Aluminium metaphosphate

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:

Septermber - December 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Arbeit, Integration und Soziales des Landes Nordrhein- Westfalen

Analytical monitoring:

yes

Details on sampling:

- Concentrations: nominal loadings of 1, 10 and 100 mg/L
- Sampling method: Samples were taken directly after test solution preparation and after 72 hours.
- Sample storage conditions before analysis: Exactly 20 mL of aqueous samples were transferred into disposable 50 mL polyethylene vials
(Sarstedt, Nuembrecht, Germany), and acidified to a target concentration of 1 % nitric acid (200
μL, dilution of sample negligible). Al concentrations were determined using ICP-OES (see
A.3.8.1) within three days.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test solution was prepared according to the Water Accommodated Fraction (WAF) approach according to the OECD
guidance documents No. 23 and 29. The test concentrations were prepared separately by adding the required amount of test substance to 1 litre sterile growth medium. After stiirring for 24 hours at 20°C the insoluble parts were separated by filtration (Sarstedt Bottle Top Filter, Filtropur
BT50, 0.2 μm PES (polyethylensulfone) membrane).

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: Pseudokirchneriella subcapitata, Chlorophycea, Chlorophyta; 61.81 SAG
- Source (laboratory, culture collection): SAG, Culture Collection of Algae at Pflanzenphysiologisches Institut of the University at Göttingen, Albrecht von Haller Institut, Untere Klarspüle 2, D-37073 Göttingen, Catalog No 61.81 SAG.
- Age of inoculum (at test initiation):
- Method of cultivation: The stock cultures are maintained fulfilling the criteria of the OECD guideline (culture medium recommended by Bringmann
und Kühn (1980)). Prior to testing a pre-culture was established in standard OECD growth medium to obtain exponentially-growing algae for the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22.0 – 22.1 °C

pH:

7.53 - 7.84 (test solutions)
7.86 - 8.01 (control)

Nominal and measured concentrations:

Nominal test item loadings: Control, 1.1, 9.9 and 99.8 mg/L, equivalent to theoretical nominal aluminium loading Control, 0.127, 1.14 and 11.5 mg Al/L.
Mean measured concentrations of aluminium are 14.7, 32.9 and 115 μg Al/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks (250 mL) covered with silicone sponge caps
- Fill volume: 100 mL
- Initial cells density: 10000 cells/mL
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 8

GROWTH MEDIUM
- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic OECD standard medium according to OECD 201


OTHER TEST CONDITIONS
- Photoperiod: continous illumination
- Light intensity and quality: 98.3 to 103.7 μmol/m²s


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: the cell concentrations was determined after 24, 48 and 72 hours using an electronic particle counter (CASY 1 Model TT,
OMNI Life Science GmbH & Co. KG, Bremen, Germany).

TEST CONCENTRATIONS
- Range finding study:yes
- Test concentrations: 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: no inhibition up to 100 mg/L (nominal)

Reference substance (positive control):

yes

Remarks:

3,5-dichlorphenol

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 115 other: µg Al /L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: Aluminium concentrations

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 115 other: µg Al /L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: Aluminium concentrations

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

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): none

Results with reference substance (positive control):

The sensitivity of the test organism is checked in regular intervals. In the latest test an ErC50 value of 3.78 mg/L was determined

Reported statistics and error estimates:

The NOEC values for growth rate and yield were determined by the Dunnett’s test using the computer program ToxRat® Professional

Inhibition of growth rate and yield compared to controls after 72 hours

Treatment, [μg Al/L]	Growth rate			Yield
	Growth rate [1/d]		% Inhibition	Yield [cells x 10^4/mL]		% Inhibition
Control	1.630	-		132.075	-
14.7	1.602	1.7 (-)		122.025	7.6 (-)
32.9	1.603	1.6 (-)		122.845	7.0 (-)
115	1.619	0.6 (-)		128.225	2.9 (-)

(-) not significantly different from controls, Dunnett’s test, significance level 0.05, one-sided smaller.

Validity criteria fulfilled:

yes

Description of key information

EC50 (72 h) > 100 mg/L (nominal)
NOEC (72 h) ≥ 100 mg/L (nominal)

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

Additional information

The acute toxicity of aluminium metaphosphate (CAS 13776-88-0) to algae was investigated in a study by Wenzel (2015). This test was conducted according to OECD 201 under GLP conditions. Since the test item is of low water solubility, the nominal test concentrations were individually prepared using the Water Accommodated Fraction (WAF) approach according to the OECD guidance documents No. 23 and 29 to obtain the maximal solubility of the test item under the test conditions.

72 h EC50 value of >100 mg/L (nominal) and NOEC of ≥100 mg/L (nominal) have been determined for the effects of the structural related aluminium metaphosphate (CAS 13776-88-0) on the growth of Pseudokirchneriella subcapitata (Wenzel, 2014).

Thus the substance is considered not acutely toxic to algae.