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short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 03-10-1980 to 10-10-1980
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: Documentation insufficient for assessment

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
no guideline available
Principles of method if other than guideline:
No data
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
2,4-dichloro-5-sulphamoylbenzoic acid
EC Number:
EC Name:
2,4-dichloro-5-sulphamoylbenzoic acid
Cas Number:
Molecular formula:
2,4-dichloro-5-sulphamoylbenzoic acid
Test material form:
solid: particulate/powder
migrated information: powder
Details on test material:
White powder

Test solutions

Details on test solutions:
As test water was deionized water (CHRIST-Ministil-ion exchange cartridge) with a conductivity of <5 pSicm. This water were added per liter of the following salts according to the recipe of MARKING and DAWSON:
192 mg NaHCO3
120 mg CaSO4. 2H2O
120 mg MgSO4
8 mg HCl
The experiment consisted of glass basin (40 x 25 x 30 cm) and were filled with 20 liters of test water.

Test organisms

Test organisms (species):
Leuciscus idus melanotus
Details on test organisms:
Type: golden orfe (Leuciscus idus f. melanotus)
Breeder: Paul Eggers, 2345 Hohenwestedt
Acclimatization: The fish were kept at least 14 days before the test begins at 20 °C in dechlorinated tap water.
Body weight: 2.0 - 2.8 g (x = 2.3 g; g s = 0.27, n = 10)
The determination was made at the beginning of testing.
Body length: 5,0 - 6,3 cm (x = 5.9 cm; s = 0.36 cm, n = 10)
Experimental groups: 0 / 1 / 10 / 100 / 500 mg/l
Food: Tetra Min (Tetra Werke, Melle)

Study design

Water media type:
Total exposure duration:
96 h

Test conditions

9.5°d (Carbonate 6.4 °d)
Test temperature:
20 +/- 1°C
8.2 - 8.3
Dissolved oxygen:
The oxygen content was above 8 mg/l.
Details on test conditions:
The pools were aerated throughout the experimental period through glass capillaries. Approximately 100 ml of air was passed through the pool per minute.
The pools were illuminated from above in a day-night rhythm of 12 hours each. The illumination intensity was directly over the bassin approximately 700 lux

About 65 hours before the beginning of the test 10 fishs were placed in each bassin.

The test substance is poorly soluble in water and was suspended using an Ultra-Turrax for 5 minutes at maximum speed in the test water, applied in the experimental basin and spread evenly with a glass rod. Consequently, the given concentrations are not related to dissolved fractions, but on the introduced total amount of substance in the basin. Immediately before the addition of the substance, as well as after 2, 24, 48, 72 and 96 hours, the parameters pH, O2 and temperature were measured in each test pool. The measurement of the oxygen content was performed using the Oxi 39 (Scientific and Technical Workshops GmbH, Weilheim, Upper Bavaria), the temperature was measured with a mercury thermometer.

During the entire experimental period, the fish were regularly observed and the behavior recorded. After completion of the experimental period the fish were killed in dissolved 0.05% MS 222 (methanesulfonate of meta-amino benzoic acid ethyl ester, Sandoz), dissected and examined macroscopically.

Results and discussion

Effect concentrations
96 h
Dose descriptor:
Effect conc.:
> 500 mg/L
Nominal / measured:
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Details on results:
During the 96-hour test period no fish died in all the tested concentration groups. The LC50 is therefore for 48 and 96 hours over 500 mg/l.

The fishes of all group has the same behaviour than the control fishes.

Macroscopic findings survey:
The section of the dead fish showed no macroscopically visible changes in all groups.

Water parameters:
The pH was slightly reduced in the 100 and 500 mg/l groups (min. 7.2 at 500 mg/l, 2 hours after addition of substance) in the 1 and 10 mg/l groups the pH is different (8.1 to 8.2) as well as the oxygen concentration of all the groups (8.4 to 8.7 mg/l) are not the values ​​of the control group.

Applicant's summary and conclusion

Validity criteria fulfilled:
The determination of the acute toxicity of Lasamid to ide conducted under the described experimental conditions to an LC 50 value of above 500 mg/ l after 48 or 96 hours.