2-chloro-N-[[[4-(trifluoromethoxy)phenyl]amino]carbonyl]benzamide

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:

Study initiated/completed: 25 October 1989- 15 November 1989.

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:

1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The test concentrations were selected on the basis of results of an earlier acute test (48 hours) with Daphnia magna and the same active ingredient. The following test concentrations were selected: 0.083, 0.26, 0.83, 2.6, 4.6, 8.3 and 14.5 µg formulation/litre.

Three times weekly (Mondays, Wednesdays, Fridays, i.e. day 2, 5, 7, 9, 12, 14, 16 and 19 after the start of the study), the animals were transferred to freshly prepared test medium. To that end, the water flea originally placed in each test container were carefully removed with a blunt pipette and transferred into the appropriate newly prepared test containers with one to two drops of water. At the same time and additionally on days 20 and 21, the number of offspring which had been born during the previous two or three days in each test container were also counted.

On day 2, 5, 7, 9, 12, 11, 16, 19, 20 and 21 after the start of the study, the surviving parents were counted; from day 7, the offspring which had been born in the previous two or three days were also counted each time. Daphnia were supposed to be dead, when no swimming and/or antennae movements were observed within a 60 second period.

Physico-chemical parameters: Prior to each transfer of the parent daphnia, the values were measured in the freshly prepared test solutions of the control, the blank formulation control, the lowest and the highest test concentration (electronic measuring equipment). For each of the algae quantities used as food, the total COD-values
were also measured once in the test medium of the control. At the end of the two or three days exposure the pH and oxygen values were again determined in one test vessel of the control, the blank formulation control, the lowest concentration and the
highest concentration. Additionally, the temperature was also measured in one control test vessel.

Details on test solutions:

The test concentrations were selected on the basis of results of an earlier acute test (48 hours) with Daphnia magna and the same AI.
The following test concentrations were selected: 0.083, 0.26, 0.83, 2.6, 4.6, 8.3 and 14.5 µg formulation/litre. The test concentrations were set up new at all transfer times as follows: 14.5 mg in 1000 mL test water (= stock solution I). 10 mL of this solution were made up to 1000 mL with test water (= stock solution II).
Of this stock solution II, 0.57 mL, 1.8 mL, 5.7 mL, 18 mL, 32 mL, 57 mL and 100 mL were each made up to 1000 mL with test water in order to produce the concentrations of 0.083, 0.26, 0.83, 2.6, 4.6, 8.3 and 14.5 µg formulation/litre. The blank formulation control was set up new at all transfer times as follows: 17.8 mg blank formulation in 1000 mL test water (= stock solution). 0.5 mL of this stock solution were made up to 1000 mL with test water. This solution had a concentration of 8.89 µg blank formulation/L according to the highest test concentration.

Test organisms (species):

Daphnia magna

Details on test organisms:

Test specimen of Daphnia magna were obtained from a culture maintained at the Institute for Environmental Biology (strain of the Bundasgesundheitsamt (Federal Health Department, Berlin). For the study, young animals 6 - 2 4 hours old, the parents of which stem from an approximately 21 day old synchronous culture, were used. Five young animals were placed in each of five test container (250 ml glass beaker), 25 animals per concentration. After seven days, the number of test containers were reduced to 4. Males were removed and replaced by females from the 5th test container at day 7. The remaining animals of this test container were discarded.

Only offspring of parents of the same age (± 12 hours) were used. The parents were kept in a climatic chamber under the test conditons: 16:3 hours light:dark cycle, 20 + 1 °C. The daphnia were fed on green algae (Scenedesmus subspicatus) and also, an aqueous suspension of a commercial fish food extract . The test water described in 1.5. was used as breeding water. The young animals used in the study were obtained by repeatedly carefully sieving the parents over plastic nets with 0.65 and 0.20 mm mesh size..

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

21 d

Test temperature:

20 ± 1°C (nominal).

pH:

7.5-8.5.

Dissolved oxygen:

> 2 mg/l

Nominal and measured concentrations:

Nominal test concentrations of 0.083, 0.26, 0.83, 2.6, 4.6, 8.3 and 14.5 µg formulation/litre were tested.

Details on test conditions:

The animals in the test containers were exposed to a temperature of 20 ± 1°C and a 16:8 hour light-dark cycle in a climatic chamber. Light intensity was about 1000 lux.

Reference substance (positive control):

yes

Remarks:

K2Cr2O7 reagent grade.

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.032 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

0.1 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Details on results:

Physico-chemical parameters:
The recorded pH values and O2 concentrations indicate that the water quality required by the guideline (pH 7.5 - 8.5, O2 content > 2 mg/L, nominal temperature 20 ± 1°C) was maintained quite well throughout the study period. Differences between the individual test medium preparations were minimal. Likewise, negligible differences could be observed between the control medium and the test medium at the highest and the lowest test concentration at the start of the exposure period and after 2 or 3 days exposure.

Survival Rate of Parents:

No mortalities exceeding a rate of 20 %, which is considered to be natural, were observed in the parent animals of the control, the blank formulation control and the concentration of 0.033 µg formulation/litre. In all concentrations higher than 0.26 ug formulation/litre all parent animals died before the termination of the study.

Number of newborn offspring: A delay in brood times could be observed only at the test concentration 0.26 µg formulation/litre (first brood on day 12). In all other concentrations all parent animals died. In the control, the blank formulation and at concentration 0.083 µg formulation/I the number of offspring per parent animal is high(about 130 per adult).

Reported statistics and error estimates:

Statistical evaluations of the numbers of offspring were carried out. The results of the Kolmogorov-Smirnov-test of goodness-of-fit to a normal distribution showed that each of the reproduction data sets fit to a normal distribution. The results of a t-test indicated no significant differences between the control and the blank formulation control (a = 0.05, p = 0.532). Therefore, the data of the control and the blank formulation control were pooled. Each dose level was compared with the pooled control data. The Bartlett's test for homogeneity of variances indicated no significant differences within the data (a = 0.05, p = 0.78).

Analysis of the data by the one-way analysis of variance indicated a significant (a = 0.05, p = « 0.01) dose response effect on reproduction. Therefore, data are compared statistically by the Dunnett's multiple t-test. The results establish a significant reduction in numbers of offspring at the concentration 0.26 µg
formulation/litre. At test concentrations 0.83 to 14.5 µg formulation/litre all
parent animals died before the termination of the study period and no offspring were observed at these concentrations.

Validity criteria fulfilled:

yes

Conclusions:

Daphnia magna were exposed to a triflumuron formulation for 21 days in a semi-static system to triflumuron at nominal a.s.concentrations of 0.083, 0.26, 0.83, 2.6, 4.6, 8.3 and 14.5 µg/L. Analyses showed actual concentrations to be 93-170% of nominal, with the exception of 0.83 µg/L. Analytical difficulties are noted and results are referred to in terms of nominal concentrations.
NOEC 0.032 µg/L (a.s.)
LOEC 0.10 µg/L (a.s.)

Executive summary:

In the semistatic test for each concentration 4 x 5 female water fleas (Daphnia magnal were transferred three times a week to freshly prepared test medium and fed with defined numbers of green algae (Scenedesmus subspicatusl and a suspension of a fishfood extract. Each time the number of dead adult daphnia and new born water fleas were recorded. The test period was 21 days.
In this test an untreated control, a blank formulation control (according to the highest test concentration) and nominal test concentrations of 0.083, 0.26, 0.83, 2.6, 4.6, 8.3 and 14.5 µg formulation/litre were tested. During the test the AI contents analysed in the freshly prepared test medium were between 93 %
and 170 % of nominal concentrations except at concentration 0.83 µg formulation/L. With respect to the difficult analysis of the AI and the fluctuating analytical results the results of this study are refered to nominal concentrations. On the whole the analytical results confirm the nominal concentrations. A
determination of AI stability under the semistatic test conditions showed no significant degradation of AI within the exposure period of 72 hours.

The mortality in control of 4 % is distinctly lower than 20 %, which is considered to be natural. In the control the mean number of 130 offspring/adult was high. At all concentrations higher than 0.26 µg formulation/L the mortality of parent daphnids was 100 %. Compared to the control, there was a statistical significant reduction of reproduction at the test concentration of 0.26 /µg formulation /L only (Dunnett's-test) . With respect to the effects on the reproduction and mortality of Daphnia magna during the 21 day test period the results obtained from this study were (nominal concentrations): NOEC: 0.083 /µg formulation/L, LOEC: 0.26 /µg formulation/L (Related to AI the NOEC for the reproduction rate was 0.032 µg AI/L and the LOEC was 0.10 µg AI/L).

Description of key information

Daphnia magna were exposed to a triflumuron formulation for 21 days in a semi-static system at nominal a.s.concentrations of 0.083, 0.26, 0.83, 2.6, 4.6, 8.3 and 14.5 µg/L. Analyses showed actual concentrations to be 93-170% of nominal, with the exception of 0.83 µg/L. Analytical difficulties are noted and results are referred to in terms of nominal concentrations. 
NOEC 0.032 µg/L 
LOEC 0.10 µg/L 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Effect concentration:

ca. 0.032 µg/L