Registration Dossier

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:
Apr - May 1998
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: According to OECD guideline under GLP
Cross-reference
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report Date:
1998

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): AD-Cyanhydrin
- Analytical Purity: 93,9%
- Lot/batch No.: 14523046

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:
COD

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
77
Sampling time:
28 d
Details on results:
The test compound ZK 5668 was degraded to 77% 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 AD-Cyanhydrin

 Test compound    Nominal concentration of carbon    Day of sampling
4 7 8 9 11 16 22 30
 ZK 74804    10 mg/l 0 3 14 27 38 52 64 77
 Sodium acetate (reference)    10 mg/l  15 40 52 59 65 74 80 86
 ZK 74804 + sodium acetate (toxicity control)    10 mg/l + 10 mg/l   7 29 43 52 60 71 77 90

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
inherently biodegradable
Conclusions:
In accordance with the OECD guideline, the test eompound AD-Cyanhydrin is not readily
biodegradable under the conditions of the test though the substance missed the 60% pass level only slightly and was degraded to 77% at the end of
the test period. This indicates that AD-Cyanhydrin is of good biodegradability and persistence has not to be expeeted. AD-Cyanhydrin was
not toxic to the microbes of activated sludge .
Executive summary:

The purpose of this study was to determine the ready biodegradability of AD-Cyanhydrin, an intermediate of the synthesis of hydroxyprogesterone (ZK 5149). The study was conducted in agreement with the following test guideline:

OECD guideline for testing of chemieals, Ready biodegradability: C02-evolution test, no. 301 B, adopted Jul. 92, OECD Paris, 93.

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 in a concentration of 10 mg carbon/I 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 test substance 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 (C02) produced during the test period.

The test compound AD-Cyanhydrin was degraded to 38% on day 11 (10 days of incubation) and up to 77% on day 30 (28 days of incubation). The degradation started after a short lag-phase. The reference compound sodium acetate was degraded to more than 60% on day 11 and up to 86% on day 30.

In the toxicity control, the reference compound (sodium acetate) plus the test compound was degraded up to 90% on day 30, which corresponded to the degree of degradation expected on the basis of the observations with the individual compounds.