2,5-dimethylhexyne-2,5-diol

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Publication describing a test method which meets basic scientific principles. Some limitations in design and reporting but outcome considered reliable and adequate for assessment.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2012

Materials and methods

Principles of method if other than guideline:

Algal inoculum (Pseudokirchneriella subcapitata, formerly known as Selenastrum capricornutum, UTEX 1648) was withdrawn from chemostat operated under steady state and transferred into 300 mL, biochemical-oxygen-demand (BOD) test bottles together with dilution water (with growth medium) and toxicants. The BOD bottles were filled completely with no headspace left. A water seal was provided to ensure a closed test environment. The bottles were then placed on an orbital shaker. Temperature and light intensity were kept at 24 ± 1°C and 65 µE·m-2·s-1 (±10%}, respectively. US EPA bottle medium, with no EDTA content, was used for toxicity testing. Two response endpoints were used to evaluate the toxicity of the toxicants: the final yield (final cell density- initial cell density) and algal growth rate based on cell density counts. The initial inoculated cell density was 15000 cells per mL, which was determined using an electronic particle counter. The initial pH for toxicity testing was set at 7.5. Thirty-four propargylic alcohols, including primary, primary homo-, secondary, and tertiary alcohols, were tested in the present study. All chemicals used were of reagent grade and were tested at least twice, i.e. , range finding test and definitive test. For the definitive test, one control and 6 (or 7) different treatments were performed in triplicate. Stock solution was freshly prepared, and its concentration was analyzed with a total organic carbon (TOC) analyzer before commencing the experiment. Toxicants with low solubility were dissolved in dimethyl sulfoxide (DMSO). Solvent controls were conducted using the highest DMSO concentration applied in treatments.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

2,5-dimethylhexyne-2,5-diol

EC Number:

205-533-4

EC Name:

2,5-dimethylhexyne-2,5-diol

Cas Number:

142-30-3

Molecular formula:

C8H14O2

IUPAC Name:

2,5-dimethylhex-3-yne-2,5-diol

Details on test material:

- Name of test material (as cited in study report): 2,5-Dimethyl-3-hexyne-2,5-diol

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

- Strain: UTEX 1648

Study design

Test type:

static

Water media type:

freshwater

Results and discussion

Effect concentrations

Effect concentrations 1

Dose descriptor:

EC50

Effect conc.:

2 098.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: No test duration is specified.

Effect concentrations 2

Dose descriptor:

EC10

Effect conc.:

193.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: No test duration is specified

Reported statistics and error estimates:

Probit analysis was applied to determine the concentration response relationship and the median effective concentration (EC50). One-tail Dunnett's procedure was applied for the calculation of NOEC and LOEC values at 5% Ievel of significance.