Chloroethane

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:

24 AUG - 21 SEP 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): sewage treatment plant Marl-Ost, predominantely domestic
- Water filtered: yes
- Type and size of filter used, if any: white-band paper filter

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral salt medium
- Test temperature: 19.0 - 21.5 °C
- Continuous darkness: yes/no


TEST SYSTEM
- Culturing apparatus: 300 mL BSB-glas flasks


SAMPLING
- Sampling frequency: 0, 7, 14, 21 and 28 days



CONTROL AND BLANK SYSTEM
- Inoculum blank: yes

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

-3

Sampling time:

28 d

Parameter:

BOD5

Value:

1.49 mg O2/g test mat.

Results with reference substance:

70% after 28 days

	% O2-consumption
Day	7	14	21	28
Test substance	-3	-9	-7	-3

Interpretation of results:

under test conditions no biodegradation observed

Description of key information

The substance is not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

The ready biodegradability of chloroethane (CAS 75-00-3) was investigated in a Closed Bottle Test according to the EU Method C4. –E (Schöberl, 1993). In the test domestic activated sludge was used as inoculum. The oxygen consumption of the inoculum was followed over an incubation period of 28 days. The oxygen demand of -3% was determined after 28 days.Thus, biodegradation of the test substance could not be demonstrated.

Literature data predict a half-life of the substance of 1-4 weeks in surface water under aerobic conditions (Printup, 1991). Whereas a degradation rate of 13% after 107 days was reported for the degradation under anaerobic conditions (Vogel and McCarty, 1987). Comparable results were predicted by Printup (1991) for the aqueous biodegradation (not acclimated) under anaerobic conditions (half-life 28 days - 16 weeks).