p-tolyl acetate

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

Study period:

04.04.2017 - 06.04.2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental test result using OECD guidelines.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Principles of method if other than guideline:

Determination of the inhibition of the mobility of Daphnids was carried out with the substance p-tolyl acetate according to OECD Guideline 202.

GLP compliance:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No. of test material: No data
- Expiration date of the lot/batch: No data
- Purity test date: No data

RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity: No data
- Specific activity: No data
- Locations of the label: No data
- Expiration date of radiochemical substance: No data

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: No data
- Stability under test conditions: No data
- Solubility and stability of the test substance in the solvent/vehicle: No data
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No data

Analytical monitoring:

no

Details on sampling:

No data

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
The stock solution 100.0 mg/L was prepared by dissolving colourless liquid in reconstituted water. The test solutions of required concentrations were prpared by mixing the stock solution of the test sample in reconstituted water.

- Controls: Reconstituted water as specified in OECD 202, used as a control and for sample dilution.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain/clone: Straus
- Source: Own breeding at University of Chemistry and Technology, Prague
- Age: Young daphnids, aged less than 24 hours used at the start of the test and they should not be first brood progeny.
- Feeding during test : Without feeding

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

QUARANTINE (wild caught)
- Duration: No data
- Health/mortality: No data

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

± 1 h

Post exposure observation period:

No data

Hardness:

No data

Test temperature:

20 °C ± 1 °C

pH:

Sample at concentration 100 mg/L : pH = 7.8 did not change during the test,
Control: pH = 7.9 changed to pH = 7.8 during the test.

Dissolved oxygen:

Higher than 7.9 mg/L both in the control and the sample.

Salinity:

No data

Conductivity:

No data

Nominal and measured concentrations:

0, 6.0, 12.0, 24.0, 50.0, and 100.0 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml glass vessel
- Material, size, headspace, fill volume: 25 ml
- Aeration: no data
- No. of organisms per vessel: 5 pieces
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): No data
- No. of vessels per vehicle control (replicates): No data
- Biomass loading rate: No data

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.

OTHER TEST CONDITIONS
- Adjustment of pH: Without adjustment
- Photoperiod: No - Darkness

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : 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.:

31.2 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI = 22.2 - 43.7 mg/L

Details on results:

No data

Results with reference substance (positive control):

- Results with reference substance valid
- 24h EC50 = 0.73 mg/L K2Cr2O7

Reported statistics and error estimates:

No data

Control solution: Reconstituted water without the sample, 0 % of the daphnids were immobilized at the end of test.

Validity criteria fulfilled:

yes

Conclusions:

The median effective concentration (EC50) for the test substance, p-tolyl acetate, in Daphnia magna was determined to be 31.2 mg/L on the basis of mobility inhibition effects in a 48 hours of study.

Executive summary:

Determination of the inhibition of the mobility of Daphnids was carried out with the substance p-tolyl acetate according to OECD Guideline 202.

The stock solution 100.0 mg/L was prepared by dissolving colourless liquid in reconstituted water. The test solutions of required concentrations were prepared by mixing the stock solution of the test sample in reconstituted water. The test substance was tested at the concentrations 0, 6.0, 12.0, 24.0, 50.0, and 100.0 mg/L. The test was performed under static conditions in a fresh water system at a temperature of 20 °C± 1 °C. EC50 was calculated using non linear regression by the software Prism 4.0.

The median effective concentration (EC50) for the test substance, p-tolyl acetate, in Daphnia magna was determined to be 31.2 mg/L for immobilisation effects with 95% CI of 22.2 to 43.7 mg/L. But the BCF value of p-tolyl acetate was not >= 500 as well as the substance was found to be readily bio-degradable in water compartment. Thus, according to CLP Criteria for aquatic classification of the substance, it is concluded that p-tolyl acetate (CAS no. 140-39-6) does not exhibit short term toxicity to aquatic invertebrate.

Description of key information

The median effective concentration (EC50) for the test substance,p-tolyl acetate, in Daphnia magna was determined to be 31.2 mg/L for immobilisation effects with 95% CI of 22.2 to 43.7 mg/L.But the BCF value of p-tolyl acetate was not >= 500 as well as the substance was found to be readily bio-degradable in water compartment. Thus, according to CLP Criteria for aquatic classification of the substance, it is concluded that p-tolyl acetate (CAS no. 140-39-6) does not exhibit short term toxicity to aquatic invertebrate.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

31.2 mg/L

Additional information

Various experimental studies following OECD guideline and predicted results from validated model for toxicity to aquatic invertebrate with the target substance p-tolyl acetate (CAS No. 140-39-6) and the relevant read across substances 2-acetoxybenzoic acid (CAS No.-50-78-2) and 3-methylbutyl 2-hydroxypropanoate (CAS No.-19329-89-6) by considering its structure-activity relationships, were summarized as follows:

 

Determination of the inhibition of the mobility of Daphnids was carried out with the substance p-tolyl acetate according to OECD Guideline 202.

The stock solution 100.0 mg/L was prepared by dissolving colourless liquid in reconstituted water. The test solutions of required concentrations were prepared by mixing the stock solution of the test sample in reconstituted water. The test substance was tested at the concentrations 0, 6.0, 12.0, 24.0, 50.0, and 100.0 mg/L. The test was performed under static conditions in a fresh water system at a temperature of 20 °C± 1 °C. EC50 was calculated using non linear regression by the software Prism 4.0.

The median effective concentration (EC50) for the test substance, p-tolyl acetate, in Daphnia magna was determined to be 31.2 mg/L for immobilisation effects with 95% CI of 22.2 to 43.7 mg/L. But the BCF value of p-tolyl acetate was not >= 500 as well as the substance was found to be readily bio-degradable in water compartment. Thus, according to CLP Criteria for aquatic classification of the substance, it is concluded that p-tolyl acetate (CAS no. 140-39-6) does not exhibit short term toxicity to aquatic invertebrate.

 

Also, based on the prediction done using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity to aquatic invertebrates was predicted for p-tolyl acetate (CAS No.140-39-6). EC50 value was estimated to be 106.27mg/L on the basis of intoxication effect for Daphnia magna for 48 hrs of duration.

Thus, it can be concluded that the p-tolyl acetate (CAS No.140-39-6) was considered to be not classified to aquatic invertebrates as per the CLP regulations. 

 

Similary, based on the Ecological Structure Activity Relationships (ECOSAR) Predictive Model version 1.11(2017), the median lethal concentration (LC50) for the test substance, p-tolyl acetate, in daphnia magna was estimated to be 53.43 mg/L on the basis of mortality effect in a 48 hour study. Based on this LC50 value the substance may qualify for aquatic classification but after compairing with CLP criteria it was found that the BCF value of p-tolyl acetate was not >= 500 as well as the substance was found to be readily bio-degradable in water compartment. Thus, according to CLP Criteria for aquatic classification of the substance, it is concluded that p-tolyl acetate (CAS no. 140-39-6) does not exhibit short term toxicity to aquatic invertebrate.

 

In another study of read across substances 2-acetoxybenzoic acid (50-78-2) which has 50-60% structural similarity, Daphnia tests were conducted following the European Guideline (Commission of the European Communities,1992) using the water flea D. magna. 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 each treatment was subdivided in four replicates, each containing 5 daphnia and observed for 24 and 48 hrs. After the experiment the EC 50 value for short term toxicity to aquatic invertebrates for 2-acetoxybenzoic acid (50-78-2) was determined to be 88.1 mg/l. As 2-acetoxybenzoic acid was determined to be readily biodegradable in nature hence, 2-acetoxybenzoic acid (50-78-2) was considered to be not classified as per the CLP regulations.

 

Another experimental study of read across substance 3-methylbutyl 2-hydroxypropanoate (19329-89-6) to aquatic invertebrates was performed by (Ecotox database, U.S Environmental Protection agency, 2017) for 48 hrs in fresh water. The concentration ranges from 168 – 232 mg/l. After the experiment the EC 50 value of 3-methylbutyl 2-hydroxypropanoate (19329-89-6) for Short term toxicity to aquatic invertebrates was determined to be 193 mg/l. Based on the result, the 3-methylbutyl 2-hydroxypropanoate (19329-89-6) was considered to be non-toxic to aquatic invertebrate and can be considered to not classified as per CLP regulation.

 

From the results of p-tolyl acetate (CAS No.140-39-6) and result of read across substances 2-acetoxybenzoic acid (50-78-2) and 3-methylbutyl 2-hydroxypropanoate (19329-89-6), as all the above weight of evidences supported the classifications, hence it can be considered that the p-tolyl acetate (CAS No.140-39-6) to be not classified as per the CLP regulations.