1-amidino-2-thiourea

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)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-amidino-2-thiourea

EC Number:

218-308-0

EC Name:

1-amidino-2-thiourea

Cas Number:

2114-02-5

Molecular formula:

C2H6N4S

IUPAC Name:

1-(Diaminomethylidene)thiourea

Test material form:

solid: crystalline

Specific details on test material used for the study:

Manufacturer: Anhui Shindo Chemical CO. LTDSupplier: Changzou Foreign Trade Corp.Batch number: 0102A26 (20151203)Physical state: Solid, crystalline substanceColour: WhiteStorage: in a cool, dry place, protected from light

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

Seven test solutions of different concentration were prepared by mixing appropriate volume of OECD medium and stock solution of the test item. The maximum separation factor between of test vessels was 1.5. Two additional replicates were prepared for controlling the abiotic degradation of the test substance. These test vessels were not inoculated with alga inoculum culture. The following table shows the preparation of test solutions. The volume of the prepared dilution levels was 300 ml except the control solution which was 600 ml.

Test organisms

Test organisms (species):

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

Details on test organisms:

Test species: Pseudokirchneriella subcapitata(Korshikov) F.Hindák(formerly known asSelenastrum capricornutum)Source: UTEX The Culture Collcetion of Algae (USA)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

The temperature inside the incubator at the test vessels was measured and registered continuously by Extech SD200 thermometer and datalogger. Throughout the test the temperature was nearly constant.

pH:

At the beginning of the test the pH values were measured in the remaining test solution of the concurrent test vessels at each dilution level. At the end of the test the pH values were measured in each test vessel. The pH of test solutions was not adjusted at the beginning of the test.

Nominal and measured concentrations:

The nominal concentration of the stock solution was 200 mg/L. In the test the following nominal concentrations were applied: 200; 180; 160; 140; 120; 80 and 60 mg/L.The following concentrations were calculated from the measured values and were applied for the statistical evaluation in the test: 205.10; 163.97; 142.27; 122.42; 80.26 and 60.32 mg test item/L. The test item concentrations of the abiotic controls were 203.77 (in light) and 204.05 (in darkness) mg/L.

Details on test conditions:

The test vessels were closed with silicone stopper and kept in the Binder KBW 400 incubator. For the proper mass transfer of carbon dioxide glass tubes with filter were placed trough silicone stoppers. The test was maintained under static conditions for a period of 72 hours. The temperature during the test remained in the 21 ± 2 °C range. The temperature data were harvested by Extech SD200 datalogger. The vessels were shaken and illuminated continuously in the incubator. The vessels were placed randomly into the incubator and were repositioned daily after sampling. One of the vessels of abiotic controls was taken into the incubator with a complete aluminium foil cover to check the stability of test item in the absence of light.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

103.18 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

137.02 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

235.77 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Applicant's summary and conclusion

Conclusions:

According to the Council Regulation (EC) 440/2008 Amidinothiourea is not hazardous to the aquatic environment [72 hr EC50 (for algae or other aquatic plants) > 100 mg/L].