Ammonium iron bis(sulphate)

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

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:

Daphnia longispina were collected from Rutland water (UK) and cultured in the laboratory in an artificial media containing 0.35 g/l magnesium sulphate, 0.54 g/l sodium hydrogen carbonate, 0.01 g/l potassium chloride and 0.21 g/l calcium sulphate. The cultures were kept at 20 °C (Enserink et al., 1990; Milbrink & Bengtsson, 1991; Jones et al., 1991), under a light regime of 16 hours light:8 hours dark (OECD, 1981; Vijverberg, 1989) in an environmental cabinet. The cultures were fed the alga Chlorella at a concentration of 1.25E6 cells per ml with yeast extract as an organic additive (Vijverberg, 1989). Acute toxicity tests were carried out over 48 hours, and chronic tests over 21 days in ferric sulphate and china clay (an inert particulate substance which acted as a control). Appropriate china clay concentrations were derived from the dry weight of ferric sulphate in each test concentration to give equivalent amounts of particulate material. Animals exposed to ferric sulphate or china clay in chronic toxicity tests were collected once mortality occurred or at the end of the test, and preserved in 4% formalin. The filtering area of the third thoracic limb was calculated from setae length, using the following equation (Egloff & Palmer, 1971; Crittenden, 1981): y=1.879x X1.966; where y = estimated the area of one comb (mm2); X = mean seta length from 5 measured setae (mm). The relationships between standard length (measured from the eye to the base of the tail) and filtering area was then compared to determine whether ferric sulphate precipitates had an impact on morphology of Daphnia. Thoracic appendage beat rate was directly observed to determine whether mechanical interference of feeding by the precipitate occurred. Daphnia were exposed to the suspended ferric sulphate in a hanging droplet. Video equipment recorded the thoracic appendage rate, and the number of times food was rejected from the food groove.

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

not specified

Test organisms (species):

other aquatic crustacea: Daphnia longispina

Details on test organisms:

Daphnia longispina were collected from Rutland water reservoir (near Leicester/UK) and cultured in artificial medium (0.35 g/l magnesium sulfate, 0.54 g/l sodium hydrogen carbonate, 0.01 g/l potassium chloride, 0.21 g/l calcium sulfate). Cultures were kept at 19 - 21 °C, under a 16/8 h light/dark cycle. Cultures were fed the alga Chlorella (1.25E6 cells/ml) with yeast extract.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

not specified

Hardness:

not specified

Test temperature:

19 - 21 °C

pH:

not specified

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

nominal concentrations / mg/l: 1, 2, 8, 10, 15, 25, 30, 50

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

11.48 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

Fe

Basis for effect:

mortality

Details on results:

The mean effective dose (ED50) was calculated using the method of Litchfield & Wilcoxen (1949), to be 11.48 mg/l between confidence limits of 12.39 and 10.63 mg/l.

Validity criteria fulfilled:

not applicable

Conclusions:

The effective dose to 50% (EC50) of daphnia longispina is 11.48 mg Fe/l. This value corresponds to 54.67 mg/l ammonium iron(III) sulfate.

Executive summary:

In this publication by Randall et al. (published 1999), the toxicity of iron sulfate to aquatic invertebrates is assessed. Test animals (Daphnia longispina) were exposed to different concentrations of the test substance and observed for 48 hours. The ED50 value was derived from the mortality of the animals. The effective dose to 50% (EC50) of daphnia longispina is 11.48 mg Fe/l. This value corresponds to 54.67 mg/l ammonium iron(III) sulfate. This study was cited by the U.S. Environmental Protection Agency in their online database ECOTOX.

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 aquatic invertebrates can be assessed by the toxicity of the solvated ions. For ammonium compounds, studies on various species with LC50 values in a range from 13 to 600 mg/l and EC50 values in range from 73.05 to 168.7 mg/l were found (cf. Additional information). For iron(III) sulfate, a study on Daphnia longispina with an EC50 (48h) of 11.48 mg iron (corresponding to 54.67 mg ammonium iron(III) sulfate) per litre was found.

Key value for chemical safety assessment

Marine water invertebrates

Marine water invertebrates

Effect concentration:

54.67 mg/L

Additional information

Test Material	Species	Dose Descriptor	Duration	Result
Ammonium Chloride	Daphnia magna	LC50	48 h	101 mg/l
Ammonium sulfate	Crangon crangon	LC50	96 h	380 - 600 mg/l
Ammonium sulfate	Perna viridis	LC50	96 h	13 mg/l
Ammonium sulfate	Daphnia magna	EC50	48 h	168.7 mg/l
Ammonium sulfate	Ceriodaphnia acanthine	EC50	48 h	121.7 mg/l
Ammonium sulfate	Daphnia magna	EC50	48 h	73.05 mg/l
Ammonium sulfate	Dugesia tigrina	LC50	96 h	> 100 mg/l
Ammonium sulfate	Daphnia magna	LC50	96 h	> 100 mg/l
Ammonium sulfate	Asellus Intermedius	LC50	96 h	> 100 mg/l
Ammonium sulfate	Gammarus fasciatus	LC50	96 h	> 100 mg/l
Iron (III) sulfate	Daphnia longispina	EC50	48 h	11.48 mg/l Fe