Chlorimuron ethyl

Long-term toxicity to fish

Administrative data

Endpoint:

fish early-life stage toxicity

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:

1999

Report date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 210 (Fish, Early-Life Stage Toxicity Test)

Deviations:

yes

Remarks:

Several hardness measurements (109-140 mg/L as Ca2C03) were recorded outside the targeted range (110-130 mg/L as Ca2C03) for this parameter. This deviation had no effect on the study.

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

Several hardness measurements (109-140 mg/L as Ca2C03) were recorded outside the targeted range (110-130 mg/L as Ca2C03) for this parameter. This deviation had no effect on the study.

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

Details on test material:

Purity: 99.38%
Impurities: Not reported

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Remarks:

Cold dilution water

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Study design

Test type:

flow-through

Water media type:

freshwater

Total exposure duration:

90 d

Test conditions

Hardness:

109-140 mg/L (as Ca2CO3)

Test temperature:

11.0 to 13.2°C

pH:

6.8 to 7.5

Dissolved oxygen:

Between 65 and 101% of saturation

Nominal and measured concentrations:

Nominal: 6.3, 12.5, 25, 50, and 100 mg/L
Measured: 7.6, 15, 29, 52, and 95 mg/L

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

90 d

Dose descriptor:

NOEC

Effect conc.:

7.6 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

number hatched

Effect concentrations 2

Key result

Duration:

90 d

Dose descriptor:

LOEC

Effect conc.:

15 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

number hatched

Effect concentrations 3

Duration:

90 d

Dose descriptor:

other: MATC

Effect conc.:

11 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

number hatched

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The NOEC was 7.6 mg/L based on mean measured concentrations of last day of hatching.
The MATC and LOEC based on the last day of hatching were 11 and 15 mg/L.

Executive summary:

The effect of the test substance on hatching, growth and survival of rainbow trout, Oncorhynchus mykiss, embryos, alevins, and fingerlings was assessed in a flow-through, 90-day early life-stage toxicity test according to the guidelines OECD 210 and EPA OPP 72-4.

Nominal test concentrations were 6.3, 12.5, 25, 50, and 100 mg/L and a water control.

Measured test concentrations were 7.6, 15, 29, 52, and 95 mg/L; less than limit of detection (LOD, 0.11 mg/L) in water control.

Age of test organisms (Unfertilized eggs and sperm) is approximately 22 hours post-fertilization at test start.

A total of 80 embryos were exposed per concentration (20 embryos per embryo cup, 2 cups per replicate, 2 replicates per concentration) at test start. On day 40, after swim-up had begun in the controls, the fingerlings were thinned to a total of 30 fish per concentration (15 fish per replicate, 2 replicates per concentration). Analytical verification of the test substance concentrations was made on test solutions sampled on day 0, once weekly, and on day 90 at test end. Additional samples were submitted or analysis as warranted. Test solutions were supplied to each replicate test chamber by a proportional diluter system at a rate of approximately 1.25 L per hour (approximately five 6-L test solution volume additions per day). Embryos and alevins were held in relative darkness until day 35, and then held under a photoperiod of 16 hours light and 8 hours darkness (which included 30 minutes of transitional light between light and dark intervals) for the remainder of the study. After thinning, the fingerlings were fed newly-hatched brine shrimp (days 40-49) or newly-hatched brine shrimp and trout chow (days 50-89). Test solutions were maintained between 11.0 and 13.2°C (mean 11.8°C). Daily observations were made for assessment of number of dead eggs at hatching, first and last day of hatching, first day of swim-up, survival and abnormalities from hatching to thinning, and survival and abnormalities from thinning to test end. Standard length and blotted wet weight of surviving fingerlings were determined at test end.

The NOEC (No Observable Effect Concentration) for the test substance a 90-day early life-stage toxicity study using rainbow trout, Oncorhynchus mykiss, was 7.6 mg/L based on mean, measured concentrations and last day of hatching. The MATC (Maximum Acceptable Toxicant Concentration) was 11 mg/L, and the LOEC (Lowest Observed Effect Concentration) was 15 mg/L.