Number of culture flasks/concentration: 2 for test item, 2 for inoculum control, 1 for procedure control, 1 for abiotic control and 1 for toxicity control.
- Method used to create aerobic conditions: continuous stirring
- Measuring equipment: BSB/BOD-Sensor-System, Aqualytic Dortmund, Germany
- Test performed in closed vessels : yes; The test flasks were closed gas-tight by a measuring head.
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: Potassium hydroxide solution (45%) was used for trapping the produced carbon dioxide.
- Other:

Test performance:

The closed test flasks were incubated in a climatised room under continuous stirring. The consumption of oxygen was determined by measuring the change of pressure in the flasks.

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Remarks on result:

other: other details not available

Results with reference substance:

The reference item sodium benzoate was sufficiently degraded to 85% after 14 days and to 86% after 28 days of incubation. The percentage biodegradation of the reference item confirms the suitability of the used aerobic activated sludge inoculum.

The oxygen demand of the inoculum control (medium and inoculum) was 25 mg O2/L and thus not greater than 60 mg O2/L within 28 days as required by the test guideline.

The pH-value of the test item flasks at the end of the test was 7.9 and therefore within the range of pH 6.0 to 8.5 as required by the test guideline.

In the toxicity control containing both the test item and reference 45% biodegradation was noted within 14 days and 56% biodegradation was determined after 28 days of incubation. According to the test guidelines the test item can be assumed to be not inhibitory on the aerobic activated sludge microorganisms because degradation was >25% within 14 days.

The oxygen demand in the abiotic control was zero. No correction of the test item degradation rates had to be done.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The biodegradation after 28 days of the test item was 0% (ThODNO3); the 10 day window criterion was not passed. Therefore, the test item is not considered to be readily biodegradable.

Executive summary:

The test chemical was investigated for its ready biodegradability in a manometric respirometry test over a period of 28 days according to the OECD Guideline for Testing of Chemicals No. 301 F: "Ready Biodegradability: Manometric Respirometry Test", adopted July 17, 1992 and the Commission Regulation 440/2008/EC, Method C.4-D of May 30, 2008: Manometric Respirometry Test (EEC Publication No. L 142/496, May 2008). The biodegradation was followed by the oxygen uptake of the microorganisms during exposure with a test item loading rate of 102 mg/L corresponding to an oxygen demand of about 195 mg/L (ThODNH4) and 255 mg/L (ThODNO3). As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. In the test flasks, containing the test item and activated sludge (inoculum), the mean biodegradation after 28 days of test item was 0% (ThODNO3); the 10 day window criterion was not passed.Therefore, the test item is not considered to be readily biodegradable. The reference item sodium benzoate was sufficiently degraded to 83% after 14 days and to 86% after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used. In the toxicity control containing both, the test item and the reference item sodium benzoate, 45% biodegradation was noted within 14 days and 56% biodegradation after 28 days of incubation. Thus, it can be assumed that the test item is not inhibitory to the aerobic activated sludge microorganisms.

Description of key information

The test item was investigated for its ready biodegradability in a manometric respirometry test over a period of 28 days according to the OECD Guideline for Testing of Chemicals No. 301 F: "Ready Biodegradability: Manometric Respirometry Test", adopted July 17, 1992 and the Commission Regulation 440/2008/EC, Method C.4-D of May 30, 2008: Manometric Respirometry Test (EEC Publication No. L 142/496, May 2008). The biodegradation was followed by the oxygen uptake of the microorganisms during exposure with a test item loading rate of 102 mg/L corresponding to an oxygen demand of about 195 mg/L (ThODNH4) and 255 mg/L (ThODNO3). As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. In the test flasks, containing the test item and activated sludge (inoculum), the mean biodegradation after 28 days of test item was 0% (ThODNO3); the 10 day window criterion was not passed.Therefore, the test item is not considered to be readily biodegradable. The reference item sodium benzoate was sufficiently degraded to 83% after 14 days and to 86% after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used. In the toxicity control containing both, the test item and the reference item sodium benzoate, 45% biodegradation was noted within 14 days and 56% biodegradation after 28 days of incubation. Thus, it can be assumed that the test item is not inhibitory to the aerobic activated sludge microorganisms.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Various experimental study have been reviewed to determine biodegradability of test chemical and their results are summarized below.

In first experimental study the test chemical was investigated for its ready biodegradability in a manometric respirometry test over a period of 28 days according to the OECD Guideline for Testing of Chemicals No. 301 F: "Ready Biodegradability: Manometric Respirometry Test", adopted July 17, 1992 and the Commission Regulation 440/2008/EC, Method C.4-D of May 30, 2008: Manometric Respirometry Test (EEC Publication No. L 142/496, May 2008). The biodegradation was followed by the oxygen uptake of the microorganisms during exposure with a test item loading rate of 102 mg/L corresponding to an oxygen demand of about 195 mg/L (ThODNH4) and 255 mg/L (ThODNO3). As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. In the test flasks, containing the test item and activated sludge (inoculum), the mean biodegradation after 28 days of test item was 0% (ThODNO3); the 10 day window criterion was not passed. Therefore, the test item is not considered to be readily biodegradable. The reference item sodium benzoate was sufficiently degraded to 83% after 14 days and to 86% after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used. In the toxicity control containing both, the test item and the reference item sodium benzoate, 45% biodegradation was noted within 14 days and 56% biodegradation after 28 days of incubation. Thus, it can be assumed that the test item is not inhibitory to the aerobic activated sludge microorganisms.

In next experimental study the test chemical was tested using a concentration of nominally 10 mg organic carbon/L (corresponding to 15.1 mg) in test medium following OECD 301B and GLP. Aniline was chosen as positive control. Activated sludge was used as inoculum (concentration in the test 30 mg dry matter/L). The test was left running for 28 days.

All validity criteria were met. Degradation of the positive control was 61 % after 9 days.

Abiotic degradation reached 2 %. Both replicates of the test item showed very good correspondence. As degradation in the toxicity flask was 29 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 15.1 mg/L".

The following data were determined for the test item :

10-day-window: day 15 – 25

degradation at the end of 10-day-window 65 %

degradation at the end of the test 77 %

pass level following guideline: 60% at the end of 10-day-window for pure substances

Ready degradability is defined in the guideline as degradation surpassing 60% within 10 days after reaching a level of 10%. Therefore, the test item can be considered as “readily biodegradable” following OECD 301B guideline. The degree of biodegradation reached 77 % after 28 days.

 

 

In another guideline study the test item was tested using a concentration of 15.2 mg /L of test item corresponding a carbon concentration of 10 mg/L in test medium following ISO 14593:2005, according to the OECD 310 guideline and following the GLP. Aniline was chosen as positive control. Activated sludge from a sewage treating plant was used as inoculum (concentration: 15 mg suspended solids/L). The test was left running for 28 days. All validity criteria were met. Degradation of the positive control was 72 % after 7 days.

The following data were determined for the test item :

10-day-window: day 12 - 22

degradation at the end of 10-day-window 72 %

degradation at the end of the test 76 %

 

According to the OECD guideline 310 the ready degradability is defined as degradation surpassing 60 % within 10 days after reaching a level of 10 %. Degradation at the end of the 10-day-window reached 72 %. Therefore, the test item can be considered as “readily biodegradable”

 

To support guideline study mentioned above experimental study was reviewed from authoritative database (J check, 2018) in this study the test chemical was subjected to biodegradation test by taking activated sludge as inoculums at 30 mg/L concentration. Biodegradation was analysed by using three parameters namely BOD, TOC and UV Vis. The initial concentration of test chemical was 100 mg/L. The percent degradation of test chemical was observed to be 0 % biodegradability by BOD parameter 12.1 % by GC parameter and 12.6 % by UV vis parameter by using activated sludge as inoculum in 28 days. On the basis of percent biodegradability it is concluded that test chemical is not readily biodegradable.

 

Another experimental study was reviewed from journal the Science of the Total Environment (1995) in this study the test chemical was tested for biodegradation at 30 mgC/l concentration by analyzing the decrease of DOC taking benzoic acid as a reference (standard) compound using inoculum obtained from synthetic sewage at concentration of 100 mgC/l using JIS BOD5 inorganic medium for 28 days in anaerobic condition less than 30% biodegradation ratio was obtained. So it is concluded that test chemical is not readily biodegradable.

 

Non biodegradability of test chemical was further supported by experimental study done by Battersby et al (1989) in this study the Biodegradation potential of test chemical was analysed under methanogenic conditions with an anaerobic digesting sludge as inoculums. The test chemical was taken at concentration 50 mg/L in a serum bottle containing 90% nitrogen and 10 % carbon dioxide in head space to maintain anaerobic condition at temperature 35 oC then gas production was measured weekly for more than 75 days with the help of hand held pressure meter. The theoretical gas production was corrected with the blank. The test chemical undergoes 9 % degradation in anaerobic condition in more than 75 days. On the basis of percent degradation it is concluded that this test chemical is not readily biodegradable.

 

Further , from journal Ecotoxicology and Environmental Safety experimental study has been reviewed in this study ,the Gerike et al (1981) done Biodegradation study for 30 days for evaluating the percentage biodegradability of test substance . The study was performed according to OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test).The percentage degradation of test substance was determined to be 1% by BOD parameter after 30 days. Thus, based on percentage degradation,test chemical is considered to be not readily biodegradable in nature.

 

By same author mentioned above one more study was done in this study Biodegradation experiment was conducted for 42 days for evaluating the percentage biodegradability of test substance . The study was performed according to other guideline “AFNOR T 90-302 Test”. The percentage degradation of test substance test chemical was determined to be 13 and 22% degradation by DOC removal parameter after 28 and 42 days.Thus, based on percentage degradation,test chemical is considered to be not readily biodegradable in nature.

 

Next study was reviewed from journal Water Pollution Control Federation (1978) in this study an experiment was performed to determine biodegradability of test chemical in this experiment two different inoculums were used first inoculums was waste water sludge obtained from primary settling tank of the city of Ithaca waste water treatment plant and another inoclum was soil Winds or loamy fine sand. The soil, kept under refrigeration until use was made up as 1 % suspension in medium, stirred allowed settling and aliquots were used. Culturing apparatus used was 160 mL milk dilution bottles with screw caps. In these bottles medium was added contained potassium phosphate, calcium chloride, zinc sulphate, ferric chloride, magnesium sulphate, sodium molybadate etc the pH of medium was 7.3 test material was added at concentration 16 mg/L then it was inoculated with both the inoclums waste water sludge and soil separately then Bottles were shaken at 30 oC. The bottle contents were examined for presence of test material using recording spectrophotometer (BecKman Acta M VI) spectra were run in range of 200-340 nm against water blank and compared with inoculated substrate free control with reference spectra of compound. After analysis it was observed that test chemical is not biodegradable in greater than 25 days for both the inoculums used.

 

Last experimental study was reviewed from Water Research journal (1976) in this study the Biodegradation experiment was performed in batch system using adapted activated sludge as inoculums. Activated sludge was obtained from sewage plant then it is adapted for 20 days with the test chemical in biological medium containing Glucose peptone etc. After activated sludge get adapted concentration of test chemical was increased upto 200 mg/L and then biodegradation was observed for test chemical. Test chemical was the only source of organic carbon. All adaption process and degradation process was taken place in dark room at 20 oC. Experiment was carried out till there is no decrease of COD. Inoculum blank flask was also set up simultaneously. Sampling was done at definite time interval 50-80 mL sample was taken for analyzing COD. The experiment is carried out till there is no decrease of COD. After that time the total percentage of COD removed (% degradation) and the rate of degradation are evaluated. Percent biodegradability of test chemical observed to be 90.5 % by COD (Organic Carbon) and rate of degradation was 10.6 mg COD /g/L per hour. Thus it is concluded that test chemical is readily biodegradable.

 

By considering results of all the studies mentioned above seven studies are showing that test chemical is not readily biodegradable in this one is experimental report and biodegradability study was done by using test guideline OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) and others are detailed studies of klimsch rating 2 from various journals on other hand only three studies are showing that test chemical is readily biodegradable. Therefore on the basis of maximum number of studies it can be concluded that test chemical is not readily biodegradable.