Heavy wax residue fraction, waste plastic derived, hydrothermal conversion

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2021-Oct-04 - 2021-Nov-03

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

OECD Guideline for the Testing of Chemicals, Part 301 B, adopted 17. Jul. 1992 “CO2-Evolution-Test (Modified STURM Test)“
and Commission Regulation (EC) No. 440/2008, Method C.4-C, adopted 30. May 2008 “CO2-Evolution-Test”

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Heavy wax residue fraction, waste plastic derived, hydrothermal conversion

Molecular formula:

Not applicable - UVCB

IUPAC Name:

Heavy wax residue fraction, waste plastic derived, hydrothermal conversion

Test material form:

other: solid - lumps

Details on test material:

- Stability: stable under storage conditions
- Storage: room temperature (20 ± 5 °C)
- Appearance: large, brown, solid lumps
- Purity: not applicable, UVCB
- Homogeneity: homogeneous
- EC no.: 950-445-8

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: Batch no. 180816 HWR
- Purity, including information on contaminants, isomers, etc.: not applicable, UVCB

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature (20 ± 5 °C) in tightly closed vessel
- Stability and homogeneity of the test material in the vehicle/solvent under test conditions (e.g. in the exposure medium) and during storage: stable under storage conditions
- Solubility and stability of the test material in the solvent/vehicle: unknown

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- The carbon content of 86.04 % was determined by elemental analysis under non-GLP con-ditions, performed at laboratory Mikroanalytisches Labor Pascher, An der Pulvermühle 1, 53424 Remagen, Germany.
The test item was added directly, the amounts were calculated from the carbon content, determined by elemental analysis.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Remarks:

The sludge was filtrated through a cloth, washed with test medium (2x) and resuspended in test medium. It was then aerated until use.

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): activation basin of the sewage treatment plant, In den Seewiesen, 67482 Edenkoben, Date of collection: 01. Oct. 2021, batch no: E20211001
- Storage conditions: not specified
- Preparation of inoculum for exposure: washed, aerated and dry matter was determined. After placing it with medium in test vessels, flasks were aerated for 72h with purified, CO2-free moistened air to purge system of CO2
- Pretreatment: The sludge was filtrated through a cloth, washed with test medium (2x) and resuspended in test medium. It was then aerated until use
- Concentration of sludge: The dry matter was determined to contain 3.54 g of suspended solids/L

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

23.3 mg/L

Based on:

TOC

Remarks:

Added amount of test item & positive control is based on the TOC content. TOC content of poorly soluble test item was determined by elemental analysis. TOC content of water-soluble positive control was determind by TOC measurement of a stock solution.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: The medium was freshly prepared. 10 mL of solution a were mixed with 800 mL H2O demin, then 1 mL of solutions b, c and d were added and filled up to 1 L with H2O demin (volumes were adapted to final volume needed in the test). Composition: Solution a 10 mL Solution b 1 mL Solution c 1 mL Solution d 1 mL H2O demin. ad 1000 mL (see "Any other information on materials and methods" below for composition of Solutions a-d Table 1-4)
- Test temperature: 19.7 – 21.7 °C without direct lighting
- pH: 7.4 - 7.5

TEST SYSTEM
- Culturing apparatus: 2000mL Schott-flasks were used as test vessels (volume 1500mL), 100mL scrubber flasks as absorbent vessels. The scrubbing of carbon dioxide was achieved by bubbling the purified air through a flask containing 1.5 M NaOH. To control the absence of CO2, the air was then led through a flask containing a solution of Ba(OH)2 before reaching the test vessels. Magnetic stirrers were used to prevent deposition of inoculum. The emitted CO2 was trapped in 0.25 M NaOH. Two scrubbers containing 100 mL each were connected in series to the test vessels.
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aerated with purified (by activated charcoal), CO2-scrubbed, moistened air
- Measuring equipment: Data logger for temperature, ebro; Analytical scales Mettler Toledo XS 205 DU; Analytical scales Mettler Toledo XSR205DU; Precision scales Sartorius CPA8201; Adjustable pipettes with one-way tips, Mettler Toledo; Carbon analyser TOC multi N/C 2100S, Analytik Jena; Magnetic stirrers; pH-meter 3310, wtw; Drying chamber Heraeus; Ultrasonic bath SONOREX RK 510H, Bandelin; Instrument TOC multi N/C 2100S
- Details of trap for CO2 and other chemicals: NaOH, 0.25 M solution, used for trapping of emitted carbon dioxide. NaOH, 1.5 M solution, used for scrubbing of purified air. HgCl2, used for poisoning of abiotic flasks. Ba(OH)2 solution, used for checking the purified air (saturated solution ,1:3 diluted). HCl, 2 M solution, used for driving off dissolved CO2 on day 28.

SAMPLING
- Sampling frequency: on day 2, 4, 7, 9, 11, 14, 18, 23 and 29
- Sampling method: 1mL sample volume, The resulting change in the volume of the front flask was considered in the calculation of emitted CO2. On day 0, only one sample of 0,25 M NaOH was sampled. This measured value was used as start value for all treatments. On day 28, 5 mL HCl 2 M was added to each test flask in order to drive off dissolved CO2. On day 29, samples from both scrubber flasks were taken.
- Sample storage before analysis: not specified
- CO2 Determination: Analyses of the emitted CO2 were made by IC measurement using the carbon analyser TOC multi N/C 2100S, Analytik Jena. Each sample was measured in duplicate or triplicate, re-spectively (depending on the variation between the measured values). The carbon analyser was calibrated with freshly prepared reference solutions containing potassium hydrogen phthalate (TC), sodium hydrogen carbonate and sodium carbonate (IC). Quality control sam-ples were measured on each measuring day.

CONTROL AND BLANK SYSTEM
- Apparatus blanks: 2, containing mineral medium only
- Blank Controls: 2, containing mineral medium and inoculum
- Positive control flasks: 2, containing positive control, mineral medium and inoculum
- Abiotic sterile control: 1, containing test item, mineral medium and HgCl2
- Toxicity control: 1, containing test item, positive control, mineral medium and inoculum
- Reference Items for Carbon Determination: Potassium Hydrogen Phthalate, C8H5KO4 for TC; Sodium Carbonate, Na2CO3 for IC; Sodium Hydrogen Carbonate, NaHCO3 for IC
- Details: Inoculum concentration 25.0 mg/L; The test was performed with a nominal start concentration of 20 mg organic carbon/L of the test item. See Table 5 below for amounts of test item and positive control in the flasks

STATISTICAL METHODS:
- Calibration: The concentration of IC and TC in the reference solutions was determined as follows:
Linear calibration curve: cmeasured [mg/L] =(k1 * I + k0)/V; see "Any other information on materials and methods" below, Table 6
- other Equations used: see Table 7

Reference substance

Reference substance:

aniline

Results and discussion

Preliminary study:

None

Test performance:

No deviations or unusual observations

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

28 d

Details on results:

The test item Heavy wax residue fraction, waste plastic derived, hydrothermal conversion is considered as “not readily biodegradable“.
- The degree of biodegradation reached 3 % after 28 days.
- The 10-day-window was not detected.
- Because the test item is a mixture, the 10-day window has not to be taken into account. As degradation missed the pass level of 60% in the course of the test, Heavy wax residue fraction, waste plastic derived, hydrothermal conversion is considered as not readily biodegradable, within 28 days.
- Abiotic degradation was not observed.

BOD5 / COD results

Results with reference substance:

Degradation of positive control ≥ 60%; Criterion: ≤ 14 days; Found: 12 days; Assessment: valid

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The valid results of this test show that Heavy wax residue fraction, waste plastic derived, hydrothermal conversion is not readily biodegradable within 28days. The degree of biodegradation reached 3%. No observations were made which might cause doubts concerning the validity of the study outcome.

Executive summary:

Degradation behaviour of positive control and toxicity control was normal. Abiotic degradation was not observed. Both replicates of the test item showed very good correspondence. The IC content of the test item solution in the medium was 2.08%. CO2 emitted by the controls was 20.4 mg/L. The Difference within the replicates was 3.1%. As degradation in the toxicity flask was 34.4 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 23.3 mg/L”.