o-anisic acid

Short-term toxicity to aquatic invertebrates

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:

comparable to guideline study

Justification for type of information:

Data is from Abitec study report.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Principles of method if other than guideline:

Determination of mobility of daphnids using OECD guideline 202.

GLP compliance:

no

Specific details on test material used for the study:

- Name of test material: 2-methoxybenzoic acid (2-MBA)
- Molecular formula: C8H8O3
- Molecular weight: 152.1482 g/mol
- Smiles notation: COc1ccccc1C(=O)O
- InChl:1S/C8H8O3/c1-11-7-5-3-2-4-6(7)8(9)10/h2-5H,1H3,(H,9,10)
- Substance type: Organic
- Physical state: Solid

Analytical monitoring:

not specified

Vehicle:

yes

Details on test solutions:

The stock solution (150mg/l) was prepared by dissolving white powdered in reconstituted water. Test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with reconstituted test water.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain: Straus
- Source: Own breeding at University of Chemistry and Technology, Prague
- Age at study initiation (mean and range, SD): The animals used for the test shall be less than 24 h old and should not be first brood progeny
- Feeding during test: No feeding

ACCLIMATION - No data available
- Acclimation period:
- Acclimation conditions (same as test or not):
- Type and amount of food:
- Feeding frequency:
- Health during acclimation (any mortality observed):

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

± 1 hr

Test temperature:

20±2°C

pH:

Sample concentrations 30 45 67.5 100 150
Start of the test 7.0 6.8 6.4 5.9 4.7
The end of the test 7.7 7.4 7.4 6.4 5.0
Control: pH: 8.0 changed to pH: 7.7 during the test

Dissolved oxygen:

higher than 7.9 mg/L at the end of test

Nominal and measured concentrations:

0, 30,45,67.5,100 and 150 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml glass vessel
- fill volume: 25 ml
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
Natural water (surface or ground water), reconstituted water or dechlorinated tap water are acceptable as culturing and dilution water if D. magna survives in it for the duration of the culturing, acclimation and testing without showing signs of stress. Waters in the range pH 6 to pH 9, with hardness between 140 mg/l and 275 mg/l (as CaCO3) are recommended.
As an example, the preparation of dilution water meeting the requirements is described below.
Dissolve known quantities of reagents in water. The dilution water prepared shall have a pH of 7.8 ± 0.5, a hardness of (225 ± 50) mg/l (expressed as CaCO3), a molar Ca + Mg ratio close to 4 + 1 and a dissolved oxygen concentration above 7 mg/l.

Prepare the solutions specified below:
- Calcium chloride solution: Dissolve 117.6 g of calcium chloride dihydrate (CaCl2.2H2O) in water (4.2) and make up to 1 l with water (4.2).
- Magnesium sulfate solution: Dissolve 49.3 g of magnesium sulfate heptahydrate (MgSO4.7H2O) in water (4.2) and make up to 1 l with water (4.2).
- Sodium bicarbonate solution: Dissolve 25.9 g of sodium bicarbonate (NaHCO3) in water (4.2) and make up to 1 l with water (4.2).
- Potassium chloride solution: Dissolve 2.3 g of potassium chloride (KCI) in water (4.2) and make up to 1 l with water (4.2).

Mixing
Mix 2.5 ml of each of the four solutions and make up to 1 l with water.
The dilution water shall be aerated until the dissolved oxygen concentration has reached saturation and the pH has stabilized. If necessary, adjust the pH to 7.8 ± 0.5 by adding sodium hydroxide (NaOH) solution or hydrochloric acid (HCI). The dilution water prepared in this way shall not be further aerated before use.

- Sodium hydroxide solution, e.g. [NaOH] : 1 mol/l.
- Hydrochloric acid, e.g. [HCl] : 1 mol/l.

Reference substance:
Dissolve 600 mg of potassium dichromate (K2Cr2O7) in water and make up to 1 l with water (4.2).

OTHER TEST CONDITIONS
- Adjustment of pH: no adjustment done
- Photoperiod: No - Darkness
- Light intensity:

CALCULATION:
EC50 was calculated using non linear regression by the software Prism 4.0

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

85.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 74.7-97-.0

Details on results:

The tested substance is an acid and that is why the higher concentration the lower pH. The optimum pH of daphnids is 6.0-9.0.The inhibition of daphnids could be influenced by pH at the concentration higher than 100 mg/l.

Results with reference substance (positive control):

- Results with reference substance valid
- EC50: 0.73 mg/L (24 hours)

Reported statistics and error estimates:

EC50 was calculated using non-linear regression by the software Prism 4.0 (GraphPad Software, Inc. San Diego CA)

Validity criteria fulfilled:

not specified

Conclusions:

the EC50 value for short term toxicity to aquatic invertebrates using OECD guideline 202 was determined to be 85.1 mg/l. Based on the value the chemical was considered as classified but as it was readily biodegradable in nature, hence can be considered as not classified as per the CLP regulations

Executive summary:

Short term toxicity to aquatic invertebrates (ABITEC, Determination of the inhibition of the mobility of daphnids.2017) was performed in Daphnia magna following the OECD guideline 202. The test was performed for 48 hrs at different concentrations as control 0, 30, 45, 67.5, 100 and 150 mg/L at 95 % confidence limit of 74.5-97.0.Reference substance used was K2Cr207. 5 pieces of daphnids after breeding were used in 4 numbers of replicates of test concentration. The test was performed in temperature 20°C±1°C with taking 25ml per replicate in 50ml glass vessel for 48 hrs. Calculations of EC50 were calculated using nonlinear regression by the software Prism4.0 (Graph Pad Software, Inc., San Diego CA).

After experiment, the EC50 value for short term toxicity to aquatic invertebrates using OECD guideline 202 was determined to be 85.1 mg/l. Based on the value the chemical was considered as classified but as it was readily biodegradable in nature, hence can be considered as not classified as per the CLP regulations.

Description of key information

Short term toxicity to aquatic invertebrates (ABITEC, Determination of the inhibition of the mobility of daphnids.2017) was performed in Daphnia magna following the OECD guideline 202. The test was performed for 48 hrs at different concentrations as control 0, 30, 45, 67.5, 100 and 150 mg/L at 95 % confidence limit of 74.5-97.0.Reference substance used was K2Cr207. 5 pieces of daphnids after breeding were used in 4 numbers of replicates of test concentration. The test was performed in temperature 20°C±1°C with taking 25ml per replicate in 50ml glass vessel for 48 hrs. Calculations of EC50 were calculated using nonlinear regression by the software Prism4.0 (Graph Pad Software, Inc., San Diego CA).

After experiment, the EC50 value for short term toxicity to aquatic invertebrates using OECD guideline 202 was determined to be 85.1 mg/l. Based on the value the chemical was considered as classified but as it was readily biodegradable in nature, hence can be considered as not classified as per the CLP regulations.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

85.1 mg/L

Additional information

Toxicity to aquatic invertebrates for 2-methoxybenzoic acid (579-75-9) was summaries with target data and by using functional read across studies are summaries as follows:

Short term toxicity to aquatic invertebrates (ABITEC, Determination of the inhibition of the mobility of daphnids.2017) was performed in Daphnia magna following the OECD guideline 202. The test was performed for 48 hrs at different concentrations as control 0, 30, 45, 67.5, 100 and 150 mg/L at 95 % confidence limit of 74.5-97.0.Reference substance used was K2Cr207. 5 pieces of daphnids after breeding were used in 4 numbers of replicates of test concentration. The test was performed in temperature 20°C±1°C with taking 25ml per replicate in 50ml glass vessel for 48 hrs. Calculations of EC50 were calculated using nonlinear regression by the software Prism4.0 (Graph Pad Software, Inc., San Diego CA).

After experiment, the EC50 value for short term toxicity to aquatic invertebrates using OECD guideline 202 was determined to be 85.1 mg/l. Based on the value the chemical was considered as classified but as it was readily biodegradable in nature, hence can be considered as not classified as per the CLP regulations.

Daphnia tests were conducted by Michael Cleuvers, (2004) on read across 2-acetoxybenzoic acid (50-78-2) following the European Guideline (Commission of the European Communities, 1992) using the water flea. Daphnids were bred in ADaM, a culture medium imitating natural freshwater. Test was performed in 20 degree C with photoperiods of 16 h light/8 h dark. Young daphnids were used in 50 ml of culture volume, each treatment was subdivided in four replicates, each containing 5 daphnia and observed for 24 and 48 hrs. After the experiment the EC50 value for short term toxicity to aquatic invertebrates for 2-acetoxybenzoic acid (50-78-2) was determined to be 88.1 mg/l. Based on the values, 2-acetoxybenzoic acid was considered to toxic to aquatic invertebrates but as it is readily biodegradable in nature hence, 2-acetoxybenzoic acid (50-78-2) was considered to be not classified as per the CLP regulations.

Another study for read across 4-methoxybenzoic acid (100-09-4) from Chemosphere 59 (2005) 255–261, short term toxicity to aquatic invertebrates was performed in Daphnia magna for 48 hrs. The young daphnids were obtained from continuous cultures in 1 liter glass beakers at 21 ± 0.3 degree C, in dechlorinated and conditioned tap water, the medium was renewed in three weeks and daphnids were fed daily with the green alga Selenastrum capricornutum. The pH of test solution was adjusted to 7.45 ± 0.05 with HCL and NaOH. The concentrations of the resultant solutions were checked before and after (48 h) exposure using a UV–visible spectrophotometer. As the experiment starts neonate were placed in 50 ml of beaker with 40 ml of test solution. All experiment was made in four replicates and performed at 21 ± 0.3 degree C under 16 h light: 8 h dark photoperiod. Immobility was observed after 24 and 48 hrs and EC 50 value was calculated. After the experiment the EC 50 value of 4-methoxybenzoic acid (100-09-4) for Daphnia magna was determined to be 943 mg/l in 48 hrs. Based on the CLP regulation the 4-methoxybenzoic acid is considered to be not toxic to aquatic invertebrates and can be concluded to be not classified as per the CLP regulations.

From the same reference, another read across Benzoic acid (65-85-0) was also studied and the EC 50 value of Benzoic acid (65-85-0) for Daphnia magna was determined to be 860 mg/l in 48 hrs.

Based on the results of target and result of read across chemical, it was considered that 2-methoxybenzoic acid (579-75-9) was likely to be non-toxic to aquatic invertebrates and can be considered to be not classified as per the CLP regulations.