Reaction mass of sulphuric acid, hydrogen peroxide and peroxomonosulphuric acid

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:

2008-12-06 to 2009-01-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Remarks:

Date of inspection 2005-09-14 to 2005-09-16 and 2005-10-26 to 2005-10-28; Date of signature 2006-01-11

Analytical monitoring:

yes

Details on sampling:

- Zero and 72 h (test system)
- Zero and 72 h (control)

Vehicle:

no

Details on test solutions:

- The only test concentration was prepared by adding 125.0 mg of test material to 1 L of dilution water.
- The pH was determined to be 2.9 and was adjusted to 8.1 with 1 M sodium hydroxide solution.
- 80 mL of the stock solution was taken and diluted with 10 mL nutrient medium and 10 mL algal inoculum with a cell density of 5000 cell/mL to give a final concentration of 100 mg/L.
- Six replicates were prepared for the test item and controls.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

- The test species was obtained from "The Collection of Algal Cultures" of the Institute of Plant Physiology at Göttingen University, Germany.
- Exponentially growing stock cultures were maintained at 23 ± 2 °C and light intensity 60-120 μE m-2 s-1 (measured in the range 400-700 nm using a spherical quantum flux meter).
- The nutrient medium was renewed once a week.
- Cell density measurements were made using a microcell counter.
- Pre-cultures were set up 4 d before the start of the test and, with the exception of the nutrient medium, were grown under identical exposure conditions to the stock cultures.
- Algal inocula for a test were taken from an exponentially growing pre-culture and were mixed with the nutrient medium (see Annex 1, attached) to give a final cell density of approximately 5,000 cell/mL in the test medium.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

Not applicable

Hardness:

Not reported

Test temperature:

21 ± 2 °C to 25 ± 2 °C

pH:

- Test system pH 7.9 (zero hours)
- Test system pH 8.7 (72 h)
- Control pH 7.8 (zero hours)
- Control pH 8.6 (72 h)

Dissolved oxygen:

Not reported

Salinity:

Not applicable

Nominal and measured concentrations:

100 mg/L (nominal)

Details on test conditions:

- Test vessels: Erlenmeyer flasks (300 mL) with cotton stoppers
- Culturing apparatus: Light chamber in which temperature range was maintained and continuous uniform illumination was provided in the spectral range 400 to 700 nm
- Light intensity: 60-120 μE m-2 s-1 or an equivalent range of 4000 to 8000 lx

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

EC50

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:

biomass

Details on results:

- Results were expressed in terms of nominal concentrations.
- Recovery rates were corrected for sulphate content of the controls.
- Recovery rates ranged from 99.1 % to 99.3 % of nominal values at zero h.
- Recovery rates ranged from 99.6 % to 101.6 % of nominal values at 72 h.
- Recovery rates relate to the concentration of 48.0 % H2SO4 in the test material.

Reported statistics and error estimates:

Not reported

JUSTIFICATION FOR USE OF READ-ACROSS DATA

See comparison of overall physico-chemical and toxicity profiles for target and source chemicals in the data matrix (attached).

Validity criteria fulfilled:

yes

Conclusions:

No toxic effects on algae were observed at a limit test concentration of 100 mg/L, the ErC50 (0-72 h) was reported as > 100 mg/L, and the No Observed Effect Concentration (NOEC) was reported as ≥ 100 mg/L.

Description of key information

ErC50 > 100 mg/L (OECD 201)
NOEC ≥ 100 mg/L (OECD 201)

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

No toxic effects on algae were observed at a limit test concentration of 100 mg/L sulphuric acid.