Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in water and sediment: simulation testing, other
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
The degradation of the test substance was studied in anaerobic sediment-water samples collected from the sediment layer of two lakes. The test substance samples were incubated with the sediment and water samples under anaerobic conditions and analysed for transformation products through HPLC analysis at selected time intervals.
GLP compliance:
no
Radiolabelling:
no
Oxygen conditions:
anaerobic
Inoculum or test system:
natural water / sediment
Details on source and properties of surface water:
The surface water was collected from the same source as the anerobic sediment and stored under nitrogen atmosphere along with the sediment samples.
Details on source and properties of sediment:
The anaerobic sediments were collected from two lakes in the Athens (Georgia) area. The sediment and associated water was collected by scooping up the top 5-10 cm layer of the sediment surface in 1 L canning jars at a depth of 30-60 cm below the water surface. The samples were passed through 1-mm sieves in the laboratory and stored under nitrogen atmosphere.
Details on inoculum:
5 mL homogenous aliquots of sediment-water samples were drawn while stirring the stored sediment under nitrogen atmosphere and were transferred to a series of screw-capped test tubes. The tubes were then spiked with an acetonitrile solution of the test substance while vortex mixing.
Initial conc.:
0 other: Molar
Based on:
test mat.
Parameter followed for biodegradation estimation:
test mat. analysis
Details on study design:
Degradation studies:

The sediment-water samples spiked with the test substance were incubated at 25°C in a water bath. At selected time intervals, a tube from the series was extracted by adding 3 mL acetonitrile followed by vortex-mixing for 60 sec. At the same time, the remaining tubes were inverted to mix uniformly. The extracted tube was then centriguged consecutively at 2500 rpm twice and the 5 mL aliquots were collected from the respective supernatants and kept in a screw-capped test tube. Thereafter, these samples were analysed through HPLC.

Product studies:
Ferric chloride is added to a suspension of disperse blue 79 and iron powder in methanol:water mixture. This suspension was heated to a gentle reflux for 1.5 h. The dark yellow reaction mixture was poured into 20 mL of water and the extracted with a series of three 25 mL aliquots of diethyl ether.These ether extracts were individually washed with 10 mL portion of brine. The ether extracts were then combined, dried and evaporated. The resulting residue was flash chromatographed on silica gel with ethyl acetate/hexane mixture.

Sediment-water ratio:

Triplicate 5 mL aliquots of sediment were transferred to tared test tubes. After reweighing, the samples were centrifuged at 2500 rpm, the supernatant was collected and the pellet was dried overnight at 100°C in an oven. After cooling, the dried samples were weighed again. Ratios of sediment and water were calculated by dividing the weight of the dried sediment by the weight of the aqueous phase.
Key result
Compartment:
natural water / sediment
DT50:
60 min
Temp.:
25 °C
Transformation products:
not specified
Remarks:
three products have been identified as aniline and azo compounds and other two products are being detected at the time of publication of the report
Details on transformation products:
Reductive cleavage of the azo linkage results in the product 2-bromo-4, 6-dinitroaniline (BDNA) and an aniline compound. Reduction of BDNA further produces two bromonitroaniline compounds. Reduction of the nitro group in the test substance will initially result in azo compounds, which eventually produce aniline counds because of further reduction.
Details on results:
The test substance was readily reduced in anaerobic sediment-water system with half-life on the order of minutes. The study of the degradation products indicated that the nitro and azo linkages are susceptible for reduction resulting in the formation of aniline and azo groups. These products accounted for approximately 40% of the parent substance. Two other degradation products were yet to be identified.
Validity criteria fulfilled:
not specified
Conclusions:
Under the condtions of this study, the test substance underwent rapid reductive degradation in anaerobic water-sediment system and the half life of degradation was determined to be 60 min.
Executive summary:

The degradation of the test substance was studied in anaerobic sediment-water samples collected from sediment layer of two lakes. The test substance samples were incubated with the sediment and water samples under anaerobic conditions and analysed for transformation products through HPLC analysis at selected time intervals. Under the conditions of this study, the test substance underwent rapid reductive degradation in anaerobic water-sediment system and the half life of degradation was determined to be 60 min (Weber, 1988).

Description of key information

Key value for chemical safety assessment

Half-life in freshwater sediment:
60 min

Additional information

A study was conducted to determine the degradation of the read across substance ‘structural analogue 1’ in anaerobic sediment-water samples collected from sediment layer of two lakes. The test substance samples were incubated with the sediment and water samples under anaerobic conditions and analysed for transformation products through HPLC analysis at selected time intervals. Under the conditions of this study, the test substance underwent rapid reductive degradation in anaerobic water-sediment system and the half-life of degradation was determined to be 60 min (Weber, 1988).