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Environmental fate & pathways

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:
2017-10-19 - 2017-09-20 (experimental phase)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Version / remarks:
OECD Guidelines for the Testing of Chemicals Part 301 F, adopted 17. Jul. 1992 „Manometric Respirometry Test“
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Version / remarks:
Council Regulation (EC) No. 440/2008, Guideline C.4-D, adopted 30. May 2008 “Manometric Respirometry Test”
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Sponsor

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: The test item was stored in a closed vessel at room temperature 16.0 – 21.6 °C, away from light and humidity.

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge from a biologic sewage treatment plant was used. The chosen plant is treating mostly household sewage.
The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf.
Date of collection: 21. Sep. 2017, batch no: 20170921.
- Pretreatment: The sludge was filtrated, washed with tap water 2x, then washed with and re-suspended in test medium. It was then aerated.
- Concentration of sludge: The dry matter was determined as 4980 mg suspended solids/L.
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
87.8 mg/L
Based on:
test mat.
Initial conc.:
100.2 mg/L
Based on:
ThOD
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium:
Stock Solutions
Solution a
Potassium dihydrogen phosphate (KH2PO4) 8.5 g
Dipotassium hydrogen phosphate (K2HPO4) 21.75 g
Disodium hydrogenphosphate dihydrate (Na2HPO4*2H2O) 33.4 g
Ammonium chloride (NH4Cl) 0.5 g
H2O demin. ad 1000 mL
The pH was to 7.4.
Solution b
Calcium chloride (CaCl2) 27.5 g
H2O demin. ad 1000 mL
Solution c
Magnesium sulphate heptahydrate (MgSO4*7H2O) 22.5 g
H2O demin. ad 1000 mL
Solution d
Iron(III) chloride hexahydrate (FeCl3*6H2O) 0.25 g
Disodium ethylene-diaminetetraacetate dihydrate (Na2EDTA*2H2O) 0.4 g
H2O demin. ad 1000 mL
Test Medium
The medium was freshly prepared (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
Mercury Chloride
HgCl2 (10 g/L), used for poisoning of abiotic flasks
Soda lime
CO2 adsorbent

- Test temperature: 20.9 - 21.1 °C
- pH: 7.2 - 7.4

TEST SYSTEM
- Culturing apparatus: 500 mL-flasks were used as test vessels (590 mL total volume including measuring head).
All glassware was cleaned with the laboratory cleaning agent and then rinsed with tap water (3x), diluted HCl (1x), tap water (3x) and deionised water (3x).
Volume test solution was 250 mL (toxicity flask 125 mL)
- Number of culture flasks/concentration:
Number of control flasks: 3 (medium and inoculum)
Number of positive control flasks: 3 (sodium-benzoate, medium and inoculum)
Number of test vessels: 3 (test item, medium and inoculum)
Abiotic control: 1 (test item and 10 mL 1% HgCl2 solution/L)
Toxicity control: 1 (200 mg/L ThOD, 100 mg/L ThOD each of test item and positive control)

- Details of trap for CO2 and volatile organics if used: soda lime
- Other: Concentration of suspended solids: 24.9 mg/L, 24.7 mg/L in the toxicity control

CONTROL AND BLANK SYSTEM
see above
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

Test performance:
All validity criteria were met.
% Degradation
Key result
Parameter:
% degradation (O2 consumption)
Value:
11
Sampling time:
28 d
Remarks on result:
other: not readily biodegradable
Remarks:
degradation missed 60 % in the course of the test

BOD5 / COD results

Results with reference substance:
Degradation of positive control was > 60% after 3 days.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The study was performed according to OECD TG301F and EU Method C.4-D (GLP) with no deviation and is therefore considered to be of the highest quality (reliability Klimisch 1). The validity criteria of the test system are fulfilled. Degradation at the end of the test (28 days) was 11 %. Therefore, regardless of the 10-day window, the test item is considered as not readily biodegradable following OECD 301F/EU C.4-D. No observations were made which might cause doubts concerning the validity of the study outcome. The result of the test can be considered valid.
Executive summary:

The biodegradability of the test substance was investigated according to EU method C.4 -D and OECD guideline 301 F (GLP).

The test item 2-Butyne-1,4-diol, reaction products with 1,2-oxathiolane 2,2-dioxide and sodium hydroxide (HBOPS-Na) was tested using a concentration of 88 mg test item/L (equivalent to a theoretical oxygen demand of 100.2 mg O2/L). Activated sludge was used as inoculum. The test was left running for 28 days.

All validity criteria were met. The positive control reached the pass level of 60% on day 3 (criterion:£14).

The following data could be determined for the test item 2-Butyne-1,4-diol, reaction products with 1,2-oxathiolane 2,2-dioxide and sodium hydroxide (HBOPS-Na):

degradation at the end of the test: 11 %

Because the test item is a mixture the 10-day-window has not to be taken into account. As degradation missed 60% in the course of the test, 2-Butyne-1,4-diol, reaction products with 1,2-oxathiolane 2,2-dioxide and sodium hydroxide (HBOPS-Na) is considered as not readily biodegradable following OECD 301F and EU C.4-D.