Aluminium ammonium bis(sulphate)

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.114 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.329 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.011 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

100 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

no exposure of sediment expected

Sediment (marine water)

Hazard assessment conclusion:

no exposure of sediment expected

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no exposure of soil expected

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Only few data were available on aluminum ammonium sulfate (fish, invertebrates, microorganisms and sediment organisms). However, aluminium ammonium sulfate is highly soluble in water (112g/L at 20°C and 120g/L at 25°C), dissociating to various aluminium, ammonium and sulfate species and therefore, the hazard of aquatic environment of this aluminium salt can be assessed by the effects of its dissociation productsaccording to a read across approach.

 

Read across approach justification

The quantitative read across approach with aluminium salts and ammonium sulfate is based on the following criteria described

-         the functional groups of the source chemicals are common with the two functional group of the target chemical and have similar dissociation products: the ions Al³⁺and NH₄⁺.

-         the data point of the source chemicals are relevant and reliable for the purpose of the read-across (according to the most current OECD test guidelines for aluminium and according to OECD SIDS assessment criteria for ammonium)

-         the water solubility of the source chemicals are higher or within the same range than the target chemical.

-         Acute toxicity results on daphnia and fish with the target substance show no toxicity differences with the source chemicals and provide additional confidence that read-across of other data is possible.

 

Ammonium

Environmental effects of ammonium sulfate are assessed in OECD SIDS Dossier (2004). Ammonium sulfate is a white solid, with solubility in water of 764 g/l at 25 °C.Under most environmental conditions, the un-ionized ammonia concentration is the primary driver of toxicity.The toxicity of ammonia to aquatic organisms is highly dependent on physicochemical factors, most notably pH. Reviewed data’s are available for the aquatic environments and for the terrestrial environment.

 

Aluminium

The toxicity of aluminium to organisms has been subject of numerous reviews, including DAR (2008); WHO (1997); INERIS (2005) or Environment and Health Canada (2010). Moreover, recent studies performed according to international guidelines are available on various aluminium salts. Data’s on aluminium sulfate (water solubility= 600g/L at 20°C) and aluminium chloride hydroxide sulfate (water solubility= 570g/L at 20°C) were selected as the most relevant data for the read across approach. The fate and behaviour of aluminium in the aquatic environment and thereby the toxic effect is largely dependent on the speciation of aluminium. The latter is affected by a wide range of environmental parameters, such as pH; hardness, dissolved organic carbon (DOC) and numerous other ligands.

 

In this report, emphasis was placed on the potential toxic impacts of aluminum and ammonium in environmental compartments of neutral or near-neutral pH as the available information suggests that releases associated with the aluminum ammonium sulfate occurs primarily into environmental compartments of pHs ranging from 6 to 8.

 

PNECs derivation

In cases where there are multiple source chemicals, and consequently a range of possible values for read-across, the use of the most conservative (lowest) value may be sufficient to account for the uncertainty in the read-across.

Taking the above points into consideration, the lowest effects identified on aquatic organisms were for aluminium. Therefore, the endpoints related to ammonia toxicity were not taken into account for the PNEC derivation, and for aluminum the lowest NOEC per endpoint and species is used. The NOEC as total aluminium is from a read-across substance and has been recalculated to aluminium hydrated salt (AlNH4(SO4)2.12H2O).

No PNEC were derived for sediment, soil and secondary poisoning based on exposure considerations.

 

References

- DAR (2008). Draft Assessment Report: Aluminium ammonium sulfate, Volume 3, Annex B, part 5, B.9. September 2008.

- Environment Canada and Health Canada (2010). Priority Substances List Assessment Report for Aluminium chloride, Aluminium nitrate and Aluminium sulphate, January 2010.

- INERIS, 2005. Aluminium et dérivés. Fiche de données toxicologiques et envi ronnementales des substances chimiques.INERIS –DRC-02-25590-02DF41.doc. Version N2-2- Janvier 2005.

- OECD (2004). SIDS Initial Assessment Report: Ammonium sulfate (7783-20 -2).

- WHO (1997). Environmental Health Criteria 194. United Nations Environment Programme, International Labour Organisation, World Health Organization, International Programme On Chemical Safety.

Conclusion on classification

Justification

As no reliable aquatic toxicity data were available on aluminium ammonium sulfate, a read across approach with other aluminium and ammonium salts was used based on the basic assumption that it is the bioavailable Al3 + and NH4 + fraction that are causing the effects. The detail justification for read across approach can be found in the PNEC discussion field. Aquatic toxicity assessment demonstrated that the toxicity of aluminium ammonium sulfate is driven by the toxicity of aluminium for all the organisms tested. Therefore the toxicity data on ammonium were not further considered for classification purpose.

Aquatic toxicity reports were screened to comply with standard acceptance criteria. Acute toxicity would be assessed using a 72h algae study (OECD Test guideline 201), two 48h daphnia studies (OECD Test guideline 202) and two 96h fish studies (OECD Test guideline 203). Chronic toxicity data are available for algae according to OECD test guideline 201, for fish according to a non standardised but equivalent Fish Early Life Stage test (60d) and for Daphnia magna according to OECD test guideline 211.

Acute L(E)C50 values lie in the range of 0.02-0.1 mg/l of dissolved aluminium and 0.35-86 mg/l of total aluminium. The classification relates to the aluminium ammonium (bis)sulfate dodecahydrate: AlNH₄(SO₄)₂.12H₂O. Conversion of the L(E)C50 aluminium values to those appropriate for AlNH₄(SO₄)₂.12H₂O implies an acute toxicity range of 5.8-32.9 mg/l for the algae, 72.2-1001.3 mg/l for daphnia and 157.9-1444.8 mg/l for fish. For chronic studies, the toxicity is 1.14 -1.48 mg/l for fish and 1.28 -2.30 mg/L for daphnia.

According to the Guidance to Regulation (EC) No 1272/2008 on Classification, Labelling and Packaging of substances and mixtures (p.490) "Aluminium, iron and tin all form metal hydroxides that are rapidly removed from the water column at various pH values. With time, these hydroxides either polymerise to form larger insoluble stable complexes or they are trapped and buried in sediments". In such cases, the metal is considered as rapidly removing from the water column without significant remobilisation.

Based on the results reported in several reviews on aluminium, ATSDR (2008), DAR (2008), Environment Canada and Health Canada (2010), WHO (1997) and ammonium, OECD SIDS (2004), both substances have a low potential of bioaccumulation in aquatic organisms.

Chemical Species Molecular Weight Ratio:

- AlNH₄(SO₄)₂.12H₂O = 453.15

Reasoning

Acute toxicity > 1mg/l, rapidly degradable (rapid partitioning from the water column), no concern for bioaccumulation and chronic toxicity NOEC > 1mg/l.

Conclusion

Not classified for environment according to Annex VI of Directive 67/548/EEC and GHS classification (GHS UN rev.2, 2007).

References

- ATSDR (2008). Agency for Toxic Substances and Disease Registry. Toxicological profile for aluminium. September 2008.

- DAR (2008). Draft Assessment Report: Aluminium ammonium sulfate, Volume 3, Annex B, part 5, B.9. September 2008. - Environment Canada and Health Canada (2010). Priority Substances List Assessment Report for Aluminium chloride, Aluminium nitrate and Aluminium sulphate, January 2010. - OECD (2004). SIDS Initial Assessment Report: Ammonium sulfate (7783-20 -2). - WHO (1997). Environmental Health Criteria 194. United Nations Environment Programme, International Labour Organisation, World Health Organization, International Programme On Chemical Safety.