Zirconium, acetate lactate oxo ammonium complexes

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

no hazard identified

Marine water

Hazard assessment conclusion:

no hazard identified

STP

Hazard assessment conclusion:

no hazard identified

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:

no potential for bioaccumulation

Additional information

Read-across approach

Zirconium, acetate lactate oxo ammonium complexes consists of a ammonium [NH4]+ and a zirconium [Zr]4+ ion as well as an acetic acid [CH3COO]2- and a lactic acid [CH3CH(OH)COO]2- anion. A complete dissociation of zirconium, acetate lactate oxo ammonium complexes resulting in ammonium, zirconium, acetate and lactate ions may be assumed under environmental conditions.

Acetate and lactate under predominating environmental pH conditions will be present in the ionic forms CH3COO- and CH3CH(OH)COO- and biodegrade rapidly.

In aquatic and terrestrial environments, ionic ammonium (NH4+) is in equilibrium with ammonia (NH3), and the respective speciation is influenced by various parameters, including temperature, pH, salinity and ionic strength. The main factors, however, that influence the equilibrium between unionized and ionized ammonia are pH and temperature (Environment Canada 2010 and references therein). Raising pH by one unit can cause the unionized ammonia concentration to increase nearly tenfold whereas a 5 °C temperature increase can cause an increase of 40-50% (Environment Canada 2010 and references therein). The ionic strength of the water is also an important influence on the unionized ammonia concentration. As the ionic strength increases in hard or marine waters, there is a decrease in the unionized NH3 concentration (Environment Canada 2010 and references therein). Ammonia (NH3) and ionic ammonium (NH4+) are referred to as total ammonia nitrogen (TAN).

Based on analysis of thermodynamic stability of aqueous zirconium species, the concentration of free Zr4+ ions under environmental conditions is barely detectable. Ionic zirconium (Zr4+) at relevant pH conditions (pH 7 - 8) of aquatic and terrestrial environments will rapidly transform to zirconium-oxide and -hydroxide complexes, precipitate and not be bioavailable to aquatic organisms. Therefore, zirconium has a very low mobility and bioavailability under most environmental conditions. 

Thus, under environmentally relevant conditions, acetate, ammonium and lactate are expected to be present in ionic form and rather mobile whereas zirconium is rather immobile and complexed as zirconium (hydr)oxides. However, ammonium, acetate and lactate are expected to be rapidly biodegraded.

Thus, in the assessment of environmental toxicity and fate of zirconium, acetate lactate oxo ammonium complexes, read-across to zirconium and ammonium substances as well as acetic and lactic acid is applied since the individual ions of zirconium, acetate lactate oxo ammonium complexes determine its environmental fate. Since the dissociation products behave differently in the environment, regarding their fate and toxicity, a separate assessment of each assessment entity is performed. Please refer to the data as submitted for each individual assessment entity.

In order to evaluate the environmental fate of zirconium, acetate lactate oxo ammonium complexes, information on the assessment entities zirconium and ammonium substances as well as acetic and lactic acid were considered. For a documentation and justification of that approach, please refer to the separate document attached to section 13, namely Read Across Assessment Report for zirconium, acetate lactate oxo ammonium complexes.

 

Reference:

Environment Canada (2010). Canadian Council of Ministers of the Environment. Canadian water quality guidelines for the protection of aquatic life: Ammonia. In: Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg.

Conclusion on classification

Aquatic toxicity studies with zirconium, acetate lactate oxo ammonium complexes are not available, thus aquatic toxicity is addressed with existing data on the dissociation products. Zirconium, acetate lactate oxo ammonium complexes dissolves and dissociates into zirconium, ammonium, acetate and lactate ions upon dissolution in an aqueous medium.

Acute aquatic toxiciy:

All available acute effect concentrations and QSAR-based estimates of acetate, ammonium and lactate for toxicity to algae, daphnia and fish are well above 1 mg/L – the classification criteria for acute (short-term) hazard.

EC/LC50 values of zirconium are above the OECD test limit of 100 mg/L for short-term toxicity tests and thus are also well above the classification criteria for acute (short-term) hazard.

Therefore, zirconium, acetate lactate oxo ammonium complexes does not meet classification criteria as acute hazard to the aquatic environment under Regulation (EC) No 1272/2008.

Chronic (long-term) toxicity data:

Available long-term effect concentrations and QSAR-based estimates are well above 1 mg/L– the classification criteria for long-term hazard of Regulation (EC) No 1272/2008 (CLP Regulation). Further, all acute effect concentrations and QSAR based estimates of acetate, ammonium, and lactate are well above 1 mg/L, and acetate, ammonium and lactate are biodegradable and not bioaccumulative. Criteria of Category Chronic 1-3 and also 4 (safety net) are not met

The potential of chronic toxicity of zirconium is expected to be low based on the following:

- no acute toxicity to algae, crustacea and fish up to the OECD test limit of 100 mg/L for short-term toxicity tests for zirconium cations

- Zirconium is poorly soluble and precipitates under most environmental conditions rendering zirconium biologically unavailable

- available chronic EC for zirconium, i.e. the 72h- NOErL (growth rate of algae) = 32 mg/L, is above the OECD test limit of 10 mg/L for chronic toxicity tests

- Criteria of Category Chronic 1-3 and also 4 (safety net) are not met

Therefore, zirconium, acetate lactate oxo ammonium complexes does not meet classification criteria as long-term hazard to the aquatic environment under Regulation (EC) No 1272/2008.

In sum, based on read-across of toxicity data available for the respective assessment entities (i.e. acetate, ammonium, lactate and zirconium), zirconium, acetate lactate oxo ammonium complexes does not meet acute or long-term aquatic hazard criteria of Regulation (EC) No 1272/2008 and subsequent adaptations.