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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2017-05-03 to 2017-08-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose for cross-reference:
reference to same study
Remarks:
tox control
Qualifier:
according to guideline
Guideline:
other: OECD301F
Version / remarks:
OECD301F July 1992
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
no
Details on sampling:
- Concentrations: 128.2 mg/L sodium acetate and 8.3 mg of the test item were added into the toxicity control vessel, corresponding to a concentration of 200.2 mg ThOD/L

- Sampling method: -
- Sample storage conditions before analysis: -
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
128.2 mg/L sodium acetate and 8.3 mg of the test item were added into the toxicity control vessel, corresponding to a concentration of 200.2 mg ThOD/L. The initial pH was 7.6 and was not adjusted.
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):
Activated sludge, municipal wastewater treatment plant sludge, municipal wastewater
Breisgauer Bucht, 30 mg dry solids per litre
sampling 2017-05-03

- Laboratory culture: no
- Method of cultivation: no
- Storage conditions: not mentioned
- Storage length: 1d
- Preparation of inoculum for exposure:
The activated sludge was washed twicece with tap
water by settling the sludge, decanting the supernatant and re-suspending the sludge

- Pretreatment:
- Concentration of sludge: 30 mg dry solids per litre


- Initial cell/biomass concentration:
- Water filtered: yes/no
- Type and size of filter used, if any:
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
28 d
Key result
Duration:
28 d
Dose descriptor:
IC0
Effect conc.:
50 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition of respiration of reference substance sodium acetate according to the criteria of OECD301F
Details on results:
The degradatiion in the toxiicity control reached a value higher than 25% within 4 days. According to the validity criterion of the guideline OECD 301 the test item had no toxic effect to the inoculum.
The pH in the toxicity control vessel at the end of the test was 8.6.
Results with reference substance (positive control):
The reference compound sodium acetate reached the pass level for ready biodegradability (60% ThOD within a 10-day window) within 8 days.

Degradation table

 

 

Test item

 

Toxicity control

Reference item

Test item

8.3

8.4

8.4

8.3

 

 

 

[mg /164 ml]

 

 

 

 

 

 

 

Reference item
[ml /164 ml]*

 

 

 

164

164

164

164

ThOD [mg/1]

100.2

101.4

101.4

200.2

100.0

100.0

100.0

Day

 

 

Degradation {%]

 

 

0

0

0

0

0

0

0

0

4

13.0

15.6

21.3

27.6

55.3

55.3

55.3

8

35.6

35.2

46.2

37.5

66.6

69.4

66.6

12

51.5

53.7

62.0

46.7

74.1

76.9

74.1

16

60.8

65.6

68.4

55.7

75.1

77.6

77.6

20

65.5

70.3

70.3

62.4

73.8

79.8

71.3

24

72.1

73.7

73.7

72.8

74.8

83.8

74.8

28

71.2

75.8

75.8

77.8

76.8

82.8

73.8

Validity criteria fulfilled:
yes
Conclusions:
In a test on readily biodegradablility according to OECD301F, the test substance has no inhibitory effect on the degradation of sodium acetate at a concentration of 50mg/l.

Description of key information

In a test on readily biodegradablility according to OECD301F, the test substance has no inhibitory effect on the degradation of sodium acetate at a concentration of 50mg/l.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
50 mg/L

Additional information