Methyl carbamate

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:

From December 4, 1986 to December 8, 1986

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to OECD Guideline 201, in compliance with GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Methyl carbamate

EC Number:

209-939-2

EC Name:

Methyl carbamate

Cas Number:

598-55-0

Molecular formula:

C2H5NO2

IUPAC Name:

methyl carbamate

Test material form:

other: solid

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Organism:Selenastrum capricornutum
- Strain no. 22662
- Source: American type culture collection

Study design

Test type:

static

Total exposure duration:

96 h

Test conditions

Test temperature:

21 - 22°C

pH:

6.4 - 6.7

Nominal and measured concentrations:

0, 180, 320, 560, 1,000 and 1,800 ppm

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL glass capped flasks
- Initial cells density: 1x10^4 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- Shaking culture was used for incubation

GROWTH MEDIUM
- Standard medium used: Sterile OECD Algal Medium (100 mL/flask)

Special Preparation/ Precautions:
(1)Sample diluted in distilled water v/v was stored in dark until used.
(2)Test concentration was established with pipettes and direct addition of dilutions

OTHER TEST CONDITIONS
- Photoperiod: continuous light
- Light intensity: 8000 lux

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

414 other: ppm

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: Correlation coefficient r^2 = 0.69

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

512 other: ppm

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: Correlation coefficient r^2 = 0.89

Effect concentrations 3

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

598 other: ppm

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: Correlation coefficient r^2 = 0.97

Effect concentrations 4

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

126 other: ppm

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: Correlation coefficient r^2 = 0.69

Effect concentrations 5

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

232 other: ppm

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: Correlation coefficient r^2 = 0.89

Effect concentrations 6

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

334 other: ppm

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: Correlation coefficient r^2 = 0.97

Any other information on results incl. tables

Table 1: Number of cells per mL x 10⁴

	48 h			72 h			96 h
	1	2	3	1	2	3	1	2	3
Control	55	43	45	131	110	128	292	280	252
x	48			123			270
180 ppm	26	28	35	117	123	140	310	320	268
x (%I)	30 (38%)			127 (0%)			299 (0%)
320 ppm	39	38	36	90	121	104	220	280	312
x (%I)	38 (22%)			105 (15%)			270 (0%)
560 ppm	40	40	15	80	65	88	180	182	174
x (%I)	32 (35%)			78 (37%)			179 (34%)
1,000 ppm	Less than 10			No viable cells			No viable cells
x (%I)	>79%			100%			100%
1,800 ppm	No viable, countable cells

Repeat: 1,000 ppm confirmed lack of growth confirmed

Note: Inoculum of 1 x10⁴ cells/mL at "0" time; cell counts at 24 h recorded as less than 10x10⁴ for all flasks. Cell growth was insufficient at 24 h to establish concentration effect relationships for all concentrations and for the blank control. The median effect, therefore, could not be calculated for that period.

x- Mean

%I - percent inhibition relative to control per time period

pH =pH of all flasks ranged 6.4 - 6.7, including control at start and finish of test.

As indicated by the calculated correlation coefficient above, the better estimate of the median algal inhibitory concentration was derived from 72 - 96 h data. This was due to more developed cell growth with time and thus better enumeration and differentiation among test concentrations

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48 h, 72 h and 96 h EbC50 of test substance for Selenastrum capricornutum were 414, 512 and 598 ppm. The 48 h, 72 h and 96 h NOEC for effect on algal growth was determined to be 126, 232 and 334 ppm.

Executive summary:

A study was conducted to evaluate the toxicity of the test substance to algae Selenastrum capricornutum under static conditions according to OECD Guideline 201, in compliance with GLP. On basis of preliminary range finding study, test concentrations were selected and test organisms were exposed to 0, 180, 320, 560, 1,000 and 1,800 ppm in 3 replicates per concentration. Incubation was done at 21 – 22⁰C in a shaking culture. Cell growth was insufficient at 24 h to establish concentration effect relationships for all concentrations and for the blank control. The median effect, therefore, could not be calculated for that period. Due to more developed cell growth with time and thus better enumeration and differentiation among test concentrations, the better estimate of the median algal inhibitory concentration was derived from 72 - 96 h data. All the validity criteria were met in this test. Percent growth was plotted versus log of concentration. Linear regression analysis was used to calculate E_bC50 and NOEC. Under the study conditions, the 48 h, 72 h and 96 h E_bC50 of test substance for Selenastrum capricornutum were 414, 512 and 598 ppm. The 48 h, 72 h and 96 h NOEC for effect on algal growth was determined to be 126, 232 and 334 ppm (Drozdowski D, 1987).