α-chloro-2-fluorotoluene

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 07 NOV 2019 to 13 MAR 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Adopted July 17, 1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

May 30, 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 001

Cas Number:

345-35-7

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of activated sludge: Sewage treatment plant Rossdorf, Germany
- Preparation of inoculum for exposure:
The aerobic activated sludge used for this study was deposited for 15 min, washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in test water and centrifuged again. This procedure was done three times.
- Pretreatment:
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 and aerated overnight. This suspension was used for the experiment.
- Concentration of sludge:
Stock suspension of 3.5 g/L on dry matter base (final sludge concentration in test flasks: 28.7 mg sludge/L)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

100.8 mg/L

Based on:

act. ingr.

Remarks:

Oxygen demand about 171.4 mg/L (ThODNH4)

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium:
Analytical grade salts were added to ultrapure 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 pure water to 1000 mL volume; The pH-value was 7.4.
B: 11.25 g MgSO4 x 7 H2O filled up with pure water to 500 mL volume
C: 18.2 g CaCl2 x 2 H2O filled up with pure water to 500 mL volume
D: 0.125 g FeCl3 x 6 H2O filled up with pure water to 500 mL volume (one drop of concentrated HCl per litre was added before storage to avoid precipitation of iron hydroxide in the stock solution)
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 ultrapure water.
- Additional substrate: no
- Test temperature: 22°C ± 1°C
- pH: 7.4 (measured at the start of the test) 7.0 to 8.1 (measured at the end of the test)
- pH adjusted: yes (The pH was adjusted to pH 7.5 with 1M HCl solution):
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Test flasks containing a volume of approx. 500 mL.
- Number of culture flasks/concentration: 2
test substance and inoculum control: 2
Procedure control, abiotic and toxicity control: 1
- Measuring equipment: BSB/BOD-Sensor-System
- Details of trap for CO2: Potassium hydroxide solution (45%)

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 replicates
- Abiotic control: yes, 1 replicate, CuSO4 added
- Toxicity control: yes, 1 replicate containing active substance and reference item.
- Procedure control: yes, 1 replicate containing reference item

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Test performance:

ThODNH4 of 2-Fluorbenzylchloride is 1.771 mg O2/mg test item and ThODNH4 of sodium benzoate is 1.666 mg O2/mg reference item

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (O2 consumption)

Value:

52

Sampling time:

10 d

% Degradation 2

Key result

Parameter:

% degradation (O2 consumption)

Value:

53

Sampling time:

28 d

Details on results:

The 10-day windows began on day 15 after application, the mean value was calculated to be 30% biodegradation (ThODNH4). Therefore, the end of the 10-day window was day 25. After correction for the mean biochemical oxygen demand of the inoculum controls, the mean biodegradation percentage based on ThODNH4 at the end of the 10-day window was 52%; the criterion of the 10 day window was not passed. The mean biodegradation percentage at the end of the 28-day exposure period was 53% (ThODNH4).

BOD5 / COD results

Results with reference substance:

The reference item sodium benzoate was sufficiently degraded to 88% after 14 days and to 96% after 28 days of incubation.

Any other information on results incl. tables

Table 1: Percentage Biodegradation based on ThOD_NH4

Time [d]	Percentage Biodegradation [%]
	2 -Fluobenzyl chloride ^1		Sodium Benzoate ^2	Toxicity control ^1,2
1	0	0	9	1
2	0	0	47	20
3	0	0	55	26
4	0	0	60	28
5	0	0	64	33
6	0	0	70	37
7	0	0	73	40
8	0	0	76	41
9	0	0	79	46
10	0	0	79	47
11	0	0	82	51
12	0	0	85	56
13	0	3	85	60
14	0	14	88	63
15	3	28	88	66
16	6	36	90	69
17	8	42	90	69
18	14	47	90	70
19	22	50	90	71
20	34	53	93	71
21	39	53	93	71
22	45	56	93	71
23	48	53	93	71
24	48	53	93	71
25	51	53	93	71
26	51	53	93	71
27	51	53	96	73
28	53	53	96	74

¹ ThOD_NH4 of 2-Fluorbenzyl chloride: 1.771 mg O₂/mg test item

² ThOD_NH4 of sodium benzoate: 1.666 mg O₂/mg reference item

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The degradation rate of 2-Fluorbenzyl chloride never reached 60%.
Therefore, 2-Fluorbenzyl chloride is considered to be not readily biodegradable but may be inherently biodegradable.

Executive summary:

The test item 2-Fluorbenzyl chloride was investigated for its ready biodegradability in a manometric respirometry test over a period of 28 days, at 22°C ± 1°C in darkness. For the test an aerobic activated sludge (microorganisms from a domestic wastewater treatment plant) was supplied by the sewage treatment plant of Rossdorf, Germany.

The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

At the end of the 10-day window (day 25), the mean degradation of 2-Fluorbenzyl chloride was 52% (ThOD_NH4) and therefore the 10 day window criterion was not passed. The mean biodegradation at test end after 28 days was 53% (ThOD_NH4).

Therefore, 2-Fluorbenzyl chloride is considered to be not readily biodegradable but may be inherently biodegradable.