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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP Guideline Study.
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Details on sampling:
For the determination of the actual test item concentrations, duplicate samples were taken from each treatment before the test start and at the end of the test after 48 hours.

For the 48-hour stability samples, the contents of the respective replicates were combined prior to sampling.

All samples were stored deep-frozen (at about -20 °C) immediately after sampling.

The concentrations of the test item RL277/09 were analyzed in the duplicate test media samples from the nominal concentrations of 53.9 to 251.3 mg test item/L from both sampling times (0 and 48 hours).

The samples of the nominal test concentrations of 11.5 and 24.9 mg test item/L (4.6 and 9.96 mg active substance/L) were not analyzed since the concentrations were below the 48-hour NOEC determined in this test. From the control, only one of the duplicate samples was analyzed from each of the sampling times.
Details on test solutions:
Reconstituted test water according to ISO 6341 was used in the study. The ratio of Ca:Mg and Na:K was 4:1 and 10:1, respectively, based on molarity.
The test water was aerated prior to the start of the study until oxygen saturation was reached.
During the test period, the test water was not aerated.

Test organisms (species):
Daphnia magna
Details on test organisms:
Species: Daphnia magna Straus
Source: A clone of this species (defined by the supplier as clone 5) was originally supplied by the University of Sheffield / UK in 1992. Since that time, the clone has been bred at Harlan Laboratories in reconstituted water of the quality identical to the water quality used in the tests (in respect to pH, main ions, and total hardness) and under temperature and light conditions identical to those of the tests.
Age: At the start of the test, the organisms used in the test were 6-24 hours old and were not first brood progeny.

For evaluation of the quality of the daphnia clone and the experimental conditions, potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test in February 2009 (48-hour EC50: 0.71 mg/L, study C36915) indicated that the sensitivity of the test organisms was within the internal historical range (48-hour EC50 from 1996 to 2009: 0.53-1.1 mg/L).
Test type:
static
Water media type:
freshwater
Total exposure duration:
48 h
Test temperature:
The test was performed in a temperature-controlled room with continuous monitoring of the room temperature. The water temperature was maintained at 20 °C.
pH:
the pH value of the test media was between 7.8 and 7.9
Dissolved oxygen:
test media and control were at least 8.1 mg/L
Nominal and measured concentrations:
The nominal test item concentrations tested were 11.5, 24.9, 53.9, 116.3 and 251.3 mg test item/L (corresponding to 4.6, 10, 22, 47 and 101 mg active substance/L).
The analytically determined concentrations of the test item in the analyzed test media of the nominal concentrations of 53.9, 116.3, and 251.3 mg test item/L (22, 47 and 101 mg active substance/L) were between 105 and 115% of the nominal values.
Details on test conditions:
A 16-hour light to 8-hour dark cycle with a 30-minute transition period was used. Light intensity during the light period was approximately between 520 and 680 Lux.

The daphnids were not fed during the test.
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
136 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 116-162 (95% CL)
Remarks:
54.4 mg active substance/L
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
53.9 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other:
Remarks:
21.6 mg active substance/L

During the first 24 hours of the test, no immobilized test organisms were determined in the control and up to and including the nominal test item concentration of 116.3 mg test item/L (46.5 mg active substance/L). At the highest test concentration of 251.3 mg test item/L (101 mg active substance/L), the immobilization was 60%.

The 24-hour EC50 of the test item was calculated to be 233 mg test item/L (93.2 mg active substance/L) (95% confidence limits could not be determined). The 24-hour EC0 was 116.3 mg test item/L (46.5 mg active substance/L), and the 24-hour EC100 was >251.3 mg test item/L (>101 mg active substance/L).

After 48 hours of exposure, no immobilized test organisms were determined in the control and up to and including the nominal test item concentration of 53.9 mg test item/L (21.6 mg active substance/L). At the concentration of 116.3 mg test item/L (46.5 mg active substance/L), all test organisms showed discoloration as a sign of stress, however, only 5 daphnids were found to be immobile. At the highest test concentration of 251.3 mg test item/L (101 mg active substance/L), all test organisms were found to be immobile.

The 48-hour EC50 was calculated to be 136 mg test item/L (95% confidence limits between 116 and 162 mg/L) corresponding to 54.4 mg active substance/L (95% confidence limits between 46.4 and 64.8 mg/L). The 48-hour EC0 and NOEC of RL277/09 were both 53.9 mg test item/L (21.6 mg active substance/L), since no effect was observed up to and including this test concentration. The 48-hour EC100 was 251.3 mg test item/L (101 mg active substanceL).

No remarkable observations were made concerning the appearance of the test media. All test media were clear solutions throughout the entire test duration.

Validity criteria fulfilled:
yes
Conclusions:
The 48-hour EC50 was calculated to be 136 mg test item/L (95% confidence limits between 116 and 162 mg/L) corresponding to 54.4 mg active substance/L (95% confidence limits between 46.4 and 64.8 mg/L). The 48-hour NOEC of the test substance was 53.9 mg test item/L (21.6 mg active substance/L), since no effect was observed up to and including this test concentration.
Executive summary:

In a 48-h acute toxicity study, Daphnia magna were exposed to the substance at measured concentrations of 0, 11.5, 24.9, 53.9, 116.3 and 251.3 mg test item/L (0, 4.6, 9.96, 21.6, 46.5 and 101 mg active substance/L) under static conditions.  The 48-h EC50 was 136 mg test item/L (54.4 mg active substance/L) based on inhibition. This toxicity study is classified as acceptable and satisfies the guideline requirement for short-term toxicity study for invertebrates.

Description of key information

Elementis Specialities (2009) reports an EC50 for short term toxicity in Daphnia magna of 136 mg/L.

A reliable (Klimisch 1) toxicity study with algae has been conducted on the substance and is included in this dossier. Elementis Specialities (2009) conducted a reliable (Klimisch 1) GLP compliant study following OECD 203 methods with the substance. Daphnia magna were exposed to the test substance at measured concentrations of 0, 11.5, 24.9, 53.9, 116.3 and 251 mg test item/L (0, 4.6, 9.96, 21.6, 46.5 and 101 mg active substance/L) under static conditions. The 48 -h EC50 was 136 mg test item/L (54.4 mg active substance/L),

based on immobility, and is taken as the short-term toxicity in invertebrates endpoint for the substance.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
136 mg/L

Additional information