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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
Study period:
22 July 2004 to 27 January 2005.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
1984
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Specific details on test material used for the study:
The substance is the Source of the read-across.
The test material hydrolyses quickly (t1/2 < 3 h). Based on advice from the UK Environment Agency, the test material was ground and stirred in diluent to allow hydrolysis, and expose test organisms to hydrolysis products.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Smaples were taken from the control and each test group at 0 and 72 h for quantitative analysis.

Test solutions

Vehicle:
no
Details on test solutions:
XP 338: The test material was known to rapidly hydrolyse releasing butane-1,3-diol and ethyl acetoacetate. These are water soluble, but the co-formed aluminium hydroxide is poorly soluble (1.5 mg/L at 20 °C), so the test material was filtered to remove solids that may have exerted a physical effect on the test organisms.

Test organisms

Test organisms (species):
Scenedesmus sp.

Study design

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

Test conditions

Test temperature:
24 °C
pH:
7.5
Nominal and measured concentrations:
Nominal test concentration were 1.0, 3.2, 10, 32, 100 and 320 mg/L, besed in terms ofparent test material.
For ethyl acetoacetate: after 72 h there was a marked decline in the measured concentration. Given that stability analyses indicated that the substance was stable in culture medium over 72 h, this decline was considered to be due to adsorption to algal cells.
For butane-1,3-diol: after 72, there was a slight decline in measured concentrations. Given that stability analyses indicated that the substance was stable in culture medium over 72 h, this decline was also considered to be due to adsorption to algal cells.
Details on test conditions:
Following a preliminary range-finding test, algae was exposed to an aqueous solution of the hydrolysed test substance for 72 h under constant illumination and shaking at 24 °C.
Samples of the algal populations were removed daily, and cell concentrations determined for each control and treatment group, using a Coulter Multisizer particle counter.

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 320 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat. (dissolved fraction)
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
7.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat. (dissolved fraction)
Basis for effect:
biomass

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
EbC50 (72 h) 7.3 mg/L; ErC50 (0 - 72 h) >320 mg/L.