Reaction mass of 2,6-dimethylpyridinium chloride and 3-methylpyridinium chloride and 4-methylpyridinium chloride

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: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 2,6-dimethylpyridinium chloride and 3-methylpyridinium chloride and 4-methylpyridinium chloride

EC Number:

941-122-2

Molecular formula:

not yet assigned

IUPAC Name:

Reaction mass of 2,6-dimethylpyridinium chloride and 3-methylpyridinium chloride and 4-methylpyridinium chloride

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Stock solutions of 500 mg/L of the test item were prepared in methanol and diluted to 5 or 10 mg/L with methanol. This solution was further diluted with methanol : HPLC water (50 : 50) containing 1 % formic acid to 7 concentrations used for calibration.
- Controls: Six replicates (without test item) were exposed under the same conditions as the test concentrations.
- Evidence of undissolved material: test concentrations were present as clear solutions

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: Desmodesmus subspicatus CHODAT SAG 86.81 (formerly Scenedesmus subspicatus CHODAT).
- Source (laboratory, culture collection): 'Sammlung von Algenkurturen', Göttingen (SAG), (Collection of Algae Cultures, Institute for Plant Physiology), University of Göttingen, Germany
- Method of cultivation: Fresh stocks were prepared every month on Z-Agar. Light intensity amounted to 35 - 70 µE·m-2·s-1 for 24 h per day.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

total hardness: This medium had a nominal hardness of 0.24 mmol Ca+Mg/L

Test temperature:

21.2-23.5°C

pH:

test start: 7.56 - 8.09
test end: 7.93 - 8.47

Nominal and measured concentrations:

nominal: 0.0316 - 31.6 mg/l
measured (mean): 0.0334 - 37.6 mg/l
recovery rates: The measured test item concentrations were all within ± 20 % of the nominal concentrations.

Details on test conditions:

- Test vessel:
-Sterile Erlenmeyer flasks, volume: 250 mL, sealed with cotton wool plugs filled with 100 mL test medium
- Aeration: no
- Control end cells density: initial cell density of 4998 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Culture medium: Nutrient medium Z according to LÜTTGE et al. (1994)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: double distilled water
- This medium had a nominal hardness of 0.24 mmol Ca+Mg/L.
- Culture medium different from test medium: yes
- Intervals of water quality measurement: no data.

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Light intensity 60 - 120 µE · m-2 · s-1

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): algal cell concentration determined by photometric measurement after 0, 24, 48 and 72 h
- Determination of cell concentrations: electronic particle counter (Microscopic evaluation), photometer (via Chlorophyll a-fluorescence) excitation at 436 nm, emission at 685 nm.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.16

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.265 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.57 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50: 0.586 mg/L (growth rate)

Reported statistics and error estimates:

The validation criteria were fulfilled as algal growth in the control between 0 and 72 h exceeded the factor of 16 as requested by the underlying OECD
guideline.
With the current test it was found to be 111-fold. The mean coefficient of variation of the section-by-section (0 - 24, 24 - 48 and 48 – 72 h) growth rate in the control cultures must not exceed 35% and it was 17.5% in the current test.
The coefficient of variation of the average specific growth rate in the control cultures, measured during the exposure period (0-72 h) must not exceed 7% and it was 3.81% in the current test.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In this study, Pyridinderivate 1_HCl was found to inhibit the growth of the freshwater green alga Desmodesmus subspicatus after 72 hours with the
following effect values: The NOEC-value for growth rate after 72 hours was 0.100 mg/L. The EC50-value for inhibition of growth rate (ErC50) with 95 % confidence intervals after 72 hours was determined to be 3.57 (2.74 – 4.74) mg/L.
All effect levels are given based on nominal test item concentrations of Pyridinderivate 1_HCl.