Physicochemical or geochemical

• Shrutia, V. C., Rodríguez-Espinosa, P. F., Martinez-Taverab, E., Hernández-Gonzalezc, D., (2018), Metal concentrations in recent ash fall of Popocatepetl volcano 2016, Central Mexico: Is human health at risk?., Ecotoxicology and Environmental Safety, 162, 324-333, 10.1016/j.ecoenv.2018.06.067