5,5'-(1H-isoindole-1,3(2H)-diylidene)dibarbituric acid

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

- Origin: SAG, Göttingen
- Cultivation at test facility: fresh stocks were prepared every month on Z-Agar; light intensity amounted to 35 - 70 µE*m-2*s-1 for 24 h per day
- Culture medium: nutrient medium Z according to LÜTTGE et al. (1994)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21 - 23 °C

pH:

7.58 - 10.22

Nominal and measured concentrations:

- Concentrations tested (mg/L): control, 0.625, 1.25, 2.5, 5, 10 (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: sterile Erlenmeyer flasks, volume: 250 ml (nominal)
- Fill volume: 100 ml (nominal)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

INOCULUM
- 3 d old preculture was used as inoculum
- Initial cell concentration of ca. 2 - 5E3 cells/mL

GROWTH MEDIUM
- Nutrient medium Z according to LÜTTGE et al. (1994)

OTHER TEST CONDITIONS
- Photoperiod: 24h/d light
- Light intensity: 60 - 120 µE*m-2*s-1
- Agitation: test flasks were placed on rotary shaker and oscillated at ca. 70 rpm.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate p.a. (Sigma)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

72 h EC10 >10 mg/L nominal test mat. growth rate
72 h EC20 >10 mg/L nominal test mat. growth rate

Reference 2

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: due to the low water solubility of the substance a saturated solution according to guideline OECD 23 The test substance (200.4 mg) was added to 2 l test medium. The mixture was placed in an ultrasonic bath for 5 minutes then stirred vigorously for about 3 days at 20 + 2 °C, to generate a saturated test solution. Undissolved test substance was removed by filtration (pore with 0.2 μm).

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): cultured at testing facility. The culture was originally obtained from the collection of algal cultures of the University of Göttingen /Germany

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

21 – 22 °C

pH:

8.0 - 8.4

Nominal and measured concentrations:

Nominal test substance concentration:
control, 100 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks (250 ml)
- Fill volume: 100 ml
- Initial cells density: 5000
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: the test medium was prepared according to the test guideline


OTHER TEST CONDITIONS
- Photoperiod: continous illumination
- Light intensity and quality: Artificial light, type universal white (OSRAM L 25), Light intensity: Average 5168 lux (within ±15% variability) at a wave length of 400 - 700 nm

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: cell counting (Neubauer haemocytometer)
- Chlorophyll measurement: in vivo-flourescence at a wave length of 432 nm


TEST CONCENTRATIONS
- Results used to determine the conditions for the definitive study: Ffluorescence C50 > 100 mg/l

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Reported statistics and error estimates:

Student’s t-test

Description of key information

With high probability acutely not harmful to aquatic algae.

Additional information

The effect of the substance on the growth rate of green algae was investigated in a guideline study according to OECD 201. After 72 hours of exposure a NOEC >= 100 mg/l was determined (BASF SE, 2008).