Antimony nickel titanium rutile

Toxicity to birds

Administrative data

Endpoint:

long-term toxicity to birds

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
According to Regulation (EC) 1907/2006, Annex X, Column 2, Section 9.6.1: “Any need for testing should be carefully considered taking into account the large mammalian dataset that is usually available at this tonnage level.”

According to the ECHA Guidance on information requirements and CSA (Chapter R.16: Environmental Exposure Estimation, Version: 2.1, October 2012), there is not a need for a detailed assessment of secondary poisoning i) if there are not any indications for bioaccumulation and ii) if there is not a potential for toxic effects if accumulated in higher organisms (based on classification on the basis of mammalian toxicity data).

Regarding the relevant uptake via the oral pathway, the potential for systemic toxicity in mammals is low. In a GLP-compliant sub-chronic study (OECD 422), CD rats were administered orally up to 1000 mg/kg bw/day Antimony nickel titanium rutile for 46 days ( MHLW, 2002). There were not any treatment-related adverse effects, and a NOAEL of ≥ 1000 mg/kg bw/day was derived for males and females. In a further sub-chronic key-study (similar to OECD 408), male and female Wistar rats were treated orally with up to 500 mg/kg bw/day for 90 days (Bomhard et al., 1982). Substance-related effects on mortality, clinical signs, body weight, hematology, clinical chemistry, organ weights, gross pathology and histopathology were also not observed. Abnormal changes or substance-related effects were furthermore not observed in three supporting studies (TSCA OTS001087, 1987), performed on rats, dogs and cats, respectively.

According to ECHA guidance on IR & CSA, R.10 (2008); “Secondary poisoning is concerned with toxic effects in the higher members of the food chain, either living in the aquatic or terrestrial environment, which result from ingestion of organisms from lower trophic levels that contain accumulated substances. Previous cases have demonstrated that severe effects can arise after exposure of animals via their food and that bioconcentration, bioaccumulation and biomagnification in food chains need to be considered.”

Antimony nickel titanium rutile can be considered environmentally and biologically inert due to the characteristics of the synthetic process (calcination at a high temperature of approximately 1000°C), rendering the substance to be of a unique, stable crystalline structure in which all atoms are tightly bound and not prone to dissolution in environmental and physiological media. This assumption is supported by available transformation/dissolution data (Klawonn, 2017) that indicate a very low release of pigment components. Transformation/dissolution tests of antimony nickel titanium rutile for 24 h at a loading of 100 mg/L (24 h-screening test according to OECD Series 29) resulted in mean dissolved antimony concentrations of 1.893 and 1.607 µg Sb/L and dissolved nickel concentrations of 24.949 and 16.407 µg Ni/L at pH 6 and 8, respectively. According to ECHA Guidance on the Application of the CLP Criteria (Version 5.0, July 2017), “Where the acute ERV for the metal ions of concern is greater than 1 mg/L the metals need not be considered further in the classification scheme for acute hazard”. Further, “Where the chronic ERV for the metal ions of concern is greater than 1 mg/L, the metals need not be considered further in the classification scheme”. Accordingly, titanium was not considered in the T/D assessment since it does not have an ecotoxic potential as confirmed by ecotoxicity reference values of > 100 mg Ti/L listed in the Metals classification tool (MeClas) database. The release of antimony and nickel from antimony nickel titanium rutile in aqueous media is highest at pH 6 and thus pH 6 is considered as pH that maximises dissolution. Metal release at the 1 mg/L loading and pH 6 resulted in dissolved antimony and nickel concentrations of 1.610 µg Sb/L and 0.598 µg Ni/L after 7 days and 1.851 µg Sb/L and 0.480 µg Ni/L after 28 days, respectively. Thus, the rate and extent to which antimony nickel titanium rutile produces soluble (bio)available ionic and other antimony- or nickel-bearing species in environmental media is limited. Hence, the pigment can be considered as environmentally and biologically inert during short- and long-term exposure. The poor solubility of antimony nickel titanium rutile is expected to determine its behaviour and fate in the environment, including its low potential for bioaccumulation and biomagnification.

The potential essentiality and bioaccumulation of the pigment components antimony, nickel and titanium can be summarized as follows:

An essential or beneficial effect of antimony is not known (Goyer et al, 2004). According to the EU Risk Assessment of diantimony trioxide (EU RAR, 2008), “The bioaccumulation potential seems to be low to moderate. No reliable bioaccumulation studies are available and measured data from different aquatic organisms have been used to calculate tentative BCF values. For marine fish the BCFs vary between 40 and 15,000 whereas for freshwater fish the BCF values are lower, the highest being 14. For invertebrates tentative BCFs below 1 up to 4000-5000 have been calculated. It should be noted that there is a considerable uncertainty in these BCF values. The BCF value finally used in the risk characterisation is 40.” Hence, antimony is not expected to biomagnify.

Due to the existing importance of nickel in the catalytic activity of certain plant and bacterial enzymes, the WHO (1991) concludes that “Nickel has been shown to be essential for the nutrition of many microorganisms, a variety of plants, and for some vertebrates.” Regarding the potential of biomagnification of nickel, the WHO (1991) states that “Accumulation factors in different trophic levels of aquatic food chains suggest that biomagnification of nickel along the food chain, at least in aquatic ecosystems, does not occur.”

Titanium has very low mobility under almost all environmental conditions, mainly due to the high stability of the insoluble oxide TiO2 under all, but the most acid conditions, i.e., below pH 2… There is no evidence to suggest that Ti performs any necessary role in the human body. Titanium is considered to be non-toxic, because of its poor absorption and retention in living organisms” (Salminen et al, 2005 and references therein). A similar conclusion was reached by WHO (1982) as follows: “There is no evidence of titanium being an essential element for man or animals”, and “…titanium is poorly absorbed and retained by both animals and plants…”. Thus, titanium is also not expected to bioaccumulate to any relevant extent or to biomagnify.

Based on available information, there is not any indication of a bioaccumulation potential for antimony nickel titanium rutile. In addition, the potential for systemic toxicity in birds and mammals is low. Hence, secondary poisoning is not considered relevant for antimony nickel titanium rutile. In accordance with Regulation (EC) 1907/2006, Annex X, Column 2, Section 9.6.1, testing of antimony nickel titanium rutile does not appear to be scientifically necessary and it is further scientifically not justified to conduct any toxicity study with birds for reasons of animal welfare.

References:

EU RAR (2008) Risk assessment - Diantimony trioxide, CAS No: 1309-64-4, EINECS No: 215-175-0. Final report, November 2008.

Goyer R et al (2004) Issue paper on the human health effects of metals. Submitted to U.S. Environmental Protection Agency, 19.08.2004.

Salminen et al. (2005) Geochemical Atlas of Europe - Part 1: Background information, Methodology and Maps. EuroGeoSurveys.

WHO (1982) Environmental Health Criteria 24 - Titanium. International Programme on Chemical Safety.

WHO (1991) Environmental Health Criteria 108 – Nickel. International Programme on Chemical Safety.