However, deafness from lead poisoning is not common, and therefore Beethoven's deafness is most likely not related to lead. Additional testing of the hair showed no evidence of mercury compounds, which are also known to cause neurologic symptoms. The next question is where did Beethoven's lead exposure come from. Pottery glazes, paint, lead foil, leaded glass, and lead pipes may all have been present in Beethoven's environment. It has been speculated that the lead used in early pipes may have leached into ancient Roman water leading to mental deficiency and the fall of the Roman Empire.
Glazes used for ceramic ware can be a source of lead.
High-acid foods can dissolve lead from the glaze and the lead can leach into the food. Lead foil is sometimes used to cap corked wine bottles. Small amounts of the lead foil can be absorbed into the wine as the wine is poured. Rehydrated dried foods or foods that require extensive boiling can contain high levels of lead. As water is boiled, the concentration of lead and other trace minerals increases.