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Short-term toxicity to aquatic invertebrates

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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:
2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Read across from toxicity study to aquatic invertebrates of pivalic acid (CAS 75-98-9), which is the hydrolysis product of trimethylacetic anhydride, is possible. Trimethylacetic anhydride ist not stable in water and hydrolyses within hours (For details see chapter 5.1.2).
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
- Purity (GC): 99,9%
- Purity (neutralization titration): 99.7%
- pKa: 4.69 (estimated value)
- Freezing point: 35.0 °C
Analytical monitoring:
yes
Details on sampling:
Sample collection frequency: Samples were taken from the new test solution at the start of exposure (0 time) and from the old test solution at the end of exposure (48 hours)
Vehicle:
no
Details on test solutions:
The purity was not corrected because the purity of the test substance was 99.9% (GC) and 99.7% (neutralization titration). A concentrated solution having a test substance concentration of 2,500 mg/L was prepared, and this concentrated solution was diluted with test water to prepare a test solution.
Test organisms (species):
Daphnia magna
Details on test organisms:
Origin:
- Source: National Institute for Environmental Studies, Japan
- Date of receipt: August 4, 1997
- Management after acquisition: subculture rearing (rearing period until generation update; 2 to 4 weeks, changing frequency; Twice a week)
- Results of sensitivity test: Reference substance Potassium dichromate; 48 h EC50 = 0.73 mg/L (95% confidence interval, 0.65-0.81 mg/L); (Within the regulations; Average value ± 30%: 0.51 to 0.96 mg / L, N = 7 (Testing period: from March 2007)]
- Exposure period September 28, 2010 - September 30, 2010
- Parent breeding period: November 16, 2010 to December 20, 2010
- Age: Juveniles less than 24-hour-old

Parent daphnia breeding conditions
- Culturing method: semi-static type (twice a week, the entire amount of breeding water is changed)
- Water temperature: 20 ± 1 ° C
- Lighting: indoor light, 16 hours light / 8 hours dark (Illumination in the vicinity of the test container: 9 to 15 µmol/mE2/s)
- Food: Leaves of single-celled green algae (algae in the culture solution was collected by centrifugation and replaced with pure water to prepare food)
- Feeding amount: 0.1 to 0.2 mg C (organic carbon)/ day per parent daphnia
- Feeding days: Supplied daily except Saturdays and Sundays, and fed Saturdays and Sundays food on Friday afternoon
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
250 mg/L (CaCO3)
Test temperature:
- Not pH-adjusted test concentrations: 20.4-20.6 °C
- pH-adjusted test concentration: 20.6 °C
pH:
- Not pH-adjusted test concentrations: 5.8-7.7
- pH-adjusted test concentration: 7.4
Dissolved oxygen:
- Not pH-adjusted test concentrations: 8.6
- pH-adjusted test concentration: 8.7
Salinity:
n.a.
Conductivity:
No data
Nominal and measured concentrations:
After 48 hours nominal test concentrations of 35, 45.5, 59, 77 and 100 mg/L equals measured arithmetic mean concentration of 35.7, 46.5, 60.3, 78.8 and 101 mg/L
Details on test conditions:
I. Exposure method
- Test solution volume: 90 mL container
- Stations: 4 containers/ test area
- Number of test organisms: 20 heads/test area; 5 test samples in each container
- Test temperature: 20 +/- 1 °C
- Lighting: 16 hours light/8 hours dark
- Aeration: none
- Feeding: None
- Types of auxilaries: None

II. Test containers and equipment
- Test container: 100 mL glass beaker A glass lid was placed on the glass beaker to prevent invasion of the dust and transpiration of the test solution)
- Thermostatic chamber: Constant temperature chamber made by Yamazaki · CEA (configurable temperature: 10 to 30 °C)
- Water thermometer: Mercury rod type standard thermometer (measurement range: 0 to 50 °C, minimum scale: 0.1 °C)
- Dissolved oxygen meter: Do Meter made by Horiba Mochizo (Model: OM12-02)
- pH meter: CANNY ATC PH meter (model: D-21) manufactured by Horiba Seisakusho
- Photon meter: Light meter manufactured by LICOR (model: L1-250
- Total hardness: Korochi Rika Research Laboratory Drop Test Total Hardness WAD-TH

III. Criteria for swimming inhibition:
- After gently moving the test container, it was judged that swimming was inhibited, when swimming never went during 15 seconds of observation

Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
87.4 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: (95%-confidence limit 78.7-101 mg/L)
Remarks:
without pH-adjustment
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 101 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: (95% confidence interval could not be calculated)
Remarks:
with pH-adjustment
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
60 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other:
Remarks:
without pH-adjustment
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
101 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other:
Remarks:
without pH-adjustment
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
101 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other:
Remarks:
with pH-adjustment
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
> 101 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other:
Remarks:
with pH-adjustment
Validity criteria fulfilled:
yes
Conclusions:
The acute toxicity of pivalic acid (CAS 75 -98 -9) to Daphnia magna was investigated in a static GLP study following OECD 202. After 48 hours of exposure the EC50 value was 87.4 mg/L (pH not adjusted). In the test system in which the pH-value was adjusted to the pH value ± 0.3 of the control group no swimming inhibition (EC0) was observed in the test system (101 mg/L). The results relate to the arithmetic mean of the measured concentration.
Executive summary:

A study was performed to assess the acute to Daphnia magna under semi-static conditions. The study was conducted in accordance the OECD Guideline for Testing of Chemicals No. 202 'Daphnia sp., Acute ’Immobilisation Test' (adopted April 13, 2004). A range finding test was performed to get information about the test concentrations in the later main test. In the main test, daphnia were exposed to 5 test concentrations (35, 45.5, 59, 77 and 100 mg/L) relating to nominal concentrations under static exposure conditions. In addition, since the pH value of the test solution fluctuated to the acidic side due to the influence of the test substance, the test was conducted by adding the test concentration group in which the pH value was adjusted to pH - value ± 0.3 of the control group. The temperature, the pH and the oxygen values were measured after 24 and 48 hours of exposure. In the test system without adjustment of the pH value, swimming inhibition of the test organism was observed in the test concentration group of 78.7 and 101 mg/L where the pH value decreased beyond the test condition range (6.0 to 9.0). On the other hand, no swimming inhibition was observed in the test system (101 mg/L) in which the pH value was adjusted to the pH value ± 0.3 of the control group. Therefore, at a concentration of 100 mg/L or less, which is the test upper limit concentration of the test method conforming to the test conducted in conducting the test, the toxicity of the test substance is caused by a decrease in the pH-value accompanying dissolution of the test substance. The pKa-value of the test substance was 4.69 (estimated value). The 48h-EC50 value was 87.4 mg/L (pH not adjusted). The results relate to the arithmetic mean of the measured concentration. This toxicity study is classified as acceptable and satisfies the guideline requirements for the acute Daphnia study.

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Data from pivalic acid (CAS 75-98-9), which is the hydrolysis product of trimethylacetic anhydride.
Reason / purpose for cross-reference:
read-across source
Specific details on test material used for the study:
- Purity (GC): 99,9%
- Purity (neutralization titration): 99.7%
- pKa: 4.69 (estimated value)
- Freezing point: 35.0 °C
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
87.4 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: (95%-confidence limit 78.7-101 mg/L)
Remarks:
without pH-adjustment
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 101 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: (95% confidence interval could not be calculated)
Remarks:
with pH-adjustment
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
60 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other:
Remarks:
without pH-adjustment
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
101 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other:
Remarks:
without pH-adjustment
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
101 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other:
Remarks:
with pH-adjustment
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
> 101 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other:
Remarks:
with pH-adjustment
Validity criteria fulfilled:
yes
Conclusions:
The acute toxicity of pivalic acid (75 -98 -9) to daphnia magna was investigated in a static GLP study following OECD 202. After 48 hours of exposure the EC50 value was 87.4 mg/L (pH not adjusted). In the test system in which the pH-value was adjusted to the pH value ± 0.3 of the control group no swimming inhibition (EC0) was observed in the test system (101 mg/L). The results relate to the arithmetic mean of the measured concentration.

Description of key information

The acute toxicity of pivalic acid (CAS 75-98-9) to Daphnia magna was investigated in a static GLP study following OECD 202. After 48 hours of exposure the EC50 value was 87.4 mg/L (pH not adjusted). In the test system in which the pH-value was adjusted to the pH value ± 0.3 of the control group no swimming inhibition (EC0) was observed in the test system (101 mg/L). The results relate to the arithmetic mean of the measured concentration.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
87.4 mg/L

Additional information

Read across from toxicity study to aquatic invertebrates of pivalic acid (CAS 75-98-9), which is the hydrolysis product of trimethylacetic anhydride, is possible. Trimethylacetic anhydride ist not stable in water and hydrolyses within hours (For details see chapter 5.1.2).