Manganese antimony titanium buff rutile

Bioaccumulation: aquatic / sediment

Administrative data

Endpoint:

bioaccumulation in aquatic species: fish

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance has a low potential to cross biological membranes

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
According to Column 2 of Information Requirement 9.3.2., Annex IX, Commission Regulation (EU) 1907/2006, ”The study need not be conducted if: the substance has a low potential for bioaccumulation (for instance a log Kow ≤ 3) and/or a low potential to cross biological membranes.”

Manganese antimony titanium buff 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 (Pardo Martinez, 2021) that indicate a very low release of pigment components at pH 6 and 8. Transformation/dissolution tests (according to OECD Series on Testing and Assessment Number 29) of manganese antimony titanium buff rutile at a loading of 1 mg/L and pH 6 and 8 resulted after 7 and 28 days in dissolved antimony and titanium concentrations below the LOD of 0.5 µg/L, and manganese concentrations below the LOQ of 10 µg Mn/L, respectively. Thus, the rate and extent to which manganese antimony titanium buff rutile produces soluble (bio)available ionic and other antimony-, manganese- and titanium-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 manganese antimony titanium buff rutile is expected to determine its behaviour and fate in the environment, including its low potential for bioaccumulation.

Further, “for naturally occurring substances such as metals, bioaccumulation is more complex, and many processes are available to modulate both accumulation and potential toxic impact. Many biota for example, tend to regulate internal concentrations of metals through (1) active regulation, (2) storage, or (3) a combination of active regulation and storage over a wide range of environmental exposure conditions. Although these homeostatic control mechanisms have evolved largely for essential metals, it should be noted that non-essential metals are also often regulated to varying degrees because the mechanisms for regulating essential metals are not entirely metal-specific (ECHA, 2008).”

The potential essentiality and bioaccumulation of the pigment components antimony, manganese 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. 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 15000 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.

Manganese is ubiquitous in the environment and an essential trace element. Manganese acts as catalytic or structural component of larger molecules, which occupy key roles in essential metabolic pathways of microorganisms, plants, and animals. Manganese as essential nutrient is actively assimilated and utilized by plants and animals. Organisms vary in their ability to take up manganese. Aquatic organisms at lower trophic levels tend to have higher manganese levels than fish, with typical BAFs of about 100 (WHO 2004 and references therein). Hence, manganese does not biomagnify.

Titanium has very low mobility under almost all environmental conditions, mainly due to thehigh 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 recached 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.

Thus, the potential of manganese antimony titanium buff rutile for bioaccumulation can safely be expected to be low. Consequently, the study on bioaccumulation does not need to be conducted based on low solubility, bioavailability and a corresponding low bioaccumulation potential of manganese antimony titanium buff rutile in accordance with Column 2 of Information Requirement 9.3.2., Annex IX, Commission Regulation (EU) 1907/2006.

References:

ECHA (2008) Guidance on IR & CSA, Appendix R.7.13-2: Environmental risk assessment for metals and metal compounds. July 2008.

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

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

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

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

WHO (2004) Concise International Chemical Assessment Document 63 - Manganese and its compounds: Environmental aspects.