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Toxicity to microorganisms

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Endpoint:
toxicity to microorganisms
Type of information:
experimental study
Adequacy of study:
other information
Study period:
1988
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Only secondary literature. Original report not available.
Principles of method if other than guideline:
Oxygen consumption test (Huels method)
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Chemical name of vehicle: Nonylphenol-10EO-5PO
Test organisms (species):
Pseudomonas putida
Test type:
static
Water media type:
freshwater
Total exposure duration:
5 h
Nominal and measured concentrations:
not stated
Reference substance (positive control):
not specified
Duration:
5 h
Dose descriptor:
EC10
Effect conc.:
> 1 630 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
not specified
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
05 - 13 Oct 1998
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP study similar to guideline study with acceptable restrictions: The test substance is tested using only one replicate for each test concentration. No analytics of the test substance is performed.
Qualifier:
according to guideline
Guideline:
other: Amtsblatt der EG L 133, Teil C: Biologische Abbaubarkeit: Prüfung der Atmungshemmung
Deviations:
yes
Remarks:
The incubation period was 3 h instead of 30 minutes under continuous aeration (this was recommended by the German federal Environmental Agency
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
yes
Remarks:
because of the high oxygen demand of the activated sludge, a inoculum concentration of only 0.48 g/L were used
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance was directly added to the test vessel and stirred overnight.
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Laboratory culture: Activated sludge collected from water treatment plant predominantly processing municipal waste water; Wupperverband, Germany; date of collection: 12 Oct 1998
- Pretreatment: none
- Initial biomass concentration: 480 mg/L
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Test temperature:
20 ± 2 °C
pH:
7.4 - 8.2
Dissolved oxygen:
5.8 - 8.6 mg/L at test start
2.5 - 8.0 mg/L at test end
Nominal and measured concentrations:
Nominal: 1000, 1800, 3200, 5600 and 10000 mg/L
Details on test conditions:
TEST SYSTEM
- Aeration: continuously
- No. of vessels per concentration: 1
- No. of vessels per control: 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water
- Intervals of water quality measurement: Oyxygen concentration was measured at the beginning and at the end of the test. Temperature and pH was measured once per test concentration after 6-8 minutes.

EFFECT PARAMETERS MEASURED: Inhibition of respiration was recorded after 3 h test duration.
Reference substance (positive control):
yes
Remarks:
3,5-Dichlorphenol
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
> 10 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: EC50 = 12 mg/L; EC10 = 2.9 mg/L

Table 1: Test results

Nominal concentration [mg/L]

Respiration rate [mg/L*h]

Abiotic loss of oxygen [mg/L*h]

Inhibition [%]

1000

27.8

0.0*

0.0

1800

27.4

0.0*

0.0

3200

25.5

0.0*

6.3

5600

29.1

0.0*

0.0

10000

28.0

0.0

0.0

Control 1

27.0

 

Control 2

27.4

 

*: The abiotic oxygen loss was measured in the 10000 mg/L treatment. As no loss of oxygen was observed, it was assessed that also no loss occurred at the lower test concentrations.

Description of key information

EC10 (3h) > 10000 mg/L (nominal) for respiration rate of activated sludge (similar to OECD 209)

Key value for chemical safety assessment

Additional information

One study investigating the short-term toxicity to aquatic microorganisms of Dibutyl adipate (CAS 105-99-7) is available. The GLP study was performed similar to OECD 209 using activated sludge of a predominately domestic sewage as inoculum (Müller, 1998). The test substance was directly added to the vessels. The effect of the test substance on the respiration rate was determined under static conditions using nominal concentrations in the range of 1000 to 10,000 mg/L. No respiration inhibition was measured. Hence, the 3 h-EC10 is determined to be > 10,000 mg/L on the basis of the nominal test concentration.