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Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From October 19, 2016 to December 20, 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))
GLP compliance:
yes
Test organisms (species):
activated sludge
Details on inoculum:
- Source of inoculum/activated sludge: Dihua sewage treatment plant, Taiwan.
Total exposure duration:
3 h
Test temperature:
20 ± 2 °C
pH:
6.78-7.77
Nominal and measured concentrations:
10, 100 and 1000 mg/L
Details on test conditions:
- Aeration: The test mixture was incubated under conditions of forced aeration at 0.5-1.0 L/min with air removed dust and oil.
- No. of vessels per abiotic control (replicates): three
- Sludge concentration: 1.50 g/L
- Nitrification inhibitor used : N-allylthiourea
Reference substance (positive control):
yes
Remarks:
3,5-Dichlorophenol
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth inhibition

Table 1. Oxygen consumption rates for the preliminary test

Group

(mg/L)

Oxygen consumption rate

(mg/Lh)

Average

Coefficient of variation (%)

Blank control group

43.44

39.00

16.10

34.56

Nitrification control group

28.68

Test group

10

28.08

100

37.56

1000

33.60

35.84

14.76

1000

32.04

1000

41.88

Reference control group

1

38.52

10

31.20

100

6.84

Abiotic control group

9.36

5.24

68.33

2.88

3.48

Table 2. Inhibition rates of total oxygen uptake and EC50 for the preliminary test

Group

(mg/L)

Inhibition rate of total oxygen uptake (%)

Average

EC50

(mg/L)

Test group

10

28.00

>1000.00

100

3.69

1000

13.85

8.11

1000

17.85

1000

-7.38

Reference control group

1

1.23

23.99

10

20.00

100

82.46

Validity criteria fulfilled:
yes
Conclusions:
According to OECD 209 test method, the EC50 of Everzol SB26 for oxygen consumption rate of sludge was greater than 1000 mg/L.
Executive summary:

This test using the procedures outlined in the SuperLab Study Plan for M62-151100136001EN which is based on the SOP for the OECD 209 (SOPE-508) and OECD 209 (OECD, 2010). The results of this OECD 209 test for Everzol SB26 show that all validity criteria were met. The EC50 of Everzol SB26 for oxygen consumption rate of sludge was greater than 1000 mg/L.

Description of key information

The EC50 of Everzol SB26 for oxygen consumption rate of sludge was greater than 1000 mg/L (OECD TG 209).

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L

Additional information

For blank control groups at the end of the test, the coefficient of variation of oxygen consumption rate were less than 30% and greater than 20.00 mg/h of per one gram of sludge, respectively. The EC50 of reference control group (3,5-Dichlorophenol) was lied in the range between 2.00 and 25.00 mg/L. All test validity criteria were met.The EC50 of Everzol SB26 for oxygen consumption rate of sludge was greater than 1000 mg/L.