4,4'-bis(chloromethyl)-1,1'-biphenyl

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:

21 April 2016 to 19 May 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source: Provided by sponsor
- Batch/Lot Number: 150701
- Expiration date of the lot/batch: 14 July 2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Controlled Room Temperature (15-25 °C), protected from humidity, under inert gas.

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): The secondary effluent was supplied from the sewage plant for domestic sewage in Veszprém, Hungary.
- Preparation of inoculum for exposure: The secondary effluent used for this study was allowed to settle for 40 minutes, then the decanted effluent was aerated until use (not later than an hour).

Duration of test (contact time):

28 d

Initial conc.:

2.9 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Adequate amount of the stock solutions a) - d) were combined and filled up with deionised water to the appropriate final volume (ratio of composition referring to 1 mL of the stock solutions a - d filled up with deionised water to a final volume of 1000 mL).
- Stock solutions: In deionised water, analytical grade salts were added to prepare the following stock solutions:
a: KH2PO4 = 2.125 g, K2HPO4 = 5.4375 g, Na2HPO4 x 12H2O = 16.795 g, NH4Cl = 0.125 g and deionised water to 250 mL.
b: MgSO4 x 7 H2O = 5.625 g and deionised water to 250 mL
c: CaCl2 x 2 H2O = 9.10 g and deionised water to 250 mL
d: FeCl3 x 6 H2O = 0.25 g and deionised water to 1000 mL
- Additional substrate: No
- Test temperature: 22 ± 2 °C. Temperature was measured continuously and registered on weekdays.
- pH: 7.32
- pH adjusted: No
- Aeration of dilution water: The test medium was aerated for 20 minutes and allowed to stand for about 20 hours at the test temperature.
- Continuous darkness: Yes
- Other: The oxygen concentration of test water was 8.9 mg/L at the start of the test.

TEST SYSTEM
- Culturing apparatus: BOD bottles (300 mL) with special neck and glass stoppers. BOD flasks was cleaned with 5 - 10 mL of a wash liquid (2.5 g iodine and 12.5 g potassium iodide per litre of 1 % w/v sulphuric acid) by shaking well to coat the bottle walls. After allowing to stand for 15 minutes, the wash liquid was poured off, and the bottles were thoroughly rinsed with tap water and deionised water. Then, the previously described test solutions were filled into the bottles bubble-free until the bottles were completely filled. Then they were tightly closed with glass stoppers.
- Number of culture flasks/concentration: 10 bottles
- Method used to create aerobic conditions: Test medium was aerated prior to use.
- Measuring equipment: The oxygen concentrations were measured with an oxygen meter with a stirring O2 electrode.
- Test performed in closed vessels: Yes

SAMPLING
- Sampling frequency: Oxygen measurements were performed in duplicate on days 0, 7, 14, 21 and 28.
- Sampling method: The oxygen concentrations were measured with an oxygen meter with a stirring O2 electrode.


CONTROL AND BLANK SYSTEM
- Inoculum blank: 10 bottles containing inoculum only.
- Toxicity control: 10 bottles containing the test item, reference item and inoculum.
- Procedure control: 10 bottles containing the reference item and inoculum.

STATISTICAL METHODS:
- Calculation of BOD
The BOD (mg O2 per mg test material) expected after each period was calculated as follows:

BOD = (mg O2/L of test and/or reference material - mg O2/L of control) / mg test and/or reference material/L in flask

- Calculation of Biodegradation %
The percentage biodegradation of the test material and of the reference material was calculated as follows:

% Biodegradation = [BOD (mg O2/mg test or reference material) / ThOD NH4 (mg O2/mg test material) or ThOD NH4 (mg O2/mg reference material)] x 100

Reference substance:

benzoic acid, sodium salt

Preliminary study:

The chosen test material concentration was based on the theoretical oxygen demand and on the performed 14 day preliminary test.

Test performance:

VALIDITY CRITERIA
- Oxygen depletion in the inoculum control did not exceed 1.5 mg O2/L after 28 days.
- The residual oxygen concentration in the test flasks did not drop below 0.5 mg O2/L at any time.
- The difference of duplicate values for the degradation at any time during the test was less than 20 %.
- The percentage degradation of the reference material reached the level for ready biodegradability (>60 %) within 14 days.
- The percentage degradation in the toxicity control containing both the test material and the reference material reached the level for ready biodegradability (> 25 %) by exposure day 14.

Key result

Parameter:

% degradation (O2 consumption)

Value:

> 25

Sampling time:

14 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

21.3

Sampling time:

28 d

Details on results:

Under the test conditions the percentage biodegradation of the test material reached a mean of 21.3 % after 28 days based on the ThOD of the test material. Therefore the test material is considered not readily biodegradable. According to the test guidelines the pass level for ready biodegradability is removal of 60 % ThOD.

In the toxicity control containing both, the test item and the reference item Sodium benzoate, a mean of 39.6 % biodegradation was noted within 14 days and 43.3% biodegradation after 28 days of incubation

Results with reference substance:

The reference material Sodium benzoate was sufficiently degraded to a mean of 77.5 % after 14 days, and to a mean of 83.3 % after 28 days of incubation, based on ThODNH4, thus confirming the suitability of the used inoculum.

Table 1. Percentage Biodegradation at Different Time Intervals during the Exposure Period of 28 Days

Treatment	Concentration[mg/L]	Flask No.	Percent of biodegradation after n days of exposure
			7	14	21	28
Test material	2.9	1a	21.3	22.1	18.0	20.5
		1b	23.0	22.1	18.0	22.1
		Mean	22.1	22.1	18.0	21.3
Reference material	3.6	2a	73.3	77.5	81.7	84.2
		2b	73.3	77.5	83.3	82.5
		mean	73.3	77.5	82.5	83.3
Toxicity control	Test material: 2.9 Reference material: 3.6	4a	37.6	39.6	41.6	43.7
		4b	37.6	39.6	40.0	42.9
		mean	37.6	39.6	40.8	43.3

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Under the conditions of the study, the test material was not considered to be have significant inhibitory effects on the secondary effluent microorganisms and is considered not readily biodegradable.

Executive summary:

The ready biodegradability of the test material was investigated in a test conducted in accordance with the standardised guidelines OECD 301 D and EU Method C.4 -E and US EPA OPPTS 835.3110 under GLP conditions.

The test material was investigated for its ready biodegradability in a Closed Bottle Test over a period of 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. The reference material Sodium benzoate was tested simultaneously under the same conditions as the test material, and functioned as a procedure control. The test system was a microbial inoculum of good quality, collected from a sewage plant for domestic sewage. The sludge was allowed to settle and then aerated until use. Under the test conditions the percentage biodegradation of the test material reached a mean of 21.3 % after 28 days based on the ThOD of the test material. The test material is therefore considered not readily biodegradable as the pass level for ready biodegradability is removal of 60 % ThOD. The test material can be assumed to be not inhibitory at the applied concentration level of 2.9 mg/L on the activated sludge microorganisms because degradation was >25 % within 14 days. The reference imaterial Sodium benzoate was sufficiently degraded to a mean of 77.5 % after 14 days, and to a mean of 83.3 % after 28 days of incubation, based on ThODNH4, thus confirming the suitability of the used inoculum. In the toxicity control containing both, the test material and the reference material Sodium benzoate, a mean of 39.6 % biodegradation was noted within 14 days and 43.3 % biodegradation after 28 days of incubation. The validity criteria of the study was fulfilled therefore the study can be considered valid.

Under the conditions of the study, the test material was not considered to be have significant inhibitory effects on the secondary effluent microorganisms and is therefore considered not readily biodegradable.

Description of key information

Under the conditions of the study, the test material was not considered to have significant inhibitory effects on the secondary effluent microorganisms. The test materials was considered not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

The ready biodegradability of the test material was investigated in a test conducted in accordance with the standardised guidelines OECD 301 D and EU Method C.4 -E and US EPA OPPTS 835.3110 under GLP conditions. The study was assigned a reliability score of 2 in accordance with the criteria for assessing data quality set forth by Klimisch et al. (1997).

The test material was investigated for its ready biodegradability in a Closed Bottle Test over a period of 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. The reference material Sodium benzoate was tested simultaneously under the same conditions as the test material, and functioned as a procedure control. The test system was a microbial inoculum of good quality, collected from a sewage plant for domestic sewage. The sludge was allowed to settle and then aerated until use. Under the test conditions the percentage biodegradation of the test material reached a mean of 21.3 % after 28 days based on the ThOD of the test material. The test material is therefore considered not readily biodegradable as the pass level for ready biodegradability is removal of 60 % ThOD. The test material can be assumed to be not inhibitory at the applied concentration level of 2.9 mg/L on the activated sludge microorganisms because degradation was >25 % within 14 days. The reference imaterial Sodium benzoate was sufficiently degraded to a mean of 77.5 % after 14 days, and to a mean of 83.3 % after 28 days of incubation, based on ThODNH4, thus confirming the suitability of the used inoculum. In the toxicity control containing both, the test material and the reference material Sodium benzoate, a mean of 39.6 % biodegradation was noted within 14 days and 43.3 % biodegradation after 28 days of incubation. The validity criteria of the study was fulfilled therefore the study can be considered valid.

Under the conditions of the study, the test material was not considered to be have significant inhibitory effects on the secondary effluent microorganisms. The test material is considered not readily biodegradable.