2,2,6,6-tetramethyl-4-substituted-piperidinyl-1-oxy

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

Study period:

May 7th-11th 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study in accordance with GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD 201

GLP compliance:

yes

Test material

Test material information

Constituent 1

Test material form:

other: Liquid

Sampling and analysis

Details on sampling:

- Sample storage conditions before analysis: Room temperature and dark

Test organisms

Test organisms (species):

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

Details on test organisms:

Source: Culture Collection of Algae and Protozoa, Institute of Freshwater Ecology, Windermere Laboratory.
Culture Conditions:
Temperature; 23±2ºC
illumination; 6000-10000 lux continuous white light
Shaking: 200 rpm

Study design

Test type:

static

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

The cell density was determined after 24, 48, 72 and 96 hour exposure periods on a small volume removed from each replicate flask. The cell counts were made using a haemocytometer and microscope. Cells showing morphological abnormalities were included in the count and noted in the observations.

Test conditions

Test temperature:

21.5-22ºC

pH:

7.3-8.0

Nominal and measured concentrations:

Definitive test concentrations were prepared as; 0 (Control), 1, 2.2, 4.5, 10, 22, 45 and 100 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 ml conical flask
- Initial cells density:1 x 10(4) cells/ml
- Control end cells density: increased by a factor of 53
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water with added nutrients (according to OECD guidelines)
- Intervals of water quality measurement: Immediately prior to initiating test and at the end of the 96-hour test period

OTHER TEST CONDITIONS
- Adjustment of pH: 7.0 -7.8
- Light intensity and quality: approximately 6000- 10000 lux continuous white light

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: haemocytometer and microscope

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0, 0.1, 1, 10 and 100 mg/l
- Results used to determine the conditions for the definitive study: 72 hour EC50 was approximately 10 mg/l by biomass and between 10-100 mg/l by growth rate

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

18 mg/L

Basis for effect:

biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

50 mg/L

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.9 mg/L

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.9 mg/L

Basis for effect:

biomass

Effect concentrations 5

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

13 mg/L

Basis for effect:

biomass

Effect concentrations 6

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

42 mg/L

Basis for effect:

growth rate

Effect concentrations 7

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

1.7 mg/L

Basis for effect:

biomass

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 96-hour EC50 value of inhibitor AHM P500 to Psuedokirchnriella subcapitata was estimated to be 13 mg/L based on biomass and 42 mg/L based on growth rate. The highest no observed effect concentration (NOEC) after 96 hours was 1.7 mg/L.

Executive summary:

A guideline study performed in accordance with OECD 201 and to GLP was performed to assess the effect of Inhibitor AHM P500 to the alga Pseudokirchneriella subcapitata over a 96 hour exposure period. The exposure concentrations were based on the results of a 72 hour preliminary study and were defined as 0, 1, 2.2, 4.5, 10, 22, 45 and 100 mg/L.

The cell density was measured after 24, 48, 72 and 96 hours exposure using a haemocytometer and microscope. The inhibition of growth was calculated using both the biomass and growth rate method. All algal cells examined microscopically appeared normal, no cells were observed that showed any morphological abnormalities.

The 96-hour EC50 value of Inhibitor AHM P500 to Psuedokirchnriella subcapitata was estimated to be 13 mg/L based on biomass and 42 mg/L based on growth rate. The highest no observed effect concentration (NOEC) after 96 hours was 1.7 mg/L.