2-(4-fluorophenyl)-5-(5-iodo-2-methylbenzyl)thiophene

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016-01-15 to 2016-02-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, December 14, 2000

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Appearance White to almost white powder (determined by WIL Research
Europe at receipt of the test item)
Batch M14KB4863
Test item storage conditions At room temperature
Stable under storage conditions until 10 November 2017 (retest date)

Analytical monitoring:

yes

Details on sampling:

- Sampling method: samples were taken before the start of the test, after 24 hours and after 72 hours from all test concentrations and from the control. The filter used for preparation of the SS was kept for possible analysis of the residue. At the end of the exposure period, the replicates with algae were pooled at each concentration before sampling. Reserve samples were taken from all test solutions for possible analysis.
- Sample storage conditions before analysis: stored in a freezer (< -15°C) until analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The preparation of test solutions started with a loading rate of 100 mg/L applying two days of magnetic stirring at room temperature in the dark to ensure maximal dissolution of the test item in the test medium. The resulting aqueous mixture was filtered through a 0.45 µm membrane filter (Whatman; RC55) to remove any non-dissolved material. The filter was pre-conditioned with a small volume of test solution that was discarded. The resulting SS was used as the highest test concentration. The lower test concentrations were prepared by subsequent dilutions in test medium. All final test solutions were clear and colourless.
- Controls: yes

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Strain: NIVA CHL 1
- Source (laboratory, culture collection): In-house laboratory culture
- Method of cultivation: Algae stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar. The suspensions were continuously aerated and exposed to light in a climate room at a temperature of 21-24°C.

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): same as the test

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

24 mg CaCO3/L

Test temperature:

22-23°C

pH:

t=0h: 8.0
t=72h: 7.9-8.1

Dissolved oxygen:

not reported

Salinity:

not applicable

Nominal and measured concentrations:

nominal test concentrations final test: 1, 10 and 100% SS prepared at 100 mg/L
measured test concentration final test t= 0 h: < 4 µg/L
measured test concentration final test t= 24h: < 4 µg/L
measured test concentration final test t= 72h: < 4 µg/L

At sampling days 0, 1 and 3 a concentration of < 4 μg/L test item was found in the biological samples. The low solubility of T003063 could be due to precipitation of colloidal dissolved amounts of the test substance during the biological test or adsorption of the test item. A sample from the residue on the filter used for preparation of the nominal 100 mg/L test solution was dissolved in acetonitrile and analysed after dilution. Based on the retention time, the residue was identified as test item indicating proper preparation of the test solution.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL all-glass flasks
- Type (delete if not applicable): capped vessels
- Material, size, headspace, fill volume: 100 mL all-glass flasks filled with 50 mL test solution
- Initial cells density: 10,000 cells/mL
Control end cells density: 434.5 x 10,000 cells/mL (mean)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: M1; according to the NPR 6505 (“Nederlandse Praktijk Richtlijn no. 6505”) formulated using Milli-RO water (tap-water purified by reverse osmosis
- Detailed composition if non-standard medium was used:
NaNO3 500 mg/L
K2HPO4.3H2O 52 mg/L
MgSO4.7H2O 75 mg/L
Na2CO3.10H2O 54 mg/L
C6H8O7.H2O 6 mg/L
NH4NO3 330 mg/L
CaCl2.2H2O 35 mg/L
C6H5FeO7.xH2O 6 mg/L
H3BO3 2.9 mg/L
MnCl2.4H2O 1.81 mg/L
ZnCl2 0.11 mg/L
CuSO4.5H2O 0.08 mg/L
(NH4)6Mo7O24.4H2O 0.018 mg/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: M2, according to the OECD 201 Guideline, formulated using Milli-RO water.
- Culture medium different from test medium: Yes (M1 versus M2). Three days before the start of the test the algal stock culture (culture in M1) was inoculated in the same culture medium (M2) used in the test. The culture was maintained under the same conditions as used in the test.
- Intervals of measurements: pH was measured at the beginning and at the end of the test. Temperature was continuously measured in a control vessel. At the end of the final test microscopic observations were performed on all test concentrations to observe for any abnormal appearance of the algae.

OTHER TEST CONDITIONS
- Sterile test conditions: no information
- Adjustment of pH: none
- Photoperiod: continuous illumination
- Light intensity and quality: using TLD-lamps with a light intensity within the range of 89 of 94 µE/m²/s

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter] At the beginning, cells were counted using a microscope and a counting chamber. Thereafter, cell densities were determined by spectrophotometric measurement of samples at 680 nm using a spectrophotometer with immersion probe.
- effect calculated parameters: specific growth rate and yield

TEST CONCENTRATIONS
- Spacing factor for test concentrations: x 10

- Range finding study
- Test concentrations: 1.00, 10 and 100 % of the SS
- Results used to determine the conditions for the definitive study: yes.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 100% v/v saturated solution, equivalent to a loading rate of 100 mg/L

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 100% v/v saturated solution, equivalent to a loading rate of 100 mg/L

Details on results:

- Exponential growth in the control (for algal test): yes
- Any stimulation of growth found in any treatment: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: clear test solution

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50: 72-h EC50 (growth rate) = 1.5 mg/L (95% C.L. 1.4 to 1.6 mg/L)
- EC50: 72-h EC50 (yield) = 0.51 mg/L (95% C.L. 0.49 to 0.53 mg/L)

Reported statistics and error estimates:

No EC50-values could be calculated because the test item proved to be non-toxic (EC50 > maximum soluble concentration tested)

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of T003063 to Pseudokirchneriella subcapitata was determined in a 72-hour static test according to the OECD guideline 201.
No biologically significant inhibition of growth rate (only 2%) was recorded at any of the tested concentrations of JNJ-39453193-AAA (T003063) and in the control up to and including the highest saturated test concentration of 100 mg/L. At this nominal loading rate of 100 mg/L, no quantifiable amounts of test item were present in the test medium from the start of testing (i.e. actual test concentration was below the lowest calibration solution of 4 µg/L). The 72 hour EC50 for T003063 could not be quantified due to the absence of toxicity up to the highest concentration tested, and was clearly higher than 100 mg/L (nominal loading rate).

Description of key information

The study of Bouwman (2016), investigating the acute toxicity of T003063 to algae according to OECD guideline 201, was considered as the key study for endpoint coverage.

No biologically significant inhibition of growth rate (only 2%) was recorded at any of the tested concentrations of JNJ-39453193-AAA (T003063) and in the control up to and including the highest saturated test concentration of 100 mg/L. At this nominal loading rate of 100 mg/L, no quantifiable amounts of test item were present in the test medium from the start of testing (i.e. actual test concentration was below the lowest calibration solution of 4 µg/L). The 72 hour EC50 for T003063 could not be quantified due to the absence of toxicity up to the highest concentration tested, and was clearly higher than 100 mg/L (nominal loading rate).