O-isopropyl ethylthiocarbamate

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:

NOV 2012

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

Analytical monitoring:

yes

Details on sampling:

The actual exposure concentration of the test product were determined by the analytical laboratory. Duplicate samples of the specially prepared test flasks at each sampling time (24h; 48h and 72H) were stored at -20 ± 2.0 °C until analyses.

Vehicle:

no

Details on test solutions:

A stock solution of 125 mg/l were prepared by weighing 125 mg of the test product and dissolve it in 1000 ml of algal test medium. The test solution were prepared by diluting the stock solution in algal test medium.

Test organisms (species):

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

Details on test organisms:

Pseudokirchnerella subcapitata is cultured at DHI. Algae from this culture were used in the study.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Nominal and measured concentrations:

The analytically determined test item concentrations are analyzed in the test media samples. Test concentrations were 10, 20, 50,100 mg/L at the start of the test. The values found at the end of the test ranged from 85 to 94 % of the initially measured values. Under the test conditions the test item was stable during the test period of 72 hours.

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

20.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

3.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Conclusions:

The test item had a statistically significant inhibitory effect on the growth rate of Pseudokirchneriella subcapitata.
After 72 h EC50 was determined to 20.8 mg/L. NOEC was determined to be 1.0 mg/L and EC10 was 1.4 mg/L. The validation of the test concentrations by chemicals analyses showed a deviation from the nominal concentration throughout the test lower than 20 %. Therefore, results are based on the nominal concentration.

Executive summary:

Toxicity to aquatic algae and cyanobacteria test was done according to OECD Guideline 201. Pseudokirchneriella subcapitata was exposed test item for 72hours under static conditions. Concentration of 10, 20, 50,100 mg/L were tested in fresh-water. The validation of the test concentrations by chemicals analyses showed a deviation from the nominal concentration throughout the test lower than 20 %. Therefore, results are based on the nominal concentration. EC50 (72h) value is determined to be 20.8 mg/L, NOEC is determined to be 1.0 mg/L and EC10 is 1.4 mg/L, respectively. 

Description of key information

Key_Toxicity to aquatic algae and cyanobacteria_Seiero, 2013: OECD 201; Raphidocelis subcapitata; 72h; EC50(72h): 20.8 mg/L; NOEC(72h): 1 mg/L; EC10(72h): 1.4 mg/L
Supp_Toxicity to aquatic algae and cyanobacteria_Flottec, 2009: similar to OECD 201; Skeletonema costatum; 96h; EC50(96h): 21mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:

20.8 mg/L

EC10 or NOEC for freshwater algae:

1.4 mg/L

Additional information

Toxicity to aquatic algae and cyanobacteria test was done according to OECD Guideline 201. Pseudokirchneriella subcapitata was exposed test item for 72hours under static conditions. Concentration of 10, 20, 50,100 mg/L were tested in fresh-water. The validation of the test concentrations by chemicals analyses showed a deviation from the nominal concentration throughout the test lower than 20 %. Therefore, results are based on the nominal concentration. EC50 (72h) value is determined to be 20.8 mg/L and NOEC is determined to be 1.0 mg/L. .