Experimental Studies on the Hygienics of Aluminum in Tea

ObjectiveTo konw the aluminum content in Chinese teas.MethodAluminum content in the different Chinese teas was measured by inductivity coupled plasma-opticald emission spectrometry(ICP-OES).ResultsThe content of aluminum was within limits of 339～1745 mg/kg in tea samples.Also measured the percent of extraction of aluminum of various kind tea leaves infusion,about 80%～90% aluminum of total extraction rate was in the first infusion of tea.Experiments have been proved aluminum in tea infusions mainly exists in inorganic species.The mole ration of fluoride to aluminum in tea infusion was 0.7～1.2,Calculated according to the equilibrium equation of Al³⁺+F^-=AlF²⁺ (K=10^6.13),95%～99% aluminum is complex compound species as AlF²⁺ in the infusion.It was calculated that drinking 5g tea infusions daily may supply aluminum about 1/140～1/17 of the provisional tolerable weekly intake(PTWI)dose set by the joint FAO/WHO Expert Committee.ConclusionOn the other hand,the species of AlF²⁺ in tea infusion is a lower toxicity compound.For these reasons,the hygienic estimation of aluminum in teas is not a dangerous factor for the human health.