Heptanoic anhydride

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Oct 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial conc.:

200 mg/L

Based on:

ThOD/L

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

79

Sampling time:

28 d

Details on results:

The reference compound sodium acetate was degraded to 89% on day 29 (28 days of incubation).
60% degradation was reached on day 5. In the toxicity control, the reference compound (sodium acetate) plus the test
compound, was degraded to 88% on day 29 (28 days of incubation), which reflected the degradation in the individual sets.

Table 1: Biological degradation (cumulative) in percent (corrected for blank O2 consumption) of ZK 56406

		Day of sampling
Test compound	Concentration expressed in theoretical O2 demand	2	6	10	14	18	22	26	29
ZK 56406	200 mg/L	0,5	26,3	53,7	63,9	70,9	74,2	77,6	78,6
Reference (sodium acetate)	200 mg/L	15,7	76,7	82,3	85,4	87,4	87,7	88,8	88,6
Toxicity control (ZK 56406 + sodium acetate)	100mg/L+ 100 mg/L	0,9	61,2	78,3	81,9	83,4	85,7	87,3	87,6

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

In accordance with the OECD guideline, the test compound or precisely, the corresponding
acid is 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 Enanthsäureanhydrid, which is an intermediate of the synthesis of different therapeutica. The test substance is an acid anhydride and hydrolyzes quickly to the corresponding acid. Therefore, the acid is the predominant compound available for the degradation process. The study was conducted in agreement with the OECD test guideline no. 301F.

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 200 mg theoretical oxygen demand (ThOD) per litre. 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 100 mg ThOD/L (reference substance) plus test substance at 100 mg ThOD/L representing a toxicity control. Furthermore, a blank control was tested in triplicate without any test or reference substance. The biological degradation ofthe test and reference substances was evaluated by measurement of the 02 consumption during the test period. 02 consumption was continuously monitored and recorded by an automated device. The O2 consumption was calculated as the percentage of total O2 that the test material could theoretically have consumed, based on the molecular formula. The blank 02 consumption was subtracted for correction.

The test compound was degraded to 79% on day 29 (28 days of incubation). The reference compound sodium acetate was degraded to 89% on day 29 (28 days of incubation). 60% degradation was reached on day 5. In the toxicity control, the reference compound (sodium acetate) plus the test compound, was degraded to 88% on day 29 (28 days of incubation), which reflected the degradation in the individual sets.

Description of key information

In accordance with the OECD guideline, the test compound or precisely, the corresponding

acid is readily biodegradable under the conditions of the test and it was not toxic to the microbes

of activated sludge.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater