Quantitative assessment of heavy metals from selected tea brands marketed in Zaria,Nigeria

Six brands of tea comprising two locally processed teas,two imported teas,one unprocessed tea and one herbal tea (coded as lit,akt,aht,get,unt and hbt,respectively) were obtained and analysed for their heavy metal concentrations. the tea samples were coded to conceal the original source. the analysed metals were zinc (zn),lead (pb),cadmium (cd) and iron (fe),and the results were compared with both world health organization (who) and european union (eu) standards. the obtained concentrations of zn,pb,cd and fe were 2.322-3.460 mg l-1,0.03-0.266 mg l-1,0.025-0.042 mg l-1 and 0.15-0.876 mg l-1,respectively. generally,the levels of metal content in all brands were comparable with the values set by both the who and eu except for fe and pb,where the concentrations were slightly higher in some samples. the variations in heavy metal concentrations of the tea brands were attributed to geographical changes,seasonal changes and chemical characteristics of the growing regions. © penerbit universiti sains malaysia,2015.