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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:
experimental study
Adequacy of study:
key study
Study period:
19.02.2018-21.03.2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
no
Remarks:
accredited by DAkkS
Analytical monitoring:
not specified
Vehicle:
yes
Remarks:
test samples diluted in water
Details on test solutions:
The test vessels contained a final volume of 10 mL (p-benzoquinone stock solution and dilution water). For each dilution stage and a control solution (contains only water) four 30 mL-test tubes with 5 daphniae were prepared. The test tubes were covered with Kapsenberg caps and left for 48 h. Incubation was performed at room temperature (20-22°C) in a 12 h/12 h light-dark rhythm without feed portion. The daphnia mobility was checked and documented after 24 h and 48 h.
Test organisms (species):
Daphnia magna
Details on test organisms:
Daphnia magna Straus
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Test temperature:
20-22°C
pH:
7,6 (+/-0,4)
Dissolved oxygen:
8,6 (+/-0,4) in the beginning of the test
7,6 (+/-0,6) in the end of the test
Salinity:
dilution water:
25 ml 0,08 M CaCl2-solution
+ 25 ml 0,02 M MgSO4-solution
+ 25 ml 0,03 M NaHCO3-solution
+ 25 ml 0,003 M KCl in 1 L deionised water
Conductivity:
606 μS/cm (dilution water)
Nominal and measured concentrations:
0,20 mg/l, 0,25 mg/l, 0,30 mg/l, 0,40 mg/l, 0,50 mg/l, 0,60 mg/l
Reference substance (positive control):
no
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.35 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
A daphnia is assessed as immobile provided that it did not move independently or after slight swinging 15 s as a minimum. Other effects of the test substance on daphniae like coloration or special stress behaviour were not observed.

The relevant concentration range for the calculation of the EC50-value was determined in preliminary tests.

Tab. 1: Mobility of Daphnia magna Straus at different methylhydroquinone concentrations

concentration [mg/l]

Mobility of Daphnia magna after

24 h

48 h

Amount

%

Amount

%

0,20

20

100

20

100

0,25

18

90

16

80

0,30

14

70

12

60

0,40

16

80

8

40

0,50

10

50

4

20

0,60

4

20

0

0

Validity criteria fulfilled:
yes
Remarks:
Reference samples did not fall below 90% daphnia mobility. Oxygen content at the test end was always above 3 mg/L.
Conclusions:
In a study according to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test), a 48 h EC50 = 0,35 mg/L for methylhydroquinone was determined.
Executive summary:

The acute toxicity of methylhydroquinone to Daphnia magna was investigated in a study according to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) under static conditions. The endpoint examined was immobilization. The daphnids (5 animals/concentration) were exposed to nominal concentrations of 0,20 mg/l, 0,25 mg/l, 0,30 mg/l, 0,40 mg/l, 0,50 mg/l and 0,60 mg/l methylhydroquinone.

The 48 h EC50 was determined to be 0,35 mg/L based on nominal concentrations.

The testing/validity criteria laid down in the OECD guideline 202 are fulfilled. This study is regarded as reliable without restriction.

Thus, a 48 h EC50 = 0,35 mg/L (recalculated based on initial concentrations) has to be taken into account for the assessment.

Description of key information

In a study according to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test), a 48 h EC50 = 0,35 mg/L for methylhydroquinone for daphnia magna was determined.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Dose descriptor:
EC50
Effect concentration:
0.35 mg/L

Additional information