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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Administrative data

Endpoint:
biodegradation in water: sediment simulation testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report Date:
2019

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 308 (Aerobic and Anaerobic Transformation in Aquatic Sediment Systems)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Details on test material:
Tetradecane chlorinated by Chemica del Cinca to specific chlorination levels.
Specific details on test material used for the study:
Chemical name C14 chlorinated N-alkane, 50% Cl (wt.)
Batch/Lot number C14CL50 20160623
Purity 100% (UVCB)
Total chlorine (see annex 2) 50.07% w/w
Expiry date 01-12-2018
Solubility in water insoluble in water
Stability not relevant
Storage at ambient temperature in the dark
The concentrations cited in this report refer to the as-received sample of C14 chlorinated N-alkane, 50% Cl (wt.)
Radiolabelling:
no

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
natural water / sediment: freshwater
Details on source and properties of surface water:
Associated water collected with the natural sediment.
Details on source and properties of sediment:
Sediments and associated waters were collected from the Brandywine Creek (Chadds Ford, Pennsylvania, USA) and the Choptank River (Denton, Maryland, USA). The test systems were selected based on previous characterization results and to be consistent with referenced study guidelines. Relative to each other, the Brandywine Creek sediment possessed high organic carbon content and a fine texture, while the Choptank River sediment had low organic carbon content and a coarse texture. Blank control samples prepared at the same time as treated samples were analyzed for background concentrations of chlorinated alkanes and none were found.
Duration of test (contact time):
120 d
Initial test substance concentration
Initial conc.:
5 other: ug/g sediment dry weight
Based on:
test mat.
Parameter followed for biodegradation estimation:
test mat. analysis
Details on study design:
The test was conducted using two sediments and their associated waters. Test systems were dosed with C14 Chlorinated Paraffin at a nominal concentration of 5 µg/g dry weight of sediment. Test systems were housed on a shaker table in an incubator set to maintain a temperature of 12 ºC for up to 120 days. The shaker table was set to provide a gentle stirring of the water layer to stimulate aeration without visible disturbance of the sediment layer. The vessels were covered with 3M Blenderm™ surgical tape to allow air transfer to the water layers during incubation.

Test subgroups established for each sediment/water system consisted of treated live vessels, treated inactivated vessels (inactivated by freezing immediately after dosing), and untreated (blank) control vessels. The purpose of the inactivated vessels was to provide a reference for non-biological losses and/or changing extraction efficiencies and analytical quantification with time. The purpose of the blank controls was to provide information regarding background concentrations of chlorinated paraffin in the sediment/water systems. Additional vessels were set up for characterization measurements, and were maintained under the same test conditions as vessels used to monitor transformation. Characterization vessels were not treated with the test substance. The characterization measurements made during the study indicated that aerobic conditions were maintained for the duration of incubation.

Duplicate live and inactivated C14 Chlorinated Paraffin-treated vessels, and duplicate live untreated (blank) control vessels were collected for processing on Days 0, 15, 30, 45, 60, 91 and 120. The vessels were placed in a standard laboratory freezer, (approximately -14 °C), then were transferred to an Ultra-Cold freezer (approximately -80 °C), and finally were lyophilized (freeze-dried) immediately upon removal from the Ultra-Cold freezer. Freeze-dried samples were stored at ambient room temperature until shipment to the Sponsor-designated analytical facility (VU Amsterdam).

Results and discussion

% Degradation
Sampling time:
120 d
Remarks on result:
not determinable
Remarks:
Percent degradation cannot be determined because there was no measureable biotransformation under the conditions of this study.
Half-life of parent compound / 50% disappearance time (DT50)
Compartment:
natural sediment: freshwater
DT50:
> 120 d
Temp.:
12 °C
Remarks on result:
not determinable
Remarks:
Chemical analysis showed no observable biotransformation under the conditions of this study.
Transformation products:
no
Remarks:
No metablolites could be specifically identified due to methodological limitations.
Details on transformation products:
No transformation products were found in the chemical analysis.
Evaporation of parent compound:
not measured
Remarks:
Volatility is not expected.
Volatile metabolites:
not measured
Residues:
not measured
Details on results:
There was no observed biotransformation or biodegradation in the study.
Results with reference substance:
Not applicable.

Any other information on results incl. tables

Full results of chemical analysis are provided in the attached study report.

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Conclusions:
Two natural sediments and associated water were used in this study to assess the biodegradation potential of C14 chloroalkanes. The sediment was spiked with the test material and incubated for up to 120 days at 12 degrees C. A chemical analysis of C14 chloroalkane congener groups was performed on samples after 0, 15, 30, 45, 60, 91 and 120 days of incubation. The chemical analysis showed no observable biotransformation or biodegradation over the course of the study duration. Based on the analysis, the conclusion was that the half-life was >120 days under the conditions of this study.
Executive summary:

Two natural sediments and associated water were used in this study to assess the biodegradation potential of C14 chloroalkanes. The sediment was spiked with the test material and incubated for up to 120 days at 12 degrees C. A chemical analysis of C14 chloroalkane congener groups was performed on samples after 0, 15, 30, 45, 60, 91 and 120 days of incubation. The chemical analysis showed no observable biotransformation or biodegradation over the course of the study duration. Based on the analysis, the conclusion was that the half-life was >120 days under the conditions of this study.