Reaction mass of Dimethyl [3-[(hydroxymethyl) amino]-3-oxopropyl] phosphonate and Dimethyl (3-amino-3-oxopropyl)phosphonate

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:

27.05.1992-05-27 - 03.09.1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Specific details on test material used for the study:

Name: FAT 80'001/I
Purity: see analytical certificate in sponsor's file
Batch No.: 746916/1991
Expiration date: September 1996
Solubility in water: > 50 g/l at 20 °C
Stability in water: >2 hours
Aggregate state at
room temperature: liquid
Colour: clear
Storage: At room temperature

Analytical monitoring:

yes

Details on sampling:

At the start of the test a sample from the freshly prepared stock solution and threefold samples from the freshly prepared test media (without algae) of all test concentrations and from the control were taken. For the determination of the stability of the test substance under test conditions, parts of these freshly prepared test media were incubated under the same conditions as in the actual test (but without algae) and sampled threefold at the end of the test (after 72 hours test period). Additionally, three samples were taken at the end of the test out of all test media of the actual test.

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

The test organism used for the study was Scenedesmus subspicatus CHODAT, Strain No. 86.81 SAG, supplied by the Sammlung von Algenkulturen, Pflanzenphysiologisches Institut der Universität Göttingen, D-3400 Göttingen, F.R.G. The algae were grown in the laboratories of RCC under standardized conditions according to the OECD Guideline No. 201.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23.0 - 23.3 °C

pH:

At the start of the test, the pH-values in the test media were in the range of pH 7.5 to 7.7, at the end of the test pH-values were measured between pH 8.2 and 10.5. This increase of the pH-values in the control and the lower test concentrations was obviously caused due to the consumption of CO2 by algae during their rapid growth respectively their high densities (although the test flasks have been intensively stirred). No remarkable observations were made concerning the behaviour of the test substance in the test media.

Nominal and measured concentrations:

0, 10.0, 32.0, 100, 320 and 1000 mg test substance/l

Details on test conditions:

The algae were cultivated and tested in synthetic test water prepared according to the OECD Guideline No. 201. The test was started (0 hours) with a biomass of nominal 10000 cells per ml test solution. These cells were taken from a preculture, which was set up 72 hours prior to the test at the same conditions as in the test.

The test design included three replicates per test concentration and six replicates in the control. Per replicate 50 ml algal suspension were continuously stirred by magnetic stirrers in 100 ml Erlenmeyer flasks. The flasks were covered with glass dishes. They were incubated in a temperated water bath and continuously illuminated at a mean measured light intensity of 7948 Lux, range: 7000 to 8720 Lux. This illumination was achieved by
fluorescent tubes (universal white L 25, 36 W), installed above the water bath in a distance of about 35 cm from the algae flasks. The test duration was 72 hours.
As a means of detecting unsatisfactory test conditions, the reference substance Potassium Dichromate p.A. has been periodically tested (at least twice a year).

Dosage and concentrations
A stock solution was prepared just before the start of the test by dissolving the test substance in test water (10.0 g/l). Adequate amounts of the stock solution were added to test water to prepare the following nominal concentrations: 10.0, 32.0, 100, 320 and 1000 mg test substance/l and a control (test water without any additions).
The test concentrations were based on the results of a range finding study.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

14 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

72.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

371.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

50.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

184.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

675.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results:

In the control the cell density has increased from nominal N = 1 *10⁴ cells/ml at the start of the test (0 hours) to N = 74.0. * 10⁴ cells/ml (mean value) after 72 hours by a factor of about 74.

The test substance DMPPA_701-402-5 had a statistically significant inhibition effect on the growth of Scenedesmus subspicatus first at the nominal concentration of 100 mg test substance/l. Thus, this concentration was determined as LOEC (lowest concentration tested with toxic effects). The EC0 (= NOEC: highest concentration tested without toxic effects) after a test period of 72 hours was determined at the nominal concentration of 32.0 mg test substance/l, since up to and including this test concentration the mean algal growth rates were not significantly lower than in control. In the highest test concentration of nominal 1000 mg test substance a decrease of the cell numbers was observed after 48 to 72 hours incubation time. At the microscopical examination of the shape of the algal cells no difference was observed between the algae in the test concentration of nominal 100 mg test substance/l and the algal cells in the control. At the start of the test, the pH-values in the test media were in the range of pH 7.5 to 7.7, at the end of the test pH-values were measured between pH 8.2 and 10.5. This increase of the pH-values in the control and the lower test concentrations was obviously caused due to the consumption of CO2 by algae during their rapid growth respectively their high densities (although the test flasks have been intensively stirred). No remarkable observations were made concerning the behaviour of the test substance in the test media. In the stock solution 102 % of the nominal value of the test substance concentration was measured. In the analysed test media without algae test substance concentrations were measured in the range of 80.3 to 112.5 % of the nominal values. The mean values of these samples, taken at the start and the end of the test, varied in the range of 93.3 to 105.3 % of the theoretical concentrations. Thus, in the test media, incubated under test conditions (but without algae), the test substance was sufficiently stable. However, in the samples from the test solutions, taken out of the actual test after 72 hours, a strong decrease of the test substance concentration to about 20 % of the nominal value was observed in the two lowest test concentrations of 10 and 32 mg/l. This loss decreased with increasing test concentrations. In the two highest test concentrations of nominal 320 and 1000 mg/l no significant loss was observed. Thus, the observed loss in the test solutions of the lower test concentrations was obviously caused by adsorption and/or accumulation of the test substance on the algal cells. The amount adsorbed or accumulated was obviously depending on the algal density. All reported results are related to the nominal concentrations of the test substance. The observed disappearence of the test substance from the water into the algal biomass was not taken into consideration at the calculation of the biological results, since the assessment of such effects is unclear.

Influence of the test substance on algae growth: area under growth curve A and percentage inhibition of A

Conc mg/l	72 h
	A	%
control	1821	0.0
10	1548	15.0
32	1711	6.0
100	664	63.5
320	74	96.0
1000	79	95.7

Influence of the test substance on algae growth: growth rate u (1/day) and percentage inhibition of u

Conc mg/l	72 h
	u	%
control	1.43	0.0
10	1.40	2.1
32	1.43	0.1
100	1.10	23.2
320	0.28	80.1
1000	0.11	92.4

Validity criteria fulfilled:

yes

Conclusions:

The test item has no acute toxic effect to algae.

Executive summary:

The influence of FAT 80'001/I on the growth of the green alga Scenedesmus subspicatus Chodat was investigated in a 72-hour static test according to the OECD Guideline No. 201, adopted June 7, 1984 and the Official Journal of the European Communities, No. L 133/89-94, May 30, 1988. The test was performed in compliance with Good Laboratory Practice Regulations. The nominal test concentrations were 10.0, 32.0, 100, 320 and 1000 mg test substance/l and a control. The test substance DMPPA_701-402-5 had a statistically significant inhibition effect on the growth of Scenedesmus subspicatus first at the nominal concentration of 100 mg test substance/l (= LOEC: lowest concentration tested with toxic effects). The EC0 (= NOEC: highest concentration tested without toxic effects) after a test period of 72 hours was determined at the nominal concentration of 32.0 mg test substance/l, since up to and including this test concentration the mean algal growth rates were not significantly lower than in control. The inhibition rate was calculated for both growth parameter, the algae biomass and the growth rate.

Biomass (determined as the area under the growth curve):

EC50 (0 - 7 2 h) 72.2 mg test substance/l

EC10 (0 - 72 h) 14.0 mg test substance/l

EC90 (0 - 72 h) 371.5 mg test substance/l

Growth rate

EC50 (0 - 72 h) 184.8 mg test substance/l

EC10 (0 - 72 h) 50.6 mg test substance/l

EC90 (0 - 72 h) 675.1 mg test substance/l

In the test media without algae test substance concentrations were measured in the range of 80.3 to 112.5 % of the nominal values. The mean values of these samples, taken at the start and the end of the test, varied in the range of 93.3 to 105.3 %. Thus, in the test media, incubated under test conditions (but without algae), the test substance was sufficiently stable. However, in the test solutions of the actual test after 72 hours, a strong decrease of the test substance concentration to about 20 % of the nominal value was observed in the two lowest test concentrations of 10 and 32 mg/l. This loss decreased with increasing test concentrations. In the two highest test concentrations of nominal 320 and 1000 mg/l no significant loss was observed. Thus, the observed loss was obviously caused by adsorption and/or accumulation of the test substance on the algal cells and the amount adsorbed or accumulated was obviously depending on the algal density. All reported results are related to the nominal concentrations of the test substance. The observed disappearance of the test substance from the water into the algal biomass was not taken into account for the calculation of the biological results.

Description of key information

The influence of DMPPA_701-402-5 on the growth of the green alga Scenedesmus subspicatus Chodat was investigated in a 72-hour static test according to the OECD Guideline No. 201, adopted June 7, 1984 and the Official Journal of the European Communities, No. L 133/89-94, May 30, 1988. The test was performed in compliance with Good Laboratory Practice Regulations. The nominal test concentrations were 10.0, 32.0, 100, 320 and 1000 mg test substance/l and a control. The test substance FAT 80'001/I had a statistically significant inhibition effect on the growth of Scenedesmus subspicatus first at the nominal concentration of 100 mg test substance/1 (= LOEC: lowest concentration tested with toxic effects). The EC0 (= NOEC: highest concentration tested without toxic effects) after a test period of 72 hours was determined at the nominal concentration of 32.0 mg test substance/1, since up to and including this test concentration the mean algal growth rates were not significantly lower than in control. The inhibition rate was calculated for both growth parameter, the algae biomass and the growth rate.

Biomass (determined as the area under the growth curve):

EC50 (0 - 7 2 h) 72.2 mg test substance/l

EC10 (0 - 72 h) 14.0 mg test substance/l

EC90 (0 - 72 h) 371.5 mg test substance/l

Growth rate

EC50 (0 - 72 h) 184.8 mg test substance/l

EC10 (0 - 72 h) 50.6 mg test substance/l

EC90 (0 - 72 h) 675.1 mg test substance/l

As a result, the test item has no toxic effect to algae.

Key value for chemical safety assessment

EC50 for freshwater algae:

184.8 mg/L

EC10 or NOEC for freshwater algae:

50.6 mg/L