Reaction mass of sodium sulphate and trisodium trioxalatoferrate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

according to OECD guideline

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of sodium sulphate and trisodium trioxalatoferrate

EC Number:

947-037-7

IUPAC Name:

Reaction mass of sodium sulphate and trisodium trioxalatoferrate

Study design

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

Secondary effluent of municipal biological waste water treatment plant, non-adapted, not pre-conditioned; source: ARA Werdhölzli, CH-8048 Zuerich

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

40 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: aerobic mineral salts medium, prepared with deionised water; conductivity < 1.5 µS/cm; DOC < 0.3 mg/L
- Test temperature: 22 ± 0.5°C
- pH: 7.4 ± 0.2
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: 1200 mL glass bottle containing a total volume of test solution of 800 mL
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: test vessels were stirred and aerated with CO2-free air for a maximum test period of 28 days.
- Measuring equipment: DOC was determined in duplicate with a SHimadzu 5050 TOC-Analyzer using the NPOC-mode. For each determination 3 single injections were performed.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (DOC removal)

Value:

58

Sampling time:

7 d

% Degradation 2

Parameter:

% degradation (DOC removal)

Value:

95

Sampling time:

14 d

% Degradation 3

Parameter:

% degradation (DOC removal)

Value:

100

Sampling time:

21 d

BOD5 / COD results

Results with reference substance:

97 % biodegradation of the reference substance sodium benzoate was observed after 14 days.

Any other information on results incl. tables

At the end of the test the pH value of both inoculum blanks and the procedure control was 7.3 and 7.4 respectively. The pH value of both test suspensions and the toxicity control was 8.2 respectively.

Complete biodegradation of the test substance was observed without any signiticant lag phase.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The biodegradability of the test item was calculated to be 99 % after 28 days of incubation. The test item reached the pass level of 70 % for ready biodegradability within the 10 day window and can therefore be termed as readily biodegradable. The procedure control sodium benzoate reached 97 % biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.