Dibutyl 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Dibutyl 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate

EC Number:

217-192-9

EC Name:

Dibutyl 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate

Cas Number:

1770-80-5

Molecular formula:

C17H20Cl6O4

IUPAC Name:

dibutyl 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

The microbial inoculum consisted of activated sludge mixed liquor, collected from the oxidation ditch bioreactor at Saginaw Charter Township Wastewater Treatment Plant (Saginaw, Michigan), on July 10, 2017. This facility treats an excess of 24 million liters of wastewater per day, of which > 80% is from domestic sources. The activated sludge was collected one day prior to initiation of the test, and was continuously aerated until used. Prior to use, the activated sludge was screened through 500 µm nylon mesh, and briefly homogenized in a Waring blender (Waring Products Inc., Torrington, Connecticut). The mixed liquor suspended solids (MLSS) content of the homogenized sludge was determined gravimetrically to be 2,640 mg/L. Based on this determination, an appropriate volume of the homogenized activated sludge was added to the sterilized mineral medium to yield a final MLSS concentration of 29.8 mg/L (dry wt.).

- Water filtered: De-ionized water used to prepare the mineral medium and test chemical/reference material stock solutions was purified through a PURELAB Ultra water treatment system (ELGA LabWater, High Wycombe, United Kingdom) producing ultrapure water.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

45.8 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

other: BOD

Reference substance

Reference substance:

other: Sodium benzoate

Results and discussion

% Degradation

Key result

Parameter:

other: % degradation based on BOD

Value:

-5.5

St. dev.:

7.6

Sampling time:

28 d

Details on results:

This negative value is the result of the Test Mixtures reaction vessels consuming less oxygen than the Inoculum Blank reaction vessels. This indicates that the test material exhibited no biodegradation under the stringent conditions of the OECD 301F test.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

When tested in a 28-day biodegradation study according to OECD 301F Manometric Respirometry Test, dibutyl chlorendate reached 0% degradation.
Hence it is not readily biodegradable.