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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Oct 05 - Dec 08, 1999
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
according to guideline
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
Purity: 99.4%
Appearance: white crystalline powder
Analytical monitoring:
Details on sampling:
start end end of the experiment
Test organisms (species):
Daphnia magna
Details on test organisms:
- Common name: Daphnia magna (Straus)
- Source: Institute of Toxicology, Merck KGaA, Darmstadt, Germany
- Age at study initiation (mean and range, SD): not older than 24 hours
- Feeding during test no

Test type:
Water media type:
Limit test:
Total exposure duration:
48 h
250 mg/L
Test temperature:
20-21 °C
7.9 ± 0.3
Dissolved oxygen:
> 95 %
Nominal and measured concentrations:
Nominal concentrations of 0.02, 0.03, 0.045, 0.067 and 0.10 g/L have been used for this study.

Below the analytical data for selected concentrations using a CE method are summarized:

nominal measured initial measured (48 h)
g/L g/L g/L
0.0200 0.0203 101.5 % 0.0196 98.0 %
0.0450 0.0449 99.8 % 0.0458 101.8 %
0.1000 0.0997 97.7 % 0.1015 101.5 %
Details on test conditions:
- Source/preparation of dilution water:
Reconstituted water according to ELENDT (1990):
Macro nutrients (mg/L):
CaCI2 x 7 H20 293.80
MgSO4 x 7 H20 123.30
NaHCO3 64.80
KCI 5.80
Na2SiO3 x 9H20 10.00
NaNO3 0.27
KH2PO4 0.14
K2HPO4 0.18

Trace elements (mg/L):
B 0.5000
Fe 0.2000
Mn 0.1000
Li, Rb and Sr 0.0500
Mo 0.0250
Br 0.0125
Cu and Zn 0.0063
Co and I 0.0025
Se 0.0010
V 0.0003

Macro nutrients (mg/L):
Na2EDTA x 2H20 2.50

Vitamins (µg/L):
Thiamine 75.00
B12 1.00
Biotin 0.75

After preparation, the reconstituded water was aerated for 24 hours.

- Hardness: about 14° dH (about 250 mg/L CaCO3)
- pH: 7.9 ± 0.3, after an aeration for 24 hours.


ELENDT, B.-P. Selenium deficiency in Crustacea. An ultrastructural approach to antennal damage in Daphnia magna Straus.
Protoplasma 154, 25-33, 1990

Reference substance (positive control):
potassium dichromate
Key result
48 h
Dose descriptor:
Effect conc.:
> 117 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
Remarks on result:
other: 0.091-0.151
48 h
Dose descriptor:
Effect conc.:
67 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:


The purpose of this assay was to identify the aquatic toxicity potential of the test material in Daphnia magna to provide a rational basis for hazard estimation for the test item in aquatic environments.

Study design

For this purpose, juvenile Daphnia magna were exposed to an aqueous test material preparation over 48 hours, under defined conditions. The study comprised of four vessels per concentration containing five Daphnia magna, i.e. 20 Daphnia per concentration. The daphnia were observed for immobilization for up to 48 hours. Nominal concentrations of 0.02, 0.03, 0.045, 0.067 and 0.10 g/L have been used for this study. The analytical check of the concentrations was performed at the start and at the end of the study using Capillary electrophoresis (CE). The GLP study was performed according to OECD TG 202.


The follwing results have been obtained after an exposure for 48 hours:


Nominal concentration Immobilization immobilized / exposed

[g/L]  24 hours  48 hours 
0.0 0/20 0/20 
0.02 0/20  0/20 
 0.03 0/20 0/20 
 0.045 0/20 0/20 
 0.067 0/20 0/20
 0.1000 2/20 5/20

Some daphnia magna exposed to an aqueous preparation of the nominal concentration of  0.1 g/L were immobilized.

For the test material the following EC50 values for Daphnia magna were determined:

48 h EC50 = 0.117 g/L 

NOEC = 0.067 g/L


Under the given experimental conditions, the 48 hours EC50 to Daphnia magna is > 100 mg/L.

Validity criteria fulfilled:

Description of key information

There is one study of short-term toxicity to daphnia magna available for TRIS HCl. The study was conducted according the OECD guideline 202 and GLP (6.1.3 -1). The test organism Daphnia magna was exposed to TRIS HCl in a static system for 48 hours, at test concentrations of 0.02, 0.03, 0.045, 0.067 and 0.10 g/L. The EC50 value was thus estimated to be > 117 mg/L (measured), the highest concentration tested.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
117 mg/L

Additional information