Registration Dossier

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:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

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 concentrationsopen allclose all
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
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.