It has been estimated that prior to World War
II, porcelain and fine china contributed 15]20%
by value to the US market for pottery tableware
earthenware contributed 60]65%. Crewson,
1948.. Historically, most of the earthenware demand
has been met by domestic production, but
basic substances in concentrations exceeding FDA
permissible limits Sheets, 1997.. The study described
here extends the investigation to imported
porcelain dinnerware.