Distribution of lead and other metals in tea leaves, dust and liquors

Abstract

Abstract When samples of certain teas were analysed for lead, repeat determinations made on the same samples showed a wide variation in the results. This was found to be due to dust particles, with a high lead content, which were dispersed throughout the tea leaves. Further work showed that there was also more iron, zinc and copper in the dust than in the leaves. Analyses of tea prepared as for drinking showed that only a small amount of the lead, cadmium, nickel, iron, zinc and copper present in the leaves passed into the brew. The proportion of each metal extracted into the brew appeared to be independent both of the strength of brew and of the type of water used. Work with tannic acid solution indicated that soluble polyphenols could be responsible for complexing metals.