“…Na, Mg, P, K, Ca, Zn, Mn, Fe, Al, Cu, Mo, and Ag were analyzed using inductively coupled plasma mass spectrometry (ICP-MS 7900, Agilent). The standard solution was diluted from an ICP-MS environmental calibration standard (Agilent), which contains 1000 mg/L each of Fe, K, Ca, Na, Mg, and 10 mg/L each of Ag, Al, As, Ba, Be, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, Zn, Th, and U in 10% HNO 3 .…”