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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Endpoint:
toxicity to aquatic algae and cyanobacteria
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Justification for type of information:
The target substance is hydrolytically unstable with hydrolysis half-life less than 5 minutes. The hydrolysis products have been identified to be 1-butanol and hydrated zirconium dioxide. The properties and toxiciteis of the hydrolysis products are therefore used for read-across.
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail
Qualifier:
according to
Guideline:
other: Cell Multiplication Inhibition Test
Principles of method if other than guideline:
Scenedesmus cell multiplication inhibition test, DIN 38412 Part 9
GLP compliance:
not specified
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
Scenedesmus quadricauda
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
8 d
Key result
Duration:
8 d
Dose descriptor:
other: toxicity threshold TT
Effect conc.:
ca. 875 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: mean extinction value
Validity criteria fulfilled:
yes
Conclusions:
The 7-day toxicity threshold of 1-butanol to Scenedesmus quadricauda is 875 mg/l.

Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
225 mg/L
EC10 or NOEC for freshwater algae:
129 mg/L

Additional information

No studies were conducted on the target substance, Zirconium tetrabutanolate. As the target substancehydrolyses rapidly (half-life < 5 minutes) the intrinsic properties are related to hydrolysis products of thetarget substance.

On the basis that if entering the environmental, this substance will quickly dissociate to form the inorganic(poorly soluble) zirconium dioxide and well-evaluated organic substances - 1 -butanol.
The zirconium dioxide is not considered further in this report as aquatic toxicity assessments do notapply.

A 96 h EC50 of 225 mg/l and 96 h NOEC of 129 mg/l for growth rate inhibition of Selenastrum capricornutum, tested according to OECD guideline 201, cited in UNEP 2004. These values were used for CSA.