Sodium methanesulphonate

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:

1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: peer reviewed data

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

None.

Analytical monitoring:

yes

Details on sampling:

At test initiation (0 hour) and termination (96 hours), one sample from each exposure solution and the control was analyzed for methanesulfonic acid concentration. Samples analyzed at test initiation were removed from the test and control solutions remaining in the 1000-mL volumetric flasks subsequent to division intro the replicate test vessels. Samples analyzed at 96 hours of exposure were removed from individually composited replicate test solutions of each treatment level and control and were centrifuged for 15 minutes at 3000 rpm, before analysis, to remove algal cells.

Vehicle:

no

Details on test solutions:

The AAP medium used to prepare the exposure solutions was formulated in the same manner as the culture medium. Several liters of AAP medium were prepared using sterile deionized water and were equilibrated to test temperature. The initial pH of this medium was adjusted, if necessary, to 7.5 units prior to use. In addition, a sample of AAP medium used in the test was analyzed for total organic carbon, which was 0.8 mg/L.
Methanesulfonic acid is totally miscible with water. The stock solution was prepared classically by diluting a relevant amount of methanesulfonic acid in a relevant amount of water.

Test organisms (species):

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

Details on test organisms:

Strain: 1648, class Chlorophyceae
Source/supplier: the algae was originally obtained from the University of Texas and maintained in stock culture
Method of cultivation: the stock cultures were maintained within the following conditions: a shaking rate of 100 rpm
A temperature of 24 °C and continuous illumination at the surface of the medium
Pretreatment: the inoculum used to initiate the toxicity test with methane sulfonic acid was taken from a stock culture that had been transferred to fresh medium three days before testing initial cell concentration: 10000 cells/ml

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Remarks on exposure duration:

None.

Post exposure observation period:

None.

Hardness:

Not measured.

Test temperature:

24 °C

pH:

7.5 to 7.6 initial (min - max)
9.3 to 9.4 after 96 hours (min - max)

Dissolved oxygen:

Not measured

Salinity:

Freshwater.

Conductivity:

80 - 330 µmhos/cm (min - max)

Nominal and measured concentrations:

Nominal test concentration: 3.1, 6.3, 13, 25, 50, and 100 mg/L; 50 and 100 mg/L adjusted to pH 7.5
Mean measured concentration: 2.7, 5.8, 12, 24, 47 and 96 mg/L; 49 and 95 mg/L adjusted to pH 7.5

Details on test conditions:

Exposure vessel type: sterile 250 ml Erlenmeyer flasks
Number of replicates: 3
Photoperiod: continuous light intensity of 3200 to 5400 lux

Reference substance (positive control):

not specified

Key result

Duration:

96 h

Dose descriptor:

EC50

Remarks:

pH adjusted

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Key result

Duration:

96 h

Dose descriptor:

EC10

Remarks:

pH adjusted

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Details on results:

Based on the results of definitive test, it is evident that the acidic nature of the test substance contributed to the toxicity observed.

Results with reference substance (positive control):

None

Reported statistics and error estimates:

Statistical analysis not necessary for EC10/EC50 determination for growth rate. No effect observed on growth rate up to the highest tested concentration.

Validity criteria fulfilled:

not specified

Conclusions:

No effect of methane sulfonic acid was detected on algal growth (pH adjusted).

Executive summary:

The toxicity of methane sulfonic acid was tested against Selenastrum capricornotum (Pseudokirchneriella subcapitata) in a GLP compliant OECD 201 guideline study. Tested nominal concentrations of methane sulfonic acid were 0 ; 3.1 ; 6.3 ; 13 ; 25 ; 50 and 100 mg/L (active substance). pH was adjusted. Each concentration was tested in triplicate. Algae were incubated for 96 hours at 24°C under constant lighting. Test concentrations remained within 80% and 120% of nominal concentrations in all treatments at both 0 and 96 hours. No effect was detected on algal growth rate at any concentration.

Description of key information

A read-across was done for sodium methanesulphonate from methanesulphonic acid (see read-across justification). The

toxicity of methane sulfonic acid was tested against Selenastrum capricornotum (Pseudokirchneriella subcapitata) in a GLP compliant OECD 201 guideline study. Tested nominal concentrations of methane sulfonic acid were 0 ; 3.1 ; 6.3 ; 13 ; 25 ; 50 and 100 mg/L (active substance). pH was adjusted. Each concentration was tested in triplicate. Algae were incubated for 96 hours at 24°C under constant lighting. Test concentrations remained within 80% and 120% of nominal concentrations in all treatments at both 0 and 96 hours. No effect was detected on algal growth rate at any concentration. Therefore sodium methanesulphonate is considered not toxic to algae up to 100 mg/L active substance.