Reaction mass of disodium [2,2'-(imino-κN)dibutanedioato-κ2O1,O4(4-)]calcium(2-), sodium chloride and aspartic acid disodium salt

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The described study is a guideline study but only the relevant publication is available. However, this publication does not contain sufficient experimental details (i.e. test substance concentrations). Since no toxicity control has been conducted although it was assumed that released cations lead to inactivation of microorganisms, toxic effects to the sludge cannot be ruled out.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

yes

Remarks:

neither toxicity control nor substance concentrations indicated

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
not applicable

Oxygen conditions:

aerobic

Inoculum or test system:

other: activated sludge (industrial and domestic, adaption not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Bürrig wastewater treatment
plant (Leverkusen, Germany)
- Measurements: The chemical oxygen demand was determined with test system LCK 314 (Dr. Lange, Düsseldorf, Germany).

Duration of test (contact time):

42 d

Initial conc.:

100 mg/L

Based on:

other: Concentration of test substance was not specified in the publication. Concentration is based on used OECD Guideline 301F.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST SYSTEM
- Measuring equipment: The test was carried out with the OxiTop Control system (WTW, Weilheim, Germany).

Reference substance:

benzoic acid, sodium salt

Preliminary study:

not applicable

Test performance:

During the test on IDS chelates, precipitation of the corresponding heavy metal hydroxide was observed, indicating liberation of free metal ions.

Parameter:

% degradation (O2 consumption)

Value:

75

Sampling time:

20 d

Parameter:

% degradation (O2 consumption)

Value:

85

Sampling time:

28 d

Results with reference substance:

Reference substance was degraded (> 50 % after 4 days and > 75 % after 10 days, both based on O2 consumption).

For the biodegradation test with metal-IDS complexes, equimolar amounts of each metal and IDS were used. The test was monitored over a period of 42 days. It is shows that Fe2-IDS and Ca2-IDS were readily biodegradable, whereas Mn2-IDS and Cu2-IDS revealed 55 and 40% biodegradation after 28 days, respectively.

Discussion

The IDS isomers of the technical mixture are readily biodegradable, according to OECD guideline 301F. Metal-IDS such as Ca2- and Fe2-IDS complexes fulfill the criteria of ready biodegradability. In contrast, Mn2- and Cu2 -IDS revealed only 55 and 40% biodegradation after 28 days,

respectively. A correlation between complex formation constants (pK) and degradation rates was not observed. The pK values of Ca2-, Mn2-, Fe2-, and Cu2-IDS were 6.7, 7.3, 8.2, and 14.3, respectively. The authors presume that metal-IDS complexes were not transported into the cells, since heavy metal precipitation was observed in the medium during biodegradation tests.

Validity criteria fulfilled:

not specified

Remarks:

Sufficient experimental details are missing.

Interpretation of results:

other: the substance is potentially biodegradable

Conclusions:

It was shown that the substance CaIDHA (also known as Ca-IDS) is biodegradable under the test conditions (85 % biodegradation after 28 days, based on O2 consumption).

Executive summary:

The biodegradation of CaIDHA and other metal complexes of IDHA was investigated according to OECD Guideline 301F (Cokesa et al., 2004). The test was carried out with the OxiTop Control system (WTW, Weilheim, Germany) and monitored for 42 days. Exact substance concentrations were not indicated in the publication.

During the test, precipitation of the corresponding heavy metal hydroxide was observed, indicating liberation of free metal ions. Based on O2 consumption, CaIDHA revealed 85 % degradation after 28 days and is considered as readily biodegradable. No toxicity control has been conducted.

Description of key information

It was shown that the substance CaIDHA (also known as Ca-IDS) is biodegradable under the test conditions (85 % biodegradation after 28 days, based on O2 consumption).  

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable