Phosphoric acid, mixed esters with biphenyl-4,4'-diol and phenol

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Testing Methods for New Chemical Substances (Nov 21, 2003, No.1121002, Pharmaceutical and Food Safety Bureau, MHLW; Nov 13, 2003 No.2, Manufacturing Industries Bureau, METI; No.031121002, Environmental Policy Bureau, Ministry of the Environment)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

(2006)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD Guidance Document No. 23 (Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures), 2000

Deviations:

not applicable

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: nominal 100 mg/L and control
- Sampling intervals: test start and end
- Sampling method:
test start: a sample was taken from the container for preparation;
test end: samples were taken from the test solution in the replicate vessels, mixed and centrifuged to remove algae
- Sample storage conditions before analysis: none

Vehicle:

no

Details on test solutions:

The test material and dilution water were mixed to produce nominal 100 mg/L. The dispersions were stirred by magnetic stirrer for about 48 hours to prepare the test solution. Undissolved test material was not removed.

Test organisms (species):

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

Details on test organisms:

- Strain: ATCC 22662
- Source (laboratory, culture collection): laboratory culture, originating from a strain obtained 1995 from the American Type Culture Collection (ATCC)
- Age of inoculum (at test initiation): Three days. Algal cells used for inoculation were exponentially growing.
- Method of cultivation: The pre-culture was incubated under the same conditions as in the test.
ACCLIMATION
- Acclimation period: 3 days (pre-culturing)
- Culturing media and conditions (same as test or not): same

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

25 mg/L as CaCO3

Test temperature:

23.3-23.5 °C

pH:

test start (0 h): 7.8
test end (72 h): 8.2

Nominal and measured concentrations:

nominal: 100 mg/L
measured concentrations at test start and end: <0.022 mg/L (LOQ)

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL Erlenmeyer flasks (sterilized), fill volume 100 mL, plugged with gas-permeable silicon rubber plugs
- Aeration/gaseous exchange: rotary shaker, continuously oscillating at approximately 100 rpm
- Initial cells density: 1x10⁴ cells/mL (corresponding to 1.8 relative chlorophyll fluorescence units)
- Control end cells density: ≥ 230 relative chlorophyll fluorescence units
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes (OECD TG 201)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: purified water was used to prepare the test medium
- Culture medium different from test medium: no
- Intervals of water quality measurement:
pH and appearance of the test solutions: start and end of the exposure
temperature and light intensity: once a day

OTHER TEST CONDITIONS
- Sterile test conditions: yes (sterilized test vessels, medium used under sterile conditions)
- Adjustment of pH: no
- Photoperiod: continuous illumination
- Light intensity and quality: 96-105 µE/m²/s, fluorescent light, wavelength range 400-700 nm

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : chlorophyll fluorescence was measured at 24, 48 and 72 hours
- Determination of cell concentrations: spectrophotofluorometer

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: nominal 100 mg/L (prepared as for the main test).
- Results used to determine the conditions for the definitive study: no growth inhibition was observed

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no microscopic abnormalities

The test solution was a white suspension, slightly green due to algea at test end.

Results with reference substance (positive control):

- 72-hour ErC50: 0.72 mg/L (normal range in this laboratory: 0.56 to 1.4 mg/L)

Validity criteria fulfilled:

yes

Remarks:

(Increase of biomass >16 after 72 hours; mean coefficient of variation for section-by-section specific growth rate <35%; coefficient of variation for average specific growth rate <7%.)

Description of key information

72-h ErC50 >100 mg/L, 72-h NOEC ≥ 100 mg/L (nominal) for Pseudokirchneriella subcapitata (OECD 201)

Additional information

The test results indicate that the test material is not inhibitory to growth of algae up to the limits of its water solubility and a NOEC and thus a PNEC cannot be determined.