Isobutyl (S)-2-chloropropionate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to the OECD guideline 301B.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Isobutyl (S)-2-chloropropionate

EC Number:

280-349-5

EC Name:

Isobutyl (S)-2-chloropropionate

Cas Number:

83261-15-8

Molecular formula:

C7H13ClO2

IUPAC Name:

isobutyl (S)-2-chloropropanoate

Constituent 2

Reference substance name:

Isobutyl 2-chloropropionate

EC Number:

263-411-6

EC Name:

Isobutyl 2-chloropropionate

Cas Number:

62108-67-2

IUPAC Name:

isobutyl 2-chloropropanoate

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Aeration tank of WWTP of Mannheim/BasdenWürttemberg (Germany)
- Storage conditions: aerated
- Storage length: 24 hours
- Preparation of inoculum for exposure: A suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size of about 1 mm. After settling the supernatant was discarded and the sludge suspension was filled up with tap water. The sludge of the suspension was adjusted to a concentration of 6.0 g/L dry weight. An aliquot of 7.5 mL was added to the test vessels, to obtain a sludge concentration of 30 mg/L dry substance. Finally the activated sludge suspension in the test vessels was preaerated for about 24 hours at a temperature of 22 ± 2 °C.
- Concentration of sludge: 30 mg/L dry substance

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

20 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: The used mineral medium complies with the test guideline OECD 301B. It was prepared as follows:
Solution A: KH2PO4 : 8.50 g, K2HPO4 : 21.75 g, Na2HPO4 × 2 H2O : 33.40 g, NH4Cl : 0.50 g
The compounds were dissolved in 1000 mL distilled water; the pH value was adjusted to 7.4.
Solution B: CaCl2 × 2 H2O : 36.40 g; the compound was dissolved in 1000 mL distilled water.
Solution C: MgSO4 × 7 H2O : 22.50 g; the compound was dissolved in 1000 mL distilled water.
Solution D: FeCl3 × 6 H2O : 0.25 g; the compound was dissolved in 1000 mL distilled water.
15 mL solution A, 1.5 mL solution B, 1.5 mL solution C and 1.5 mL solution D was used for the preparation of the test assays.

- Test temperature: 22 +/- 2°C
- pH: 7.4 +/- 0.2
- pH adjusted: yes
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2 L incubation bottles filled up to a volume of 1.5 L, connected with two serial scrubbing bottles for carbon dioxide absorption
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: aeraion with carbn dioxide free air at a flow of 800 ml per hour
- Measuring equipment: TOC-analyzer with auto sampler (Shimadzu TOC-5000A)
- Test performed in closed vessels due to significant volatility of test substance: closed

SAMPLING
- Sampling frequency: after 0, 2, 3, 6, 10, 14, 17, 20, 23, 27, 28 and 29 days
- Sampling method: auto sampler of Shimadzu TOC-5000A

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 blank controls, 1 inhibition control, 1 reference substance control

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

80 - 90

Sampling time:

28 d

Details on results:

- Duration of the adaptation phase (days): 4
- Degradation of the test subst. at the end of the ten-day window (% CO2/ThCO2): 70 - 80
- Degradation degree of the reference substance after 14 days (% CO2/ThCO2): 80
- Degradation degree in the inhibition control after 14 days (% CO2/ThCO2): 82

Applicant's summary and conclusion

Interpretation of results:

readily biodegradable