Registration Dossier

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from January 31, 2003 to March 31, 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
The study has been conducted according to the appropriate OECD guideline, under GLP and analytical monitoring was carried out.
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
'Some of the description of the revised proposal, "Daphnia sp., Acute Immobilization Test" (2002), is used.
Deviations:
no
GLP compliance:
yes
Remarks:
(Certificate is not included in the study report.
Analytical monitoring:
yes
Details on sampling:
The test solution of 0.75 mL was collected from one test vessel for each of all test areas at the starting of exposure and before water renewal (24 houes after the starting of exposure), equal amount of acetone was added, mixed and analyzed by GC.
Vehicle:
no
Details on test solutions:
Test substance solution;
For the dilution water at preparation of the test solution, aeration was performed before preparation and temperature was set to be 20 ± 1°C in the thermostat bath.
Preparation of the stock solution of the test substance;
The test substance of 1000 mg was sampled and added in the purified water and made to constant volume of 10 mL with purified water to give 100000 mg/L test substance concentration. This stock solution was prepared at the start of exposure and stored in refrigerated and dark place. This solution was stable for 48 hors or more.
The stock solution containing the test substance was collected in the appropriate amount to the test concentrations, quantified to 500 mL with the dilution water to prepare test solution. 100 mL of this solution was put into 4 test vessels each per test concentration.

Control area;
Only dilution water was used for the control area.
Dilution water;
Elendt M4, the prepared water described in OECD Guideline for testing of Chemicals No.211, "Daphnia sp., Reproduction Test", was used.
Test organisms (species):
Daphnia magna
Details on test organisms:
1) Japanese name: Oomijinko
2) Scientific name: Daphnia magna
3) Obtained from: National Institute for Environmental Studies, Environmental Agency (current, National Institute for Environmental Studies, independent administrative agency)
4) Date of obtainment: July 18, 1995
5) Sensitivity: An acute immobilization test is periodically (about every six months) performed with the standard material (potassium bichromate, special grade chemicals) to examine the sensitivity of the test living organism. 48-hour 50% immobilization concentration (EC50) since June in 1998 is as follows; Mean ± Standard deviation = 0.75 ± 0.17 mg/L, n = 10 (Minimum value to maximum value = 0.57 to 1.02 mg/L)
6) Developing stage: female juveniles (in 24 hours after being produced)
7) Breeding conditions for parental Daphnia to obtain juveniles for testing:
Breeding water: dilution water
Breeding density: one organism/80 mL (25 organisms/2 L) or less
Breeding vessel: 2 L glass vessel
Water temperature: 20 ± 1°C
Dissolved oxygen concentration: 60% or more of the saturation concentration
pH: 6.7 to 8.5
Lighting: room light, 16/8 hours light (800 lux or less)/dark cycle
Rearing period: from February 5, 2003 to February 26, 2003
The mortality of the parent Daphnia during 2 weeks before the start of exposure: 0%
Occurrence of ephippia and male: absent
Type of feed: Chlorella vulgaris (monocellular green alga) (alga culture solution was centrifuged, replaced with dilution water and used.)
Amount of food: 0.2 mg C (content of organic carbon)/animal/day
Renewal of the rearing water: renewed periodically (3 times/week).
The juveniles are removed as much as possible every day.
Test type:
semi-static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Hardness:
Total hardness of freshly prepared test solution and test solution after 24 hours exposure in both of control area and 100 mg/L of test substance concentration area was 260 mg/L (as CaCO3).
Test temperature:
Control; 19.8°C (0 hour), 19.6°C (after 24 hours)
Test solution (91.7 mg/L); 20.0°C (0 hour), 19.8°C (after 24 hours)
pH:
Control; 8.3 (0 hour), 8.2 (after 24 hours)
Test solution (91.7 mg/L); 8.3 (0 hour), 8.2 (after 24 hours)
Dissolved oxygen:
Control; 8.8 mg/L (0 hour), 8.7 mg/L (after 24 hours)
Test solution (91.7 mg/L); 8.8 mg/L (0 hours), 8.5 mg/L (after 24 hours)
Salinity:
no description
Nominal and measured concentrations:
Test concentration;
The test concentration in this study was determined as 100 mg/L (nominal value) (the limiting test).
Measured test substance concentration; see Table 2
Details on test conditions:
1) Exposure method: Semi-static (the total amount of the test solution is replaced at every day). (The water surface was covered with Teflon sheet.)
2) Exposure duration: 48 hours
3) Amount of the test solution: 100 mL/vessel
4) Replicate number: 4 vessels/test area
5) The number of the test living organisms: 20 organisms/test area (5 organism/vessel)
6) Test temperature: 20 ± 1°C
7) Dissolved oxygen concentration: 60% or more of the saturation concentration. Aeration was not performed during the exposure period.
8) pH: pH of the test solution was not adjusted.
9) Hardness: about 250 mg/L (converted to CaCO3)
10) Lighting: room light, 16/8 hours light (800 lux or less)/dark cycle
11) Feeding: no feeding
Reference substance (positive control):
yes
Remarks:
potassium bichromate
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 91.7 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: immobility
Remarks on result:
other: The calculation of 95% confidence limit was impossible.
Details on results:
(1) Concentration of the test substance in the test solution;
The concentration of the test substance in the test solution was measured at the starting of exposure and before water renewal (24 hours after starting of exposure).
As the results of the analysis of the test solution, the percentage of the measured value to the nominal value was 92% at the starting of exposure and 92% before the water renewal. (see. Table 2)
(2) 50% immobilization concentration (EiC50);
The immobility was 0% and percentage of Daphnia magna that floated on the water surface was 0% in the control area during the exposure period, the conditions for establishment of the study was fulfilled. (see Table 3)
Therefore,
24-hour EiC50: >91.7 mg/L (95%CL: cannot be calculated)
48-hour EiC50: >97.1 mg/L (95%CL: cannot be calculated)
Results with reference substance (positive control):
- Results with reference substance valid? yes (between 0.57 and 1.02 mg/L)

- EC50/LC50: 0.75 mg/l

Table 3; The number of immobilized Daphnia magna

Nominal

concentration

(mg/L)

Mean measured

Concentration*

(mg/L)

Cumulative number of immobilized Daphnia magna

(Percent immobility (%))

24 hours

48 hours

Control

--

0 (0)

0 (0)

100

91.7

0 (0)

0 (0)

*; geometric mean

Validity criteria fulfilled:
yes
Conclusions:
A 48 h EC50 value of >91.7 mg/l has been determined for the effects of the test substance on mortality of the freshwater invertebrate Daphnia magna. The result is based on geometric mean measured concentration.

Description of key information

48 h, EC50 >91.7 mg/L, Daphnia magna, measured.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
mg/L

Additional information

A 48 h EC50 value of >91.7 mg/l has been determined for the effects of the test substance on mortality of the freshwater invertebrate Daphnia magna. The result is based on geometric mean measured concentration.