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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:
key study
Study period:
2006
Justification for type of information:
see analogue justification attached to chapter 13
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: control and 100 mg/L. Samples were taken at 0 and 48 h
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution of test substance was prepared by adding 1.0111g to the test water and fill up to the marker in 100 mL volumetric flask. 2 mL of stock solution was added in the test water and filled up to the marker in 200 mL beaker to prepare test solutions.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Age at study initiation (mean and range, SD): <24 h
- Source: Environmenal toxicity lab., Safety Assessment Center, Korea Testing and Research Institute
- Food type (breeding): unicellular green algae, Chlorella vulgaris, daily
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Hardness:
224 mg/L CaCO3
Test temperature:
20.28 ± 0.2 ℃
pH:
7.8-8.14
Dissolved oxygen:
7.73-8.18 mg/L
Nominal and measured concentrations:
Nominal test concentration: 100 mg/L
The mean concentration was analyzed to be 2.75 mg/L at a nominal concentration of 100 mg/L (2.9% of nominal concentration) at 0 and 48 hours.
Details on test conditions:
TEST SYSTEM
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: M4 medium


OTHER TEST CONDITIONS
- Photoperiod: 16:8 h day-night regime

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Immobility after 0, 24 and 48 hours

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: control, 0.1, 1, 10, and 100 mg/L.
- Results used to determine the conditions for the definitive study: No immobility was observed at 100 mg/L
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 2.9 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
After 24 hours and 48 hours exposure, no daphnia was immobilised in 100 mg/L of test solution. No abnormal behavior and intoxication symptoms were observed in control and treatment groups during limit test.
Reported statistics and error estimates:
No statistics performed

Table 1. Cumulative immobilization data forDaphnia magna

Nominal concentration (mg/L)

Measured concentration (mg/L)

Number of daphnids tested

Cumulative immobilized Daphnia magna (%)

24 hours

48 hours

Control

ND

30

No immobilization

No immobilization

100

2.9

30

No immobilization

No immobilization

Table 2. Symptoms on intoxication of the test substance toDaphnia magna

Nominal concentration (mg/L)

Measured concentration (mg/L)

Symptoms of intoxication

24 hours

48 hours

Control

ND

NOR (30)

NOR (30)

100

2.9

NOR (30)

NOR (30)

ND : Not detected, ( ) : Number of Daphnia magna, NOR : Normal

Description of key information

Key value for chemical safety assessment

Additional information

Data on the acute toxicity of magnesium hydrogen orthophosphate (CAS 7757-86-0) to aquatic invertebrates are not available. The assessment was therefore based on studies conducted with the analogue substance calcium hydrogen orthophosphate (7757-93-9) as part of a read across approach, which is in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5.

The acute toxicity of calcium hydrogen orthophosphate to aquatic invertebrates was investigated in a study following OECD guideline 202 (Kim et al. 2013). The study was conducted as a limit test under static conditions. Daphnia magna were exposed to a nominal test substance concentration of 100 mg/L for 48 hours. The mean measured substance concentration was 2.75 mg/L. Mortality or symptoms of intoxication were not observed. At test termination an EC50(48 h) >2.75 mg/L (nominal: EC50(48 h) >100 mg/L) based on the mean measured concentration was determined. Based on the study results for the read across substance calcium hydrogen orthophosphate the assessed substance magnesium hydrogen orthophosphate is considered not acutely toxic to aquatic invertebrates.