Physicochemical or geochemical

• Yano, E., Takeuchi, A., Nishii, S., Koizumi, A., Poole, A., Brown, R. C., Johnson, N. F., Evans, P. H., Yukiyama, Y. , (1985), In vitro biological effects of volcanic ash from Mount Sakurajima, Journal of Toxicology and Environmental Health, 16(1), 127-35., 10.1080/15287398509530724