Registration Dossier

Ecotoxicological information

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:
other: The study was conducted according to the O.E.C.D. test guideline 201 with GLP compliance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
Nominal concentrations only.
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
2,3-epoxypropyl o-tolyl ether
EC Number:
218-645-3
EC Name:
2,3-epoxypropyl o-tolyl ether
Cas Number:
2210-79-9
Molecular formula:
C10H12O2
IUPAC Name:
oxirane
Constituent 2
Reference substance name:
Oxirane, 2-[(2-methylphenoxy)methyl]-
IUPAC Name:
Oxirane, 2-[(2-methylphenoxy)methyl]-
Details on test material:
As per IUCLID Sections 1.1. 1.2. and 4.1.

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
Test substance treatment solutions were prepared by by adding the required nominal amount of test substance in stock culture medium (Woods Hole) and mixing.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The green algae Selenastrum capricornutum was maintained by Stillmeadow, Inc. Mass culture initiated 3-7 ±1 days prior to dosing and were used on-study at a density of 50,000 cells/mL. The algal cultures were maintained in Algal stock culture medium (Woods Hole) with EDTA up to 0.300 mg/L in 250-mL sterile Erlenmeyer flasks with stoppers and aeration tubing. The test containers received constant aeration. The temperature was maintained at 24 ±2°C with continuous lighting (400 ±40 ft. c.).

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
None

Test conditions

Hardness:
No data
Test temperature:
24ºC
pH:
7.4-8.9 treminal
Dissolved oxygen:
no data
Salinity:
Freshwater
Nominal and measured concentrations:
1.25, 2.5, 5, 10 and 20 mg/L nominal.
Details on test conditions:
The five concentrations of the test substance were used. The test cultures (50,000 cells/mL) were divided into 250-mL flasks containing the appropriate concentration of test substance (three flasks per test concentration and six flasks for the control). A positive control group consisted of three flasks treated with 10 mg/L zinc chloride. The flasks were set on a shaker table for constant agitation at approximately 100 cycles/minute. At 24, 48 and 72 hours following dosing, observations of inhibition were made for each test container by measuring the mean cell density with a hemacytometer. The temperature was recorded daily and the pH of each container was recorded at study termination.
Reference substance (positive control):
yes
Remarks:
10 mg/L zinc chloride

Results and discussion

Effect concentrations
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
ca. 5.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Remarks on result:
other: 95% confidence Limits = 0.0 - 9.85 mg/L nominal
Details on results:
At 10 mg/L test substance after 72 hr the relative percent cell growth inhibition was 35.9%. Complete cell growth inhibition was observed at 20 mg/L of test substance at 72 hr.
Results with reference substance (positive control):
The positve control zinc chloride at 10 mg/L caused complete (100%) cell growth inhibiton at 72 hr relative to the untreated control cultures.
Reported statistics and error estimates:
The EC50 95% Confidence Limits were 0.0 - 9.85 mg/L (nominal).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The EC50 value for the test substance in this study of 5.1 mg/L demonstrates that it is toxic to algae under the conditions of the study.
Executive summary:

The test substance, 2,3 -epoxypropyl o-tolyl ether, was accesed for toxicity to green algae in a GLP, O.E.C.D. test gudeline 201 study.The EC50 value for the test substance in this study of 5.1 mg/L demonstrates that it is toxic to algae under the conditions of the study.