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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:
1994-11-29 tol 1994-11-30
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
Principles of method if other than guideline:
A defined amount of activated sludge is mixed with synthetic medium and measured the rate of respiration. This respiration rate is compared with those in the test preparations with different concentrations of the test substance be measured. The sensitivity of the activated sludge is examined with 3.5-dichlorophenol as a reference.
GLP compliance:
yes
Analytical monitoring:
no
Details on sampling:
- Test concentrations: 100, 180, 320, 560 and 1000 mg/L
- Control concentration: 10000 mg/L
Vehicle:
no
Test organisms (species):
activated sludge, domestic
Details on inoculum:
- Type: activated suldge (mixed population various microorganisms)
- Origin: Laboratory sewage treatment plant, which is operated with synthetic (the municipal wastewater approximate) growth medium.
- Prepreration: no
- pH of the culture solution before depletion: 7.9
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
30 min
pH:
20 ± 2 °C
Details on test conditions:
- direct weighing
- Concentration of activated sludge in the test system: 800.0 mg/L
- Contact time / duration: 30 min. under continuous aeration
Reference substance (positive control):
yes
Remarks:
3.5-Dichlorphenol
Key result
Duration:
30 min
Dose descriptor:
EC50
Effect conc.:
171 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Details on results:
Prüfkonzentration Respirationsrate Hemmung
[mg/L] [mg/L x h] [%]
100 28.3 32.9
180 22.3 47.2
320 11.1 73.7
560 4.8 88.6
1000 3.0 92.9
Control 42.2
Results with reference substance (positive control):
The sensitivity of the activated sludge was the reference substance 3,5-dichlorophenol reviewed. For 3,5-dichlorophenol, an EC 50 value of
12.0 mg/L determined graphically.
Validity criteria fulfilled:
yes
Conclusions:
An activated sludge respiration inhibition test (according to OECD guideline 209) with activated sludge resulted in a 30 min EC50 = 171 mg/L.
Executive summary:

The potential toxicity of dibenzylamine to microorganisms was tested according to EU Method C.11 (1994), which is equal to OECD Guideline 209. Toxicity to microorganisms of dibenzylamine was determined as EC50 = 171 mg/L after 30 minutes exposure.

Description of key information

The study of Bayer (1995), investigating the toxicity of dibenzylamine to microorganisms according to OECD  guideline 209, was considered as the key study for endpoint coverage (Klimisch score of 2). The 30 min EC50 was 171 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:
171 mg/L

Additional information