One hundred and fifteen pieces of Chinese Jingdezhen porcelain from late Ming to 1983 were analysed by cadmium¹⁰⁹ isotope excited, x-ray fluorescence spectrometry. Zinc was found to remain at levels of less than 70 parts per million until after WWII at which time most pieces are found to possess much higher levels. Prior to the war arsenic remains below detection limits. Subsequently it is sometimes observed up to 350 parts per million. -- AATA