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Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
April to June 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
Read across data is presented from the structurally related substance, 1,1'-Bis(ferrocenyl)octane, CAS Number 501410-94-2, EC Number 479-710-1. This substance bears a close similarity to 1,1''-isopropylidenediferrocene, CAS Number 12609-95-9, EC Number 235-719-0, the distinction being that the alkyl bridging functionality between the two ferrocene moieties is an octyl derivative as opposed to an isopropyl derivative.
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The soldi material was re-suspended in isotonic saline solution and again centrifuged. This procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 4 g dry material per litre were mixed with test water and then aerated until use. Before use the sludge was filtered through cotton wool.
Duration of test (contact time):
28 d
Initial conc.:
2 mg/L
Based on:
COD
Remarks:
Acetone was used as a co-diluent
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance:
acetic acid, sodium salt
Key result
Parameter:
% degradation (O2 consumption)
Value:
3
Sampling time:
28 d
Results with reference substance:
The reference substance degraded to a level of 81% after 28 days under identical laboratory conditions to the test item.
Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
1,1'-Bis(ferrocenyl)octane, CAS Number 501410-94-2, EC Number 479-710-1 is not readily biodegradable. In a 28 day OECD 301D study the substance demonstrated 3% biodegradation.
Executive summary:

The ready biodegradability of 1,1'-Bis(ferrocenyl)octane, CAS Number 501410-94-2, EC Number 479-710-1 was investigated in accordance with the standardised guideline OECD 301D.

An OECD 301D study conducted to GLP in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results was performed on 1,1'-Bis(ferrocenyl)octane, CAS Number 501410-94-2, EC Number 479-710-1.

The study was assigned a reliability score of 1 in accordance with the criteria for assessing data quality set forth by Klimisch et al. (1997).

This substance is considered to be sufficiently close in structural integrity to 1,1''-isopropylidenediferrocene, CAS Number 12609-95-9, EC Number 235-719-0 so as to justify valid read across.

Under the conditions of the study 3% biodegradation was observed in 28 days. The substance therefore is not regarded as readily biodegradable.

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1987
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
not specified
GLP compliance:
not specified
Specific details on test material used for the study:
Read across data is presented from the structurally related substance, iron(2+) dicyclopenta-2,4-dienide (ferrocene), CAS Number 102-54-5, EC Number 203-039-3. This substance bears a close similarity to 1,1''-isopropylidenediferrocene, CAS Number 12609-95-9, EC Number 235-719-0. Therefore, it is considered that read-across is valid.
Oxygen conditions:
anaerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Duration of test (contact time):
41 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
11
Sampling time:
8 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
34
Sampling time:
21 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
56
Sampling time:
28 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
65
Sampling time:
40 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
73
Sampling time:
41 d
Details on results:
The microbial degradation of ferrocene was on average 11% after 8 days and rose nearly linearly to the 40th Day. On 27 days, after contact of the medium, the mean reduction was 56%, rising to 73% on the 41st Day. Degradation occurs in a linear pattern so, by extrapolation, 100% mineralisation will occur < 60days
Validity criteria fulfilled:
yes
Interpretation of results:
inherently biodegradable
Conclusions:
In a study performed to OECD Guideline 301 B, ferrocene failed to meet the criteria for ready biodegradability. It has been classified as Inherently biodegradable because by day 27 degradation was 56%, rising to 73% by day 41. Degradation occurs in a linear pattern so, by extrapolation, 100% mineralisation will occur.
Executive summary:

The ready biodegradability of iron(2+) dicyclopenta-2,4-dienide (Ferrocene), CAS Number 102-54-5, EC Number 203-039-3 was investigated in accordance with the standardised guideline OECD 301B.

The study was assigned a reliability score of 2 in accordance with the criteria for assessing data quality set forth by Klimisch et al. (1997).

This substance is considered to be sufficiently close in structural integrity to 1,1''-isopropylidenediferrocene, CAS Number 12609-95-9, EC Number 235-719-0 so as to justify valid read across.

In this study ferrocene failed to meet the criteria for ready biodegradability. It has been classified as Inherently biodegradable since by day 27 degradation was 56%, rising to 73% by day 41. Degradation occurs in a linear pattern so, by extrapolation, 100% mineralisation will occur.

Description of key information

Two studies are presented on structurally related substances as valid read across candidates: 1,1'-Bis(ferrocenyl)octane, CAS Number 501410-94-2, EC Number 479-710-1 (OECD 301D) and Iron(2+) dicyclopenta-2,4-dienide (Ferrocene), CAS Number 102-54-5, EC Number 203-039-3 (OECD 301B).

1,1'-Bis(ferrocenyl)octane, CAS Number 501410-94-2, EC Number 479-710-1 acheived a biodegradation rate of 3% in 28d in the OECD 301D study. Therefore, this substance is not readily biodegradable.

Iron(2+) dicyclopenta-2,4-dienide (Ferrocene), CAS Number 102-54-5, EC Number 203-039-3 failed to meet the criteria for ready biodegradability in an OECD 301B study. It has been classified as Inherently biodegradable since by day 27 degradation was 56%, rising to 73% by day 41. Degradation occurs in a linear pattern so, by extrapolation, 100% mineralisation will occur.

Since 1,1'-Bis(ferrocenyl)octane, CAS Number 501410-94-2, EC Number 479-710-1 is more closely trelated in structural integrity to 1,1''-isopropylidenediferrocene, CAS Number 12609 -95 -9, EC Number 235 -719 -0 this substance is not expected to be readily biodegradadble. However, evidence from the study conducted on Iron(2+) dicyclopenta-2,4-dienide (Ferrocene), CAS Number 102-54-5, EC Number 203-039-3 indicates that inherent biodegradation is to be expected.

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable

Additional information