2-(2,4-diaminophenoxy)ethanol dihydrochloride

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:

From 2013-06-28 to 2014-11-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: I61119
- Expiration date of the lot/batch: 2014-02-04
- Purity test date: no data

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature, dark

TREATMENT OF TEST MATERIAL PRIOR TO TESTING no

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): Activated sludge from the sewage plant at Hildesheim, which is well suited as it receives predominantly municipal sewage and hardly any industrial chemical waste. 31137 Hildesheim, Germany. receipt the 2013-08-02

- Preparation of inoculum for exposure: the activated sludge was washed twice with chlorine free tap water. After the second washing the settled sludge was resuspended in mineral salts medium and was maintained in an aerobic condition by aeration for 2 hours. Thereafter the sludge was homogenized with a blender. The supernatant was ecanted and maintained in an aerobic condition by aeration with CO2 free air until test start. 10 mL of this mixture were used to initiate inoculation.

- Initial cell/biomass concentration: Approx. 10E+7 - 10E+8 CFU/L in the test vessel.

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

test mat.

Initial conc.:

12 mg/L

Based on:

TOC

Initial conc.:

0.4 other: mg C/mg

Based on:

TOC

Initial conc.:

1.47 other: mg CO2/mg test item

Based on:

ThCO2

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral salt medium according to 301B/CO2 evolution test
- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: actual measured: 21-24°C
- pH: pH values on day 28 (prior to acidification): inoculum control: 7.63-7.64; functional control: 7.7; test item: 7.52; toxicity control: 7.56
- pH adjusted: no
- Aeration of dilution water: 30-100 mL/min
- Continuous darkness: no, but low light conditions (brown glass bottles)
- Other: continuous stirring

TEST SYSTEM
- Culturing apparatus: 5000 mL, brown glass; volume of the test medium: 3000 mL
- Number of culture flasks/concentration: 2 for the test item concentration, 1 for the functional control, 2 for the inoculum control and 1 for the toxicity control.
- Method used to create aerobic conditions: aeration
- Measuring equipment: pH-meter, digital buret
- Test performed in closed vessels due to significant volatility of test substance: no
- Test performed in open system: yes
- Details of trap for CO2 and volatile organics if used: the vessels were aerated for 24 hours with CO2 free air. After 24 H the CO2 adsorption vessels were connected to the air outlets of the incubation vessels via a series of 3 gas wash bottles, each containing 100 mL of a 0.0125 mol/L Ba(OH)2 solution.

SAMPLING
- Sampling frequency: Back titration of the residual Ba(OH)2 with 0.05N HCl was carried out three times a week during the first 10 days and thereafter twice weekly. On day 28, 1 mL 37% HCl was added to each of the vessels. Aeration was continued for further 24H and the quantity of CO2 released was determined. 12 measurements.
- Sampling method: /
- Sterility check if applicable: /
- Sample storage before analysis: at room temperature, dark

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2
- Abiotic sterile control: 0
- Toxicity control: 1
- Other: 1 functional control

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

> 0 - < 1

Sampling time:

28 d

Details on results:

The adaptation phase of the functional control changed after 3 days into degradation phase (degradation >=10%). The course of the degradation was rapid and the functional control reached the pass level of 60% after 10 days and a biodegradation of 70% after 28 days. The validity criterion degradation >=60% after 14 days is fulfilled.
In the toxicity control containing both test and reference item a biodegradation of 33% was determined within 14 days and remained at 33% until test end. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.
For the test item, the mean 10% level (beginning of biodegradation) was not reached until test end.
In the inoculum control the total CO2 production was 39.8 mg CO2/L after 28 days.

Results with reference substance:

The adaptation phase of the functional control changed after 3 days into degradation phase (degradation >=10%). The course of the degradation was rapid and the functional control reached the pass level of 60% after 10 days and a biodegradation of 70% after 28 days. The validity criterion degradation >=60% after 14 days is fulfilled.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Under the test conditions the test item is classified as not readily biodegradable in the 10-day-window and within 28 days.

Executive summary:

The ready biodegradability of the test item was determined with a non-adapted activated sludge over a test period of 28 days in the modified Sturm test (OECD 301B, under GLP). The test item was tested at a concentration of 30 mg/L with 2 replicates, corresponding to a carbon content (TOC) of 12.0 mg C/L in the test vessels. The test vessels were incubated at low light conditions and at a temperature of 21 -24°C. The biodegradation of the test item was followed by titrimetric analysis of the quantity of CO2 produced by respiration of bacteria. The percentage CO2 production was calculated in relation to the theoretical CO2 production (ThCO2) of the test item. Functional and toxicity controls were used. All passed the validity criteria. The biodegradation of the test item showed that the mean 10% level (beginning of the biodegradation) was not reached until test end. The mean biodegradation remained in the range 0 -1% until test end. Under the test conditions the test item is classified as not readily biodegradable in the 10-day-window and within 28 days.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2017-06-26 to 2018-02-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

yes

Remarks:

Temperature range was 19.4 – 21.6 °C instead of 20.0 – 24.0 °C. As degradation of the positive control was in the normal range, this is considered as uncritical concerning the outcome of the study.

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

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): The sludge was collected from the aeration basin of the sewage treatment plant, Maxeville WWTP, 54320, France, 1 day before the start of the test.
Date of collection: 24. Aug. 2017, batch no: 20170824.
- Pretreatment: The same day of the collection, the pre-treatment of the activated sludge was performed. The sludge was washed by threefold centrifugation for 10 minutes at 1100 x g. After centrifugation the supernatant was removed and the sludge was resuspended in mineral medium and after the third centrifugation filtrated using a stainless steel sieve (100 μm diameter). It was then aerated. The dry matter was determined as 3020 mg suspended solids/L.
- Concentration of sludge: 30 mg dry matter/L

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

other: organic C (calculated)

Initial conc.:

25.7 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: The medium was prepared from the stock solutions. The stock solution of the positive control was prepared and its DOC was measured. The inoculum was taken from its source, washed, aerated and the dry matter was determined.
The test vessels were filled with medium and inoculum. Then, all flasks were aerated for 72 hours with purified, CO2-free, moistened air to purge the system of CO2.
The medium was freshly prepared.
Composition:
Solution a 10 mL
Solution b 1 mL
Solution c 1 mL
Solution d 1 mL
H2O demin. ad 1000 mL
Solution a:
Potassium dihydrogenephosphate (KH2PO4) 8.5 g
Di-potassium hydrogenephosphate (K2HPO4) 21.75 g
Di-sodiumhydrogenephosphate dihydrate (Na2HPO4*2H2O) 33.4 g
Ammonium chloride (NH4Cl) 0.5 g
H2O demin. ad 1000 mL
The pH was 7.4
Solution b:
Calcium chloride dihydrate (CaCl2*2H2O) 27.5 g
H2O demin. ad 1000 mL
Solution c:
Magnesium sulfate heptahydrate (MgSO4*7H2O) 22.5 g
H2O demin. ad 1000 mL
Solution d:
Iron(III) chloride hexahydrate (FeCl3*6H2O) 0.25 g
Di-sodium-ethylendiamintetraacetate dihydrate (Na2EDTA*2H2O) 0.4 g
H2O demin ad 1000 mL

- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: 19.4 – 21.6 °C
- pH: at day 28, pH ranged from 6.7 (abiotic control) to 7.4 (blanck control); test flask: 7.2
- pH adjusted: no
- Aeration of dilution water: all flasks were aerated for 72 hours
- Suspended solids concentration: The dry matter was determined as 3020 mg suspended solids/L.
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2000 mL-SCHOTT-flasks were used as test vessels, 100 mL scrubber flasks as absorbent vessels.Test volume: 1500 mL
- Number of culture flasks/concentration:
Test flasks: 2, containing test item, mineral medium and inoculum, 2 additional replicates for COD determination (under non-GLP conditions)
- Method used to create aerobic conditions: The test vessels were aerated with purified (by activated charcoal), CO2-scrubbed, moistened air. The scrubbing of carbon dioxide was achieved by bubbling the purified air through a flask containing 1.5 M NaOH. To control the absence of CO2, the air was then led through a flask containing a solution of Ba(OH)2 before reaching the test vessels.
- Measuring equipment: Analyses of the emitted CO2 were made by IC measurement using the carbon analyser TOC multi N/C 2100S, Analytik Jena. Each sample was measured in duplicate or triplicate, respectively (depending on the variation between the measured values). The carbon analyser was calibrated with freshly prepared reference solutions containing potassium hydrogen phthalate (TC), sodium hydrogen carbonate and sodium carbonate (IC) every month. After every start, quality control samples were measured.
- Details of trap for CO2 and volatile organics if used: The emitted CO2 was trapped in 0.25 M NaOH. Two scrubbers containing 100 mL each were connected in series to the test vessels.
- Other: Magnetic stirrers were used to prevent deposition of inoculum.

SAMPLING
- Sampling frequency: From each front scrubber flask, 10 samples were taken in order to determine the emitted CO2 (on day 0, 2, 4, 7, 9, 11, 14, 18, 23 and 29). On day 28, 5 mL HCl 2 M was added to each test flask in order to drive off dissolved CO2. On day 29, samples from both scrubber flasks were taken.
- Sampling method: The sample volume was 1 mL. The resulting change in the volume of the front flask was considered in the calculation of emitted CO2.
- Sterility check if applicable: no
- Sample storage before analysis: no

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 (+2 for COD determination)
- Abiotic sterile control: 1
- Toxicity control:1
- Other: positive control flasks: 2; apparatus blanck (containing mineral medium only): 2

Reference substance:

aniline

Key result

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

28 d

Details on results:

Degradation behaviour of positive control and toxicity control was normal. Both replicates of the test item showed very good correspondence.
As degradation in the toxicity flask was 42.3 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 25.7 mg/L”.
Because the test item is water soluble, the COD could be related to the concentration of dissolved organic carbon (DOC) in the test solutions. However, this is only the case if no precipitation and no adsorption has taken place because COD is determined in unfiltered solutions. The COD values in the test flasks were scattering but until the end of the test in a similar range. That means no DOC elimination had taken place. This was in agreement with the missing biodegradation of the test item based on measurement of the emitted CO2.

Results with reference substance:

Degradation of the positive control was 73 % after 9 days.

Degradation values in %

Day	Positive Control 1	Positive Control 2	Positive Control Mean	Test 1	Test 2	Test Mean	Abiotic Control	Toxicity Control
2	-2.1	-1.6	-1.8	-5.6	-1.4	-3.5	1.2	-0.9
4	12.4	19.4	15.9	-4.2	1.5	-1.3	1.6	6.1
7	51.0	60.1	55.6	-5.1	0.4	-2.3	1.5	24.8
9	67.3	77.6	72.5	-2.9	2.9	0.0	0.8	34.6
11	77.3	84.5	80.9	-3.9	2.1	-0.9	-0.1	38.9
14	85.6	87.5	86.6	-6.6	2.5	-2.0	0.4	42.3
18	93.5	90.9	92.2	-3.4	4.3	0.5	-0.9	47.3
23	91.1	85.5	88.3	-5.8	0.0	-2.9	-1.9	43.9
29	96.6	90.1	93.3	-5.3	-1.0	-3.2	-4.6	48.1

 

Validity criteria fulfilled:

yes

Remarks:

IC content of test item solution in medium: 0% (should be <=5% of TC). CO2 emitted by the controls: 12.9 mg/L (should be <70 mg/L). Difference within replicates: 4.3 % (should be <=20%). Degradation of positive control > 60%: 9 days (should be <=14d).

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

No biodegradation was measured until day 28. The test item can be considered as “not readily biodegradable”.

Executive summary:

The test item was tested using a concentration of nominally 10 mg organic carbon/L (corresponding to 25.7 mg test item/L) in test medium according to OECD 301B and EU Method C.4-C, and following GLP.

Activated sludge was used as inoculum (concentration in the test 30.0 mg dry matter/L). The test was left running for 28 days. All validity criteria were met.

Aniline was chosen as positive control. Degradation of the positive control was 73 % after 9 days.

The following data were determined for the test item :

10-day-window: not detected

degradation at the end of 10-day-window: none

degradation at the end of the test: none

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

Therefore, regardless of the 10-day-window, the test item is not readily biodegradable following OECD 301B and EU C.4-C respectively.

Reference 3

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2017-06-26 to 2018-02-06

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

Temperature range was 19.6 – 22.2 °C instead of 20.0 – 25.0 °C. As degradation of the positive control was in the normal range, this is considered as uncritical concern-ing the outcome of the study.

Qualifier:

according to guideline

Guideline:

EU Method C.9 (Biodegradation: Zahn-Wellens Test)

Deviations:

yes

Remarks:

The composition of the medium is taken from OECD Guideline. As in EU-Method C.9, a different composition is stated, this is stated as a deviation from the EU-Method. For pH adjustment HCl was used instead of H2SO4.

GLP compliance:

yes (incl. QA statement)

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): The sludge was collected from the aeration basin of the sewage treatment plant, Maxeville WWTP, 54320, France, 1 day before the start of the test.
Date of collection: 19. Jul. 2017, batch no: 20170719
- Pretreatment: The sludge was washed by threefold centrifugation for 10 minutes at 1100 x g. After centrifugation, the supernatant was removed and the sludge was resuspended in mineral medium and after the third centrifugation filtrated using a stainless steel sieve (100 μm diameter). It was then continuously aerated until usage.
The dry matter was determined as 2880 mg suspended solids/L.
- Concentration of sludge: 800 mg dry matter/L

Duration of test (contact time):

28 d

Initial conc.:

200 mg/L

Based on:

DOC

Initial conc.:

500 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium:
The medium was freshly prepared (volumes were adapted to final volume needed in the test).
Composition:
Solution a 10 mL
Solution b 1 mL
Solution c 1 mL
Solution d 1 mL
H2O demin ad 1000 mL
Solution a:
Potassium dihydrogen phosphate (KH2PO4): 8.5 g
Dipotassium hydrogen phosphate (K2HPO4): 21.75 g
Disodium hydrogenphosphate dihydrate (Na2HPO4*2H2O): 33.4 g
Ammonium chloride (NH4Cl): 0.5 g
H2O demin. ad 1000 mL
The pH was 7.4.
Solution b:
Calcium chloride (CaCl2): 27.5 g
H2O demin ad 1000 mL
Solution c:
Magnesium sulphate heptahydrate (MgSO4*7H2O): 22.5 g
H2O demin ad 1000 mL
Solution d:
Iron(III) chloride hexahydrate (FeCl3*6H2O): 0.25 g
Disodium ethylene-diaminetetraacetate dihydrate (Na2EDTA*2H2O): 0.4 g
H2O demin: ad 1000 mL

- Additional substrate: no
- Test temperature: 19.6 – 22.2 °C
- pH: in test item flask, pH varied from 6.6 to 7.9 during the 28d.
- pH adjusted:pH was measured at each sampling time and, if necessary, adjusted to pH 7.0 ± 1.0
- Aeration of dilution water: For aeration, glass tubes which reach to 2 cm above the bottom of the respective flask, were used. The air was purified by activated charcoal and moistened. An orbital shaker was used for shaking.
- Suspended solids concentration: The dry matter was determined as 2880 mg suspended solids/L.
- Continuous darkness: yes, without direct lighting


TEST SYSTEM
- Culturing apparatus: Erlenmeyer flasks (nominal volume 2000 mL), test volume: 1500 mL
- Number of culture flasks/concentration:
2 test item flasks (test item + inoculum)
2 positive control flasks (aniline + inoculum)
2 blanck control flasks (inoculum)
1 abiotic degradation flask (test item +10 mL/L HgCl2 (100 mg/L))
1 adsorption control flask (test item +10 mL/L HgCl2 (100 mg/L) + inoculum)
1 toxicity flask (test item + aniline)

- Method used to create aerobic conditions: For aeration, glass tubes which reach to 2 cm above the bottom of the respective flask, were used. The air was purified by activated charcoal and moistened.
- Measuring equipment: Measurement of DOC was performed using a TOC multi N/C 2100S, Analytik Jena. The carbon analyser was calibrated with freshly prepared reference solutions containing potassium hydrogen phthalate (TC), sodi-um hydrogen carbonate and sodium carbonate (IC) every month. After every start, quality control samples were measured.

SAMPLING
- Sampling frequency and method: From each flask, samples of 2 mL were taken before addition of the inoculum and after 3 hours and on day 1, 2, 3, 4, 5, 6, 7, 14, 21, 27 and 28. The samples were membrane fil-trated and the DOC was measured.
- Sterility check if applicable: no
- Sample storage before analysis: no

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2
- Abiotic sterile control: 1
- Toxicity control: 1
- Other: 2 blanck control flasks, 1 abiotic degradation flask, 1 adsorption control flask

Reference substance:

aniline

Key result

Parameter:

% degradation (DOC removal)

Value:

84

Sampling time:

28 d

Details on results:

The degree of biodegradation reached 84 % after 28 days. Both test replicates showed very good correlation of the degradation parameters.
The lag phase started immediately on day 0 (graphic evaluation).
A plateau of degradation was reached on day 14.
The pass level of 70 % degradation was reached on day 6
The degradation in the toxicity flask was 89 % at the end of the test. The test item can be stated as “not toxic towards the inoculum in a concentration of 500.7 mg/L”.
Abiotic degradation reached 30 % at the end of the test. Belated DOC elimination in the abiotic control might be caused by precipitation of dissolved test item or volatilisation of test item.
The adsorption control reached 86 % degradation at the end of the test Degradation after 3 hours reached 8.0 % in the test vessels and 5.7 % in the adsorption control. DOC elimination in the adsorption control was based by on adsorption of the test item onto the inoculum or on other abiotic processes (as for example precipitation resulting from reaction with HgCl2). That means DOC elimination in the test vessels might be also caused by adsorption or precipitation effects and not only by biodegradation. DOC elimination in the test replicates was higher than in the adsorption control until day 14. This should indicate that DOC elimination was partly caused by biodegradation.

Results with reference substance:

99 % after 5 days

The calculated degradation values are presented in the following table.

Table9.2‑a     Calculated Degradation in %

Day	Positive Control			Test Item			Abiotic	Adsorp. Control	Toxicity
	1	2	Mean	1	2	Mean
1	6.0	6.4	6.2	33.1	36.3	34.7	3.4	20.9	21.9
2	15.1	15.9	15.5	49.7	50.4	50.1	5.1	33.6	32.9
3	22.4	22.8	22.6	57.4	57.6	57.5	6.5	42.2	39.3
4	35.9	38.9	37.4	63.1	61.4	62.3	9.8	46.9	45.1
5	98.6	98.6	98.6	67.3	65.4	66.4	7.6	51.1	49.2
6	98.4	97.1	97.8	71.5	70.0	70.8	13.4	59.4	56.8
7	98.1	98.2	98.2	77.0	76.6	76.8	12.9	68.4	67.5
14	101.0	100.4	100.7	82.3	81.4	81.8	19.2	79.6	87.5
21	100.9	100.8	100.8	84.8	83.1	84.0	22.0	83.1	87.7
27	97.4	94.9	96.2	85.8	84.3	85.1	32.2	85.3	89.0
28	96.3	96.2	96.3	84.4	82.8	83.6	29.6	85.8	88.8

 

Table9.2‑b     Calculated Degradation in %

For the test flasks and the adsorption control additional the degradation after 3 h was calculated. The values in the test replicates ant the adsorption control was in the same range.

Time	Test Item			Adsorp. Control
	1	2	Mean
3 hour	9.2	6.9	8.0	5.7

 

 

Validity criteria fulfilled:

yes

Remarks:

Degradation of positive control > 70%: 99% after 5d (should be <=14d)

Interpretation of results:

other: Abiotic processes may also have been responsible for the DOC disappearance.

Conclusions:

The degree of biodegradation reached 84 % after 28 days. Both test replicates showed very good correlation of the degradation parameters. After 6 days 70 % was reached.
The degradation in the toxicity flask was 89 % at the end of the test. The test item can be stated as “not toxic towards the inoculum in a concentration of 500.7 mg/L”.
Abiotic degradation reached 30 % at the end of the test. Belated DOC elimination in the abiotic control might be caused by precipitation of dissolved test item or volatilisation of test item.
The adsorption control reached 86 % degradation at the end of the test Degradation after 3 hours reached 8.0 % in the test vessels and 5.7 % in the adsorption control. DOC elimination in the adsorption control was based by on adsorption of the test item onto the inoculum or on other abiotic processes (as for example precipitation resulting from reaction with HgCl2). That means DOC elimination in the test vessels might be also caused by adsorption or precipitation effects and not only by biodegradation. DOC elimination in the test replicates was higher than in the adsorption control until day 14. This should indicate that DOC elimination was partly caused by biodegradation.

Executive summary:

The purpose of the study was to determine the aerobe inherent biodegradability of the test item in the Zahn-Wellens following OECD 302B (resp. EU C.9) and GLP. The test item was tested using a concentration of nominal 200 mg organic carbon/L. Activated sludge from a sewage treatment plant (Maxeville WWTP, 54320, France) was used as inoculum (concentration 800 mg dry matter/L). The test was left running for 28 days. To measure the degradation of test item and positive control, the content of dissolved organic carbon (DOC) in the test vessels was measured 12 times during the test. All validity criteria were met.

Aniline was chosen as positive control. Degradation of the positive control was 99 % after 5 days.

The following data could be determined for the test item :

degradation at the end of the test: 84 %

lag-phase: day 0–day 1

end of degradation phase: day 14

pass level of 70% degradation: day 6

The degree of biodegradation reached 84 % after 28 days. Both test replicates showed very good correlation of the degradation parameters. After 6 days 70 % was reached.

The degradation in the toxicity flask was 89 % at the end of the test. The test item can be stated as “not toxic towards the inoculum in a concentration of 500.7 mg/L”.

Abiotic degradation reached 30 % at the end of the test. Related DOC elimination in the abiotic control might be caused by precipitation of dissolved test item or volatilisation of test item.

The adsorption control reached 86 % degradation at the end of the test Degradation after 3 hours reached 8.0 % in the test vessels and 5.7 % in the adsorption control. DOC elimination in the adsorption control was based by on adsorption of the test item onto the inoculum or on other abiotic processes (as for example precipitation resulting from reaction with HgCl2). That means DOC elimination in the test vessels might be also caused by adsorption or precipitation effects and not only by biodegradation. DOC elimination in the test replicates was higher than in the adsorption control until day 14. This should indicate that DOC elimination was partly caused by biodegradation.

Description of key information

Three GLP tests were conducted on the test substance. Two following the OECD 301B guideline and one following the OECD 302B guideline.

In the OECD 301B test, the test item was tested using a concentration of nominally 10 and 12 mg organic carbon/L in test medium. Functional and toxicity controls were used. All validity criteria were met. The biodegradation of the test item showed that the mean 10% level (beginning of the biodegradation) was not reached until test end. The mean biodegradation remained in the range 0 -1% until test end. Under the test conditions the test item is classified as not readily biodegradable in the 10-day-window and within 28 days

In the OECD 302B test, the test item was tested using a concentration of nominal 200 mg organic carbon/L (500.7 mg/L of test substance). To measure the degradation of test item and positive control, the content of dissolved organic carbon (DOC) in the test vessels was measured 12 times during the test. All validity criteria were met. Degradation of the positive control was 99 % after 5 days. The degree of biodegradation reached 84 % after 28 days. Both test replicates showed very good correlation of the degradation parameters. After 6 days 70 % was reached. The degradation in the toxicity flask was 89 % at the end of the test. The test item can be stated as “not toxic towards the inoculum in a concentration of 500.7 mg/L”. Abiotic degradation reached 30 % at the end of the test. DOC elimination in the adsorption control was based by on adsorption of the test item onto the inoculum or on other abiotic processes (as for example precipitation resulting from reaction with HgCl2). That means DOC elimination in the test vessels might be also caused by adsorption or precipitation effects and not only by biodegradation. DOC elimination in the test replicates was higher than in the adsorption control until day 14. This should indicate that DOC elimination was partly caused by biodegradation.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

[Type of water: freshwater]