(R)-α-phenylethylammonium (-)-(1R, 2S)-(1,2-epoxypropyl)phosphonate monohydrate

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:

August 2, 1994 - August 5, 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 1 mg/l (0 h), 1 mg/l (72 h), 10 mg/l (72 h)
- Sampling method: Samples were removed from the vessels of the lowest and highest treatment level for analysis of Fosfomycin PEA salt. At 0 and 72 hours samples were removed from the lowest level (1 mg/l) while only a 72 hours sample was removed from the highest (10 mg/l). All samples were analysed by Istituo G. Donegani.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 10 mg of test article were made up to 1000 ml with algae culturing medium in order to obtain the concentration of 10 mg/l from which the remaining concentrations were prepared by dilution.
- Controls: Yes, 0 mg/l of test substance in water.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: ATCC 22662
- Source (laboratory, culture collection): American Type Culture Collection, 12301 Parklawn Drive - Rockville, Maryland 20852 USA.
- Age of inoculum (at test initiation): 3 days
- Method of cultivation: The algae were cultured in a chamber with a temperature range of 23 ± 2 ºC and with continuous uniform illumination of approximately 6000 Lux in the spectral range 400-700 nm. The algae were cultured in the double-strength EPA algal assay medium.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23 ± 2 ºC

pH:

7.53 - 8.35

Nominal and measured concentrations:

Nominal concentrations: 0 (control), 1, 1.8, 3.2, 5.6 and 10 mg/l
Measured concentrations: 0.97 (0 h - nominal concentration 1 mg/l), 0.93 (72 h - nominal concentration 1 mg/l) and 9.41 (72 h nominal concentration 10 mg/l)

Details on test conditions:

TEST SYSTEM
- Test vessel: Conical flasks
- Type (delete if not applicable): closed, stoppered with a cotton plug.
- Material, size, headspace, fill volume: Glass, 100 ml
- Aeration: Yes, the algae were kept in suspension by aeration.
- Initial cells density: 10000 cells/ml.
- Control end cells density: 239.67E+04 cells/ml
- No. of organisms per vessel: 10000 cells/ml
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes (double-strength EPA algal assay medium)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: double-strength EPA algal assay medium
- Culture medium different from test medium: No.
- Intervals of water quality measurement: pH was measured at 0 and 72 hours

OTHER TEST CONDITIONS
- Photoperiod: continuous uniform illumination
- Light intensity and quality: 6000 Lux in the spectral range 400-700 nm

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : growth of the unicellular green alga (cell concentration) at 24, 48 and 72 h.
- Determination of cell concentrations: Microscope with counting chamber

TEST CONCENTRATIONS
- Spacing factor for test concentrations: constant factor 1.8
- Range finding study: preliminary studies.
- Test concentrations: 0 (control), 1, 1.8, 3.2, 5.6 and 10 mg/l

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

31.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 24.4-44.4 (95% CL)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

4.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 4.52-4.73 (95% CL)

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

17.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 16.7-18.9 (95% CL)

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

5.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): No

Reported statistics and error estimates:

EC50 and its statistical limits by the modified probit method set up by the Flemish Institute for Technological Research (VITO).
NOEC by Dunnett's procedure.

Table 1. Summary of results.

Concentration	Parameter	24 h	48 h	72 h
0 mg/l	Mean area under the growth curve A	64.20	620.80	3967.60
	Mean specific growth rate µ	0.057	0.066	0.068
1 mg/l	Mean area under the growth curve A	47.60	449.60	2778.40
	% Growth inhibition IA	25.9	27.6	30.0
	Mean specific growth rate µ	0.049	0.060	0.063
	% Mean specific growth rate inhibition I µ	15.6	9.9	7.5
1.8 mg/l	Mean area under the growth curve A	47.60	425.60	2682.40
	% Growth inhibition IA	25.9	31.4	32.4
	Mean specific growth rate µ	0.049	0.058	0.063
	% Mean specific growth rate inhibition I µ	15.6	11.9	8.0
3.2 mg/l	Mean area under the growth curve A	44.40	411.20	2548.0
	% Growth inhibition IA	30.8	33.8	35.8
	Mean specific growth rate µ	0.047	0.058	0.062
	% Mean specific growth rate inhibition I µ	19.0	12.7	9.2
5.6 mg/l	Mean area under the growth curve A	44.40	371.20	2016.00
	% Growth inhibition IA	30.8	40.2	49.2
	Mean specific growth rate µ	0.047	0.055	0.058
	% Mean specific growth rate inhibition I µ	19.0	16.6	15.0
10 mg/l	Mean area under the growth curve A	41.2	368.80	1137.60
	% Growth inhibition IA	35.8	40.6	71.3
	Mean specific growth rate µ	0.044	0.055	0.044
	% Mean specific growth rate inhibition I µ	21.6	16.2	35.6

Validity criteria fulfilled:

yes

Remarks:

The cell density in the control culture was increased by a factor > 16 within three days. The concentrations of the test substance was maintained > 80 % of the initial concentration during the test.

Conclusions:

The EC50 value based on biomass for Selenastrum capricornutum at 24, 48 and 72 hours was >100, 31.7 and 4.6 mg/l respectively.
The NOEC value based on biomass for Selenastrum capricornutum was always less than the lowest concentration tested.
The EC50 value based on growth rate for Selenastrum capricornutum at 24 and 48 was >100 mg/l and 17.7 mg/l at72 hours
The NOEC value based on growth rate for Selenastrum capricornutum was 3.2, 5.6 and < 1 mg/l respectively.

Executive summary:

The study was performed to assess the effects of the test article Fosfomycin PEA salt on the growth of the unicellular fresh-water green alga Selenastrum capricornutum followed the EU Method C.3. Approximately 10000 cells/ml of algae for each replicate and 3 replicates for each concentration were exposed to test material at the nominal concentrations of 0 (control), 1, 1.8, 3.2, 5.6 and 10 mg/l. A static toxicity test procedure was followed. The algae were treated and observed at 24, 48 and 72 hours. A microscope with counting chamber was used to determine cell concentrations. The EC50 (based on biomass) at 24, 48 and 72 hours was >100, 31.7 and 4.6 mg/l respectively. The NOEC (based on biomass) was always less than the lowest concentration tested (<1 mg/l). The EC50 (based on growth rate) at 24 and 48 hours was >100 mg/l and at 72 hours was 17.7 mg/l. The NOEC (based on growth rate) at 24, 48 and 72 hours was 3.2, 5.6 and <1 mg/l respectively.

Description of key information

Key study: Test method according to EU Method C.3. GLP study.

The EC50 value (based on growth rate) for Selenastrum capricornutum at 72 hour exposure period was 17.7 mg/l and the NOECD < 1 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

17.7 mg/L

EC10 or NOEC for freshwater algae:

1 mg/L

Additional information

Key study: Test method according to EU Method C.3. GLP study. The EC50 value (based on growth rate) for Selenastrum capricornutum at 72 hour exposure period was 17.7 mg/l and the NOEC < 1 mg/L.