2',3,4',5,7-pentahydroxyflavone

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

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II) (January 2012)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2',3,4',5,7-pentahydroxyflavone

EC Number:

207-542-9

EC Name:

2',3,4',5,7-pentahydroxyflavone

Cas Number:

480-16-0

Molecular formula:

C15H10O7

IUPAC Name:

2',3,4',5,7-pentahydroxyflavone

Constituent 2

Reference substance name:

Morin

IUPAC Name:

Morin

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

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

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.83 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.77 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

9.77 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.05 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 5

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.04 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

& biomass

Effect concentrations 6

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

1.47 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

& biomass

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72-h EC50 was determined to be 9.77 mg/L (based in growth rate)

Executive summary:

The effect of the test item Morin was assessed on algal growth using the unicellular green alga Raphidocelis subcapitata (formerly known as Pseudokirchneriella subcapitata and Selenastrum capricornutum), over an exposure period of 72 hours.

Based on the results of a preliminary experiment, the calculated geometric mean test item concentrations (based on the analytical measurements) of 0.73, 1.04, 1.47, 19.21 and 53.68 mg/L were tested in the main study.

Exponentially-growing cultures of Raphidocelis subcapitata were exposed to the test item over several generations under defined conditions. The algal growth in relation to a control culture was determined over a fixed test period of 72 hours and, thus, over several algal generations. The test design included three replicates at each test concentration and six replicates for the untreated control. The alga cell concentration was approximately 104 cells/mL at the start of the test in all of the test cultures. Glass flasks with total capacity of 250 mL were used as test vessels. The volume of the test liquid in the vessels was 100 mL. The alga cell concentration was determined by microscope in each testing flask during the 72-hour test, in 24-hour intervals.

With respect to the inhibitory effect of the test item, the 0-72 h average specific growth rates and yield were significantly different from that of the control group in the concentrations of 1.47, 19.21 and 53.68 mg/L.

Accordingly the NOEC related to the average specific growth rates and yield was determined to be 1.04 mg/L and the LOEC was determined as 1.47 mg/L. The 72-h ErC50 was determined to be 9.77 mg/L and the 72-h EyC50 as 3.05 mg/L.