Phosphinic acid, P-[3-(acetyloxy)-3-cyanopropyl]-P-methyl-, butyl ester

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:

From 01 Jul 2010 to 26 Jul 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all
- Sampling method: samples from control and test concentrations at 0 and 72 h
- Sample storage conditions before analysis: Routinely, the samples were analysed immediately. Only in exceptional cases,
they were stored overnight deep frozen and protected from light.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
stock solution was prepared: 100.7 mg of the test item were added to 1 litre of dilution water and treated for 1 h on a magnetic stirrer. The pH was measured to be 7.8.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: No. 86.81 SAG
- Source: 'The Collection of Algal Cultures' of the Institute of Plant Physiology at the University of Göttingen (Germany)
- Age of inoculum (at test initiation):
- Method of cultivation: Exponentially-growing stock cultures were maintained in the test facility under constant temperature conditions (21-24°C with a maximum fluctuation of +/- 2°C) at a light intensity in the range 60 – 120 µE. x m-2 x s-1 (measured in the range 400 to 700 nm using a spherical quantum flux meter). The growth medium (according to BRINGMANN & KÜHN (1977) was renewed once a week. Cell density measurements were made using a microcell- counter, Sysmex F300, Digitana.

ACCLIMATION
- Acclimation period: 3 days (Pre-cultures)
- Culturing media and conditions (same as test or not): yes. but different to cultivation conditions

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

22.5 mg/L CaCO3 (nutrient medium)

Test temperature:

21 - 24 °C

pH:

8 +/- 0.1

Nominal and measured concentrations:

Nominal: 0.032, 0.1, 0.32, 1.0, 3.2, 10 and 32 mg/L
Mean Measured: 0.013, 0.041, 0.162, 0.421, 1.138, 2.381, 15.285 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 mL Erlenmeyer flasks with cotton stoppers
- Type (delete if not applicable): closed
- Initial cells density: 5000 cells/mL, cell number = 0.500
- Control end cells number: 56.000
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: To prepare the growth medium 10 mL of stock solution 1 were mixed with 500 mL
sterilised millipore water. Then 1 mL each of the stock solutions 2-4 were added and filled up to 1 litre with sterilised millipore water. Afterward the growth medium was bubbled with sterile, filtered air for at least 1 hour.
- Medium composition: see table 1
- Culture medium different from test medium: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH:
- Photoperiod: continious light
- Light intensity and quality: spectral range = 400 to 700 nm; intensity = 4000 to 8000 lx


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations:microcell counter (Sysmex F300, Digitana)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- Range finding study: yes, non GLP
- Concentrations (range finder): 0.1, 1.0, 10 and 100 mg/L, additionally 100 mg/L without algae inokulum

CULTURING APPARATUS
-Details on culturing apparatus used: shaking incubator, light chamber

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.129 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.082 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.041 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control: yes
- Observation of abnormalities: no

Reported statistics and error estimates:

Growth rates were also used to calculate a No Observed Effect Concentration according to Welch-t test for Inhomogeneous
Variances with Bonferroni-Holm Adjustment.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of this study the substance is toxic to algae.

Executive summary:

A study was performed to assess the adverse effects of the test item on the growth rate (= rate of increase in cell density with time) and the yield (= biomass at time t minus initial biomass) of the planktonic freshwater algal species Desmodesmus subspicatus  over several generations.
The study was conducted in accordance with Commission Regulation (EC) No 761/2009 amending Regulation No 440/2008, Method C.3 ‘Freshwater Alga and
Cyanobacteria, Growth inhibition test’ (2009) which is equivalent to OECD Guideline for Testing of Chemicals No. 201 (2006).
Exponentially growing algal cells were exposed for a period of 72 hours a range of
concentrations, nominally 0.032, 0.1, 0.32, 1.0, 3.2, 10 and 31 mg/L of the test item.
The test item dissolved in dilution water. Auxiliaries used to prepare the test media were an ultrasonic bath, a magnetic stirrer and folded filters.
The cell densities were measured at 24 hour intervals. Inhibition of the algal
population was measured as reduction in growth rate (index r), relative to control
cultures grown under identical conditions. Growth rates were also used to calculate a No Observed Effect Concentration according to Welch-t test for Inhomogeneous
Variances with Bonferroni-Holm Adjustment. The following values were determined:
Results [mg/L]:
ErC 50* (0-72 h): 1.129
ErC 10* (0-72 h): 0.082
NOEC [r] (ta 0.05): 0.041

The results are expressed in terms of geometric mean measured concentrations.
Effective concentrations ranged from 85.8 - 104.7 % of nominal values at 0 hours,
and from 6.3 - 26.6% of nominal values at 72 hours, respectively.

Description of key information

The test item is acutely toxic to aquatic algae and toxic based on long term data.

Key value for chemical safety assessment

EC50 for freshwater algae:

1.129 mg/L

EC10 or NOEC for freshwater algae:

0.082 mg/L

Additional information

A study was performed to assess the adverse effects of the test item on the growth rate (= rate of increase in cell density with time) and the yield (= biomass at time t minus initial biomass) of the planktonic freshwater algal species Desmodesmus subspicatus  over several generations.
The study was conducted in accordance with Commission Regulation (EC) No 761/2009 amending Regulation No 440/2008, Method C.3 ‘Freshwater Alga and
Cyanobacteria, Growth inhibition test’ (2009) which is equivalent to OECD Guideline for Testing of Chemicals No. 201 (2006).
Exponentially growing algal cells were exposed for a period of 72 hours a range of
concentrations, nominally 0.032, 0.1, 0.32, 1.0, 3.2, 10 and 31 mg/L of the test item.
The following values were determined:
Results [mg/L]:
ErC 50* (0-72 h): 1.129
ErC 10* (0-72 h): 0.082
NOEC [r] (ta 0.05): 0.041

The results are expressed in terms of geometric mean measured concentrations.
Effective concentrations ranged from 85.8 - 104.7 % of nominal values at 0 hours,
and from 6.3 - 26.6% of nominal values at 72 hours, respectively. The validity criteria were fulfilled. Based on these results the test item can be considered acutely and chronic toxic to fresh water algae.