(S)-2-chloropropionic acid

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

5th May 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

(S)-2-chloropropionic acid

EC Number:

411-150-5

EC Name:

(S)-2-chloropropionic acid

Cas Number:

29617-66-1

Molecular formula:

Hill formula: C3H5ClO2 CAS formula: C3H5ClO2

IUPAC Name:

(2S)-2-chloropropanoic acid

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Any other information on results incl. tables

The inhibition results are summarised in Table 1.

 

Table 1.

Flask No.	Test Material	Test Concentration (mg/L)	Aeration time = 3 hours
			Respiration Rate (mg O2l^-1h^-1)	% of Mean control respiration rate	% Inhibition
1	Control	Control	44.0	-	-
2	Control	Control	46.8	-	-
3	^a3,5-DCP	1.0	45.8	95.9	<5
4	3,5-DCP	3.2	35.3	73.9	26
5	3,5-DCP	10	20.0	41.9	58
6	3,5-DCP	32	9.5	19.9	80
7	3,5-DCP	100	4.5	9.4	91
8	^bL-CPA	10	50.5	105.9	<5
9	L-CPA	10	48.0	100.6	<5
10	L-CPA	32	50.0	104.8	<5
11	L-CPA	32	49.5	103.8	<5
12	L-CPA	100	48.0	100.6	<5
13	L-CPA	100	44.0	92.2	<5
14	Control	Control	51.5	-	-
15	Control	Control	48.5	-	-

 

^a3,5-Dichlorophenol

^bL-2-Chloropropionic acid

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The results summarised in table 1 show the 3 hour IC50 for L-Chloropropionic acid to be >100mg/L with a NOEC of 100 mg/L.
The reference substance showed substantial inhibition of the respiration rate of the activated sludge. The IC50 calculated for the reference substance was 7.7mg/L; this was within the normal expected range of 5-30 mg/L. This confirms the viability of the activated sludge.

Executive summary:

The effect of L-2-Chloropropionic acid on the respiration rate of activated sludge micro-organisms was assessed in a study according to OECD 209 over a period of 72 hours.

 

The respiration rate was measured with and without the presence of the test chemical.

 A reference chemical, 3, 5-Dichlorophenol was also tested to ensure that the batch of sludge showed a normal level of sensitivity.

Nominal concentrations of the test substance, L-2-Chloropropionic acid, were prepared at 10, 32, 100mg/L in duplicate cultures, together with four blanks and five flasks containing the reference material. The reference material was tested at nominal concentrations of 1, 3.2, 10, 32 and 100 mg/L.

The respiration rate of each culture was measured after 3 hours and the rate compared with the mean respiration rate of the four control cultures.

Measurement of the respiration rate was determined by measuring the rate of oxygen uptake in a confined Perspex cell fitted with a polargrahic oxygen electrode.

The results showed the 3 hour IC50 for L-2-Chloropropionic acid to be >100mg/L with a NOEC of 100 mg/L.

The reference substance showed substantial inhibition of the respiration rate of the activated sludge. The IC50 calculated for the reference substance was 7.7mg/L; this was within the normal expected range of 5-30 mg/L. This confirms the viability of the activated sludge.