Registration Dossier

Administrative data

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 07 aug 2009 to 28 jan 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
yes
Remarks:
fish biomass to solution ratio > 1 mg/L. No impact on results.
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 1 mg/L
- Sampling method:
Aliquots of the newly prepared test solutions of the control and the 1.0 mg test item treatment were sampled at start of exposure and hour 72. Aliquots of the aged test solutions were sampled at hour 24 and at test termination (hour 96). The samples were analyzed to determine the concentration of p-TFMA in the test solution.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION:
- Method:
A 100 mg test item/L stock solution was prepared prior to test initiation and daily thereafter by dissolving approximately 0.1 g test item in 1000 mL dilution water. To obtain the 1.0 mg test item/L test solution, 100 mL of the stock solution were diluted to 10000 mL with dilution water. All resulting test solutions were mixed for 30 seconds using a glass rod to yield a homogenously distributed test solution. They were observed to be clear and colorless, with no visible undissolved test item.
A control vessel containing only dilution water was established and maintained under the same conditions as the treatment solution.

Test organisms

Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
TEST ORGANISM
- Common name: rainbow trout
- Strain: Oncorhynchus mykiss
- Source: from Forellenzucht P. Hohler-Gasser, a commercial supplier located in Zeiningen, Switzerland.
- Age at study initiation (mean and range, SD):
- Length at study initiation (length definition, mean, range and SD): mean total length of 48 mm (range 40 to 55 mm).
- Weight at study initiation (mean and range, SD): mean wet weight of 1.25 g (range 0.66 to 2.21 g)
- Feeding during test
- Food type: The fish were fed Hokovit 502, a dry, commercially available food, generally once daily. Fish were not fed during the 24-hour period prior to test initiation and during the exposure period.
- Frequency: once daily

ACCLIMATION
- Acclimation period: 12 days
- Acclimation conditions (same as test or not): under renewal conditions. Prior to testing, the fish were maintained in a holding tank (under renewal conditions) under a photoperiod of 16 hours light and 8 hours darkness with a 30 minute transition period.
- Type and amount of food: same as above
- Feeding frequency: daily
- Health during acclimation (any mortality observed): no mortality observed

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
96 h

Test conditions

Hardness:
160 to 168 mg/L CaCO3
Test temperature:
15 +/-2°C
pH:
7.40 to 7.64
Dissolved oxygen:
8.39 to 9.18 mg/L
Nominal and measured concentrations:
1 mg/L (nominal concentration)
Details on test conditions:
TEST SYSTEM
- Test vessel: The test vessels were 12.5 L vessels constructed of stainless steel, each containing 10 L of test solution.
- Type (delete if not applicable): closed. The test vessels were loosely covered with a glass plate during the 96-hour exposure.
- Material, size, headspace, fill volume: The test vessels were placed in a water bath in order to maintain exposure solution temperatures at 15 ± 2°C.
- Aeration: Test solutions were gently aerated (with oil-free air) throughout the duration of the exposure period.
- Renewal rate of test solution (frequency/flow rate):
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dilution water consists of deionized, reconstituted, unchlorinated Horn well water. The water is passed through a Culligan water softener with a synthetic ion exchange resin to lower total hardness prior to use.
-Hardness: 160 to 190 mg/L CaCO3
- Conductivity: 350 to 550 µS/cm
- Culture medium different from test medium:
- Intervals of water quality measurement: Water quality variables have been measured and recorded in each new test concentration and control solution at experimental start and in both the new and the aged solutions at each renewal interval of each test aquarium.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: A 16-hour light, 8-hour dark photoperiod was maintained with an automatic timer.
- Light intensity: 200 to 500 lux using fluorescent bulbs

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : temperature, pH and dissolved oxygen concentrations.

TEST CONCENTRATIONS
- Test concentrations: 1 mg/L
- Results used to determine the conditions for the definitive study: results available in other studies.
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
> 0.93 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
Following 96 hours of exposure, no mortality was found in the 0.93 mg test item/L treatment.
No sublethal effects were observed throughout the duration of the study. Statistical analysis (Fisher’s Exact Test, p > 0.05) demonstrated no significant difference in mortality among trouts exposed to the 0.93 mg test item/L treatment when compared to the control.

Validity of the test: At test completion (hour 96), no mortality was observed in the control, which met the minimum standard criteria established by the OECD guideline (i.e., ≤ 10% mortality in the control(s)). The DO concentration measured in the test solutions ranged from 8.39 to 9.18 mg/L, corresponding to air saturation values (ASV) of > 60% throughout the study, which also met the validity criterion established by the OECD guideline.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
No toxicity observed at concentrations up to 0.93 mg/L.
Executive summary:

In an acute toxicity study (Springbornmithers, 2010), Oncorhynchus mykiss were exposed to paratrifluoromethylaniline at nominal and measured (geometric mean) concentrations of 1 and 0.93 mg/L respectively, under semi-static conditions. This concentration was chosen as it is the lowest LC50 observed in the algae and daphnia tests. Then tests on vertebrates animals are limited to a minimum with this strategy.

No toxicity was observed at concentrations up to 0.93 mg/L.

The LC50 (96h) was then higher than 0.93 mg/L based on mean geometric measured concentration.

Validity criteria were fulfilled (≤ 10% mortality in the control(s); the dissolved oxygen air saturation values (ASV) > 60% throughout the study).

This study is reliable without restrictions and satisfies the guideline requirements.