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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: study according OECD guideline

Data source

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

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
name: Cyanamide, (4,5-dihydroxy-2-thiazolyl)-
molecular formula: C4 H5 N3 S
molecular weight: 127.2
physical state: solid
analytical purity: 98 %

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Daphnia magna

Study design

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

Test conditions

Hardness:
178 mg/l CaCO3
Test temperature:
20.2°C
pH:
at the start of the study: 7.9
at the end of the study: 8.0
Dissolved oxygen:
at the start of the study: 9.4
at the end of the study: 8.7
Nominal and measured concentrations:
see below
Reference substance (positive control):
yes
Remarks:
K2Cr2O7

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
35 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95 % CL-limits: 29-43 mg/L
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
ca. 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Results with reference substance (positive control):
An acute toxicity test was carried out on September 24, 1996 under the same conditions using the
reference substance K2Cr2O7, reagent grade (test concentrations: 0.75, 1.00, 1.33, 1.78, 2.37
and 3.16 mg/liter). The 24 hour EC50 of 1.71 mg/1 (95% confidence limits 1.58 - 1.85 mg/l)
determined in this test lies within the required range of 0.9 - 1.9 mg/l. The gradient of the line of
regression (after Litchfield & Wilcoxon) was s = 1.37. ('Results on the toxicity to water fleas of
the reference substance potassium dichromate', report HBF/Dm 163 of September 25, 1996).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
EC50 (48 hours) was 35 mg/l.
The substance is subject to classification based on the results of this study.
Executive summary:

The control mortalities are below the 10 % value which is regarded as the limit for natural

mortality. As the physico-chemical measurements show, the composition of the test water

corresponds to the nominal values. The EC50 of the reference substance lies within the required

range. Thus, the study conditions correspond to the standard.

At the beginning of the test, the content of active ingredient was analyzed at all test

concentrations. The measured concentrations were 103.9 % to 108.0 % (mean: 106.8 %) of the

nominal ones. A stability test at the end of the 48 hours exposure period showed no degradation

of the test substance. These results indicate that the test concentrations prepared in this test

correspond to nominal concentrations for the study duration.

The EC50 (24 hours) determined for 2-Cyanimino-l,3-thiazolidine was about 100 mg pure

substance/l and the EC50 (48 hours) was 35 mg pure substance/1 (95 %-confidence limits 29 to 43

mg pure substance/l).

Based on nominal concentrations, the no-observed-effect-concentration (NOEC) after 24 hours

was 18 mg pure substance/l and after 48 hours 10 mg pure substance/l, the lowest-observedeffect-

concentration (LOEC) after 24 hours was 32 mg pure substance/l and after 48 hours 18 mg

pure substance/l. The threshold effect concentration after 24 hours was 24 mg pure substance/l

and after 48 hours 13 mg pure substance/l (TEC, geometric mean of NOEC and LOEC).