Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 406-420-4
CAS number: 69430-40-6
Combined Limit/range-finding test:
The mean cell densities measured during the combined limit/range-finding
test are presented in Table 1. Table 2 presents the percentages growth
inhibition and growth rate reduction per concentration. No significant
treatment related effects on algal growth rate were observed during the
Table 1: Mean cell densities (x 104 cells/ml)
during the combined limit/range finding test.
* Ten-fold dilution from the WAF prepared at 1 mg/l
Table 2: Percentage reduction of growth rate and inhibition of total
the combined limit/range finding test
* Ten-fold dilution from the WAF prepared at 1 mg/l
Analyses of samples taken at the highest tested concentration, being a
Water Accomodated Fraction (WAF) prepared at 100 mg/l, did not result in
reliable resuIts. As a cansequence, the Analytical (extraction) method
was improved. After the extraction procedure was improved, the project
was continued with a limit test as no significant effects were expected.
Hence, both the EL50, for cell growth
lnhibition and growth rate reduction were expected to be above the
concentration reached after preparation of a WAF at a nominal loading of
The mean cell densities measured during the limit test are presented in
Table 3. Table 4 presents the percentages growth inhibition and growth
rate reduction per concentration. Unexpectedly, algal cell growth was
more inhibited (46%) than observed during the combined
limit/range-finding test (19%). Simultaneously, growth rate was
biologically significantly reduced (14%). No clear founded reason for
this inconsistency could be given. It was thought that the differences
in effects were related to the nature of the test substance, i.e. a
mixture with various components with various solublllty limits. Hence,
one or more components could have been present in different
concentrations when comparing the test solutions in the limit test with
those prepared in the combined limit/range-finding test. This problem
often rises when testing WAFs. It was decided to continue testing with a
range of WAFs prepared at loadings between 5.6 and 56 mg/l in order to
be able to define a NOELR.
Analyses of the samples was based on the two major peaks that were
observed in the chromatograms. No correlation could be given between
the observed peaks and the various test substance components. The
measured concentration in the WAF prepared at 100 rng/l corresponded
with approximately 20 mg/l at the start and decreased to ca. 10 m/l at
the end of the test period (results were comparable for both peaks;
see Tables 4 and 5 of the appended Analytical report). Temperalure and
pH were maintained within the optimum limits for testing with algae.
Table 3: Mean cell densities (x 104 cells/ml)
during the limit test.
Actual (mg/l) based on analyses of the two major peaks at t=0 and t= 72
Table 4: Percentage reduction of growth rate and inhibition of total
growth during the limit/range test
Actual (mg/l) based on analyses of the two major peaks at t=0 and t=
Selenastrum capricornutum, Fresh Water Algal Growth Inhibition Test with
DOW CORNING(R) 2-5067 SURFACTANT.
The batch of DOW CORN ING(R) 2-5067 SURFACTANT tested was a slightly
yellowish coloured liquid. DOW CORNING(R) 2-5067 SURFACTANT is a mixture
consisting of at last 9 different components. The test substance was not
completely soluble in test medium at the concentrations tested. Owing to
the poor solubifity of the test substance and the fact that the test
substance was a mixture, it was decided to separately prepare Water
Accomodated Fractions (WAFs) at various nominal loadings. A 24-hour
magnetic stirring period was followed by phase separation for either 4
or 24 hours. The water fractions were then tested.
A limit test and a range-finding test combined with a limit test were
conducted. The initial cell density was 104
cells/ml. The total test period was 72 hours. Samples for determination
of actual exposure concentrations were in general taken at the start,
after 24 hours and at the end of the test period. Analyses were based on
the two major peaks observed in the chromatograms of the DOW CORNING(R)
2 -5067 SURFACTANT mixture. Results are presented in tables 1 - 4 under
Results and Discussions.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
Welcome to the ECHA website. This site is not fully supported in Internet Explorer 7 (and earlier versions). Please upgrade your Internet Explorer to a newer version.
Do not show this message again