Chlorimuron ethyl

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: OECD 202 Part II

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPP 72-4 (Fish Early Life-Stage and Aquatic Invertebrate Life-Cycle Studies)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

ethyl 2-({[(4-chloro-6-methoxypyrimidin-2-yl)carbamoyl]amino}sulfonyl)benzoate

EC Number:

618-690-2

Cas Number:

90982-32-4

Molecular formula:

C15H15ClN4O6S

IUPAC Name:

ethyl 2-({[(4-chloro-6-methoxypyrimidin-2-yl)carbamoyl]amino}sulfonyl)benzoate

Test material form:

solid: particulate/powder

Details on test material:

Purity: 96.7%

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Remarks:

Dilution water

Test organisms

Test organisms (species):

Daphnia magna

Study design

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

21 d

Test conditions

Hardness:

132 - 136 mg/L as CaCO3

Test temperature:

20±1°C

pH:

8.3 - 8.6

Dissolved oxygen:

> 60% of saturation throught the test

Conductivity:

Specific conductance: 300 - 330 µmhos/cm

Nominal and measured concentrations:

Nominal: 25, 50, 100, 200 and 400 mg/L
Measured: 26, 53, 106, 211 and 418 mg/L

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

106 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

other: Survival, reproduction and growth

Effect concentrations 2

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

211 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth

Effect concentrations 3

Duration:

21 d

Dose descriptor:

other: MATC

Effect conc.:

150 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

NOEC: 106 mg/L (Survival, reproducton and growth)
LOEC: 211 mg/L (Growth)
MATC: 150 mg/L

Executive summary:

This study was conducted to evaluate the toxicity of the test substance on the survival, growth and reproduction of the cladoceran (Daphnia magna) during a 21-day exposure period under semi-static test conditions according to the guidelines OECD 202 part II and EPA OPP 72-4.

Daphnids were exposed to a series of five test concentrations of 26, 53, 106, 211 and 418 mg/L (measured) and a negative (dilution water) control. First-generation daphnids were observed daily for survival, the onset of reproduction, and clinical signs of toxicity, with the onset of reproduction, the number of second generation neonates of individually exposed organisms were counted (number of live neonates, number of dead or immobile neonates and number of aborted eggs) every Monday, Wednesday and Friday during test. At test termination, die length and dry weight of each individually-exposed first-generation daphnid was determined.

There were no adverse effects on survival, reproduction or growth of daphnids exposed to the test substance at concentrations ≤106 mg/L. In this study, the most sensitive endpoint was growth (length). Daphnids exposed to 211 and 418 mg/L had significantly reduced lengths in comparison to the control. Daphnids exposed to 418 mg also had statistically significant reductions in reproduction and dry weight. The LOEC, based on growth (length), was 211 mg/L. The NOEC was 106 mg/L and the MATC was calculated to be 150 mg/L.

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