Ferric ammonium citrate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

1.35 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.8 mg/L

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

5 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

no hazard identified

Sediment (marine water)

Hazard assessment conclusion:

no hazard identified

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

46 mg/kg food

Assessment factor:

30

Additional information

PNECaquatic

A short-term toxicity study with invertebrates is available with the registered substance in which no effects were reported at the highest concentration tested (100 mg/l). The ammonia toxicity was expected to contribute to the toxicity of the study and an EC₅₀in the range 10-100 mg/l at pH 8 with the registered substance was expected from the presence of ammonia. Therefore it is not possible to derive a PNEC based on this study.

In the study report a range finding test was conducted with ferric citrate in which no effects were reported up to 100 mg/l. Therefore it is also not possible to derive a meaningful PNEC for ferric citrate.

The substance is expected to dissociate in solution therefore PNECs for each constituent are considered separately.

Iron

Any concentration of iron in water that can be considered as stable can only be due to the complexing effects of natural constituents in the water. The amount of complexed iron in water will already be at saturation and the saturation concentration will vary with location. It is not realistically possible to consider that any further addition of iron to the aquatic compartment will increase the stable complexed concentration and therefore no PNEC can be set for water.

Citric acid

Citric acid is a metabolic intermediate vital to the TCA respiration pathway found in all animal and plant cells. It is also found in appreciable steady state levels in animals and in even higher amounts in plants, with actual levels being influenced by rates of respiration and photosynthesis. There is little evidence for deleterious effects even with large doses. As a consequence it is not appropriate to derive PNEC values for citric acid.

Ammonia

A PNEC_{aqua(freshwater)} for ammonia has been derived by the UK Environment Agency for the purpose of setting an Environmental Quality Standard (EQS) under Annex VIII of the Water Framework Directive (WFD). A PNEC of 0.0011 mg NH3/L is equivalent to 0.20 mg ammonia/ammonium/l at pH 7. This is equivalent to a loading in 1.35 mg/l of the registered substance at pH 7 and 0.14 mg/L of FAC at pH 8. In reality, the PNEC in terms of total loading would vary significantly according to test conditions.

The lowest reliable NOEC for long-term effects of ammonia on marine biota is 0.066 mg NH₃-N l-1 for growth of Dover sole (Solea solea). Short-term test data are available that indicate this may not be the most sensitive taxonomic group (molluscs and echinoderms are more sensitive following acute exposure) and so an assessment factor of 100 is recommended to protect these taxa, resulting in a PNEC_{aqua(marine water)}of 0.66 μg/l un-ionised ammonia (EA 2007). At pH 7.0, this is equivalent to 0.12 mg ammonia/ammonium/l.This is equivalent to a loading in 0.8 mg/l of the registered substance at pH 7 and 0.08 mg/l of the registered substance at pH 8. In reality, the PNEC in terms of total loading would vary significantly according to test conditions.

Conclusion on classification

Reaction mass of ammonium iron (III) citrate and ammonium sulfate will dissociate in solution to form citric acid, ammonium and iron.

Since the ammonia fraction of ammonium sulfate is considered to be the most toxic part of the substance, the registered substance is conservatively classified based on this substance.

Ammonia is an inorganic substance and based on the short-term toxicity data available (EC/LC50 0.76 mg NH3/l for fish, equivalent to 100 mg/l of the registered substance at pH 8) the registered substance should not be classified for aquatic Acute effects in the EU according to the Regulation (EC) No. 1272/2008.

At a loading rate of 100 mg/l the registered substance in solution at pH 8 (worst case) would produce 0.77 mg NH3/l.

Based on long-term toxicity data the lowest NOEC is 0.004 mg un-ionised NH3/l for invertebrates, equivalent to 0.57 mg/l of the registered substance, which indicates that the substance is classified as Chronic Category 2 for the environment since the citric acid fraction of the substance is considered to be rapidly degradable for the environment in the EU according to the Regulation (EC) No. 1272/2008.