1,1'-isopropylidenebis(ethylferrocene)

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

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

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

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 structural similarity to 1,1"-isopropylidenebis(ethylferrocene), CAS Number 37206 -42 -1, EC Number 310 -202 -3, the distinction being that the alkyl bridging functionality between the two ferrocene moieties is an octyl derivative as opposed to an isopropyl derivative and that two cyclopentadienyl moieties in the target substance bear ethyl substituents.

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"-isopropylidenebis(ethylferrocene), CAS Number 37206 -42 -1, EC Number 310 -202 -3 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.

Reference 2

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:

other: Guideline study without detailed documentation

Qualifier:

according to guideline

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 structural similarity to 1,1"-isopropylidenebis(ethylferrocene), CAS Number 37206 -42 -1, EC Number 310 -202 -3. 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"-isopropylidenebis(ethylferrocene), CAS Number 37206 -42 -1, EC Number 310 -202 -3 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).

Both substances are considered to be sufficiently close in structural integrity to 1,1"-isopropylidenebis(ethylferrocene), CAS Number 37206 -42 -1, EC Number 310 -202 -3 so as to justify valid read-across.

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.

As a consequence, it can be stated that 1,1"-isopropylidenebis(ethylferrocene), CAS Number 37206 -42 -1, EC Number 310 -202 -3 will not be readily biodegradable but indications are that inherent biodegradation may be observed.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater