2-Propanol, 1,3-bis[(3-methyl-2-buten-1-yl)oxy]-

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:

2019-09-03 to 2019-10-01

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:

1992-07-17

Deviations:

no

Principles of method if other than guideline:

'Standard Concerning Testing Facility Relating to New Chemical Substances' of Japanese Chemical Substances Control Law (March 31, 2011, Yakushokuhatsu 0331 No. 8, Heisei 23.03.29 Seikyoku No. 6; Kampokihatsu No. 110331010)

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge was obtained from an aeration tank of a sewage treatment plant treating predominantly domestic sewage in Kurume-shi, Fukuoka, Japan.
- Method of cultivation: The activated sludge was aerated at approximately 22 °C until use for the test.
- Storage conditions:
- Storage length: 2019-09-02
- Preparation of inoculum for exposure: Additive amount of the activated sludge into the test vessel was 4.05 mL on the basis of the concentration of suspended solid in the activated sludge which was determined by the following method: Japanese Industrial Standards (JIS) K 0102:2016 Section 14.1.
- Concentration of sludge: 30 mg/L (as concentration of suspended solid)
- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

not specified

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: The mineral medium (4 L) was prepared at the same proportion as the following method: 10 mL of solution A and each 1 mL of solutions B, C, and D prescribed in the test methods in Section 5. were made up to 1 L with purified water (The Japanese Pharmacopoeia, Takasugi Pharmaceutical).
- Test temperature: 22 ± 1
- pH: 7.4
- pH adjusted: yes
- Aeration of dilution water: yes
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Closed system consumption measuring apparatus (No. CM-058) Temperature controlled bath with measuring unit OM3100A (Ohkura Electric)
- Number of culture flasks/concentration: 1-2 (see below)
Test solution (sludge + test item): 2 replicate
Procedure control (sludge + sodium benzoate): 1 replicate
- Method used to create aerobic conditions: Aeration
- Measuring equipment: Soda lime No. 1 (for absorption of carbon dioxide, FUJIFILM Wako Pure Chemical)
- Test performed in closed vessels: yes

SAMPLING
- Sampling frequency: BOD continuously, analytical samples at end of incubation period
- Sampling method:
BOD: closed system oxygen consumption apparatus, TOC analyzer
Chemical analysis: HPLC & LC-MS

CONTROL AND BLANK SYSTEM
- Inoculum blank (test solution; control blank): 2 replicates
- Toxicity control (sludge + test item + sodium benzoate): 1 replicate

STATISTICAL METHODS:
The percentage biodegradation was rounded of to the whole number.
In the calculation of TOD of the test item, the compositional formula C18H33O5 obtained by elemental analysis of the test sample was used.
The TOD of the test solution (sludge + test item + sodium benzoate) was the sum of TOD of the test item and that of sodium benzoate.
In addition, the percentage biodegradation by BOD of the test item at the end of the 10-day window (the 10 days immediately following the attainment of 10% biodegradation) was calculated.
The atomic weight of each element used in this study was based on the 4-digit atomic weight table 2017 provided by the Chemical Society of Japan.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (test mat. analysis)

Remarks:

by HPLC

Value:

100

Sampling time:

28 d

Key result

Parameter:

% degradation (DOC removal)

Value:

>= 87 - <= 90

Sampling time:

28 d

Results with reference substance:

Criteria: Percentage degradation of the reference compound has reached the pass levels by day 14 (60%):
Yes, 89% measured.

Validity criteria

Difference between extreme of replicate values of percentage biodegradation in test solutions (sludge + test item) on Day 28 should not be greater than 20 %:

• BOD: 3 %


• DOC: 3 %

BOD in test solutions (control blank) on Day 28 should not be greater than 60 mg/L: 

• Measured values: 23 and 25 mg/L

pH values should be in a range from 6-8.5:

• Measured values: 7.3-7.4

Biodegradability of test item

The averages of the percentage biodegradation were 69% by BOD and 89% by DOC on Day 28. In addition, growth of the sludge was observed at the end of the incubation. These results showed that most of the test item underwent biodegradation under the test conditions of the study. 

According to OECD test guideline 301F, the pass level for biodegradability is 60% biodegradation by BOD on Day 28 and in the 10-day window. In the study, the percentage biodegradation by BOD of the test item at the end of the 10-day window was 49% and 54%. These values did not reach the pass level. However, since both of the percentage biodegradation by BOD were 67% and 70% and the BOD cuves were rising on Day 28 in the test solutions (sludge + test item), the test item was considered to have inherent biodegradability.

Quantitative analysis of test item and qualitative analysis of degradation products

The percentage residue of the test was 0% and a peak corresponding to the degradation product (D2) was 13% and 10%. These results showed that water-soluble degradation products were produced. As a result of the qualitative analysis by LC-MS, two degradation products (D1 and D2) were detected on the TIC chromatogram. Since the degradation products were water-soluble, it was presumed that the percentage production of the degradation products was equal to the percentage residue of DOC (13% and 10%). The averages of the percentage biodegradation were 69% by BOD and 89% by DOC on Day 28, and the BOD curves were rising on Day 28 in the test solutions (sludge + test item). That is, the degradation products were intermediates in the process of biodegradation and they will completely biodegrade eventually. 

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

The test item disappeared completely and two degradation products were produced under the test conditions of the study. The degradation products were intermediates in the process of biodegradation and they will be completely biodegraded eventually. The test item was considered to have inherent biodegradability.

Description of key information

The test item disappeared completely and two degradation products were produced under the test conditions of the study. The degradation products were intermediates in the process of biodegradation and they will be completely biodegraded eventually. The test item was considered to have inherent biodegradability.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater