(3H)-benzofuran-2-one

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:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to current OECD-Guideline and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-Coumaranone 100

IUPAC Name:

2-Coumaranone 100

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

In addition to the analysis of the test item, concentrations of the hydrolysis product AOHPA were determined in the test media.

For measurement of the actual concentrations of the test item 2-Coumaranone 100 and hydrolysis product AOHPA, duplicate samples were taken from the test media of all test concentrations at the start of the test (without algae) and at the end of the test (containing algae). At the same sampling times, duplicate samples were also taken from the control.

For sampling at the end of the test, the test medium of the treatment replicates was pooled.

All samples were stored deep-frozen (at about -20 °C) immediately after sampling until analysis.

The concentrations of the test item 2-Coumaranone 100 and hydrolysis product AOHPA were determined in the duplicate test medium samples from the nominal test concentrations of 3.2 to 100 mg/L. The samples from the nominal test concentration of 1.0 mg/L were not analyzed, since this concentration was below the NOEC determined in this test. From the control samples, one of the duplicate samples was analyzed from the corresponding sampling times.

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

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

Details on test organisms:

The test organism used for the study was Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum), Strain No. 61.81 SAG, supplied by the Collection of Algal Cultures (SAG, Institute for Plant Physiology, University of Göttingen, 37073 Göttingen / Germany). The algae were cultivated at Harlan Laboratories under standardized conditions according to the test

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

24 mg/L as CaCO3

Test temperature:

22 C

pH:

Nominal
test item concentration pH values
(mg/L) Start End
Control 8.2 9.3
1.0 8.2 9.2
3.2 8.2 9.1
10 8.1 9.0
32 8.0 8.7
100 7.4 6.3

Nominal and measured concentrations:

The biological results were related to the mean measured test item concentrations (based on 2-Coumaranone 100 equivalents):

Nominal test concentration Mean measured concentration of the test item
(geometric mean)
(mg/L) (mg/L) (% of nominal)
1.0 --- ---
3.2 0.45 14
10 0.80 8
32 2.3 7
100 86 86

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: 2-Coumaranone 100 equivalents

Basis for effect:

growth rate

Remarks on result:

other: 0.66-1.8 mg/L

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

60 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: 2-Coumaranone 100 equivalents

Basis for effect:

growth rate

Remarks on result:

other: 44-86 mg/L

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.39 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: 2-Coumaranone 100 equivalents

Basis for effect:

biomass

Remarks on result:

other: 0.15-0.59 mg/L

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: 2-Coumaranone 100 equivalents

Basis for effect:

biomass

Remarks on result:

other: 1.3-2.7 mg/L

Details on results:

The measured concentrations of 2-Coumaranone 100 (based on 2-Coumaranone 100 equivalents calculated from the measured concentrations of AOHPA and 2-Coumaranone 100) in the test media of the nominal test concentrations of 3.2 to 100 mg/L were between 94 and 102% of the nominal values at the start of the test. During the test period of 72 hours, a decrease of test item concentration in the test media occurred. At the end of the test, the test item concentrations of the nominal test concentrations of 3.2 and 10 mg/L were below LOQ (limit of quantification, LOQtest item: 0.133 mg/L). At the two next higher concentrations, 1 to 73% of the nominal values were found, respectively. The mean measured test concentrations (calculated as the geometric means of the concentrations measured at the start and end of the test) were between 7 and 86% of the nominal values.

The quantification was made based on the analysis of 2-Coumaranone and its degradation product AOHPA.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The test item had a inhibitory effect on the growth of the algae after the test period of 72 hours. The 72-hour EC10 (growth rate) was determined to be the mean measured concentration of 1.2 mg/L. The 72-hour EC50 (growth rate) was determined to be the mean measured concentration of 60 mg/L.