3-(dimethylamino)propylurea

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:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Scenedesmus sp.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

Temperature was maintained at 24 -/+ 1°C throughout the study.

pH:

The pH values of the control cultures were observed to increase from pH 7.3 at 0 hours to pH 9.4 at 72 hours. This increase was considered to be due to the amount of carbon dioxide required by the large number of algal cells in the log phase of growth exceeding the transfer rate of C02 from the gaseous phase to the aqueous phase. In this situation C02 required for photosynthesis and growth is derived from bicarbonate in solution which results in an increase in the pH of the culture.
The increase in pH after 72 hours was in excess of that recommended in the EEC Guidelines (1.5 pH units after 72 hours). This was considered to have had no adverse effect on the results of the study given that the increase in cell concentration in the control cultures exceeded the validation criterion given in the Test Guidelines.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Remarks:

Analysis of the test solutions at 0 and 72 hours showed the measured test concentrations to be in the range of 100 % to 101 % of nominal and so it was considered justifiable to estimate the EC50 values in terms of the nominal test concentrations only.

Conclusions:

The effect of the test material on the growth of Scenedesrnus subspicatus has been investigated and gave EC50 values of greater than 100 mg/l. Correspondingly the No Observed Effect Concentration was 100 mg/l.

Executive summary:

The effect of the test material on the growth of Scenedesrnus subspicatus has been investigated and gave EC50 values of greater than 100 mg/l. Correspondingly the No Observed Effect Concentration was 100 mg/l.

Description of key information

The effect of the test material on the growth of Scenedesrnus subspicatus has been investigated and gave EC50 values of greater than 100 mg/l. Correspondingly the No Observed Effect Concentration was 100 mg/l.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L