ethyl 2-(4-phenoxyphenyl)lactate

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

429-220-9

EC Name:

-

Cas Number:

132584-17-9

Molecular formula:

C17 H18 O4

IUPAC Name:

ethyl 2-hydroxy-2-(4-phenoxyphenyl)propanoate

Test material form:

liquid

Specific details on test material used for the study:

Purity: 73.5%
Batch: IN-JG303-7

Sampling and analysis

Analytical monitoring:

yes

Remarks:

HPLC

Details on sampling:

Concentrations of IN-JG303 for each of the test, solvent control, and blank control solutions were verified for the 0-hour (day 0) samples

Concentrations of IN-JG303 for each of the test, solvent control, blank control, and abiotic
control (nominal 10 mg/L) solutions were verified for the 72-hour (day 3) samples. Samples from each of the test, solvent control, blank control, and abiotic control solutions also
were collected at test termination. These samples were prepared by pooling all three replicates
for each of the test and control solutions. Aliquots were taken from each of the pooled samples and also given to the analytical chemist for analysis.

All samples were analyzed on day of receipt.

Test solutions

Vehicle:

yes

Remarks:

DMF

Details on test solutions:

Identity and concentration of auxiliary solvent for dispersal: DMF at a maximum 0.1 ml/l

Test organisms

Test organisms (species):

Selenastrum sp.

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: Selenastrum capricornutum
- Source (laboratory, culture collection): The original culture source was supplied by Michael Ziegenfuss, The Academy of Natural Sciences of Philadelphia, 1900 Benjamin Franklin Parkway, Philadelphia, PA, 19103-1195

ACCLIMATION
Prior to the study, Selenastrum capricornutum cultures were maintained under the same environmental conditions used in the study. The organisms were cultured in sterilized 250 mL Erlenmeyer flasks containing approximately 50 mL of filtered (= filter-sterilized) AAP nutrient medium and were aseptically transferred to fresh medium every 3 to 7 days. The flasks were fitted with foam stoppers to permit gas exchange.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

24.7 to 24.8°C

pH:

7.28 to 7.73 at the 0-hour and from 7.44 to 7.89 at the 72-hour interval

Nominal and measured concentrations:

Nominal: 0, 0.63, 1.25, 2.5, 5, and 10 mg/L
Measured: 0, 0.53, 0.97, 1.9, 3.9, and 7.8 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: sterilized 250 mL Erlenmeyer flasks each fitted with sterilized foam stoppers
- Initial cells density:
- Control end cells density: To achieve the desired nominal concentration of approximately 10,000 Selenastrum capricornutum cells/mL at test initiation, a volume (approximately 0.162 mL) of algal inoculum from a logarithmically growing stock culture was aseptically transferred to each, excluding the
abiotic control, flask (test unit).

GROWTH MEDIUM
Synthetic algal-assay-procedure (AAP) nutrient medium(3-4) was prepared by adding one mL of each of the six macronutrient stock solutions and one mL of the micronutrient stock solution to approximately 800 mL of Milli-Q® water (deionized), mixing after each addition. The volume of the medium was brought to one liter with additional Milli-Q® water. Since larger volumes of the medium were required for the definitive and recovery tests, appropriate proportions (one mL of each stock solution for each one liter of medium) were used. The medium pH was adjusted to approximately 7.5 with 0.1 N hydrochloric acid. For both the
definitive and recovery tests, the medium was filter-sterilized using Corning® pre-sterilized filtration systems with 0.22 μm cellulose acetate filters. The containers with the resulting filtersterilized AAP nutrient medium for use in the definitive and recovery tests were stored in the refrigerator in the dark at approximately 4°C and acclimated to room temperature prior to use. Any remaining unused medium was properly stored.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: 24 hours
- Light intensity and quality:6,000 to 10,000 Lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
-The mean healthy cell count, area under the growth curve, and growth rate at the 72-hour interval for each test concentration were expressed relative to the pooled blank and solvent controls.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.6 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

5.2 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.63 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.63 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

72-hr EC50 (healthy cell count) = 1.5 mg/L (95% C.I. = 1.4 to 1.6 mg/L)
72-hr NOEC (healthy cell count) = 0.63 mg/L

72-hr EC50 (area under the curve) = 1.6 mg/L (95% C.I. = 1.4 to 1.7 mg/L)
72-hr NOEC (area under the curve) = 0.63 mg/L

72-hr EC50 (growth rate) = 5.2 mg/L (95% C.I. = 4.9 to 5.6 mg/L)
72-hr NOEC (growth rate) = 0.63 mg/L