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Environmental fate & pathways

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Aluminum zirconium chloride hydroxide is an inorganic substance which will rapidly dissociate into aluminum, zirconium, chloride and hydroxide ions upon dissolution in the environment. However, zirconium ions will not remain as such in solution. Thus, regarding the environmental fate and toxicity of aluminum zirconium chloride hydroxide (if any), it can be assumed that it will not be driven by zirconium. Therefore, focus on the fate of aluminum is justified.

In general, metals do not biomagnify unless they are present as, or having the potential to be, in an organic form (e. g. methylmercury). The available evidence shows the absence of aluminium biomagnification across trophic levels in the aquatic and in the terrestrial food chains. The existing information suggests not only that aluminium does not biomagnify, but rather that it tends to exhibit biodilution at higher trophic levels in the food chain. More detailed information can be found in the attached document (White paper on waiving for secondary poisoning for Al & Fe compounds final report 02-02-2010.pdf; IUCLID section 6.3.5). BCFs for Aluminium can be found to range from quite low (~100) to quite high values (11,000 – see attached White paper for waiving secondary poisoning for iron and Aluminium). This variance can in large part be explained by the difference in exposure conditions for the various studies. The inverse relationship between water and BCF/BAF values limits the ability to describe hazard as a result of the size of the BCF, i. e., the most pristine ecosystems have the highest BCFs. A better approach is to directly assess the concentrations of Al at various trophic levels in the ecosystem.

Herrmann and Frick (1995) studied the accumulation of aluminium at low pH conditions in benthic invertebrates with time and representing different functional feeding groups (predators and detritus feeders). Invertebrates of different taxa and feeding type were collected in springtime, when acidity and A1 levels mostly increase from seven streams in southern Sweden. Four of the streams typically had pH values of 4 - 4.5 and contained 0.40 - 0.70 mg inorganic A1/L. The other three streams showed pH values around 6 and A1 concentrations of 0.05 mg inorganic A1/l. For most taxa that could be compared, the animals from the most acidic streams (pH 4) contained more A1 than those from the less acid streams (pH 6). At both pH levels there was a clear tendency that predators contained significantly less amounts of aluminium than shredders. The latter results do not support the hypothesis that aluminium can be accumulated along a food chain in an acidic environment.

In sum, it can safely be assumed that aluminum zirconium chloride hydroxide does not have a potential for bioaccumulation/biomagnification along the food chain.