Zirconium, acetate lactate oxo ammonium complexes

Endpoint summary

Description of key information

In the assessment of zirconium, acetate lactate oxo ammonium complexes, read-across to the assessment entities zirconium and ammonium substances as well as acetic and lactic acid is applied since the ions of zirconium, acetate lactate oxo ammonium complexes determine its fate and toxicity in the environment.

 

Acetate:

Reliable acute data for acetate, mostly in form of acetic acid, and QSAR-basaed estimates are available for three trophic levels: algae, invertebrates and fish:

- a 96-h LC50 of 78 mg/L (non-adapted pH) for freshwater fish P. promelas; 96-h LC50 of 25.8 g/L (QSAR-based estimate) for fish

- 24h-EC50 values of 6000 (adapted pH) and 95 mg/L (non- adapted pH) for D. magna; 48-h LC50 of 12.3 g/L (QSAR-based estimate) for daphnia

- an 8-d LOEC of 90 mg/L (non-adapted pH) for cyanobacteria M. aeruginosa; 96-h EC50 of 4.4 g/L (QSAR-based estimate) for green algae

- Microorganisms in the STP use acetate as carbonaceous substrate and it is rapidly degraded and thus not expected to accumulate in the STP and to be toxic.

Regarding the long-term toxicity,

- a 90d-LOEC of 1.47 mg/L for freshwater species O. mossambicus; Chronic Value (ChV) of 2046 mg/L (QSAR-based estimate) for fish,

- Chronic Value (ChV) of 732 mg/L (QSAR-based estimate) for daphnia, and

- Chronic Value (ChV) of 778 mg/L (QSAR-based estimate) for green algae are available.

 

In sum, the acute and chronic aquatic toxicity of acetate is considered to be very low.

 

Ammonium:

Reliable acute data for ammonium in form of ammonium chloride as reviewed by OECD SIDS (2004) are available for three trophic levels: algae, invertebrates and fish

- a 96-h LC50 of 74.2 mg/L obtained for L. macrochirus

- a 48-LC50 of 101 mg/L (D. magna) and

- a 5d-EC50 of 1300 mg/L and freshwater (C. vulgaris) algal species, respectively

- Microorganisms in the STP rapidly oxidize ammonium to nitrate (“Ammonium oxidation”), one of the endpoints of OECD 209. Ammonium is therefore not expected to accumulate in the STP and to be toxic..

 Regarding the long-term toxicity,

- a 28-d NOEC of 2.7 mg/L NH4+for marine fish species inland silverside (M. beryllina),

-a 10-d EC50 of 42 mg/L for bivalve M. lateralis, and

- a 10-d NOEC of 26.8 mg/L for saltwater diatom Navicula sp. are available.

In sum, ammonium has a low potential for acute and chronic aquatic toxicity.

Lactate:

Reliable acute data for lactate, mostly in form of lactic acid, and QSAR-based estimates are available for three trophic levels: algae, invertebrates and fish:

- a 96 h LC50 of 130 mg/L for freshwater fish L. macrochirus; 96-h LC50 of 177 g/L (QSAR-based estimate) for fish

- 48h-EC50 of 240 mg/L for D. magna; 48-h LC50 of 79 g/L (QSAR-based estimate) for daphnia

- a 70h-EC50 of 3500 and > 2800 mg/L for growth and biomass of green algae P. subcapitata, respectively; 96-h EC50 of 21 g/L (QSAR-based estimate) for green algae

- Microorganisms in the STP use lactate as carbonaceous substrate and it is rapidly degraded and thus not expected to accumulate in the STP and to be toxic.

Regarding the long-term toxicity,

- a 90d-LOEC of 2.18 mg/L for freshwater species O. mossambicus; Chronic Value (ChV) of 13 g/L (QSAR-based estimate) for fish,

- Chronic Value (ChV) of 3.9 g/L (QSAR-based estimate) for daphnia, and

- Chronic Value (ChV) of 3.2 g/L (QSAR-based estimate) for green algae are available.

In sum, the acute and chronic aquatic toxicity of lactate is considered to be very low.

 

Zirconium:

Reliable acute data are available from OECD and EU-guideline studies for three trophic level algae, invertebrates and fish indicating that acute effect concentrations are above corresponding OECD test limits:

- 96h-LL50 > 100 mg/L, OECD 203 test with zirconium dioxide and freshwater fish Dario rerio

- 48h-EC50 > 100 mg/L, acute static test according to EU method C2 with zirconium dioxide and Daphnia magna

- 72h- NOErL (growth rate) = 32 mg/L, 72h- EL50 > 100 mg/L; OECD 201 test with zirconium dioxide and Scenedesmus subspicatus. Inhibition of growth may be explained (at least in parts) with the measured phosphate depletion.

- STP Microorganisms are not be exposed to zirconium since zirconium is poorly soluble and precipitates under most environmental conditions

The potential of chronic toxicity of zirconium ions is also 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

- Zirconium is poorly soluble and precipitates under most environmental conditions

- 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.

In sum, zirconium has very low potential for acute and chronic aquatic toxicity.

 

Zirconium, acetate lactate oxo ammonium complexes:

Using existing aquatic toxicity data of the dissociation products zirconium, acetate, lactate and ammonium, the aquatic hazard of zirconium, acetate lactate oxo ammonium complexes was assessed.

 

Regarding acute (short-term) toxicity, the potential is low since most of the relevant EC/LC50 values (and all QSAR-based estimates) of acetate, ammonium, lactate and zirconium are above respective OECD test limit of 100 mg/L. Observed effects can be explained with experimental artefacts such as nutrient depletion (i.e. algae test with zirconium), pH decrease (i.e. non-pH adapted acute tests with acetate) or intra-species-variability (i.e.96-h LC50 values for fish and ammonium ranging from 74.2 to 218 mg/L with the majority of endpoints being above the OECD test limit of 100 mg/L).

Regarding the toxicity to aquatic microorganisms, zirconium in the form of ZrO2 is unavailable to sludge microorganisms due to complexation and a very low water solubility. Acetate as carbonaceous substrate is rapidly consumed by sludge organisms, positively effecting their growth. Lactate, as common fermentation product and substrate for anaerobic microorganisms, is rapidly degraded and therefore not expected to be toxic to microorganisms from a STP. Ammonium, as important source of bioavailable nitrogen, is rapidly degraded in wastewater treatment systems. A process called “Ammonia oxidation” which represents one of the endpoints investigated in activated sludge respiration inhibition tests according to OECD 209. Thus, toxicity of zirconium, acetate lactate oxo ammonium complexes to aquatic microorganisms is not expected.

Regarding chronic (long-term) toxicity , acetate, ammonium and lactate due to the lack of an acute potential for toxicity, available data and QSAR-based estimates and being biodegradable are not expected to be toxic to aquatic organisms. The potential of chronic toxicity of zirconium ions is also expected to be low.

In sum, an acute or chronic hazard to aquatic organisms, including fish, daphnia, algae and aquatic microorganisms was not identified for any of the dissociation products of zirconium, acetate lactate oxo ammonium complexes and thus a low potential for toxicity is assumed.

Additional information

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.