Dihydrogen bis[monoperoxyphthalato(2-)-O1,OO1]magnesate(2-)

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:

2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Fresenius

Analytical monitoring:

yes

Details on sampling:

initially and after 72 hours

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Scenedesmus subspicatus CHODAT
- Strain: 86.81
- Source: Sammlung für Algenkulturen, Pflanzenphysiologisches Institut der Unversität Göttingen, Germany
- Pretreatment: 3 days of preculture prior to the test
- Age of inoculum (at test initiation):
- Method of cultivation: Not stated

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24.2 – 25.3 °C

pH:

7.25 – 8.13 (initial)
9.96 – 10.53 (after 72 h)

Nominal and measured concentrations:

Control, 5, 10, 20, 40, 80 and 100 mg/L (nominal)
It is assumed, that the tests substance is sufficiently stable during the test duration. Therefore the results can be based on the nominal concentrations

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL glass cylinder
- Aeration: prior to the test
- Initial cells density: 6.42 • 104 cells/mL (equals to an extinction E578nm of 0.2)
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 7


OTHER TEST CONDITIONS
- Photoperiod: 24 h/d light
- Light intensity and quality: 8000 lux ± 20 % in a wavelength range between 400 and 700 nm

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Cell multiplication inhibition using a spectrophotometer (extinction measurement at 578 nm);
calculation of growth rate and biomass production
- Sampling: 24, 48 and 72 hours

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

11 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

19.7 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

200 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

7.8 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

99.8 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

The EC50 values are extrapolated and the NOEC values are calculated as EC0 from the dose-response relationship. Based on the percent reductionin growth rate, the NOErC is assumed to be ≥80 mg/L. This value is in good correspendance with the ErC10.

Results with reference substance (positive control):

Not performed

Reported statistics and error estimates:

ECX and NOEC calculated according to guideline (no further information)

 

Actual concentrations of test substance

Nominal [mg/L]	Measured t0[mg/L]	Measured t72[mg/L]
100	127.61	106.89
80	104.03	82.27
40	45.83	46.87

 

Cell concentration data

Test substance Concentration (nominal) [mg/l] Cell concentrations (mean values) [10^4cells/ml] Percent of control after 72 h [%] measured 0 h growth rate 48 h 72 h biomass growth rate Control 6.42 0 114 326 0 0 5 6.96 2.0 136 327 -8.7 2.0 10 6.91 3.6 116 305 2.7 3.6 20 6.14 1.6 99.8 293 11.9 1.6 40 6.63 4.2 104 286 10.9 4.2 80 6.78 6.7 88.4 265 23.0 6.7 100 6.13 14.2 46.9 178 53.8 14.2

 

Validity criteria fulfilled:

yes

Conclusions:

The test results indicate that MMPP is acutely of low toxicity towards algae

Executive summary:

The green alga Scenedesmus subspicatus CHODAT (new scientific name: Desmodesmus subspicatus) was used as the test organism on toxicity tests of MMPP towards algae, and the test was performed according to the guidelines OECD 201 and 92/69/EWG, C.3.

Algae were exposed to seven concentrations of the test substance, ranging from 5 to 100 mg/L in a geometric series and a control group. Initial cell densities were 6.42 • 10⁴ cells/mL. The test was performed at 24 - 25 °C in a fully artificial medium according to OECD guideline 201. Cell densities were assessed at 24, 48 and 72 hours using a spectro­photometer at 578 nm. Physico-chemical water parameters and MMPP concentrations were measured at 0 and 72 hours. Concentrations were analysed by an appropriate HPLC method with UV detection at 412 nm.

MMPP was found to be of low toxicity towards S. subspicatus. The effect data are re-evaluated by the applicant and the resulting numerical results are given below. A clear concentration-response relationship can be established from the study results only for the parameter biomass. However, an NOEC can be estimated from the growth rate results. In addition, the highest concentration tested was set as EC₅₀ (without extrapolation).

The analytical monitoring of the actual test concentrations indicatesthat the tests substance is sufficiently stable during the test duration. Therefore, the results can be based on the nominal concentrations.These results confirm that volatility and adsorption of MMPP from aqueous solutions can be neglected. Although MMPP hydrolyses in aqueous solution, the aqueous solution of MMPP reflects the emission of the active substance (hydrolyses products) to aquatic organisms. In addition, MMPP is regarded as readily biodegradable. The analytical monitoring shows that this property has no influence on the results due to the relatively short test duration.

All validity criteria according to the OECD guideline 201 are met within the study.