[No public or meaningful name is available]

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1996-01-12 (date of study plan) - 1996-03-01 (date of final report)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Remarks:

DIN-Norm 38 412 L8, GLP

Qualifier:

according to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

Version / remarks:

DIN-Norm 38 412 L8

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

not specified

Vehicle:

yes

Remarks:

aqua ad iniectabilia

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: WAF
- Eluate: water
- Differential loading: 10 g/l

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Laboratory culture: Stock culture was sored frozen at -80°C in Casein-Soyflourpepton-boullon with 7.5 % DMSO
- Method of cultivation: Working culture was stored in solid medium in agar tubes. New cultures were prepared every week and cultured at 25°C
- Preparation of inoculum for exposure:
Pre-culture: The inoculum for the pre-culture was taken from a up to 7 day old stem culture under sterile conditions to reveal a turbidity of approx. TE/F = 10 in the pre-culture. the preparation was incubated for 7 hours at 21±1°C. Afterwards it was diluted to reveal a defined turbidity of approx. TE/F = 50.
Test culture: The diluted preparations (each 80 ml) of the test item were added into test vessels (300 ml Erlenmeyer flasks) with 10 ml test culture solution and 10 ml of the TE/F = 50 inoculum to reveal a calculated turbidity of TE/F = 5. Afterwards the test cultures were incubated in triplicates at 21±1°C for 16±1 hour. As control, 5 Erlenmeyer flasks with 80 ml water instead of the test item solution were incubated, too.
- Source: Deutsche Sammlung von Mikroorganismen (Braunschweig, Germany)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Test temperature:

21±1°C

Nominal and measured concentrations:

Nominal: 3.0, 1.5, 0.75, 0.38, 0.19, 0.1, 0.05, 0.025, 0.013, 0.007, 0.0035 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 ml Erlenmeyer flasks
- Material, size, headspace, fill volume: 100 ml fill volume
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 5
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : turbidity
TEST CONCENTRATIONS
- Spacing factor for test concentrations: factor 2

Key result

Duration:

16 h

Dose descriptor:

EC50

Effect conc.:

0.4 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr. (dissolved fraction)

Basis for effect:

growth inhibition

Duration:

16 h

Dose descriptor:

EC10

Effect conc.:

0.004 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr. (dissolved fraction)

Basis for effect:

growth inhibition

Validity criteria fulfilled:

not specified

Conclusions:

The toxicity of the test item towards microorganisms was determined scientifically reasonable acc. DIN-Norm 38 412 L8, the given information indicates that testing was properly conducted, hence, the results can be considered sufficiently reliable. The EC10 was determined as 0.0035 mg/l, the EC50 to 0.4 mg/l.

Executive summary:

The toxicity of the test item towards Pseudomonas putida was determined scientifically reasonable acc. DIN-Norm 38 412 L8. For the main experiment two stock solutions of the test item, 5g ad 500 ml aqua ad iniectabilia, were prepared and stirred with a magnetic stirrer for 24h at room temperature. The highest concentration was prepared by 1:2,5 dilution of the pooled and clear filtered stock solution. Measured concentration of the stock solution was 3.7 mg/l, so it was tested at the following concentrations: 3.0, 1.5, 0.75, 0.38, 0.19, 0.1, 0.05, 0.025, 0.013, 0.007, 0.0035 mg/l. pH was not adjusted. Test item was tested in triplicates, control in 5 replicates. Effective concentrations were determined by graphical plot of the measured values of the mean experiment. The EC10 was determined as 0.0035 mg/l, the EC50 to 0.4 mg/l.

Description of key information

Toxicity to microorganisms: EC50(16h) = 0.4 mg/l for Pseudomonas putida (static, DIN-Norm 38 412 L8, GLP)

Key value for chemical safety assessment

EC50 for microorganisms:

0.4 mg/L

EC10 or NOEC for microorganisms:

0.004 mg/L