Poly(polyalkylammonium) poly(µ-alkoxy)-µ6-oxido-polyhedropoly(chloridometal)ate polyalkanol solvate

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study according to OECD and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Bis(dimethylammonium) dodecakis(µ-methoxy)-µ6-oxido-octahedro-hexakis(chloridoindium)ate dimethanol solvate

Cas Number:

1381802-10-3

Molecular formula:

C18H60Cl6In6N2O15

IUPAC Name:

Bis(dimethylammonium) dodecakis(µ-methoxy)-µ6-oxido-octahedro-hexakis(chloridoindium)ate dimethanol solvate

Details on test material:

Batch number V107 – V110
Purity > 99 %
Molecular weight 1446.302 g/mol
Appearance Colorless, crystalline powder
Water solubility Reacts (sensitive to hydrolysis, t ½ (pH 7): approx. 5 minutes

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples were taken at the start of the exposure (0h) and at the end of the exposure (72h). At the start and end of the exposure, samples were taken out of additionally prepared samples without algae. Samples after 72 hours were prepared at the start of the exposure and incubated under test conditions.

Test solutions

Vehicle:

no

Details on test solutions:

Based on a preliminary test 5 concentration levels were tested in a geometrical series with a dilution factor of 2 : 12.5 - 25.0 - 50.0 - 100 - 200 mg/L. Three replicates were tested for each test item concentration and six replicates for the control. The test item dispersion was stirred with a magnetic stirrer (approx. 900 rpm) at room temperature for 2 hours. Since the test item is known to hydrolyse quickly (t1/2 pH 7: approx. 5 min), the reaction product was used for testing.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Desmodesmus subspicatus CHODAT SAG 86.81 (formerly Scenedesmus subspicatus CHODAT) was chosen according to the guideline. Cultures originated from Sammlung von Algenkulturen (SAG), Pflanzenphysiologisches Institut der Universität Göttingen. Fresh stocks are prepared every month on Z-Agar. Light intensity amounts to 35-70 µE • m-2 • s-1 for 24 h per day. Cultures are cultivated in nutrient medium Z according to LÜTTGE et al. (1994).

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

Room temperature [°C]: min.: 21.0 max.: 22.0 mean value: 21.5

pH:

Nominal test item
concentration pH-value
[mg/L] Start; 0 hour End; 72 hours
200 8.00 8.00
100 8.08 8.08
50.0 8.03 8.07
25.0 8.11 8.16
12.5 8.14 8.25
Control 8.18 8.33

Nominal and measured concentrations:

Nominal test item
concentration
[mg/L] TOC mg/L
Start of the exposure End of the exposure
(without algae) 0hours (without algae) 72 hours

200 28.7 28.8
100 14.5 14.7
50.0 7.65 7.89
25.0 4.18 4.18
12.5 2.36 2.30
Control <2.00 <2.00

Details on test conditions:

Light intensity
[µE•m-2•s-1] n = 20

mean value: 74.4
min.: 65.0
max.: 84.9
CV [%]: 7.85

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

115 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 110-122

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

12.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

ErC50 0.590 mg/L
95 % confidence interval 0.564 - 0.623 mg/L

Reported statistics and error estimates:

EC10-, EC20- and EC50-values of the growth rate and yield inhibition after 72 hours were calculated by sigmoidal dose-response regression. Calculation of the confidence intervals EC10-, EC20- and Ec50-values were carried out using standard procedures. NOEC/LOEC were determined by calculation of statistical
significance of growth rate and yield. As a standard One Way Analysis of Variance (ANOVA) and DUNNETT’s test were used for NOEC/LOEC calculations. When running a One Way Analysis of Variance a Normality test and an Equal Variance test were done first. The SHAPIRO-WILK-Test was used to test for normally distributed populations. The Levene median test was used for equal variance. P-values for both Normality and Equal Variance tests are 0.05. The -value (acceptable probability of incorrectly concluding that there is a difference) is =0.05

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In this study inhibition on growth of the freshwater green alga Desmodesmus subspicatus was found after 72 hours exposure to the test item. Since the test item is known to hydrolyse quickly (t1/2pH 7: approx. 5 min), the reaction product was used for testing. The EC50-values for inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were 115 (110 - 122) mg/L and 52.3 (46.9 – 58.2) mg/L, respectively. The NOEC-values for inhibition of growth rate and yield after 72 hours were 12.5 mg/L and < 12.5 mg/L, respectively.