Registration Dossier

Administrative data

Endpoint:
toxicity to microorganisms
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Jun 1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: According to DIN guideline under GLP
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)
Deviations:
no
Principles of method if other than guideline:
Not relevant
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Ethyltetraenon
- Analytical purity: 95.9%
- Lot/batch No.: 11614001

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Pseudomonas putida

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
16 h

Results and discussion

Effect concentrations
Duration:
16 h
Dose descriptor:
EC50
Effect conc.:
> 1 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth inhibition

Any other information on results incl. tables

Table 1: Turbidity (expressed as TE/F) and growth inhibition as a function of the concentration

 Dilution of ZK 47568    TE/F ± stand ara deviation (mean value ( 16 hours))  Growth inhibition (%)  
 Control    671 ± 7   0
 1 :1000 diluted    751 ± 25   -12
 1:100 diluted    774 ± 9   -15
 1 : 1 0 diluted    766 ± 20   -14
 Saturated, filtered    788 ± 12   -18

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Ethyltetraenon in a saturated solution « 1 mg/I) had no inhibitory effect on the growth of
Pseudomonas putida. The slight increase of growth is not considered to be relevant in
ecotoxicological terms, since the test is not designed to assess growth-stimulating effects.
Executive summary:

The purpose of this study was to determine the effects of the test compound Ethyltetraenon (ZK 47568) on the growth of the bacterium Pseudomonas putida. The study was conducted in agreement with the standard DIN 38412 L8, March 1991.

The test substance ZK 47568 was incubated in an aqueous solution including nutrients with a bacterial population of Pseudomonas putida for a test duration of approximately 16 hours. The nutrient solution was made up of mainly nitrate, phosphates, carbohydrates, some trace elements and vitamins. For the preparation of the test solutions 100 mg/l of ZK 47568 were suspended and stirred for 24 hours. The suspension was filtered through a glassfibre filter and used as highest concentration (saturated solution). Then it was further diluted (1:10, 1:100 and 1:1000). Additionally, one control without the test substance was used. All test solutions including the control were incubated in triplicate.· Furthermore, for each test concentration one test ves~el was incubated without addition of the inoculum in order to analyse the inherent turbidity of the test compound. The concentration of the saturated, filtered stock solution was estimated by a TOC analysis and subsequent calculation based on the molecular formula. It was < 1 mg/L.

As a parameter for the growth of the bacterial population, the turbidity of the test and control solutions was analysed photometrically at a wave-Iength of 436 nm.

The measurements showed that there was no growth inhibition of the bacterial population. However, there was a slight growth increase in comparison with the control group.