Registration Dossier

Administrative data

Endpoint:
biodegradation in soil: simulation testing
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: Despite no guideline being available in 1966, methods are reproducible and straightforward, and results are reasonable.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1966
Report Date:
1966

Materials and methods

Principles of method if other than guideline:
Test solution contained substituted benzenes as the sole carbon source. Inoculum was Niagara silt loam. Absorbancy of the centrifuged supernatant aliquot was monitored up to 64 days to monitor cleavage of benzene ring (cleavage results in loss of UV absorbancy).
GLP compliance:
no
Test type:
laboratory

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
No details provided in the publication.

Study design

Oxygen conditions:
aerobic
Soil classification:
other: Niagara silt loam

Results and discussion

Half-life / dissipation time of parent compound
Remarks on result:
other: Neither of the phenylenediamine isomers (ortho and meta) exhibited ring cleavage within 64 days.

Any other information on results incl. tables

Neither of the phenylenediamine isomers (ortho and meta) exhibited ring cleavage within 64 days.

Most of the substituted anilines were not suitable substrates under the test conditions. The resistance of the anilines was rather surprising because amino compounds are universal cellular constituents, by contrast with nitro, chloro, and sulfonate compounds. Seven of the 15 anisoles were also largely inert when exposed to the mixed soil population, but six of the seven contained either a nitro or an amino substituent.

Applicant's summary and conclusion

Conclusions:
Neither of the phenylenediamine isomers (ortho and meta) exhibited ring cleavage within 64 days.
Executive summary:

The rate of degradation of mono- and disubstituted benzenes (approx. 80 substances) by soil microorganisms was determined by a spectrophotometric technique. Chloro, sulfonate, and nitro groups retarded the rate of biodegradation whereas carboxyl and phenolic hydroxyl groups favored decomposition of the substituted benzenes. The meta isomer was commonly the most resistant to attack by soil microorganisms, but the ortho isomer was the most resistant for certain classes of compounds.

 

The loss of UV absorbancy was not observed over the 64 day period for ortho and meta phenylenediamine indicating slow decomposition under test conditions.