Chlorbutanol

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:

14-Sep-2017 to 09-Mar-20 18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Version / remarks:

Two treatments with sodium benzoate were used instead of one treatment as stated in
chapter 9.3 of the study plan. On the other hand, in chapter 1 0.3.1.2 of the study plan two
treatments with Na-Benzoate are given. This discrepancy in the study plan may be
regarded a deviation of the study plan which is not considered to have an influence on the
integrity of the study.
• Temperature values were temporarily outside the range 22 ± 2°C being set. The reason for
this is due to failure of the air conditioning on day 22. Thus, this deviation has no influence
on the results and the integrity of the test.
• ln deviation to the study plan, the sampling date planned on l21d was done on hod and the
sampling date planned on t27d was omitted.

Deviations:

yes

Remarks:

see remarks

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1,1,1-trichloro-2-methyl-2-propanol hemihydrate

Cas Number:

6001-64-5

Molecular formula:

C4H7Cl3O H2O

IUPAC Name:

1,1,1-trichloro-2-methyl-2-propanol hemihydrate

Test material form:

solid: crystalline

Details on test material:

transparent and crystalline solid at ambient temperature

Study design

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

The effluent from the municipal sewage treatment plant at Taunusstein-Bleidenstadt was filtered through cotton filter. The first approximately 200 ml of filtrate were discarded. The inoculum obtained was used on the same day of preparation.

Duration of test (contact time):

28 d

Reference substance

Reference substance 1

Reference substance:

benzoic acid, sodium salt

Remarks:

control ltem

Reference substance 2

Reference substance:

other: Potassium hydrogenphthalate

Remarks:

reference item for the DOC analyses

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (DOC removal)

Remarks:

first experiment

Value:

88

Sampling time:

28 d

Remarks on result:

other:

Remarks:

for detailed information see table 1

% Degradation 2

Key result

Parameter:

% degradation (DOC removal)

Value:

99

Sampling time:

28 d

Remarks on result:

other:

Remarks:

for detailed information see table 2

Any other information on results incl. tables

table 1: results first experiment

time (d)	DOC (mg/l)	Degradation
0	33.33	-
1	31.17	6
7	22.17	34
9	20.62	38
14	19.28	42
20	15.57	53
28	3.99	88

table 2: results second experiment

time (d)	DOC (mg/l)	Degradation
0	31.62	-
1	29.18	8
7	13.68	57
9	11.16	65
14	4.42	86
20	4.19	87
28	0.49	99

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Study is valid an the test substance is readily biodegradable.

Executive summary:

Chlorobutanol Hemihydrate was tested for biodegradability according to OECD 301 E. Calculated from the DOC content of the test item at time to and the measured DOC at different times, 88% of the DOC has been removed from the 1st test solution with the test item within 28d of test period. 99% of the DOC has been removed from the secend treatment with the test item within 28d. The calculated mean degradation value of the test item was 93% and thus beyond the threshold for "ready biodegradability of 70% DOC-removal. By graphical analysis, the "10-days-window" was met only in the secend treatment with the test item. The first treatment did not fulfil this criterion. Thus, the test item may be regarded as "not readily biodegradable" though a mean degradation value of 93% was achieved within 28 days. The control item sodium benzoate was degraded 100% within 20 days of incubation. The conditions of the "10 -days-window" were met within 7 days (95% degradation) in the secend treatment. According to graphical analysis, the conditions of the 10-days-window were also met in the 1st treatment though there was a slight delay in that treatment. 99% degradation was obtained in that 1st treatment with Na-benzoate after 14 days. Thus the test is regarded to be valid. The results obtained with the toxicity control indicate that there was no toxicity of the test item towards microorganisms at the concentration used within the test as a degradation value of >30% (here: 97%) was achieved in total within that treatment. The 10-days-window was also met in that treatment. This indicates that the test item is rapidly co-metabolized together with sodium benzoate, and thus, the failure of the "10-days-window" in the first treatment with the test item alone should be neglected.