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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:
Jun - Jul 2000
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: According to OECD guideline under GLP
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2001
Report Date:
2001

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
Principles of method if other than guideline:
Not relevant
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Estren-Cyanhydrid-3-Neopentenketal
- Analytical purity: 91.7%
- Lot/batch No.: 1368

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
10 mg/L
Based on:
DOC

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
3
Sampling time:
28 d
Details on results:
The reference compound sodium acetate was degraded to 87% on day 29 (~ 28 days of
incubation). In the toxicity control, the reference compound (sodium acetate) plus the test compound
ZK 30367, was degraded to 48% on day 29 (~ 28 days of incubation).

Any other information on results incl. tables

Table 1: Biological degradation (cumulative) in percent (corrected for blank CO2 production) of ZK 30367

          Nominal              
    Concentration   4 8 11 16 21 25 29
 Test compound    of carbon                       
 ZK 30367    10 mg/L   1 1 2 2 3 4 3
 Reference    10 mg/L   33 65 74 80 84 87 87
 (sodium acetate)                          
 Toxicity control    10 mg/L +   17 33 38 43 46 47 48
 (ZK 30367 +    10 mg/L                       
 sodium acetate)                       

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
inherently biodegradable
Conclusions:
In accordance with the OECD guideline, the test compound ZK 30367 is not readily
biodegradable under the conditions of the test and it was not toxic to the microbes of activated sludge.
Executive summary:

The purpose of this study was to determine the ready biodegradability of Estren-Cyanhydrin-3 -Neopentylketal (ZK 30367), which is an intermediate of the synthesis of gestonorone. The study was conducted in agreement with the OECD test guideline no. 301 B.

The test substance was incubated in an aqueous solution including nutrients with microorganisms from a municipal sewage treatment plant for 28 days (start of treatment = day 1). The nutrient solutions were made up of phosphates, magnesium sulphate, iron chloride, ammonium chloride and calcium chloride. The test substance was incubated at a concentration of 10 mg carbon/L in triplicate. Additionally, a reference substance (sodium acetate) was tested in a single set according to the same procedure, in order to verify the viability and activity of the degrading microorganisms. One further set was incubated with sodium acetate at 10 mg carbon/L (reference substance) plus ZK 30367 at 10 mg carbon/L representing a toxicity control. Furthermore, a blank control was tested in triplicate without any test or reference substance. The biological degradation of the test and reference substances was evaluated by measurement of the carbon dioxide (C00 produced during the test period. CO2 production was determined on days 4,8,11,16,21,25 and 29. On day 28 the solutions were acidified in order to expel all dissolved CO2, and CO2 was determined on day 29. The CO2 production was calculated as the percentage of total CO2 that the test material could theoretically have produced, based on carbon content. The blank CO2 production was subtracted for correction.

The test compound was degraded to 3% on day 29 (~ 28 days of incubation). The reference compound sodium acetate was degraded to 87% on day 29 (~ 28 days of incubation). In the toxicity control, the reference compound (sodium acetate) plus the test compound, was degraded to 48% on day 29 (~ 28 days of incubation).