Guanidinium nitrate

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:

30.11.2009 - 17.03.2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

EC regulation 761/2009

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

sampling at the beginning (t=0h) and at the end of testing (t=72h)

Vehicle:

no

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: ATCC (Amerian Type Culture Collection) 22662
- Source (laboratory, culture collection): LGC Promochem GmbH, Wesel, Germany
- Age of inoculum (at test initiation): 4 days
- Method of cultivation: continiously maintained in cornical flasks containing nutrient medium at 21 to 24°C , continious light 4400-8800lux

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Test temperature:

21°C

pH:

7.3-7.4 (start in test cultures)
7.2 (start in control cultures)
7.5-9.9 (after 72h in test cultures)
9.7 (after 72h in control cultures)

Nominal and measured concentrations:

nominal concentrations: 0.39, 0.78, 1.56, 3.13, 6.25, 12.50, 25.00, 50.00, 100.00mg/L
measured concentrations: 0.38, 0.75, 1.42, 2.83, 6.86, 12.37, 24.69, 50.38, 100.53 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): cornical flasks (Erlenmeyer)
- Material, size, headspace, fill volume: 250ml, 100ml fill volume
- Initial cells density: 10000/ml
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6



GROWTH MEDIUM
- Standard medium used: yes


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: continiously
- Light intensity and quality: 5193lux +-14%



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: determined by Casy Cell Counter, Model DT, Schärfe System GmbH, Germany (pore size:60micro m)



TEST CONCENTRATIONS
- Test concentrations: 0, 0.39, 0.78, 1.56, 3.13, 6.25, 12.50, 25.00, 50.00, 100.00mg/L nominal concentrations

Reference substance (positive control):

yes

Remarks:

K2Cr2O7

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

6.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

6.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

11.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

33.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

72 hr EC50 growth rate: 0.87mg/L K2Cr2O7
72 hr EC50 yield: 0.65mg/L K2Cr2O7

Mean yield, average specific growth rates and percent inhibition:

 

Nominal test substance conc. (mg/L)	Yield (cells x 10^3/ml)    0-72h		Growth rate (per day)   0-72h		Percent Inhibition based on
	Mean	SD	Mean	SD	yield	growth rate
0 (control)	855.0	104.3	1.48	0.04	0.0	0.0
0.39	827.9	147.2	1.47	0.06	3.2	0.9
0.78	876.1	110.4	1.49	0.04	-2.5	-0.5
1.56	964.9	110.1	1.52	0.04	-12.9	-2.7
3.13	833.4	241.3	1.46	0.11	2.5	1.5
6.30	889.0	201.8	1.49	0.08	-4.0	-0.4
12.50	371.1	32.3	1.21	0.03	56.6	18.3
25.00	120.5	15.7	0.85	0.04	85.9	42.5
50.00	51.3	21.4	0.58	0.11	94.0	60.6
100.00	6.8	0.9	0.17	0.02	99.2	88.4

Validity criteria fulfilled:

yes

Conclusions:

Test Organism: Pseudokirchnerella subcapitata Test Type: Static
Based on yield/growth rate: 72hr EC50: 11.8 mg a.i./L
72 hr NOEC, based on yield: 6.3mg a.i./L; based on growth rate: 33.5 mg a.i./L
Endpoint Effected: toxicity to aquatic algae and cyanobacteria

Executive summary:

In a 72 hour acute toxicity study, the cultures of Pseudokirchneriella subcapita were exposed to Guanidine Nitrate at nominal concentrations of 0, 0.39, 0.78, 1.56, 3.13, 6.25, 12.50, 25.00, 50.00, and 100.00 mg a.i./L under static conditions in accordance with the EC regulation 761/2009 Part C.3.

The 72h-EC50 values based on yield ( and growth rate) were 11.8mg a.i./L (11.8 mg a.i./L) and

the 72h-NOEC values based on yield (and growth rate) were 6.3 mg a.i./L (33.5 mg a.i./L), respectively.

This toxicity study is classified as acceptable and satisfies the guideline requirements for algal growth inhibition test.

 

Results Synopsis

Test Organism: Pseudokirchnerella subcapitata Test Type: Static

Based on yield/growth rate: 72hr EC50: 11.8 mg a.i./L

72 hr NOEC, based on yield: 6.3mg a.i./L; based on growth rate: 33.5 mg a.i./L

Endpoint Effected: toxicity to aquatic algae and cyanobacteria

Description of key information

In a 72 hour acute toxicity study, the cultures of Pseudokirchneriella subcapita were exposed to Guanidine Nitrate.

The 72h-EC50values based on yield ( and growth rate) were 6.3mg a.i./L (6.3 mg a.i./L) and the 72h-NOEC values based on yield (and growth rate) were 11.8 mg a.i./L (33.5 mg a.i./L), respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:

33.5 mg/L

EC10 or NOEC for freshwater algae:

6.3 mg/L

Additional information

In a 72 hour acute toxicity study (Seibersdorf, 2010), the cultures of Pseudokirchneriella subcapita were exposed to Guanidine Nitrate. The 72h-EC50 values based on growth rate (yield) were 33.5mg a.i./L (11.8 mg a.i./L) and the 72h-NOEC values based on yield (and growth rate) were 6.3 mg a.i./L, respectively.

The study was performed under static conditions in accordance with the EC regulation 761/2009 Part C.3.