Lithium bis(oxalato)borate

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:

2004-10-25 to 2004-10-07

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

EEC directive 92/69, Part C; Publication No. L383

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 1992-07-17

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

other: nominal concentration of the test item

Initial conc.:

30 mg/L

Based on:

other: nominal concentration of the test item

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral Medium (8.5 mg/L KH2PO4, 21.75 mg/L K2HPO4, 67.20 mg/L Na2HPO4*12 H2O, 0.5 mg/L NH4Cl, 22.5 mg/L MgSO4*7 H2O, 36.4 mg/L CaCl2*2 H2O, 0.25 FeCl3*6 H2O)
- Additional substrate: no
- Test temperature: 21.1 - 22.9 °C
- pH: 7.3-7.6
- pH adjusted: yes, with 1 N NaOH
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 250-300 ml BOD bottles with glass stoppers
- Number of culture flasks/concentration: duplicates
- Method used to create aerobic conditions: The concentration of dissolved oxygen was measured for control purposes. The mineral medium was left at
test temperature to obtain a saturated solution at the start of the test.
- Measuring equipment: oxygen meter

SAMPLING
- Sampling frequency: ln duplicate; immediately at the start of the experiment (day 0), and at day 4, 8, 12, 16, 20, 24 and 28

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: yes
- Other: positive control: yes: Sodium acetate (2 mg/L)

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

39

Sampling time:

4 d

Parameter:

% degradation (O2 consumption)

Value:

89

Sampling time:

8 d

Parameter:

% degradation (O2 consumption)

Value:

80

Sampling time:

12 d

Parameter:

% degradation (O2 consumption)

Value:

83

Sampling time:

16 d

Parameter:

% degradation (O2 consumption)

Value:

95

Sampling time:

28 d

Details on results:

The results indicated above refer to 10 mg/L and are mean values from duplicates.
Additional results - that could not be filled in the table above - are as follows: 85 % at day 20 and 89 % at day 24.
The following results refer to 30 mg/L and are mean values: 15 % (4d), 68 % (8d), 77 % (12d), 79 % (16d), 72 % (20d), 82 % (24d), 86 % (28d).

Results with reference substance:

The following results refer to 2 mg/L reference substance and are mean values: 44 % (4d), 93 % (8d), 79 % (12d), 79 % (16d), 73 % (20d), 75 % (24d), 84 % (28d)

There was no inhibition of microbial activity in the toxicity control.

There was no significant degradation in the abiotic control.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Lithium bis(oxalato)borate was ready biodegradable under the conditions in the closed bottle test and therefore considered to be "ready biodegradable".

Executive summary:

A study on biodegradation (closed bottle test) of lithium bis(oxalato)borate was assessed according to OECD guideline 301D and EU method C.4. The relative biodegradation values calculated from the 2 measurements performed during the test period of 28 days revealed 95 % degradation of test substance at 10 mg/L and 86 % degradation of test substance at 30 mg/L. Furthermore, at least 60 % degradation was reached within the 10 days immediately following the attainment of 10 % biodegradation (10-day window). Except for a deviating difference of duplicate values of the reference substance at the end of the test (24 %), which was considered not to have affected the integrity of this study, all criteria for acceptability of the test were met. Therefore, this study was considered to be valid.

Thus, lithium bis(oxalato)borate was ready biodegradable under the conditions in the closed bottle test. (NOTOX, 2004)

Description of key information

Lithium bis(oxalato)borate was ready biodegradable under the conditions in the closed bottle test and  therefore classified as "ready biodegradable".

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Key study:

The screening test on biodegradation in water (closed bottle test) according to OECD guideline 301D revealed a ready biodegradation for lithium bis(oxalato)borate. At least 60 % degradation was reached within the 10 days immediately following the attainment of 10 % biodegradation (10-day window). Except for a deviating difference of duplicate values of the reference substance at the end of the test (24 %), which was considered not to have affected the integrity of this study, all criteria for acceptability of the test were met. Therefore, this study was considered to be valid.

Supporting study:

The test substance lithium bis(oxalato)borate was found to be readily degradable under the present test conditions according to OECD guideline 301D. The abiotic degradation was the main cause of readily degradation in this study. However, another study confirms the ready biodegradability of Lithium bis(oxalato)borate through an biotic mechanism (key study: Notox, 2004).