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Diss Factsheets

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Mar - Apr 2000
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: According to OECD guideline under GLP
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Principles of method if other than guideline:
Not relevant
GLP compliance:

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
Details on test material:
- Name of test material (as cited in study report): Methoxyestradien-Cyanhydrin
- Analytical purity: 91.3%
- Lot/batch No.: 57046805

Study design

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

Results and discussion

% Degradation
% degradation (CO2 evolution)
0 - 16
Sampling time:
28 d
Details on results:
The reference compound sodium acetate was degraded to 80 % on day 14 and to 89 % on day 28.
In the toxicity control, the reference item (sodium acetate) plus the test item ZK 74834, was degraded to 28 % on day 28.

Any other information on results incl. tables

Table 1: Biological degradation (cumulativ) in percent (corrected for CO2 production in the blank control) of ZK74834

 Day of sampling  
Test item    Nominal concentration of carbon 1 4 6 8 11 14 18 21 25 28 29
   11,5 mg/l  1 st rep.   2 3 3 2 7 11 13 13 14 16 16
 ZK 74834    2 nd rep.   0 1 0 3 7 7 7 8 8 9 11
    3 rd rep.   1 2 1 0 2 1 0 0 0 0 0
 Reference    10,2 mg/L   8 34 56 66 72 80 86 86 87 88 89
 (sodium acetate)                                      
 Toxicity control    11,5 mg/L +   4 20 29 30 31 30 28 27 27 27 28
 (ZK 74834 + sodium acetate)    10,2 mg/L                                   

Applicant's summary and conclusion

Validity criteria fulfilled:
Interpretation of results:
inherently biodegradable
The test item ZK 74834 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 Methoxyestradien-Cyanhydrin (ZK 74834). ZK 74834 is an intermediate of the synthesis of Gestonorone. The study was conducted in agreement with the OECD test guideline no. 301 B.

The test item was incubated in an aqueous solution including nutrients with microorganisms from a municipal sewage treatment plant for 28 days (start of treatment = day 0). The nutrient solutions were made up of phosphates, magnesium sulphate, iron chloride, ammonium chloride and calcium chloride. The test item was incubated at a concentration of 11.5 mg carbon/L (15 mg test item/L) in triplicate. Additionally, a reference item (sodium acetate) was tested at a concentration of 35 mg/L 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 10.2 mg carbon/L (reference item) plus ZK 74834 at 11.5 mg carbon/L representing a toxicity control. Furthermore, a blank control was tested in triplicate without any test or reference item. The biological degradation of the test and reference items was evaluated by measurement of the carbon dioxide (C02) produced during the test period. C02 production was determined on days 1,4, 6, 8, 11, 14, 18, 21, 25, 28 and 29. On day 28 the solutions were acidified in order to expel all dissolved CO2, and C02 was determined on day 29. The CO2 production was calculated as the percentage of total C02 that the test item could theoretically have produced, based on carbon content. The C02 production in the blank control was subtracted for correction.

The test compound was degraded to 0 - 16 % in the triplicates on day 28. The reference compound sodium acetate was degraded to 80 % on day 14 and to 89 % on day 28. In the toxicity control, "the reference item (sodium acetate) plus the test item ZK 74834, was degraded to 28 % on day 28.