157 samples were analyzed for copper using Inductively Coupled Plasma. 156 samples were analyxed for zinc, cobalt and nickel using Inductively Coupled Plasma. 157 samples were analyzed for gold, silver, lead, antimony and arsenic using Atomic Absorption Spectroscopy. 156 samples were analyzed for molybdenum using Atomic Absorption Spectroscopy. 155 samples were analyzed for iron, manganese, cadmium and chromium using Inductively Coupled Plasma. The published analytical methods are ambiguous but to the best of our knowledge: 107 samples were analyzed for tin using Atomic Absorption after aqua regia digestion and hydride generation. 103 samples were analyzed for tungsten using colorimetric methods. Some results in this publication appear [...]