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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:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Remarks:
Experimental data of read across substances
Justification for type of information:
Data for the target chemical is summarized based on the closely related read across chemicals.
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
other: as mention below
Principles of method if other than guideline:
WoE report was prepared based on short term toxicity of test chemical to aquatic invertebrates study.
GLP compliance:
not specified
Analytical monitoring:
not specified
Vehicle:
not specified
Details on test solutions:
WOE2: Details on test solutions
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution from each metal salt was prepared in double Glass-distilled water. Serial dilutions were prepared from the respective stocks to the desired range.


Test organisms (species):
other: Cypris subglobosa, aquatic crustacea and Daphnia magna were used
Details on test organisms:
WOE2: Details on test organisms
TEST ORGANISM
- Common name: Ostracod
- Strain: C. subglobosa Sowerby, 1840
- Source: fish ponds situated at Gheru Campus of IITR, Lucknow, India
- Method of breeding: Living specimens were taken to the laboratory and placed in 5-l glass beaker filled with filtered well water.
- Feeding during test: No

ACCLIMATION
- Acclimation period: 2-3 days
- Acclimation conditions (same as test or not): Test animals were acclimatized to laboratory conditions in environmental growth chamber at 21±1 ◦C for 2–3 days. Growth chamber was equipped with two 60W cool white fluorescent lights. Tests were carried under light: dark cycle of 12:12 h.
- Type and amount of food: Food consisted of a 1000mgl−1 suspension of dry fish food and yeast. The composition of fish food was as crude protein 52%, crude fiber 7%, crude fat 8% and moisture 8%.

WoE 4: Details on test organisms
TEST ORGANISM
- Common name: Water flea
Test type:
other: WoE 2: Semi-static, WoE 3 and WoE 4: Static
Water media type:
freshwater
Total exposure duration:
48 h
Hardness:
245 mg/L CaCO3 (230–250)
Test temperature:
21 (20–22) °C
pH:
7.6 (7.4–7.7)
Dissolved oxygen:
5.4 (5.1–6.1) mg/L
Details on test conditions:
WoE 2: Details on test conditions
TEST SYSTEM
- Test vessel: Petri- plate dishes
- Material, size, headspace, fill volume: 20 ml glass Petri- plate dishes were used
- Renewal rate of test solution (frequency/flow rate): After 24 hrs
- No. of organisms per vessel: 10 for each concentration
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of vessels per control (replicates) (Reference control): 9-12
- No. of vessels per vehicle control (replicates): 3


TEST MEDIUM / WATER PARAMETERS
ALKALINITY: 400 390 TO 410 mg/L CaCO3


OTHER TEST CONDITIONS
- Photoperiod: 12 hours light and 12 hours dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobility of test organisms after the 24 hrs

TEST CONCENTRATIONS
- Range finding study: Final test concentrations were based on the results of preliminary range-finding short-term (48 h) tests. Ostracods were exposed for 48 h to logarithmic series of concentrations (7–10) of metals and reference toxicants. Nominal test concentrations in the range of 0.001, 0.01, 0.1, 1, 10, 100, 1000 and 10,000mg/l were selected for range-finding tests.

- Results used to determine the conditions for the definitive study: Endpoint used in the bioassay was immobility, i.e., the inhibition to swim within 15 second after gently agitation of the test container. Immobility implies the organism usually swim helplessly at the bottom of the container and use their limbs to crawled with difficulty.
Reference substance (positive control):
yes
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
634 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95 % CI was 574 to 685 mg/l
Duration:
48 h
Dose descriptor:
LC0
Effect conc.:
940 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: WoE- 3
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
410 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
not specified
Remarks on result:
other: WoE - 4
Reported statistics and error estimates:
The 24 h and 48 h EC50 [effective concentration at which 50% immobilized response was recorded] values and their 95% confidence limits were calculated by the moving average-angle method.
Validity criteria fulfilled:
not specified
Conclusions:
By applying weight of evidence approach the EC50 value of test chemical was determined to be in range from 410 mg/L to 940 mg/l after exposure of test chemical for 48 hrs. The range EC50 value indicates that the substance is likely to be nonhazardous to aquatic invertebrates and cannot be classified as per the CLP classification criteria.
Executive summary:

Based on the experimental data for the test chemical, toxicity of test chemical were determine by observing the effect of chemical on the immobility of aquatic invertebrates. The studies are summarized as below: 

 

Aim of this study was to determine the toxicity of test chemical on the mobility of aquatic invertebrate Cypris subglobosa. A stock solution from each metal salt was prepared in double glass-distilled water. Serial dilutions were prepared from the respective stocks to the desired range. Living specimens were taken to the laboratory and placed in 5 liter glass beaker filled with filtered well water. Test animals were acclimatized to laboratory conditions in environmental growth chamber at 21±1 °C for 2 to 3 days. Growth chamber was equipped with two 60W cool white fluorescent lights. Tests were carried under light and dark cycle of 12:12 h. 20 ml glass Petri- plate dishes were used in which 10 test organism added in each concentrations. Immobility implies the organism usually swim helplessly at the bottom of the container and use their limbs to crawl with difficulty. The 24 h and 48 h EC50 [effective concentration at which 50% immobilized response was recorded] values and their 95% confidence limits were calculated by the moving average-angle method. Based on the immobility of Cypris subglobosa by the test chemical exposure for 48 hrs, (EC50) was observed at 634 mg/l. Based on the EC50 value, chemical was consider to be nontoxic and not classified as per the CLP classification criteria.

 

Above study further supported by the second study from authoritative database. Principle of this study was to determine the effect of test chemical on aquatic invertebrate. The test chemical exposed with invertebrate for 48 hours. Based on the effects observation on the Crustaceans by the chemical exposure 48 hours, the LC50 was observed to be 410 mg/l. Thus based on the LC50 value, chemical was consider as nontoxic and can be consider to be not classified as per the CLP classification criteria.

 

 Similar study was conducted to investigate the effect of test chemical on the growth of Daphnia magna. Study conducted according to the ISO 6341 15 "Water quality – Determination of the inhibition of the mobility of Daphnia magna Straus (Cladocera, Crustacea)". Test chemical exposed with the Daphnia magna for 48 hrs. After the exposure of test chemical with the Daphnia magna for 48 hrs, no effect (EC0) was observed on the mobility at the concentration 940 mg/l. Thus on the basis of above result, it can be concluded that the chemical was nontoxic and not classified as per the CLP classification criteria.

 

Thus based on the overall studies from various sources, it is concluded that the test chemical is nontoxic and not classified as per the CLP classification criteria.

Description of key information

By applying weight of evidence approach the EC50 value of test chemical was determined to be in range from 410 mg/L to >940 mg/l after exposure of test chemical for 48 hrs. The range EC50 value indicates that the substance is likely to be nonhazardous to aquatic invertebrates and cannot be classified as per the CLP classification criteria.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
410 mg/L

Additional information

Based on the experimental data for the test chemical as well as read-across analogues which is extracted by using mechanistic approach and structurally similar to the test chemical, toxicity of test chemical were determine by observing the effect of chemical on the immobility of daphnia magna. The studies are summarized as below: 

 

Aim of this study was to determine the toxicity of test chemical on the mobility of aquatic invertebrate Cypris subglobosa. A stock solution from each metal salt was prepared in double glass-distilled water. Serial dilutions were prepared from the respective stocks to the desired range. 0.2 ml of acetone were used as a vehicle. Living specimens were taken to the laboratory and placed in 5 liter glass beaker filled with filtered well water. Test animals were acclimatized to laboratory conditions in environmental growth chamber at 21±1 °C for 2 to 3 days. Growth chamber was equipped with two 60W cool white fluorescent lights. Tests were carried under light and dark cycle of 12:12 h. 20 ml glass Petri- plate dishes were used in which 10 test organism added in each concentrations. Immobility implies the organism usually swim helplessly at the bottom of the container and use their limbs to crawl with difficulty. The 24 h and 48 h EC50 [effective concentration at which 50% immobilized response was recorded] values and their 95% confidence limits were calculated by the moving average-angle method. Based on the immobility of Cypris subglobosa by the test chemical exposure for 48 hrs, (EC50) was observed at 634 mg/l. Based on the EC50 value, chemical was consider to be nontoxic and not classified as per the CLP classification criteria.

 

Above study further supported by the second study from authoritative database. Principle of this study was to determine the effect of test chemical on aquatic invertebrate. The test chemical exposed with invertebrate for 48 hours. Based on the effects observation on the Crustaceans by the chemical exposure 48 hours, the LC50 was observed to be 410 mg/l. Thus based on the LC50 value, chemical was consider as nontoxic and can be consider to be not classified as per the CLP classification criteria.

 

 

Similar study was conducted to investigate the effect of test chemical on the growth of Daphnia magna. Study conducted according to the ISO 6341 15 "Water quality – Determination of the inhibition of the mobility of Daphnia magna Straus (Cladocera, Crustacea)". Test chemical exposed with the Daphnia magna for 48 hrs. After the exposure of test chemical with the Daphnia magna for 48 hrs, no effect (EC0) was observed on the mobility at the concentration 940 mg/l. Thus on the basis of above result, it can be concluded that the chemical was nontoxic and not classified as per the CLP classification criteria.

 

Thus based on the overall studies from various sources, it is concluded that the test chemical is nontoxic and not classified as per the CLP classification criteria.