Disodium tartrate

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:

08 July - 22 July 1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Circular on Test Methods of New Chemical Substances (Japan), biodegradation test

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: cool and dark
- Stability under test conditions: verified at the beginning and at the end of the test by IR

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

- Source of inoculum/activated sludge: in June 1988, sludge was sampled at the following 10 places in Japan: 1. Fukogawa city sewage plant, 2. Fukashiba industry sewage plant, 3. Nakahama city sewage plant, 4. Ochiai city sewage plant, 5. Kitakami river, 6. Shinano river, 7. Yoshino river, 8. Lake Biwa, 9. Hiroshima bay, and 10. Dookai bay.
- Sampling method: return sludge at sewage disposal plants was taken. Surface water and surface soil on the beach which is in contact with atmosphere were taken from rivers, lake and sea.
- Method of cultivation: 5 L of the filtrate of the supernatant of old activated sludge was mixed with 500 mL of the filtrate of the supernatant of new sludge and cultured at pH 7.0 ± 1.0 under sufficient aeration using filtered air. About 30 minutes after ceasing aeration to the sludge mixture, supernatant corresponding to about 1/3 of the whole volume was removed. Then the equal volume of dechlorinated water was added to the remaining portion and aerated again, followed by addition of synthetic sewage at a concentration of 0.1% (w/v). This procedure was repeated once every day. The culturing was carried out at 25 ± 2 °C. During the cultivation, appearance of the supernatant, precipitability, formation of flock, pH, dissolved oxygen concentration in the solution and temperature were checked and necessary adjustments were made. Microflora in the activated sludge was microscopically observed and sludge with no abnormal symptom was used for the test.
- Concentration of sludge: 30 mg/L

Duration of test (contact time):

14 d

Initial conc.:

100 mg/L

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

TOC removal

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

TEST CONDITIONS
- Composition of medium: 3 mL of each four stock solutions, as described in Japanese Industrial Standards K 0102-1986-21, are diluted in 1000 mL of purified water
- pH: 6.4 - 7.0 (before start), 6.6 - 8.7 (at the end of the study)
- pH adjusted: no
- Suspended solids concentration: determined according to Method Japanese Industrial Standards (JIS) K 0102-1986-14.1

TEST SYSTEM
- Culturing apparatus: closed system oxygen consumption measuring apparatus (Coulometer: Ohkura Electric Co., Ltd.); 300 mL vessels).
- Number of culture flasks/concentration: 3 (sludge + test sub.)
- Measuring equipment: Coulometer, Ohkura Electric Co., Ltd.
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: soda lime, extra pure, Wako Pure Chemical Industries, Ltd.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 1 (sludge)
- Inoculum control: 1 (sludge + reference substance)
- Abiotic control: 1 (water + test substance)
- Toxicity control: no

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

> 71 - < 80

Sampling time:

14 d

Remarks on result:

other: based on BOD

Parameter:

% degradation (TOC removal)

Value:

> 91 - < 93

Sampling time:

14 d

Remarks on result:

other: based on TOC

Parameter:

% degradation (test mat. analysis)

Value:

100

Sampling time:

14 d

Remarks on result:

other: based on HPLC

Results with reference substance:

The oxygen consumption for aniline in the above used test system reached 63% and 73% degradation after 7 days and 14 days, respectively.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Description of key information

Disodium tartrate (CAS 868-18-8) is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

One study is available testing the biodegradability of disodium tartrate (CAS 868-18-8). The study was conducted according to the OECD guidance 301 C and GLP standards. A mixture of sewage sludge, soil and natural water was used as inoculum and was exposed to an initial test item concentration of 100 mg/L. The biodegradation was monitored based on O2 consumption, TOC removal and test material analysis using HPLC. After 14 d incubation following biodegradation was recorded: 71 – 80% based on BOD, 91 – 93% based on TOC removal and 100% based on test material analysis. The results reveal that the substance is readily biodegradable.