Bis(2-ethylhexyl) 2-(4-hydroxy-3,5-dimethoxybenzylidene)malonate

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:

2004-10-26 to 2005-01-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 17 July 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

31 July 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Species: activated sludge, micro organisms from a domestic waste water treatment plant.
Origin: supplied by the sewage plant Groß-Zimmern, Germany
Conditioning: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and again centri¬fuged. This procedure was repeated twice. 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 slud ge suspension, corresponding to 1.5 g dry material per litre were mixed with test water and then aerated until use.

Duration of test (contact time):

28 d

Initial conc.:

ca. 100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Preparation of test solutions

Test Item (flasks 1 and 2): 25.6 mg (flask 1) and 25.2 mg (flask 2) test item and activated sludge were filled up with test water to a volume of 244 mL (activated sludge final concentration: 30 mg suspended solids per litre).

Inoculum Control (flasks 3 and 4): Activated sludge was filled up with test water to a volume of 244 mL (activated sludge final concentration: 30 mg suspended solids per litre). The inoculum control was also used for other projects which ran in parallel.

Procedure Control (flask 5): 25.4 mg Aniline and activated sludge were filled up with test water to a volume of 244 mL (activated sludge final concentration: 30 mg suspended solids per litre). The procedure control was also used for other projects which ran in parallel.

Abiotic Control (flask 6): 25.6 mg test item filled up with test water (sterile filtered, 0.2 - 0.45 p.m filter) to a volume of 244 mL.

Toxicity Control (flask 7): 24.9 mg test item, 25.3 mg Aniline and activated sludge were filled up with test water to a volume of 244 mL (activated sludge final concentration: 30 mg suspended solids per litre).


Test unit: Manometric Test System with test flasks containing a volume of 500 mL .

Identification: Each test unit was uniquely identified with the study number. treatment and replicate number.

Conditions: climate chamber, dark, 21.6-21.8°C, initial pH 7.6

Incubation: The closed test flasks were incubated in a climatic chamber under continuous stirring. The consumption of oxygen was determined by measuring the change of pressure in the flasks. Evolved carbon dioxide was absorbed in an aqueous solution (45 %) of potassium hydroxide.

Flask preparation.: The amounts of test item and reference item were directly weighed into the test flasks. No emulsifiers or solvents were used, but the solutions were dispersed by stirring to achieve a homogeneous solution of the test item.

Duration: 28 days

Measurement of Oxygen: The change of pressure in the test flasks was measured by means of a manometric method (BSBIBOD-Sensor-System, Aqualytic, 63231 Neu lsenburg, Germany) each day.

Temperature: Temperature was measured each working day in the climatic chamber.

pH-Value: pH-values were measured in all flasks at the start and end of the test using a pH-electrode WTW pH 340i.

Reference substance:

aniline

Test performance:

Biodegradation of Aniline: 87 % after 14 days, 98 % after 28 days, based on ThODNH4.
If nitrification is considered (ThODNO3): 68% after 14 days, 76% after 28 days

Biodegradation in the Toxicity Control: 50% after 14 days, 55% after 28 days
If nitrification is considered (ThODNO3): 44% after 14 days, 48% after 28 days

Parameter:

% degradation (O2 consumption)

Value:

2

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

4

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

3

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

4

Sampling time:

28 d

Results with reference substance:

69 % degradation after 7 d, 87 % degradation after 14 d, 97 % degradation after 21 d, 98 % degradation after 28 d

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Under the test conditions the biodegradation of the test item reached 4% after 28 days of incubation. Therefore, the test item is considered to be not readily biodegradable.

Executive summary:

Purpose
The purpose of this assay was to provide information on the biodegradability of the test item in aqueous environment and thus serve as a rational basis for risk assessment for environmental fate in aqueous compartments.

Study Design
The test was conducted according to the OECD Guideline for Testing of Chemicals "Ready Biodegradability : 301F.

Results

The reference item aniline was sufficiently degraded to 87 % after 14 days, and to 98 % after 28 days of incubation, based on ThODNH4. If nitrification is considered (ThODNO3), aniline was degraded to 68% after 14 days and 76% after 28 days of incubation.
The pass level of 40% on day 7 (criterion: </= 7 days) and the pass level of 60 % on day 14 (criterion </= 14 days) was met confirming  the suitability of the used activated sludge inoculum.

In the toxicity control containing both, the test item and the reference item aniline 50 % biodegradation was noted within 14 days and 55 % biodegradation was determined after 28 days of incubation based on ThODNH4. If nitrification is considered (ThODNO3), the degradation rate in the toxicity control was 44% after 14 days and 48% after 28 days of incubation. According to the test guidelines the test item can be assumed to be not inhibitory on the activated sludge micro organisms because degradation was > 25 % within 14 days

The following data were determined for the test item:
10-day window: failed
Degradation after 28d: 4 %
The test item is therefore considered not to be readily biodegradable.

Conclusion
The degradation of the test item did not reach 60 % within the 10 -day window and after 28 days of incubation a degradation of 4 % was observed. Therefore, the test item is considered to be not readily biodegradable.  

Reference 2

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013-09-05 to 2014-03-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 C (Inherent Biodegradability: Modified MITI Test (II))

Version / remarks:

adopted 1981

Deviations:

no

GLP compliance:

yes

Remarks:

China GLP

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

Activated sludge, surface soil and surface water were sampled from 10 sites distributed in 4 districts throughout Nanjing city/China.
1 Liter of the sludge, soil and water were collected and mixed thoroughly together. After removing floating matter, the mixture was allowed to stand and then the supernatant was filtrated. After that the filtrate was adjusted to pH 7.0 with sodium hydroxide or phosphoric acid. Finally an appropriate volume of the filtered supernatant was transferred to a fill-and-draw activated sludge vessel and aerated for about 23.5 h.
Thirty minutes after stopping the aeration, about one third of the whole volume of supernatant was discarded. Then an equal volume of the solution (pH 7.0) containing 0.1% each of glucose, peptone and potassium orthophosphate was added into the settled material and aerated again. This procedure was repeated once per day during one month.
Before use the mixture was allowed to stand, and the supernatant was removed. A small quantity of sludge was taken to be centrifuged (10000 rpm×10 min) and then weighed. Then the sludge was dried in the oven and weighed again in order to calculate the content of dry sludge was 10%. At last 10 g of centrifuged sludge was diluted 1 L with basal culture medium (BSM) to get activated sludge suspension with a concentration of 1000 mg/L (dry basis).

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

test mat. analysis

Reference substance:

benzoic acid, sodium salt

Test performance:

The validity of the study was demonstrated: The biodegradation of sodium benzoate was 74.4% after 7 days (> 40%) and 80.4% after 14 days (> 65%). In addition, the recovery rate of the test compound in the abiotic control was 81% (> 10%). According to the specifications of OECD 302C, the study is considered to be valid.

Parameter:

% degradation (O2 consumption)

Value:

8.11

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

15.4

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

24

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

30

Sampling time:

28 d

Details on results:

The degradation of the test substance based on analytical results was 26.8% after 28 days.

Results with reference substance:

The biodegradation of the reference substance (sodium benzoate) was 74.4% after 7 days (> 40%) and 80.4% after 14 days (> 65%).

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

Based on the results of this study, the test item was shown to be inherent biodegradable.

Executive summary:

An inherent biodegradation test (modified MITI test (II)) was performed with the item according to“The guidelines for the testing of chemicals”(HJ/T 153-2004), “The guidelines for the testing of chemicals” (SEPA.:Environmental Sciences Press. 2004), and OECD Guideline No. 302C of the ‘Guidelines for Testing of Chemicals’ of the OECD: “Inherent Biodegradability: Modified MITI Test (II)” (adopted 1981).Test solutions were prepared in an inorganic salts medium, inoculated with a number of microorganisms collected from10 places in Nanjing city.During the test, the temperature was kept at (25±1) ºC. The test was valid because the level of biodegradation of the reference substance sodium benzoate was 74.4% after 7 days (> 40%), and 80.4% after 14 days (> 65%), and recovery rates of residual amount of the test compound in the “abiotic” test is found to be more than 10% after 28 days.

Based on chemical analysis, biodegradation of the test substance was 26.8% during the testing period. The BOD results showed that biodegradation ofthe test item was 30.0%（> 20%）after 28 days. Based on the results of this study, the test item was shown to be inherent biodegradable.

Description of key information

Two screening studies on biodegradation are available for the substance. Based on a manometric respirometry test, the substance is considered to be not readily biodegradable. However, the substance is inherent biodegradable based on a modified MITI test (II).

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater