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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study, GLP, analytical monitoring, closed vessels

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Methyacrylic acid (CAS: 79-41-4)
Purity: 99.87 %; supplied by ICI Acrylics. Certificate of Analysis stated sample purity determined by GC.
Clear and colorless liquid, stored under refrigeration.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
At the start of the test, samples were taken of each test solution, using the excess remaining after filling the test vessels, and were analyzed for test substance concentration. At the end of the test each blank solution was sampled and analyzed in the same manner.

Test solutions

Vehicle:
no
Details on test solutions:
Two stock solutions were prepared by direct addition of the test substance to 1000 ml of sterile culture medium to give final concentrations of 410 and 10000 mg/L. The three lowest concentrations were prepared by addition of aliquots of the nominal 410 mg/L solution to sterile medium, to a final volume of 1000 ml. The remaining test concentrations were prepared by addition of aliquots of the nominal 10000 mg/l solution to sterile medium, to a final volume of 1000 ml. Test solutions were all clear and colorless.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Test organisms were from laboratory cultures maintained under axenic conditions. A culture in the exponential growth phase was used as inoculum
for the test.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Hardness:
standard test medium used
Test temperature:
24°C
pH:
start of test 6.39-8.21
end of test 6.11 - 9.69
Nominal and measured concentrations:
Nominal = 0.86, 1.9, 4.1, 9.1, 20, 45 and 100 mg/L
Geometric mean measured = 0.85, 2.0, 3.7, 8.2, 19, 45, 100 mg/L
Details on test conditions:
Test vessels were borosilicate glass bottles of 50 ml nominal capacity, filled completely with airtight, teflon faced disc/crimp closures. Cultures were incubated at 24+/-2C under continous "cool white" illumination with orbital shaking. Four replicates of the control and duplicates of the test substance were employed. At 24, 48 and 72 hours replicate vessels were sacrificed and counted.
Ph was measured at the start of the test and at the end of the test the pH of two repliacte test solutions (containing algae) from each control and test concentration was determined.
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
8.2 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: growth rate and biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
45 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
20 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
Mean measured concentration of the test substance ranged from 88 -105% of nominal exposure concentrations

Applicant's summary and conclusion

Conclusions:
In a valid guideline study, the 72 hr EbC50 and ErC50 were 20 and 45 mg/L, respectively for MAA with Selenastrum capricornutum (new name: Pseudokirchnerella subcapitata). The NOEC for growth and biomass was 8.2 mg/L.
Executive summary:

In a valid guideline study, the 72 hr EbC50 and ErC50 were 20 and 45 mg/L, respectively for MAA with Selenastrum capricornutum (new name: Pseudokirchnerella subcapitata). The NOEC for growth and biomass was 8.2 mg/L.