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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011-07-14 to 2011-08-08
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Details on sampling:
- Concentrations: Concentration of 100 mg/L was measured at 0 and 48 h; and concentration of 0 mg/L at 48 h only.
- Sample storage conditions before analysis: Routinely, the samples were analysed immediately. Only in exceptional cases, they were stored overnight deep frozen and protected from light.
Vehicle:
no
Details on test solutions:
A direct weighing was prepared to produce the only test concentration. 60.1 mg of the test item were added to 1 litre of dilution water, treated for 60 sec. at 8000 rpm with an ultra turrax and then stirred for 24 h on a magnetic stirrer. Finally undissolved particles of the test item were removed by filtration using a folded filter with a pore size of 7-12 μm. The pH was measured to be 8.6.
19 mL of the solution were taken and diluted with 1 mL of dilution water containing 10 daphnids resulting in a final concentration of 100 mg/L. For each test item concentration and the control 2 replicates were prepared.
Test organisms (species):
Daphnia magna
Details on test organisms:
- Daphnia magna STRAUS, parthenogenetic females, strain of Bundesgesundheitsamt Berlin
- Maintenance and Acclimatisation :
A population of parthenogenetic females of synchronized age structure has been maintained for more than 15 years in the test facility under constant temperature conditions (20 ± 1 °C) at a 16 : 8 hour light-dark photoperiod (light intensity: < 20 μE x m-2 x s-1). The culture water (so-called 'M4 medium') was partly renewed once a week. The Daphnia were exclusively fed with unicellular green algae (Desmodesmus subspicatus) 'ad libitum'. Mortalities of parent Daphnia during the culture period were recorded daily in a semi-quantitative way. The neonates were separated from their parent Daphnia by filtration prior to the acute test.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
14.5 °dH (= 259 mg/L CaCO3)
Test temperature:
20.7 - 21.1 °C measured at each test vessel at the beginning and the end of the test
pH:
7.9 - 8.5 measured at each test vessel at the beginning and the end of the test
Dissolved oxygen:
8.2 - 8.5 mg/L with 94 - 96 % saturation measured at each test vessel at the beginning and the end of the test
Nominal and measured concentrations:
a range of concentrations: 2.5, 5, 10, 20 and 40 mg/L (nominal) plus control
Results of analyses of test substance concentration (0 and 100 mg/L) in test solutions at 0 and 48 h showed that the substance stayed stable through the test test duration (Measured concentrations were range of 99.52 - 101.08 % of nominal concentrations).
Details on test conditions:
PRETREATMENT OF TEST ITEM:
- 60.1 mg of the test item were added to 1 litre of dilution water
- treated with an ultra turrax at 8000 rpm of 60 seconds
- stirred for 24 h on a magnetic stirrer
- filtration using a folded filter with a pore size of 7-12 μm
- 19 ml of the solution were taken and diluted with 1 mL of dilution water resulting in a final concentration of 57.1 mg/L

TEST SYSTEM:
- Test vessels: 50 mL glass beakers covered with watch glasses 10 neonates in 20 mL of test medium
- Experimental design : 5 test concentrations plus 1 control
- 10 neonates per vessel, 2 replicates per concentration/control
- no feeding during the exposure period
- static system
- Method of initiation : neonates were placed in prepared media
- Photoperiod : 16 h light : 8 h dark
- Temperature of incubation unit : 19.6 to 19.9 °C
- Aeration : none
- Method of administration : stock solution
- Medium renewal : none
- Duration of exposure: 48 hours
- Criteria of effects : The criterion of adverse effects used in this study was the item-induced alteration of the normal mobility behaviour and the loss of locomotory actions of the neonates, observed at 24 and 48 hours.

Reference substance (positive control):
no
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
40 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
9.7 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 0.98 - 95.2
Validity criteria fulfilled:
yes
Remarks:
The immobilisation and other abnormalities in the controls did not exceed 10 % by the end of the test. The dissolved oxygen concentration remained above 3 mg/L throughout the exposure period.
Conclusions:
The acute toxicity of dibenzylamine to Daphnia magna was determined in a 48 hour static test according to OECD guideline 202. Based on nominal concentrations, the 48-h EC50 was determined to be 9.7 mg/L. The results of the test can be considered reliable without restriction.
Executive summary:

In order to test acute toxicity to invertebrates of the substance, Daphnia Manga was exposed to the test solution of five nominal concentrations of the test substance (2.5, 5, 10, 20 and 40 mg/L) and blank control solution for a period of 48 h under static conditions.

Mobility and visible abnormalities were recorded at 24 h and 48 h. The measured concentrations confirmed that deviation from the nominal concentrations was less than 20 % (measured concentrations were in the range 99.52 - 101.08 % of nominal concentrations). An EC50 of 9.7 mg/L was determined. This toxicity study is realized according to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test).

Description of key information

The study of Currenta (2011), investigating the acute toxicity of dibenzylamine in Daphnia magna according to OECD guideline 202, was considered as the key study for endpoint coverage. An EC50 of 9.7 mg/L (based on nominal test concentrations) was found after an exposure of 48 hours in a static test in freshwater.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
9.7 mg/L

Additional information