Magnesium glycerophosphate

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:

2017-12-06 to 2018-04-23

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD Guideline Study; EU method; GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

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:

Magnesium glycerophosphate

EC Number:

213-149-3

EC Name:

Magnesium glycerophosphate

Cas Number:

927-20-8

Molecular formula:

C3H9O6P.Mg

IUPAC Name:

magnesium glycerophosphate

Test material form:

solid: particulate/powder

Details on test material:

Batch: INVG003917

Specific details on test material used for the study:

Name: Magnesium glycerophosphate
Batch No.: INVG003917
Active Ingredient Purity: Magnesium glycerophosphate: 96.5 % (w/w) (calculated)
α-Glycerol phosphate magnesium salt: 96.5 % (w/w) (13C-NMR)
β- Glycerol phosphate magnesium salt : 0.0 % (w/w) (13C-NMR)
according to analytical report
Certificate of Analysis Date:September 01, 2017
Aggregate State at Room Temperature: Solid (fine powder)
Colour: White
Expiry Date: June 10, 2021
Storage Conditions at Test Facility: At 20 +/- 5 °C, in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Duplicate samples from the freshly prepared test media (containing algae) of the test concentration and from the control were taken at the start of the test.
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentration during the test period, duplicate samples from the test media of the test concentration and the control (containing algae) were taken at the end of the test (after the 72 hours test period) by pouring together the contents of the test beakers of each treatment.

Test solutions

Vehicle:

no

Details on test solutions:

The test medium of the only test item concentration of nominal 100 mg/L was prepared by dissolving 43.9 mg test item into 439 mL test water by intense stirring for 10 minutes. The test medium was freshly prepared just before the start of the test (= introduction of algae).

Test organisms

Test organisms (species):

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

Details on test organisms:

Species: Pseudokirchneriella subcapitata (KORSHIKOV), Strain No. 61.81 SAG, formerly known as Selenastrum capricornutum, and recently renamed as Raphidocelis subcapitata (KORSHIKOV)
Origin: The algae were supplied by the „Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Universität Göttingen", 37073 Göttingen, Germany.
Breeding Conditions: The algae were cultivated in the laboratories of ibacon under standardised conditions according to the test guidelines.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Hardness:

Calculated water hardness of the test water: 0.24 mmol/L (= 24 mg/L) as CaCO3

Test temperature:

22 to 22.5°C

pH:

8.1 at test start and 9.4 at test end

Nominal and measured concentrations:

Test Concentration:100 mg test item/L and a control

Details on test conditions:

Water Temperature: The temperature was measured daily in an Erlenmeyer flask filled with water and incubated under the same conditions as the test flasks.
Water temperature was:
22.0 to 22.5 °C pH-Values: The pH was measured in all test item concentrations and the control at the start and the end of the test.
pH was: 8.1 at test start and 9.4 at test end
Light Regime: Continuous illumination
Light Intensity: The light intensity was measured once during the test at 6 positions distributed over the experimental area at the surface of the test media.
Mean light intensity: 5462 lux (range: 5170 to 5960 lux)

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 3

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 4

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

The 72-hour EyC50 was calculated to be >100 mg test item/L and the ErC50 >100 mg test item/L. The 72-hour EyC10 was calculated to be >100 mg test item/L and the ErC10 >100 mg test item/L. The 72-hour NOEyC was determined to be ≥100 mg test item/L and the associated 72-hour LOEyC of >100 mg test item/L. The 72-hour NOErC was determined to be ≥100 mg test item/L and the associated 72-hour LOErC is >100 mg test item/L.

Results with reference substance (positive control):

Most Recent Test with Pseudokirchneriella subcapitata performed with the Reference Item Potassium Dichromate in July 2017:
72-hour EC50:
Yield [mg test item/L] 0.415
Growth rate [mg test item/L] 1.02
Biomass [mg test item/L] 0.455
72-hour NOEC:
Yield [mg test item/L] 0.094
Growth rate [mg test item/L] 0.094
Biomass [mg test item/L] 0.094
72-hour LOEC:
Yield [mg test item/L] 0.21
Growth rate [mg test item/L] 0.21
Biomass [mg test item/L] 0.21

Reported statistics and error estimates:

Based on the calculated cell densities, the 72 hours ErC50 and the 72 hours EyC50 could not be calculated by Probit analysis due to the lack of effects and were therefore determined directly from the raw data. For the determination of the 72 hours LOEC and the 72 NOEC, the calculated growth rates and yields at the only test concentration were tested for significant differences compared to the control values by Two sample Mann Whitney U-test (yield) and two sample t-test (growth rate). The software used to perform the statistical analysis was ToxRat Professional, Version 3.2.1, ToxRat Solutions GmbH.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Cell Density Increase in Control Cultures: 157.6-fold increase within 72 hours; Coefficient of Variation of Sectional (Daily) Growth Rates in Control Cultures: 16.3 %; Coefficient of Variation of Average Growth between Control Replicates: 0.6 %

Conclusions:

The influence of Magnesium glycerophosphate on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static concentration-response limit test. The 72-hour EyC50 was calculated to be >100 mg test item/L and the 72-hour ErC50 value was calculated to be >100 mg test item/L. The 72-hour NOEyC was determined to be ≥100 mg test item/L and the associated 72-hour LOEyC was >100 mg test item/L. The 72-hour NOErC was determined to be ≥100 mg test item/L and the associated 72-hour LOErC was >100 mg test item/L. The initial concentrations and the maintenance of the exposure concentrations during the test were verified in the analytical part. All reported results refer to nominal values since the concentrations of the test item were within ± 20% of the nominal concentrations during the test.

Executive summary:

Title: Magnesium glycerophosphate: Toxicity to Pseudokirchneriella subcapitata in an Algal Growth Inhibition Limit Test

Purpose: The purpose of this test was to determine the inhibitory effect of the test item Magnesium glycerophosphate on the growth of the freshwater green algae Pseudokirchneriella subcapitata. For this purpose, exponentially growing cultures of this unicellular green algal species were exposed to the only test item concentration of nominal 100 mg/L under defined conditions. The inhibition of growth in relation to control cultures was determined over a test period of 72 hours, and thus over several algal generations. This limit test was performed in compliance with the test guidelines to demonstrate that the test item has no toxic effect on Pseudokirchneriella subcapitata up to at least this concentration. The test method of application and the test system are recommended by the test guidelines and Pseudokirchneriella subcapitata is one of the recommended test species. The purpose of the analytical part of this study was to verify the concentration of the test item in the test medium.

Guidelines/Recommendations:

OECD Guideline for Testing of Chemicals, Section 2, No. 201: "Freshwater Alga and Cyanobacteria, Growth Inhibition Test", adopted March 23, 2006, corrected July 28, 2011

Commission Regulation (EC) No 761/2009, Annex, Part C, C.3.: "Freshwater Algae and Cyanobacteria, Growth Inhibition Test", Official Journal of the European Union (EN), dated August 24, 2009

SANCO/3029/99 rev.4 11/07/00: Residues: Guidance for generating and reporting methods of analysis in support of pre-registration data requirements for Annex II (part A; Section 4) and Annex III (part A; Section 5) of directive 91/414

Material and Methods  

Test Item: Magnesium glycerophosphate; Batch No.: INVG003917;

Test Species: Pseudokirchneriella subcapitata, Strain No. 61.81 SAG formerly known as Selenastrum capricornutum, and recently renamed as Raphidocelis subcapitata (KORSHIKOV).

Cultivated in the laboratories of ibacon; original source: "Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzenwissen-schaften, Universität Göttingen", 37073 Göttingen, Germany.

Test Design: This study encompassed two treatment groups (one dose rate of the test item and a control) with six replicates per test concentration and six replicates for the control. At test start 50 mL of the only test concentration was inoculated with approx. 5000 algal cells per mL test medium and defined volumes of the algal suspensions were sampled after 24, 48 and 72 hours for determination of cell densities by spectrophotometrical measurement.

Endpoints: Yield and growth rate of the algae

Test Concentration: 100 mg test item/L and a control

Test Conditions: Water temperature: 22.0 to 22.5 °C; pH values at test start 8.1, at the end of the test 9.4; continuous illumination; mean light intensity: 5462 lux (5170 to 5960 lux).

Results

The quantification of the test item Magnesium glycerophosphate in the test samples was performed using liquid chromatography with MS/MS. At the start of the test 98% of the nominal test concentration was found (average of the test concentration). After 72 hours test duration, 97% of the nominal value was determined (average of the test concentration). During the test the algae were exposed to a mean of 98% of nominal.

The influence of Magnesium glycerophosphate on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static concentration-response limit test. The 72-hour EyC50 was calculated to be >100 mg test item/L and the 72-hour ErC50 value was calculated to be >100 mg test item/L. The 72-hour NOEyC was determined to be ≥100 mg test item/L and the associated 72-hour LOEyC was >100 mg test item/L. The 72-hour NOErC was determined to be ≥100 mg test item/L and the associated 72-hour LOErC was >100 mg test item/L. The initial concentrations and the maintenance of the exposure concentrations during the test were verified in the analytical part. All reported results refer to nominal values since the concentrations of the test item were within ± 20% of the nominal concentrations during the test.

This study is classified acceptable and satisfies the guideline requirements for growth inhibition algae studies.