Registration Dossier

Ecotoxicological information

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:
13 July 1988 to 03 August 1988
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report Date:
1988

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA OPP 72-4 (Fish Early Life-Stage and Aquatic Invertebrate Life-Cycle Studies)
Deviations:
no
Principles of method if other than guideline:
A dynamic 21-day life cycle toxicity study of Fenitrothion Technical to Daphnia magna was conducted to determine the Maximum Acceptable Toxicant Concentration (MATC) limits. Each concentration consisted of four replicates containing 10 daphnids for a total of 40 daphnids. Exposure concentrations of Fenitrothion Technical were measured analytically on days -n, 0, 4, 7, 10, 14, 17 and 21. All results were based on the mean measured concentrations of Fenitrothion Technical.


GLP compliance:
yes
Remarks:
(Self certification by the laboratory)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
Fenitrothion (Batch No.: 60553, Purity: 94.5%, Specification No. 01 - Document J)

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Exposure concentrations of fenitrothion were determined on days-N (analytical sampling prior to study initiation), 0, 4, 7, 10, 14, 17 and 21. The mean measured concentrations were 0.029, 0.042, 0.087, 0.23 and 0.44 µg/l. These were 102 ± 16% of the nominal concentrations.

Test solutions

Vehicle:
yes
Remarks:
acetone
Details on test solutions:
A half-liter proportional diluter system was used to maintain constant test concentrations. The nominal concentrations were 0.024, 0.048, 0.10, 0.20 and 0.40 µg/l. The mean measured concentrations, were determined by GLC: 0.029, 0.042, 1.87, 0.23 and 0.44 µg/l. The mean measured levels averaged 102 ±16% of expected nominal concentrations .

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
In-house culture. The primary culture was obtained from the Columbia National Fisheries Research Laboratory.

Study design

Test type:
flow-through
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d

Test conditions

Hardness:
160-180 mg/lCaCO3
Test temperature:
19-20°C
pH:
7.7-8.2
Dissolved oxygen:
7.3-8.4 mg/L
Nominal and measured concentrations:
The nominal concentrations were 0.024, 0.048, 0.10, 0.20 and 0.40 µg/l.
The mean mesured concentrations were 0.029, 0.042, 0.087, 0.23 and 0.44 µg/l
Details on test conditions:
Temperature, which was recorded continuously, ranged from 19-21°C throughout the daily observations of the study. The dissolved oxygen concentrations which ranged from 7.3 to 8.4 mg/l, represented which between 84 and 94% saturation at 20° and 19°C. These values were considered adequate for testing and no supplemental aeration was necessary. The pH values of the treated chambers were consistent with the control throughout the study, ranging from 7.7 to 8.2.

Results and discussion

Effect concentrationsopen allclose all
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
0.19 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
21 d
Dose descriptor:
other: point estimate MATC
Effect conc.:
0.14 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
other: survival, young/adult/repro­ duction day, adult mean length and length in days to first brood
Key result
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.087 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
other: survival, young/adult/repro­ duction day, adult mean length and length in days to first brood
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
0.23 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
other: survival, young/adult/repro­ duction day, adult mean length and length in days to first brood
Details on results:
Statistical analysis of survival for Daphnia magna after a 21-day exposure to Fenitrothion Technical indicated that daphnid survival was significantly different (P<0.05) from the pooled controls in the mean measured concentrations of 0.23 and 0.44 µg/l. A day 21 EC50 was calculated to be 0.19 µg/l. The mean young/adult/reproduction day for 21 days were significantly affected in the mean measured exposure levels of 0.23 and 0.44 µg/l of Fenitrothion Technical .
The daphnid lengths in the Fenitrothion Technical mean measured concentration of 0.23 µg/l were significantly different from the pooled controls. Length measurements could not be made on the 0.44 µg/l test level daphnids since all had died by day 12 of the study.The time in days to first brood for the controls and all treatment levels was 9.0 days. Therefore, no significant difference occurred in time to first brood for any test level.

Based on the statistical analysis of survival, young/adult/repro­ duction day, adult mean length and length in days to first brood from this 21-day Daphnia magna dynamic life cycle study, the MATC limits were estimated to be 0.087 and 0.23 µg/l . The point estimate MATC value was 0.14 µg/l.

Any other information on results incl. tables

Adult daphnid length: The length of adultDaphnia magnain the control and solvent control were not significantly different, so they were pooled.

A one-way analysis of variance and Dunnett's multiple means test indicated that the daphnid length in the 0.23 µg/l dosage was significantly different from those of the pooled controls. Since all daphnids had died in the 0.44 µg/l test level by day 12, no length data was available for statistical analysis.

 

Young/adult reproduction days (Total number of young produced/Total number of reproduction days):

Young/adult reproduction days in the control and solvent control were not significantly different, so they were pooled.

The mean young/adult reproduction days were significantly reduced in the 0.23 and 0.44 µg/l dosages. All young produced during this study appeared normal in all test concentrations.

 

Time to first brood: The time in days to first brood for the controls and all treatment levels was 9 days.

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
A day 21 EC50 was calculated to be 0.19 µg/l. The mean young/adult/reproduction day for 21 days were significantly affected in the mean measured exposure levels of 0.23 and 0.44 µg/l of Fenitrothion Technical.

The daphnid lengths in the Fenitrothion Technical mean measured concentration of 0.23 µg/l were significantly different from the pooled controls. Length measurements could not be made on the 0.44 µg/l test level daphnids since all had died by day 12 of the study.
The time in days to first brood for the controls and all treatment levels was 9.0 days. Therefore, no significant difference occurred in time to first brood for any test level.

Based on the statistical analysis of survival, young/adult/repro­ duction day, adult mean length and length in days to first brood from this 21-day Daphnia magna dynamic life cycle study, the MATC limits were estimated to be 0.087 (NOEC) and 0.23 µg/l (LOEC) . The point estimate MATC value was 0.14 µg/l.
Executive summary:

A dynamic 21-day life cycle toxicity study of Fenitrothion Technical to Daphnia magna was conducted to determine the Maximum Acceptable Toxicant Concentration (MATC) limits.  Each concentration consisted of four replicates containing 10 daphnids for a total of 40 daphnids. Exposure concentrations of Fenitrothion Technical were measured analytically on days -n, 0, 4, 7, 10, 14, 17 and 21. All results were based on the mean measured concentrations of Fenitrothion Technical.

A day 21 EC50 was calculated to be 0.19 µg/l. The mean young/adult/reproduction day for 21 days were significantly affected in the mean measured exposure levels of 0.23 and 0.44 µg/l of Fenitrothion Technical . The daphnid lengths in the Fenitrothion Technical mean measured concentration of 0.23 µg/l were significantly different from the pooled controls. Length measurements could not be made on the 0.44 µg/l test level daphnids since all had died by day 12 of the study. The time in days to first brood for the controls and all treatment levels was 9.0 days. Therefore, no significant difference occurred in time to first brood for any test level. Based on the statistical analysis of survival, young/adult/repro­ duction day, adult mean length and length in days to first brood from this 21-day Daphnia magna dynamic life cycle study, the MATC limits were estimated to be 0.087 (NOEC) and 0.23 µg/l (LOEC) . The point estimate MATC value was 0.14 µg/l.