Ammonium formate

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:

2005-11-24 to 2005-12-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

adopted June 1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

IC

Details on sampling:

- Concentrations: 0, 76.8; 192; 480; 1200;and 3000 mg/L
- Sampling method: The samples were filtered with a 0.45 um sieve. The filtrates were injected to the IC System.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The highest test concentration was prepared by dissolving 3000 mg of the test item in 1L growth medium. This test item solution was subsequently diluted with growth medium by a factor of 2.5 to obtain the other test concentrations and the test solutions were distributed into the test vessels (test medium volume 100 mL each) per test concentration.
- Controls: yes, concurrent no treatment

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum)
- Source (laboratory, culture collection): SAG, Culture Collection of Algae at Pflanzenphysiologisches lnstitut of the University at Göttingen, Albrecht von Haller lnstitut, Untere Klarspule 2, D-37073 Göttingen, Catalog No 61.81.
- Method of cultivation: The stock cultures are maintained fulfilling the criteria of the OECD guideline (OECD No. 201). Prior to testing a pre-culture is established in test medium to obtain exponentially-growing algae for the test.

ACCLIMATION
- Culturing media and conditions (same as test or not): same as test
- Any deformed or abnormal cells observed: Not reported

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22.0 - 22.2°C

pH:

The pH of the control cultures did not deviate by more than 0.43 units during the test within one treatment group.The initial pH values were between 8.40 and 7.23.

Nominal and measured concentrations:

Nominal concentrations: 76.2, 192, 480, 1200, 3000 mg/L
Measured concentrations: 68.94, 162.1, 422.9, 1073.5, 2622.3 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: conical flasks
- Type: covered with silicone-sponge caps
- Material, size, headspace, fill volume: conical glass flasks of 250 mL volume filled with 100 mL growth medium at test
- Aeration: not reported
- Initial cells density: 10000 cells/mL
- No. of vessels per concentration (replicates):3
- No. of vessels per control (replicates):6

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used:
NaHCO3: 50 mg/L
NH4Cl:15 mg/L
K2HPO4:1.6 mg/L
MgSO4 x 7H2O:15 mg/L
MgCl2 x 6 H2O:12 mg/L
CaCl2 x 2 H2O:18 mg/L
FeCl2 x 6 H2O:0.064 mg/L
H3BO3:0.185 mg/L
MnCl2 x 4 H2O:0.415 mg/L
ZnCl2:0.003 mg/L
CoCl2 x 6 H2O:0.0015 mg/L
CuCl2 x 2 H2O:0.00001 mg/L
Na2MoO4 x 2 H2O:0.007 mg/L
Na2EDTA x 2 H2O: 0.1 mg/L
pH at test start: 7.5-8.0

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:Testmedium is identical to growth medium


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH:no
- Light intensity and quality: light intensity adjusted to approximately 8000 Lux (= 120 uE/m2s) ± 20 %

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations:Cell concentrations were determined using an electronic particle counter (CASY 1 Model TT, Scharfe System, Reutlingen, Germany).
TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.5
- Test concentrations: 76.8; 192; 480; 1200;and 3000 mg/L
- Results used to determine the conditions for the definitive study: From preliminary study

Reference substance (positive control):

yes

Remarks:

zinc sulfate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1 240 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.:

298 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 76.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 76.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 76.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Other: not reported

Results with reference substance (positive control):

- Results with reference substance valid? Yes
Eb,C50, of Zn2+ for inhibition of biomass increase: between 13.5 and 46.9 µg/L (n=5)
ErC50 of Zn2+ for inhibition of growth rate: between 34.1 and 68.3 µg/L (n=5)
Effect data ofthe test with primary standard of August 9, 2005:
EbC50 of Zn2+ for inhibition of biomass increase: 20.1 µg/L
ErC50 of Zn2+for inhibition of growth rate: 34.1 µg/L
The results are in agreement with published EC50-values regarding biomass increase related to the Zn2+-ion ranging between 45.0 and 65.4 µg/L

Reported statistics and error estimates:

The mean value of the celi counts for each concentration plot was used for plotting growth curves.
Calculation of the percent inhibition of growth rate {r], biomass integral [b] and yield [y] was performed according to the guideline (1) (2) and listed in a table.
The evaluation of the concentration-effect-relationships and the caiculations of effect concentrations was based on the nominal concentrations.
Since the test resuits showed an inhibition with levels around 50 % they were statistically analyzed to determine EC10, and EC50 values together with 95 % confidence intervals, if possible, using Probit-anaiysis assuming log-normal distribution of the vaiues by using a computer programme (e.g. ToxRat ).

Validity criteria fulfilled:

yes

Conclusions:

The test item caused concentration-dependent inhibition of algal growth in the exposed cultures. The EC50 values for growth rate, yield and biomass were calculated to be 1240, 298 and 320 mg test item/L, respectively, based on the analytically confirmed nominal concentrations.The EC10 values for growth rate, yield and biomass were calculated to be 295, 68.4 and 78.6 mg test item/L, respectively. For growth rate, yield and biomass integral the NOEC was calculated to be < 76.8 mg/L.

Executive summary:

In a 72 hour acute toxicity study, the cultures of green gresh water algae, Pseudokirchneriella subcapitata were exposed to Ammonium formate at nominal concentrations of 76.8, 192, 480, 1200 and 3000 mg a.i./L under static conditions in accordance with OECD Guideline 201.  he EC10 values for growth rate, yield and biomass were calculated to be 295, 68.4 and 78.6 mg test item/L, respectively. The EC50 values for growth rate, yield and biomass were calculated to be 1240, 298 and 320 mg test item/L, respectively.

 No other abnormalities were noted.

 

This toxicity study is classified as acceptable and satisfies the guideline requirements for aquatic algae and cyanobacteria toxicity study.

 

Results Synopsis

 

Test Organism: Green alga,

Pseudokirchneriella subcapitata

Test Type: Static

 

….hr EC10:  295 mg a.i./L                 

….hr EC_50: 1240 mg a.i./L                95% C.I.: 720 to 2344 mg a.i./L

….hr NOEC: <76 mg a.i./L                   

Endpoint(s) Effected:  growth

Description of key information

Test according to OECD Guideline 201, static conditions, freshwater, 72h, Pseudokrichneriella subcapitata, nominal concentrations of 76.8, 192, 480, 1200, 3000 mg/L; EC50 = 1240 mg/L, EC10 = 295 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

1 240 mg/L

EC10 or NOEC for freshwater algae:

295 mg/L