3-Isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, oligomers, reaction products with 2-butanone oxime

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001-04-19 to 2001-07-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

INOCULUM/TEST ORGANISM
- Source: STP Gross-Zimmern (Germany)
- Preparation of inoculum: Centrifugation, decantation and resuspension in tap water (repeated twice); preparation of 1.5 g dry weight/l in test  wate aeration until use

Duration of test (contact time):

28 d

Initial conc.:

103.5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

METHOD OF PREPARATION OF TEST SOLUTION
- Direct weighing of substances  into test flasks, continuous stirring during the exposure period

TEST SYSTEM
- Culturing apparatus: 500 mL flasks filled with 244 mL test solution
- Number of culture flasks per concentration: 2 with test substance and inoculum; 2 with inoculum only (inoculum control); 1 with reference substance (25.7 mg/244 mL = 105.3 mg/L) and inoculum (procedure control); 1 with test substance (102.9 mg/L) and sterile filtered test water (abiotic control); 1 with test (104.1 mg/L) and reference (102.9 mg/L) substances and  inoculum (toxicity control)
- Measuring equipment: manometer (BSB/BOD-Sensor-System, Aqualytic)
- Closed vessels used: yes

TEST CONDITIONS
- Composition of medium: (A) Dissolved deionized water, total volume 1000 mL: 8.50 g KH2PO4; 21.75 g K2HPO4; 33.40 g Na2HPO4 * 2 H2O; 0.50 g NH4Cl; (B) Dissolved deionized water, total volume 1000 mL: 22.50 g MgSO4 * 7 H2O; (C) Dissolved deionized water, total volume 1000 mL: 36.40 g CaCl2 * 2 H2O; (D) Dissolved deionized water, total volume 1000 mL: 0.25 g FeCl3 * 6 H2O; 1 drop of concentrated HCl; 10 mL (A) + 1 mL each (B), (C), (D) in deionized water, total volume  1000 mL
- Test temperature: 21-22 °C
- pH value: 7.6 (start); 7.6 (end)
- Concentration of suspended solids: 30 mg dry solids/L
- Other relevant factors: darkness; absorption of evolved CO2 in 45 % KOH  solution

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

- Toxicity control
41 % degradation (14 days)
49 % degradation (28 days)
Conclusion: The test substance does not inhibit the microorganisms.
- Abiotic control
No oxygen demand was determined.

Results with reference substance:

Kinetic of control substance (in %):
= 10 after 4 day(s)
= 87 after 14 day(s)

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance can therefore be considered to be not readly biodegradable.

Executive summary:

The substance can therefore be considered to be not readly biodegradable.

Description of key information

In a biodegredation study according to OECD Guideline 301 F 0 % degredation were observed (Hertl, 2001). The substance can therefore be considered to be not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Additional information

Study rel.2, Müller, 1992:

Ready biodegradability of the substance was assessed according to EC method C.4.D fulfilling all validity criteria. Bacterial respiration was measured as theoretical oxygen demand and gave 21 % biodegradation within 28 days (positive control aniline: 80 % within 28 days). Test sample included 35 % solvent naphtha and observed biodegradation is expected to be that of the solvent. As a conclusion these results are considered to support the results of the respective key study.