Propanoic acid, 2-hydroxy-, 2-ethylhexyl ester, (2S)-

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

No details provided. However, in the publication it is stated that actual concentrations were determined by chemical analysis.
Samples of 50-100 mL volume were immediately extracted with 5 mL hexane adding n-dodecane as an internal standard.

Vehicle:

no

Details on test solutions:

Not reported

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain: No data
- Source: No data
- Age at study initiation (mean and range, SD): No data
- Weight at study initiation (mean and range, SD): No data
- Length at study initiation (length definition, mean, range and SD): No data
- Valve height at study initiation, for shell deposition study (mean and range, SD): No data
- Peripheral shell growth removed prior to test initiation: No data
- Method of breeding: No data
- Feeding during test: No data
- Food type: No data
- Amount: No data
- Frequency: No data

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

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

No data

Test temperature:

No data

pH:

No data

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

According to the authors, "the average measured concentrations of lactate esters were generally between 70 and 80 % of the nominal concentrations in both the newly prepared and spent test media during the (...) D. magna tests". Details on measured test concentrations were not reported.

Details on test conditions:

TEST SYSTEM
- Test vessel: No data
- Material, size, headspace, fill volume: No data
- Aeration: No data
- Renewal rate of test solution (frequency/flow rate): Not applicable - static test
- No. of organisms per vessel: No data
- No. of vessels per concentration (replicates): No data
- 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: No data
- Total organic carbon: No data
- Particulate matter: No data
- Metals: No data
- Pesticides: No data
- Chlorine: No data
- Alkalinity: No data
- Ca/Mg ratio: No data
- Conductivity: No data
- Culture medium different from test medium: No data
- Intervals of water quality measurement: No data

OTHER TEST CONDITIONS
- Adjustment of pH: No data
- Photoperiod: No data
- Light intensity: No data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study: No data
- Test concentrations: 3.2, 5.6, 10, 18, 32, 56, and 100 mg/L

Reference substance (positive control):

not specified

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

83 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CI = 73-96 mg/L

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

ca. 56 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

58 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other:

Remarks:

predicted via SAR

Reported statistics and error estimates:

EC50 with associated 95 % confidence interval.
NOEC assessed by 10 % effect as a significant deviation.

Validity criteria fulfilled:

not specified

Remarks:

Due to limited reporting (published academic research paper), the validity criteria of OECD guideline 202 cannot be exhaustively assessed.

Conclusions:

The 48-h EC50 of 2-ethylhexyl lactate in Daphnia magna was determined to be 83 mg/L (nominal).
In addition an EC50 of 58 mg/L was calculated via structure activity relaion (SAR).

Executive summary:

The 48-hr-acute toxicity of 2-ethylhexyl lactate to Daphnia magna was studied under static conditions. Immobility was assessed as endpoint. The 48-hour EC₅₀ was 83 mg/L (nominal). The 48-hr NOEC based on immobility was 56 mg/L (nominal). In addition, an EC₅₀ of 58 mg/L was calculated via structure-activity relationship (SAR).

Despite some reporting deficiencies, being a consequence of the concise format of published research papers, this study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates, as far as determinable from the limited information.

Results synopsis

Test organism age (e.g. 1^st instar): Not reported

Test type (flow-through, static, static renewal): Static

EC₅₀: 83 mg/L (95 % C.I. = 73–96 mg/L)

NOEC = 56 mg/L

Endpoint(s) effected: Mobility

Description of key information

The 48-h EC50 of 2-ethylhexyl lactate in Daphnia magna was determined to be 83 mg/L (nominal).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

83 mg/L