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Short-term toxicity to aquatic invertebrates

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short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: EPA guideline similar to OECD-guideline.

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guideline
according to
EPA OTS 797.1300 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)
GLP compliance:

Test material

Specific details on test material used for the study:
purity: 99.72 %
Lot 5-0523-88 was received frozen from Rohm and Haas Company and stored at room temperature. The substance was a clear light yellow liquid.

Sampling and analysis

Analytical monitoring:
Details on sampling:
At each sampling period 5 ml aliquots of test water were collected from each of the four replicates of each test solution. Two replicates at each time
point were composited.

Test solutions

Details on test solutions:
A primary stock standard of MAA was prepared and stored at room temperature. Subsequent dilutions were prepared in Milipore water for use as
spiking solutions and test dilution water.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
ABC Laboratories in house culture. The primary culture was obtained from the Columbia National Fisheries Research Laboratory (CNFRL), Columbia, Missouri, in 1977
Age at study initiation: first instar (<=24 hours old).
Organisms were held in temperature controlled area at 20°C.
Lighting was 50-70 footcandles on a 16 hr photoperiod, with 30 minute dawn and dusk transition periods.
During the holding period, the daphnids were fed a suspension of algae (Selenastrum capricornutum) supplemented with Tetramin®/cereal leaves/yeast suspension.
Organisms were not fed during the 48 hr treatment period.

Study design

Test type:
Water media type:
Limit test:
Total exposure duration:
48 h

Test conditions

172-178 mg/L
Test temperature:
Dissolved oxygen:
7.7-8.2 mg/L
Nominal and measured concentrations:
Nominal = 7.2, 14, 30, 60 and 120 mg/L.
Mean measured (sampling at 0 and 48 hrs) = 6.7, 13, 32, 62 and 130 mg/L.
Details on test conditions:
Method: flow-through bioassay as described in American Public Health Association and Standard Methods for the Examination of Water and 

A half liter proportional diluter system was used for intermittent introduction of dilution water and MAA into the test chambers. The test system contained six sets of four replicate one liter test chambers designated as control, and level 1 through level 5. The proportional diluter was calibrated preior to use in the test.

Dilution water was a blend of reverse osmosis water and ABC laboratory well water.

10 organisms were assigned to each of the four replicate test chambers (40 Daphnids per concentration).
Water quality measurements were recorded at 0 and 48 hours.
Reference substance (positive control):

Results and discussion

Effect concentrationsopen allclose all
48 h
Dose descriptor:
Effect conc.:
130 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
Remarks on result:
other: based on lack of immobilization and or abnormal effects
Key result
48 h
Dose descriptor:
Effect conc.:
> 130 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
Remarks on result:
other: The 48 hr dose response slope could not be determined because of the lack of an effect level
Details on results:
Overall, the measured concentrations represent 101-7.4% of nominal concentrations. Quality control samples analyzed with each sample day over a range of 6.00 to 150 mg/L with recoveries averaging 94+/-19%. Low recovery for the 0 hour sampling was obtained. Duplicate low spikes at teh 48 hour sampling were analyzed to verify the recovery of MAA at the 6.00 mg/l concentration.

Measurement at 0 and 48 hrs of the MAA diluter stock solution averaged 12,000 mg/L which represented 100% of the nominal concentration (12,000 mg/L).

Applicant's summary and conclusion

Validity criteria fulfilled:
In a valid guideline study, the 48 hour EC50 for Daphnia magna was >130 mg/L MAA.
Executive summary:

Methacrylic acid was tested in an acute test to aquatic invertebrates acc. EPA OTS 797.1300 (Aquatic Invertebrate Acute Toxicity test Test) with Daphnia magna. The definitive flow-through acute toxicity of Methacrylic Acid to Daphnia magna was conducted the following nominal concentrations: 7.2, 14, 30, 60 and 120 mg/1.

Forty first-instar daphnids were exposed to each of the test concentrations and control.

The mean measured concentrations calculated from analytical sampling at 0 and 48 hours are as follows: 6.7, 13, 32, 62 and 130 mg/1. The toxicity of Methacrylic Acid based on mean measured test

concentrations were EC50 (48h): > 130 mg/l, NOEC (48h): 130 mg/l

Water quality parameters of temperature, dissolved oxygen and pH were measured in all test concentrations at 0- and 48-hours and were determined to be within acceptable limits. The overall ranges for these

parameters were: daily diluter temperature observations = 20°C, pH = 7.0 - 7.9 and dissolved oxygen= 7.7 - 8.2 mg/1.