Toxicity of richterite in hemolysis test and macrophage cultures

Richterite is a fibrous mineral associated with apatite deposits in eastern Finland. Fibre size features suggest potential toxicity but no data is available of fibrogenic effects on human lungs. The toxicity of richterite in a hemolysis test and in lung macrophage cultures was studied. In the hemolysis test richterite-rich samples showed the same degree of hemolysis as titanium dioxide whereas anthophyllite, crocidolite, chrysotile, wollastonite and quartz samples had distinctly higher degree of hemolysis. In the macrophage toxicity assay the percentage of dead cells was counted, and LDH, ASAT and acid phosphatase were determined from the culture medium. In this assay richterite showed lower toxicity than anthophyllite, crocidolite, chrysotile or quartz but gave higher values than titanium dioxide. Wollastonite showed similar level of toxicity. Differences were statistically highly significant. The results suggest that richterite (with wollastonite) belongs to a group of fibrous minerals which have distinctly smaller biological effect than traditional asbestos minerals.