3-(dimethylamino)propylurea

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 March - 19 September 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Version / remarks:

2012

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: Manufacturer, UA21412002
- Purity, including information on contaminants, isomers, etc.: Content: 75% 3-(N,N-Dimethyl)propyl-urea and 25% Polyethylenglycol

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store container tightly closed at a well-ventilated place. Store in the original container. Do not store with acids.

Analytical monitoring:

yes

Details on sampling:

The test item concentrations of PU-2021-971 were analytically verified via LC-MS/MS three times during the test (once within a period of 7 days) in the fresh media at the start of an exposure-renewal interval (0 hours; on test days 0, 7 and 14) as well as in the old media at the end of an exposure-renewal interval (48 hours; on test days 2, 9 and 16) in all test item concentrations and in the control.
Details of the analytical method are presented in the attachement in the results section - overall remarks

Vehicle:

yes

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain/clone: STRAUS
- Justification for species other than prescribed by test guideline: Daphnia magna is the preferred species in accordance with the test guideline
- Age at study initiation (mean and range, SD): Less than 24 hours old daphnids from a healthy stock were used for the study. To achieve this, juvenile daphnids were removed from the culture vessels at the latest 24 hours before the start of the exposure and discarded. The juveniles born within the following period were used for the test. No first brood progeny was used for the test.
- Weight at study initiation (mean and range, SD):
- Length at study initiation (length definition, mean, range and SD):
- Valve height at study initiation, for shell deposition study (mean and range, SD):
- Source: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu), 14195 Berlin, Germany
- Age of parental stock (mean and range, SD):
- Feeding during test
- Food type: Daily feeding with unicellular green algae, e.g., Pseudokirchneriella subcapitata and Desmodesmus subspicatus
daphnia and day
- Amount: max. 0.2 mg C /day
- Frequency: at least 5 times per week ad libitum

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

The total hardness should be above 140 mg/L CaCo3

Test temperature:

The temperature was in the range of 18 – 22 °C and did not vary by more than 2°C.

pH:

6-9

Dissolved oxygen:

The oxigen concentration should be > 3 mg/L at the start and during the test period.

Nominal and measured concentrations:

Nominal concentrations: 0.954 - 3.05 - 9.77 - 31.3 - 100 mg/L. Measured concentrations: The measured concentrations of the test item in the fresh media were between 99 and 117% of the
nominal values. In the aged media after 48 hours were the concentrations were in the range of 107 to 119% of the nominal values.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (5 (ID) x 8 (H) cm), 100 mL capacity, loosely covered with watch glasses
- Type (delete if not applicable): closed
- Aeration: Test vessels were not aerated during the test.
- Renewal rate of test solution: The test solutions were renewed 3 times per week (after 48 or test solutions 72 hours). For this purpose, a second set of test vessels were filled with the freshly prepared test solutions and the daphnids were transferred by pipette
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- No. of vessels per vehicle control (replicates): one daphnid per replicate
OTHER TEST CONDITIONS
- Adjustment of pH: The pH value should be in the range of 6-9. Deviation between the initial and the final pH-values should be < 1.5 units.
- Photoperiod: 16/8 hours light/dark cycle
- Light intensity: Max. 1500 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Mortality of parental daphnids: The number of parental daphnids, which were immobilized or dying during the test and the dates of death were observed and recorded once a day at least at the same time as the offspring was counted. Dead daphnids were removed as soon as they were detected.
Neonates: First appearance of juveniles was checked daily. The number of neonates (alive and dead progeny) was counted, and dates of release were recorded once a day from the first day of appearance of neonates until the end of the exposure. The neonates (alive and dead) were removed after counting and before addition of algae to prevent them from consuming food intended for the adults. The number of aborted eggs or dead offspring and dates of observation were recorded.
Additional observations/Condition of parental daphnids: Abnormalities (e.g., abnormal swimming behavior, number of males and winter eggs) were observed and recorded on each day of observation.
Total body length/Mean dry weight of parental daphnids: At the end of the test, the total length excluding the anal spine of each survived parental daphnid and the mean dry weight of the survived parental daphnids of all the test concentrations and the control were determined. As stated in the OECD 211 protocol, this may be useful additional information but is not used for determination of a NOEC.
Additional endpoints: The time to the first brood, the intrinsic rate of population increase and the number and size of the first brood per animal were reported, but not used for endpoint calculations.


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- Range finding study: A non-GLP preliminary range finding test was conducted at the test facility as a shortened reproduction test under semi-static conditions with renewal of the test solutions every 2 – 3 days over a period of 12 days. A control and three test concentrations of the test item of 0.800, 8.00 and 80.0 mg/L were tested in the range finding test. The preliminary range finding test was conducted under diffuse light conditions (light intensity of max. 1500 lx, 16/8 hours light/dark cycle). Five daphnids, one daphnia per replicate, were exposed to each concentration level and the control. The concentration levels and the control were analytically verified via LC-MS/MS at the start of the exposure and in the old media (test vessels containing daphnia and algae) at the end of an exposure-renewal interval
- Test concentrations: Five concentrations were tested in a geometric series with a dilution factor of 3.2: 0.954 - 3.05 - 9.77 - 31.3 - 100 mg/L.
- Results used to determine the conditions for the definitive study: The concentration levels and the control were analytically verified via LC-MS/MS at the start of the exposure and in the old media (test vessels containing daphnia and algae) at the end of an exposure-renewal interval

Reference substance (positive control):

not specified

Key result

Duration:

96 h

Dose descriptor:

EC10

Effect conc.:

21.9 mg/L

Nominal / measured:

nominal

Basis for effect:

reproduction

Details on results:

See overall remarks

Validity criteria fulfilled:

yes

Conclusions:

The effects on reproduction were evaluated based on the reproduction per introduced parent animal, since this parameter is the ecologically most relevant response variable and is required by the OECD test guideline 211 (2012), when a significant trend in mortality is detected.
The overall effect threshold for effects of the test item under the test conditions was 0.954 mg/L (NOEL) and 3.05 mg/L (LOEL) based on the nominal concentrations of the test item PU-2021-971. The EC10 was 21.9 mg/L based on the nominal concentrations of the test item.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC10

Effect concentration:

21.9 mg/L