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Biodegradation in water: screening tests

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biodegradation in water: inherent biodegradability
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
supporting study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: well documented study without GLP

Data source

Reference Type:
Chapter 9, Microbial Degradation of EDTA: New EDTA-degrading Bacterial strains
Satroutdinov, A; Chistyakova, T.; Dedyukhina, E. & Minkevich, I.
Bibliographic source:
Biogeochemistry of chelating agents (eds Nowack, B. and VanBriesen, J.)

Materials and methods

Principles of method if other than guideline:
EDTA degrading strains were isolated and incubated to EDTA and EDTA complexes with Mg, Ca, Mn, Zn, Co, Cu and Pb
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Edetic acid
EC Number:
EC Name:
Edetic acid
Cas Number:
Molecular formula:
C10 H16 N2 O8
2,2',2'',2'''-(ethane-1,2-diyldinitrilo)tetraacetic acid
Details on test material:
no data available

Study design

Oxygen conditions:
Inoculum or test system:
not specified
Duration of test (contact time):
24 h

Results and discussion

Details on results:
Uncomplexed EDTA and metal-EDTA chelates with low stability constants (log K below 16), such as Mg-, Ca-, Ba-, and Mn-EDTA, were degraded by the washed cell suspensions of both isolates at constant specific rates ranging from 0,310 to 0.525 mmol EDTA/(g cells h). Zn-EDTA with a higher stability constant (log K 18.3) was not completely degraded by resting cell suspensions of Pseudomonas sp, LPM-410 and LPM-4 after an incubation period of 24 h. Initially, the degradation rates of Pseudomonas sp. LPM-410 and LPM-4 were 0.195 and 0.143 mmol EDTA/(g cells h), respectively. After 8 h, degradation rates declined. No degradation of the stable chelates of Pb-, Co-, Cu-EDTA, and Fe(III)-EDTA was observed.

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Interpretation of results:
inherently biodegradable
EDTA-degrading bacterial strains (Pseudomonas sp. LPM-410 and EDTA-dependent strain LPM-4) degraded EDTA and EDTA complexes with Mg, Ca, Mn, and Zn at higher rates (0.143-0.525 mmol EDTA/(g h)), but were unable to degrade EDTA complexes with Co, Cu, and Pb.