Potassium dimethyl 5-sulphonatoisophthalate

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source of test material: sponsor
- purity: 96.6%
- Solubility in water: 14 g/L

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature in the dark

Analytical monitoring:

yes

Details on sampling:

The analytically measured test substance concentrations in the analyzed test solutions were
106.9 and 101.8 mg/L at the beginning and the end of the test.

Vehicle:

no

Test organisms (species):

Scenedesmus sp.

Details on test organisms:

Set up the algal pre-culture Scenedesmus obliquus a week before the start of the test. The pre-culture is incubated at 23 °C ± 2°C, under continuous light of 8000 Lux, and with a light-dark cycle of I Oh: 14h for 2 or 3 days, after which time it should be exponentially growing. Transfer the pre-culture into fresh medium and incubate other 3 days, make sure the alga is in exponential growth and of sufficient cell density to be used as inoculum for the test.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

23 ± 1 "C

pH:

test substance vessels: 7.52 - 8.42
control vessels: 7.23 - 8.22

Details on test conditions:

Based on the result of the preliminary test, a limit test may be performed at 100 mg/L in order to
demonstrate that the 72h-EbC50 is greater than this concentration. The culture conditions and test procedures are the same as the preliminary test. The pH of the controls and the test solutions should be measured at the beginning and the end of the test, and the test substance concentrations in the test solutions should be measured at the end of the test.

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

Validity criteria fulfilled:

yes

Conclusions:

Based on these results the test substance, potassium dimethyl 5-sulphonatoisophthalate, has no obvious inhibitory effect on the Scenedesmus obliquus growth under these test conditions,

Executive summary:

The growth inhibition of the test substance potassium dimethyl 5-sulphonatoisophthalate to a unicellular green species (e.g. Scenedesmus obliquus) was determined by using the Algal Growth Inhibition Test Method.
Exponentially-growing cultures of se]ected green algae were exposed to various concentrations of the test substance for several generations under defined conditions. The inhibition of growth in relation to a control culture was determined over a fixed period of 72 hours.

The analytically measured test substance concentrations in the analyzed test solutions were 106.9 and 101.8 mg/L at the beginning and the end of the test. In the controls and the treatments at the loading rate of 100 mg/L (mean measured concentration 104.3 mg/L) no obvious growth inhibitory effects were determined during the lest period of 72 hours. Therefore, 72h-EbC50 of the test substance to Scenedesmus obliquus was higher than the loading rate of 100 mg/L (mean
measured concentration 104.3 mg/L).

In conclusion, the test substance potassium dimethyl 5-sulphonatoisophthalate had no obvious inhibitory effects on algal growth under these test conditions.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L