2-chloropropionic acid

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Modern day guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-chloropropionic acid

EC Number:

209-952-3

EC Name:

2-chloropropionic acid

Cas Number:

598-78-7

Molecular formula:

C3H5ClO2

IUPAC Name:

2-chloropropanoic acid

Details on test material:

The certificate of analysis indicates 94.3% purity. The substance is a clear, colourless liquid. It has a pungent odour and is stored in the dark in a cool, well ventilated area.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

The activated sludge was obtained from Cambridge Sewage Treatment Works. The sludge was sieved to 850 µm, settled, decanted and resuspended using mineral media. This was then centrifuged at 4000 rpm for 10 minutes and the supernatant discarded. The sludge was then resuspended and centrifuged again at 4000 rpm for 10 minutes and the supernatant again discarded. Dry sludge solids determination was conducted on the pellet produced.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

60.3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Conical flasks of nominal volume 2000 ml were filled with 1500 ml of inoculated mineral medium.The blanks, references and test bottles were set up in duplicate with a single replicate for a toxicity control. Test and reference materials were added to the appropriate bottles to a final concentration of 20 mg carbon/litre. Atmopsheric air was pumped into the test system and scrubbed clean of carbon dioxide by passing over soda lime. The air then continued into the test vessel where it collected any evolved carbon dioxide before moving into the carbon dioxide traps, each containing 200 ml of 0.05 M sodium hydroxide solution. The test solutions were stirred for the duration of the study.

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

Preliminary study:

Not applicable

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

88

Sampling time:

28 d

Details on results:

2-Chloropropionic acid gave a positive result (> 60% degradation relative to the theoretical CO2 value) with a maximum of 99% recorded on day 29. It is concluded therefore that there is potential for biodegradation under environmental conditions. The inoculum blank should not normally produce more than 40 mg/l CO2 (10.9 mg/l C) for the test to be valid. A value of 29.6 mg/l (8.1 mg/l C) was recorded. The guideline requires that the reference material degrades by at least 60% of its theoretical CO2 value. A maximum value of 88% degradation of the sodium acetate was achieved on day 29. The test protocol requires that a 10 day window is applied to the degradation result (60% degradation to be reached within 10 days of 10% of the theoretical carbon dioxide produced). 10% degradation was achieved after approximately 5 days and 60% was achieved after 8 days. 2-Chloropropionic acid therefore achieved the 10 day window.

BOD5 / COD results

Results with reference substance:

The guideline requires that the reference material degrades by at least 60% of its theoretical CO2 value. A maximum value of 88% degradation of the sodium acetate was achieved on day 29.

Any other information on results incl. tables

The biodegradation rate of the test material in comparison to the reference material over the period of the test is tabulated below:-

Time (days)	Biodegradation		Biodegradation
	Reference Material, Sodium Acetate		Test Material, 2-Chloropropionic acid
0	0		0
2	35		7
5	56		8
7	63		40
10	66		63
14	76		78
19	80		82
23	82		86
28	84		88
29	87		89
29	88		99

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

All the test and validity criteria were successfully achieved during this study. The final conclusion is that 2-chloropropionic acid is readily biodegradable in an aerobic aqueous environment.

Executive summary:

2 -Chloropropionic acid was tested in a biodegradation study according to OECD guideline 301B - CO2 evolution test. The reference substance was sodium acetate. The study was conducted to GLP. 2 -Chloropropionic acid gave a positive result (> 60% degradation relative to the theoretical carbon dioxide value) with a maximum of 99% degradation being recorded on day 29. Therefore, the conclusion is that 2-chloropropionic acid is readily biodegradable in an aerobic aqueous environment.