In vitro toxicity studies of aluminum compounds.

A standardized in vitro system of human lung cells (A459) in RPMI medium is beneficial for investigations concerning the toxicity of inhalable biopersistent fibrous or granular dusts such as asbestos or titanium dioxide. However, the use of non-biopersistent (soluble) dusts such as aluminum sulfate or aluminum chloride revealed an undesirable precipitate in the cell culture system. In contrast, under the same condition, the soluble dust aluminum citrate did not form any precipitate. The precipitate could be identified as aluminum phosphate by the use of electron microscopy, TG and DSC. Further examinations showed that the composition of the precipitate depends on the admitted quantity of aluminum sulfate or aluminum chloride, respectively. For example, at low dosages, besides aluminum phosphate calcium phosphate can also be detected. Furthermore, the composition of the precipitate (especially the content of crystal water) is modified by aging processes. Phosphate as well as calcium ions are ingredients of the RPMI medium (nutrient solution) and hamper the investigation of soluble aluminum-containing dusts in standardized A459 lung cell system. [ABSTRACT FROM AUTHOR]