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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
disregarded due to major methodological deficiencies
Study period:
March 04, 2002 - October 08, 2003
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
unsuitable test system
Remarks:
The study was disregarded as the test item reacted violently with water to form hydrochloric acid, ammonium phosphates and insoluble inorganic polymeric structures. Both, the pH shift and the formation of the precipitate, likely have influenced the results of the study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report date:
2003

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
adopted April 4, 1984
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Sampling and analysis

Details on sampling:
Due to the low solubility of the test substance a filtrate of the supersaturated stock suspension of nominal 100 mg/L, which was shaken for 4 h and filtered through a cellulose-acetate filter (pore size 0.45 µm), was used as stock solution for lower concentrated test media in the first test set. The test was conducted in successive steps starting with concentrations of nominal 10 and 100 mg/L in order to assess the toxicity followed by possible further concentrations. Every step included a control.
Adequate volumes were taken from the filtered stock suspension and were diluted with test water to prepare the test media of all other test concentrations. Finally,the following nominal concentrations were employed for the first test set: 1.00, 2.15, 4.64, 10.0 and 100 mg/L.
Due to acidic reactions of the test substance, a second test set was carried out to avoid pH-value related reactions onto the Daphnia. The medium for the second test set was prepared by mixmg 100 mg test item into
1 liter test water and by shaking for 4 h. The pH-value of the medium was adjusted With NaOH to pH 7.9.

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Daphnia magna STRAUSS / IRCHA
Breeder: LPT Laboratory of Pharmacology and Toxicology KG, branch Lohndorf
D-24601 Lohndorf / Post Wankendorf
- Age: 6 - 24 hours, laboratory bred
- Acclimatisation: at least 1 week
- Holding and dilution water: reconstituted, aerated fully demmeralised water
- Breeding vessels: all glass vessels with watch glass dishes,diameter: 190 mm, height: 90 mm, volume: 2 L
- Illumination: white type fluorescent light, 500 lux (approx.) ± 20% (approx. 0.045 x 1020 photons/m2 x s), 16 hours light / 8 hours darkness


Study design

Test type:
static
Water media type:
freshwater
Total exposure duration:
48 h

Test conditions

Hardness:
250 mg CaCO3/L
Test temperature:
20°C +/- 1°C
pH:
7.9 +/- 0.3
Dissolved oxygen:
> 80% of maximum saturation
Salinity:
not applicable
Conductivity:
not given in the report
Nominal and measured concentrations:
Adequate volumes were taken from the filtered stock suspension and were diluted with test water to prepare the test media of all other test concentrations. Finally, the following nominal concentrations were employed for the first test set: 1.00, 2.15, 4.64, 10.0 and 100 mg/L.
Details on test conditions:
Test vessels: all glass vessels, diameter: 38 mm, height: 60 mm, volume: 50 mL
Number of animals per test concentration: 20, divided into 4 groups of 5 animals each, 5 animals per vessel
air conditioning: continous registration of temperature
Illumination: by atuomatic time switch
O2-meter: OXI 530 with oxygen electrode
pH-meter: pH 90 with glass electrode
Mercury thermometer: 0.1°C subdivisions
Equipment for titrimetric analysis of ion concentration of Ca++ and Mg++, for measurement of flow through and consumption of test solutions: normal laboratory equipment
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC50
Remarks:
without pH adjustment
Effect conc.:
7.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Remarks:
without pH adjustment
Effect conc.:
< 1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mortality
Duration:
48 h
Dose descriptor:
EC50
Remarks:
with pH adjustment
Effect conc.:
> 10 - < 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Remarks:
with pH adjustment
Effect conc.:
< 10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mobility
Details on results:
behaviour of the test item:
- first test set: After suspension of the test item the stock preparation was shaken for 4 h. Two phases were obtained. To avoid physical effects of undissolved test substance onto Daphma the stock suspensions were filtered through a cellulose-acetate filter (pore size 0.45 µm) each.
- Second test set: Due to marked acidic reactions in the first test set the pH-value was adjusted in the second test set. After 4 hours of shaking no filtration was performed for the second test set as it appeared that a clear solution was obtained. A misty precipitation was observed after 24 h at 100 mg/L and after 48 h at 10 mg/L in the second test set
Reported statistics and error estimates:
The EC50 (50% immobilisation of the Daphnia after 24 and 48 hours) for the first test set (w/o pH adjustment) was calculated by linear regression analysis employing probit analysis (Probit Program Vers1on 1.5, U.S. Environmental Protection Agency, 1992). The NOEC, EC0 and EC100 values for the first set were taken directly from the raw data.
The NOEC, EC0 and EC50 (after 48h) values for the second set (with pH adjustment) were taken directly from the raw data. The EC50 (after 24 h) and EC100 values of the second test could not be quantified due to the absence of adequate toxicity of the test item.

Applicant's summary and conclusion

Conclusions:
In the first test set without adjustment of the pH, a 48-hour EC50 value of 7.8 mg/L has been determined for the effects of the test substance on mobility of Daphnia magna based on nominal exposure concentrations of the substance. The pH decreased depending on the concentration: compared to the control dilution water of pH 8.09, at a concentration of 10 mg/L of the test item the pH was 6.5, at 100 mg/L the pH was < 3.
During the preparation of the stock solution two phases were obtained. Although filtered, it is not clear if the non-aqueous phase was removed completely because filtration is no adequate technique to separate two liquids from each other. Thus, it is likely that physical effects have influenced the results.
Due to acidic reactions of the test substance, a second test set was carried out to avoid pH-value related reactions onto the Daphnia. In this second set with adjustment of the pH, a 48-hour EC50 value of > 10 mg/L - < 100 mg/L has been determined for the effects of the test substance on mobility of Daphnia magna based on nominal exposure concentrations of the substance. At the beginning of the study the solution of the test item appeared clear (but only eye inspection, no Tyndall lamp), however, a misty precipitate was observed after 24 h at 100 mg/L and after 48 h at 10 mg/L. Before precipitation no mortality was observed. Thus, it is likely that physical effects have also influenced the results of the second test set.
In conclusion, it can be stated that the test system is unsuitable due to the nature of the test item.