Chlorbutanol

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

Study period:

15-Sep-2017 to 09-Mar-2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

The tempereture values were partially outside the range given in the study plan and thus represents a deviation of the study plan which is not considered to have an influence an the
integrity of the test. The whole temperature range is in accordance with the OECD Test Guideline
201.

Deviations:

yes

Remarks:

see remarks

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1,1,1-trichloro-2-methyl-2-propanol hemihydrate

Cas Number:

6001-64-5

Molecular formula:

C4H7Cl3O H2O

IUPAC Name:

1,1,1-trichloro-2-methyl-2-propanol hemihydrate

Test material form:

solid: crystalline

Details on test material:

transparent and crystalline solid at ambient temperature

Sampling and analysis

Analytical monitoring:

yes

Remarks:

GC-MS

Details on sampling:

Specimens were drawn from freshly prepared treatments and those incubated for 72 hrs. The supporting analysis of the specimens could not be performed on the same day of collection of the specimens. Therefore, all specimens from freshly prepared test solutions and those incubated for 72 hrs were stored deep-frozen at <= -18°C in glass bottles and analysed after thawing.

Test solutions

Vehicle:

no

Details on test solutions:

An aliquot of the algal stock culture was diluted with test medium to an absorbance value of E578 nm = 0.015 of the algal suspension giving an initial algal cell concentration of 3*103 cellslml. The determination of cell concentration was performed by photometrical measurement using a calibration curve prepared by using a spectrophotometer at 578 nm. The test item was prepared as follows: Separate solutions (see below) were made for each test concentration in ultrapure water. Aliquots of these solutions were made up with "intermediate dilution" (see section above) and algal inoculum (or diluted "intermediate dilution") to give 50 ml of final volume. The test item was introduced into the test solutions using individual stock solutions for each concentration (screening). The solutions were used directly without any further dilution step. By the addition of the "intermediate dilution" of minerar nutrients and the algal inoculation the final nominal concentrations were achieved. For the inoculated test solutions with the test item, as well as those without any test item, 7 parallals (main test) were incubated under constant light. As reagents' Blank without algal inoculation three test solutions were prepared containing a 1:10 diluted intermediate dilution of the mineral nutrients stock solution instead of the algal pre-culture. Theseblanks were incubated under the same conditions under constant light as the test solution to be tested. The measured turbidity in those test solutions was subtracted from those with the algal inoculation. ln the same way, seven control solutions without any test item but with algal inoculation were prepared as weil as one test solution without any test item and without algal inoculation.

Test organisms

Test organisms (species):

other: Desmodesmus subspicatus CHODAT

Details on test organisms:

Origin: Sammlung von Algenkulturen, Pflanzenphysiologisches Institut der Universität Göttingen [SAG], Strain-No. 86.81.

Study design

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

Temperature was controlled by means of a min/max-Thermometer and registered additionally by means of a data Iogger. The temperature range registered by the data Iogger is documented below as a graph. The temperature measured during this test was in the range of 24.6 and 25.3°C (mean 24.9°C) and thus in the required range of the OECD-test guideline.

pH:

8.1 - 9.6
pH values increased during the course of the study upon growth of the algae. This increase of pH in the controls by 1.41 units was in the required range of s 1.5 units indicated in OEGD test guideline 201.

Nominal and measured concentrations:

0 and 100 mg/l
As a result of the supporting analyse it can be stated that the measured concentration of nominally 100 mg/L remained stable >98% during incubation and thus, the results of the biological part should be based on the nominal concentrations applied because the necessary stability of ~ 80% could be shown.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The validity criteria for the study as given by the OECD-Test Guideline 201 were all met and the study is therefore considered to be valid.
EC50 > 100 mg/l

Executive summary:

The toxicity of Chlorobutanol Hemihydrate towards algae was tested according to OECD-Test Guideline No. 201, in the Version dated 23-March-2006. The toxic effect was investigated by determination of the inhibition of the growth rate of the algae and the yield during the exposure period of 72 hours. The test was performed as a Iimit test using 100 mg/L as the sole nominal concentration.