4-ethylbenzaldehyde

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:

19 Apr 1979 to 03 May 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: Kanpogyo No. 5

Qualifier:

according to guideline

Guideline:

other: Yakuhatu No. 615

Qualifier:

according to guideline

Guideline:

other: Kikyoku No. 392

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of the test substance (as cited in study report): 4-Ethylbenzaldehyde
- Molecular formula: C9H10O

Oxygen conditions:

aerobic

Inoculum or test system:

other: sludge (not further specified)

Details on inoculum:

- Source: Purchased from Chemical Safety Center of Chemicals Inspection & Testing Institute on February 27, 1979 and cultured

Duration of test (contact time):

14 d

Initial conc.:

100 mg/L

Based on:

test mat.

Remarks:

30 mg test substance was used, corresponding to 78.7 mg ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

Biological Oxygen Demand (BOD)

Details on study design:

TEST SYSTEM
- Temperature: 25 °C
- Sludge concentration: 30 mg/L

MEASUREMENTS: O2 demand, test substance concentration
- O2 demand: After 14 days, the biological oxygen demand was determined using an Automatic oxygen consumption meter (Okura Electric Coulometer, Model of the Hokkaido National Industrial Research Institute)
- Test substance concentration: Using a UV spectrophotometer, the pre-degradation concentration and post-degradation concentration of the test substance was measured and the dissappearance was calculated.

DESIGN
- 1 basal respiration flask containing 30 mg/L sludge
- 1 water + sample flask
- 2 test flasks containing 100 mg/L test substance and 30 mg/L sludge
- 2 positive control flasks containing 100 mg/L reference substance and 30 mg/L sludge

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

80.1

Sampling time:

14 d

Parameter:

% degradation (test mat. analysis)

Value:

98

Sampling time:

14 d

Remarks on result:

other: results obtained using UV spectrophotometer

Details on results:

The BOD of the test substance was determined to be 66.0 mg after 14 days.

Results with reference substance:

The degree of biodegradation of the reference substance after 7 days was 65.6 %.

Sample	BOD (mg)
Basal respiration (B)	3.0
Sludge + sample (BOD)	66.0

 

Degradation% = (BOD – B)/ThOD x100 = (66.0-3.0)/78.7 x100 = 80.1%

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Description of key information

The test substance was determined to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The biodegradation potential of the substance in water was determined in a non-GLP preliminary screening study in accordance to Japanese national guidelines (Niigata Research Laboratory, 1979). In this study, 100 mg/L test substance was inoculated with sludge for 14 days under aerobic conditions. During the incubation period the biological oxygen demand (BOD) was measured and thereafter compared to the theoretical uptake (ThOD), to determine the degree of biodegradation. Furthermore, Using a UV spectrophotometer, the pre-degradation concentration and post-degradation concentration of the test substance was measured and the dissappearance was calculated. After the 14-day incubation period 80.1% of the substance was found to be biodegraded by oxygen demand. Test substance UV spectrophotometry showed a disappearance of 98% of the test substance at study termination. Based on these findings, the test substance is determined to be readily biodegradable.