Dibutyl carbonate

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

2011

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Dibutyl carbonate

EC Number:

208-816-0

EC Name:

Dibutyl carbonate

Cas Number:

542-52-9

Molecular formula:

C9H18O3

IUPAC Name:

dibutyl carbonate

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Analytical evaluation of the test concentrations of Dibutyl
carbonate and the control was carried out from freshly prepared
media after 0 hours (with algae) and old test media after 72 hours
(with algae). Separate replicates for each test item concentration
and control for the test item analysis at the beginning of the exposure
were prepared with algae. The samples for the test item analysis
after 72 hours were prepared with algae and incubated under test
conditions. Samples were delivered in the original test vessels (59
mL, without headspace). The analyses were performed on the same
day. One additional retain sample was taken for each test
concentration on each occasion in the same way and stored at room
temperature for an additional analysis in case of inconclusive
results. In this study the retain samples of the test concentration
100 mg/L were analysed additionally after a maximum storage
period of three days.

Test solutions

Vehicle:

no

Details on test solutions:

Five stock solutions with a dilution factor of '110 (1.00 - 3.16-
10.0 -31.6 - 100 mg/L) were freshly prepared by pipetting the
test item to the dilution water (see Table 2). The density was
taken into account.
The stock solutions were stirred for 15 minutes at 1100 rpm,
room temperature. After this, the solution were left to stand for 30
minutes and were carefully checked for turbidity or a surface
layer. At all concentration levels no turbidity or surface layer was
observed.

Test organisms

Test organisms (species):

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

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

26.7 CaCO3 mg/L

Test temperature:

22-23°C

pH:

8.0-9.3

Salinity:

0.8 mmol/L

Conductivity:

180 pS/cm

Nominal and measured concentrations:

The measured concentrations of item Dibutyl carbonate at the start of the exposure (0 h) were in
the range of 58 to 102% of the nominal concentrations without a concentration-related tendency.
At the end of the exposure (72 h), the measured concentrations of item Dibutyl carbonate were
in the range of 63 to 83% of the nominal concentrations and in the range of 80 - 133% of the
initial measured concentration. Since not all measured test item concentrations were within ± 20%
of the nominal concentrations, the contents of item Dibutyl carbonate were evaluated as
geometric mean measured concentrations.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

10.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL 9.43 - 11.7

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

5.43 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 94% CL 4.12 -6.70

Details on results:

It cannot be excluded that the effects were partly caused by undissolved test item.

Results with reference substance (positive control):

ErC50 = 0.559 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes