1-[2-fluoro-6-(trifluoromethyl)benzyl]-5-iodo-6-methylpyrimidine-2,4(1H,3H)-dione

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23rd October 2018 to 14th November 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: China Environmental Press, Guidelines for the Testing of Chemicals no. 211 Daphnia Reproduction Test (version 2. 2013)

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: EC, DG Health and Consumer Protection: Guidance on analytical quality control & validation procedures for pesticide residue analysis in food & feed SANCO/1257/2013 19/11/13 rev 0

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1-{[2-fluoro-6-(trifluoromethyl)phenyl]methyl}-5-iodo-6-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione

EC Number:

687-893-6

Cas Number:

1150560-54-5

Molecular formula:

C13H9F4IN2O2

IUPAC Name:

1-{[2-fluoro-6-(trifluoromethyl)phenyl]methyl}-5-iodo-6-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Remarks:

HPLC - UV

Details on sampling:

Test group and control group: fresh media and old media once every 7 days

Test solutions

Details on test solutions:

Method of preparation of stock solution:
A stock solution of nominal concentration 500 mg/L was prepared with acetonitrile. A weight of 0.10002 g test item was dissolved in acetonitrile to 100 mL

Method of preparation of test solutions:
The stock solution was used to prepare the working standard solutions with acetonitrile of 0.05, 0.1, 0.5, 1.0, 5.0, 10 and 20mg/L

On the last day of analysis, another stock solution was prepared (0.10000g was weighed and dissolved in 100ml of acetonitrile) and diluted to 0.5mg/L with acetonitrile to assess the stability of the stock solution under storage conditions.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia of stock culture were originally obtained from the College of Applied Chemistry of China Agricultural University. The test Daphnia were derived from the same healthy pre-cultured population (i.e. showing no signs of stress such as high mortality, presence of males and ephippia, delay in the production of the first brood, discoloured animals, etc.). The pre-cultured animals were maintained in culture conditions (light, temperature, and medium) similar to those to be used in the test. The test animals were less than 24 hours old and not the first brood progeny. The batch used for this definitive test was Daphnia C20181024.
A concentrated living algal suspension of Chlorella sp. and Desmodesmus subspicatus was fed to the Daphnia at a level of 0.1 - 0.2 mg/C/Daphnia/day.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

21 d

Post exposure observation period:

Mortality and number of offspring produced were recorded daily.
Other parameters were measured at the end of the test.

Test conditions

Hardness:

180mg/L (as CaCO3)

Test temperature:

19 - 20.5 oC

pH:

7.74 - 8.25

Dissolved oxygen:

9.10 - 9.37mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers
- Fill volume: 200 - 250ml
- Volume of solution: 100ml
- Aeration: none during the test period
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- Frequency of solution renewal: 3 times per week

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: water treated with Aquapro Pure Water System
- Total organic carbon: <2mg/L
- Alkalinity: pH 6.0 - 9.0

OTHER TEST CONDITIONS
- Photoperiod: 16 hours photoperiod daily, 8 hours dark
- Light Intensity: 1145 - 1210 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Daily: Mortality and number of offspring produced
At end of test: Reproductive output per surviving parent and body length of surviving parent.

RANGE-FINDING STUDY
- Test concentrations: 10, 30 and 100mg/L (nominal)
- Results used to determine the conditions for the definitive study: At 10mg/L the number of juveniles from parent animals was significantly different in comparison to the control (p<0.05) whereas there were no surviving juveniles at 30mg/L. Based on the results of the preliminary test the definitive test was conducted with five nominal concentrations of 2.0, 3.9, 7.7, 15 and 30mg/L.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.373 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks on result:

other: Total broods

Effect concentrations 2

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 0.373 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks on result:

other: Total broods

Effect concentrations 3

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.373 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks on result:

other: Body length of parent

Effect concentrations 4

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 0.373 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks on result:

other: Body length of parent

Effect concentrations 5

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.373 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks on result:

other: First Brood Time

Effect concentrations 6

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 0.373 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks on result:

other: First Brood Time

Effect concentrations 7

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.044 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks on result:

other: Mortality: Number of living offspring produced per surviving parental animal {for Daphnia magna, TG 211}

Effect concentrations 8

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

0.086 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks on result:

other: Mortality: Number of living offspring produced per surviving parental animal {for Daphnia magna, TG 211}

Details on results:

No deaths of daphnia parents were observed in either the test or control groups.
No immobilisation was observed in either the test or control groups.
First brood began at Day 7 and there was no significant difference between test or control groups.
There was no significant difference between test or control groups for total broods per parent.
The total live offspring for each parent of 2.0 and 3.9mg/L and control. There was extreme significance difference between test groups of 7.7, 15 and 30mg/L and the control group (P<0.01).
For test groups 15 and 30mg/L, dead offspring were observed during the test. No significant difference was reported for body length of parents between test and control groups.

Reported statistics and error estimates:

Student t-test with 5% significance level

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 21-day No Observed Effect Concentration (NOEC) and the Lowest Observed Effect Concentration (LOEC) based on mean measured concentration were as follows: 

First brood time: NOEC mg/L - 0.373 LOEC mg/L - >0.373
Total number of live offspring per parent: NOEC mg/L - 0.044 LOEC mg/L - 0.086
Body length of parents: NOEC mg/L - 0.373 LOEC mg/L - >0.373
Total broods: NOEC mg/L - 0.373 LOEC mg/L - >0.373

Executive summary:

A study was performed to assess the effect of the test item on the reproduction rate of Daphnia magna over a 21-day exposure period.

Based on the results of the preliminary test, the definitive test was carried out at five nominal concentrations of 2.0, 3.9, 7.7, 15 and 30.0mg/L.

For each group, (test and control) 10 daphnia were individually held (1 per test vessel). The test was performed with the renewal of the test solutions three times per week. 

No mortality of parents was reported in either the test group or the control group.  No signigficant difference betweeen all test groups and control group was noticed for the first brood time, the body length of the parent and the total broods (p>0.05). The total live offspring for each parent of 7.7, 15 and 30mg/L (nominal concentration) showed extreme significance difference compared to the control group. 

During the test period, chemical analysis on test item concentration in test media by HPLC showed that for the test media of 2.0, 3.9, 7.7, 15 and 30.0mg/L, the mean measured concentrations of fresh solutuion was 0.024, 0.045, 0.090, 0.182 and 0.379mg/L. The mean measured concentrations in old solution were 0.024, 0.044, 0.083, 0.178 and 0.367mg/L. The mean concentrations were 0.024, 0.044, 0.086, 0.180 and 0.373mg/L. The mean measured concentrations were maintained within 20% of measured initial concentratiosn throughout the test, so results were based on mean measured concentrations. 

The 21-day No Observed Effect Concentration (NOEC) and the Lowest Observed Effect Concentration (LOEC) based on mean measured concentration were as follows: 

Parameter	NOEC mg/L	LOEC mg/L
First brood time	0.373	>0.373
Total number of live offspring per parent	0.044	0.086
Body length of parents	0.373	>0.373
Total broods	0.373	>0.373