Dimethyl carbonate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 November 2000 to 1 December 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study conducted according to recognised guideline. No significant deviations reported.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

samples were withdrawn from the treatment solutions at 0 and 72 hours. Concentrations of the test article were determined by a GC chromaotographic method of analysis.

Storage conditions and times not recorded.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Weighed amount (25 mg) of DIMETILCARBONATO was added to 250 ml of
algal growing medium in order to obtain a final nominal concentration of 100 mg/L.
Suitable volumes of this solution were directly introduced into study vessels.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: Supplier: laboratory breeding algae cultured from the line purchased from CCAP
Culture Collection of Algae and Protozoa, Institute of FreshWater Ecology,
Windermere Laboratory, Far Sawrey, Ambleside, Cumbria LA22 OLP.
-Culturing apparatus : Algae were cultured in a chamber with a temperature range of
24 ± 2° C and with continuous uniform illumination of approximately 8000 Lux in
the spectral range 400-700 nm.
-Culturing medium: the algae were cultured in the double- strength EPA algal assay
medium (EPAl600/4-85/014, Section 14,method 1003.0).

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

none

Hardness:

not stated

Test temperature:

not recorded

pH:

T0: 7.6
T72: 9.0/9.1

Dissolved oxygen:

not recorded

Salinity:

not recorded

Nominal and measured concentrations:

Nominal concentration test article 0 and 100 mg/L
Measured concentrations:
Control 0 h: 0 mg/L
0 h 100 mg/L: 70.26 mg/L
72 h 100 mg/L without algae: 73.04 mg/L
72 h 100 mg/L with algae: 46.72 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open / closed: closed (orbital shaker used)
- Material, size, headspace, fill volume: glass, 100 mL
- Aeration: not stated
- Type of flow-through (e.g. peristaltic or proportional diluter): static
- Renewal rate of test solution (frequency/flow rate): static
- Initial cells density: 10,000 cells/mL
- Control end cells density:
- No. of organisms per vessel:
- No. of vessels per concentration (replicates): three
- No. of vessels per control (replicates): six
- No. of vessels per vehicle control (replicates): not applicable


GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used:


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Culture medium different from test medium: no
- Intervals of water quality measurement: 72 h


OTHER TEST CONDITIONS
- Sterile test conditions: yes/no: not stated
- temperature: 24 +/- 2C
- Photoperiod: continuous
- Light intensity and quality: 8000 Lux spectral range 400 - 700 nm



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : cell concentrations counted 24, 48 and 72 h after start of study
- Determination of cell concentrations: microscope with counting chamber
- Chlorophyll measurement: not done
- Other:


TEST CONCENTRATIONS
- Spacing factor for test concentrations: limit test
- Justification for using less concentrations than requested by guideline: not applicable
- Range finding study
- Test concentrations: not reported
- Results used to determine the conditions for the definitive study: not reported

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: EbC50

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: ErC50

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: NOEC (b)

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: NOEC (r)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 57.29 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

biomass

Remarks on result:

other: EbC50

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 57.29 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Remarks on result:

other: ErC50

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 57.29 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

biomass

Remarks on result:

other: NOEC (b)

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 57.29 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Remarks on result:

other: NOEC (r)

Details on results:

- Exponential growth in the control (for algal test): not stated

Reported statistics and error estimates:

EbC50, ErC50 and its statistical limits were not calculated

Test article concentrations

Time (h)	Nominal concentration test article (mg/L)	Mean measured concentration test article (mg/L)
0	100	70.26
72 without algae	100	73.04
72 with algae	100	46.72

Cell densities - Control 0 mg/L

	Cell density 104 cells/ml
	T(0)0	T(1)24	T(n-1)48	T(n)72
	0.32	1.56	7.81	64.84
	0.32	1.56	7.03	85.16
	0.32	1.56	7.81	63.28
	0.32	2.34	7.03	69.53
	0.32	1.56	7.03	72.66
	0.32	1.56	7.81	73.45
	N(0)	N(1)	N(n-1)	N(n)
	0.32	1.69	7.42	71.49
pH	7.6	-	-	9.1
Mean area under growth curve A	-	16.44	118.08	1057.28
Mean specific growth curve rate µ	-	0.069	0.065	0.075

 

Cell densities - 100 mg/L

	Cell density 10^4cells/ml
	T(0)0	T(1)24	T(n-1)48	T(n)72
	0.32	1.56	8.59	91.41
	0.32	2.34	7.81	67.19
	0.32	2.34	7.81	92.19
	N(0)	N(1)	N(n-1)	N(n)
	0.32	2.08	8.07	83.60
pH	7.6	-	-	9.0
Mean area under growth curve A	-	21.12	135.24	1227.56
% inhibition: IA	-	-28.47	-14.53	-16.11
Mean specific growth curve rate µ	-	0.078	-0.067	0.077
% mean specific growth rate inhibition: I µ	-	-12.48	-2.67	-2.89

Validity criteria fulfilled:

no

Remarks:

Data available but required calculations not made

Conclusions:

Experimental data from an algal inhibition growth study in which the unicellular green algae Selenastrum capricomutum were treated with the test article dimethylcarbonate at the nominal concentration of 100 mglL are given in this report.

After 72 h exposure time EbC, ErC NOEC (b) and NOEC (r) were higher than the nominal concentration 100 mgIL (57.29 mg/L mean measured concentrations).

Description of key information

Experimental data from an algal inhibition growth study in which the unicellular green algae Selenastrum capricornutum were treated with the test article dimethylcarbonate at the nominal concentration of 100 mg/L are given in this report. After 72 h exposure time EbC5o, ErC5o NOEC (b) and NOEC (r) were higher than the nominal concentration 100 mg/L (57.29 and 71.64 mg/L measured concentrations).

Key value for chemical safety assessment

EC50 for freshwater algae:

57.29 mg/L

EC10 or NOEC for freshwater algae:

57.29 mg/L

Additional information

.