Ammonium iron bis(sulphate)

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Qualifier:

no guideline followed

Principles of method if other than guideline:

In the SIDS for ammonium chloride peer-reviewed studies are used to assess the hazardous potential of this substance.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Chlorella vulgaris

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

5 d

Test temperature:

26.0 °C

pH:

8.0 - 8.5

Duration:

5 d

Dose descriptor:

EC50

Effect conc.:

1 300 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

In the cited study, the toxicity is expressed as total ammonia nitrogen (NH3-N) or un-ionized NH3. Therefore, these values were converted by the authors to ammonium chloride concentrations.

Validity criteria fulfilled:

not specified

Conclusions:

The EC50 (5d, Chlorella vulgaris) obtained for ammonium chloride is 1300 mg/l.

Executive summary:

In the OECD SIDS for ammonium chloride (published 2006), a study by Przytocka-Jisiak et al. (1977) is cited. In this study the aquatic toxicity of ammonia (using ammonium chloride as a source of ammonia) to Chlorella vulgaris is investigated. The toxicity is expressed as total ammonia nitrogen (NH3-N) or un-ionized NH3. Therefore, these values were converted by the authors to ammonium chloride concentrations. The EC50 (5d, Chlorella vulgaris) obtained for ammonium chloride is 1300 mg/l.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Stock culture of Chlorella vulgaris (Carolina Biological Supply) was kept aseptically in a commercial Bristol medium (also called Bold Basal medium containing 40mgN/l in the form of KNO3 and 53 mg P/l in the form of KH2PO4). After 14 days of growth, stock algal suspension was transferred to 250 ml conical flasks containing 150 ml sterilized culture media of different ammonia concentrations. The culture media were prepared in the same method as that of the Bristol medium except the nitrate component was replaced by different amounts of ammonium sulphate. A total of 12 ammonia concentrations: 0, 10, 20, 40, 50, 60, 80, 125, 250, 500, 750 and 1000 mg N/l, were prepared. The commercial Bristol medium was used as the control. The initial cell density was 1E6 cells /ml. The pH values of all culture media were adjusted to 7.0 before algal inoculation. The algae were axenically grown at 20°C, with an illumination of 4300 lux from cool white fluorescent tubes and light-dark cycles of 16-8 h for 21 days. Each flask was aerated with filtered air which provided atmospheric CO2 and a mixing process. All treatments were in duplicate. At 3 or 4 day intervals, algal cell number was determined by using the improved Neubauer haemacytometer and two counts were performed for each flask. The specific growth rate constant (k, 1/day) of C. vulgaris in each culture was determined by a simple linear regression analysis. The k value was the slope of the regression line. The pH values of the cultures were measured and maintained at neutral pH by the addition of either sterilized and diluted NaOH or HCI. The chlorophyll content was determined at 7-day intervals by methanol-chloroform extraction. At the same time intervals, algal suspensions were centrifuged at 3000 g for 10 min and the amounts of ammonia and nitrate ions remaining in the culture medium were respectively examined by Nesslerization method and ultraviolet spectrophotometry (APHA, 1989). All samplings and measurements were carried out at the same time of the day and during the light period. At the end of the cultivation period, the percentages of NH3-N removal and the specific NH3-N uptake rates were calculated. The algal proteins were extracted in 0.5 N NaOH and assayed by modified Folin-Lowry method (Lowry et al., 1951). The algal growth (cell number) and chlorophyll content were treated by two-way analysis of variance to determine any significant difference between ammonia concentration and incubation time.

GLP compliance:

not specified

Analytical monitoring:

yes

Vehicle:

not specified

Test organisms (species):

Chlorella vulgaris

Details on test organisms:

Stock culture of Chlorella vulgaris (Carolina Biological Supply) was kept aseptically in a commercial Bristol medium (also called Bold Basal medium containing 40 mg N/l in the form of KNO3 and 53 mg P/l in the form of KH2PO4).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

18 d

Hardness:

not specified

Test temperature:

20 °C

pH:

7

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

nominal concentrations/ mg N/l: 0,10,20,40,50,60,80,125,250,500,750,1000

Details on test conditions:

After 14 days of growth, stock algal suspension was transferred to 250 ml conical flasks containing 150 ml sterilized culture media of different ammonia concentrations. The culture media were prepared in the same method as that of the Bristol medium except the nitrate component was replaced by different amounts of ammonium sulfate. The commercial Bristol medium was used as the control. The initial cell density was 1E6 cells/ml. The algae were axenically grown, with an illumination of 4300 lux from cool white fluorescent tubes and light-dark cycles of 16-8 h for 21 days. Each flask was aerated with filtered air which provided atmospheric CO2 and a mixing process. All treatments were in duplicate.

Reference substance (positive control):

no

Duration:

18 d

Dose descriptor:

EC50

Effect conc.:

ca. 2 700 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Details on results:

In the first about 10 days after start, in all investigated concentration a lag phase was observed. Thereafter in some concentrations an exponential growth was observed up to day 17 or 18. Based on data presented in Tam and Wong (1996) an EC50 (18 d) for the endpoint cell count of about 2700 mg/l ammonium sulfate could be calculated for Chlorella vulgaris.

Reported statistics and error estimates:

The algal growth (cell number) was treated by two-way analysis of variance to determine any significant difference between ammonia concentration and incubation time.

Validity criteria fulfilled:

not applicable

Conclusions:

An EC50 (18 d) for the endpoint cell count of about 2700 mg/l ammonium sulfate could be calculated for Chlorella vulgaris.

Executive summary:

In this article by Tam and Wong (published 1996), experiments regarding the toxicity of ammonium sulfate to aquatic algae are described. The influence of the concentration of ammonium on the growth of Chlorella vulgaris was observed by measuring the algal cell number. This study was cited by OECD in the OECD SIDS Ammonium Sulfate. Based on the data of Tam and Wong an EC50 (18 d) for the endpoint cell count of about 2700 mg/l ammonium sulfate could be calculated for Chlorella vulgaris.

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Test organism was grown axenically in modified Allen and Arnon’s medium buffered with 4 mM Tris HCl (pH 7.5) under 14.4 W/m² light intensity and a 14/10 h photoperiod at 26 °C. Alga was subcultured weekly into fresh medium and only the cultures in the logarithmic phase were used for toxicity tests. Survival of the alga was scored by the plate-colony count method after two weeks (Rai and Raizada, 1985). Growth was measured in a Bausch & Lomb Spectronic-20 spectrocolorimeter by recording the absorbance directly at 663 nm.

GLP compliance:

not specified

Specific details on test material used for the study:

Supplier: BDH (India)

Analytical monitoring:

yes

Vehicle:

not specified

Details on test solutions:

Stock solutions of FeCl3, were filter sterilized by passing through a Millipore membrane filter (0.45 µm) before supplementing the culture medium.

Test organisms (species):

other: Anabaena doliolum Bharadwaja

Details on test organisms:

A. doliolum Bharadwaja was grown axenically in modified Allen and Arnon’s medium buffered with 4 mM Tris HCl (pH 7.5) under 14.4 W/m² light intensity and a 14/10 h photoperiod at 26 °C. Alga was subcultured weekly into fresh medium and only the cultures in the logarithmic phase were used for toxicity tests.

Water media type:

other: culture medium

Limit test:

no

Total exposure duration:

2 wk

Post exposure observation period:

not specified

Hardness:

not specified

Test temperature:

25-27 °C

pH:

7.5

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

nominal: 0.09, 0.18, 0.36, 0.54, 0.72 mM Fe

Reference substance (positive control):

no

Duration:

2 wk

Dose descriptor:

IC50

Effect conc.:

0.36 mmol/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

other: survival

Validity criteria fulfilled:

not applicable

Conclusions:

About 50% survival of the test alga was scored at 0.36 mM of Iron.

Executive summary:

In this article by Mallick and Rai (published 1990), experiments regarding the toxicity of some heavy metals to a filamentous heterocystous cyanobacterium are described. The influence of the concentration of iron on the survival of Anabaena doliolum was scored by the plate-colony count method after two weeks. About 50% survival of the test alga was scored at 0.36 mM of Iron.

Description of key information

By dissolution of ammonium iron(III) sulfate in water ammonium, iron(III) and sulfate ions are generated. Therefore, the toxicity of ammonium iron(III) sulfate to algae can be assessed by the toxicity of the three solvated ions. Based on a study on ammonium sulfate (Tam and Wong, 1996) an EC50 (18 d, Chlorella vulgaris) of about 737 mg/l ammonium and 1963 mg/l sulfate could be calculated. Based on a study on ammonium chloride (Przytocka-Jisiak et al.,1977) the EC50 (5d, Chlorella vulgaris) obtained for ammonium is 438 mg/l. In a study on iron(III) chloride 50 % survival of the test alga Anabaena doliolum after two weeks was scored at a concentration of about 20 mg/l iron (corresponding to 95.27 mg/l ammonium iron(III) sulfate.