Soil fluoride fractions and their bioavailability to tea plants ( Camellia sinensis L.)

AbstractDrinking teas containing high fluoride (F) imposes fluorosis risk. The soil F bioavailability is an important factor influencing its uptake and contents in teas. The present work was conducted to investigate F fractions in soil and their bioavailability to tea plants. Tea seedlings were cultivated on 6 typical soils treated with a mixture consisting of dolomite, lime, peat and KCl at variable rates in the pot experiment. Soils and young shoots were collected in pairs from 63 sites of 21 plantations in a field experiment. Soil fluoride was sequentially separated into hot water soluble\([{\text{F}}_{{ ( {\text{h, H}}_{ 2} {\text{O,s)}}}} ]\), exchangeable\({\text{F}}\;[{\text{F}}_{{({\text{MgCl}}_{ 2} , {\text{ s}})}} ]\) (by 1  mol L−1 MgCl2, pH  = 7.0), F bound to Mn and Fe hydroxides [F(oxides,s)], and organic matter [F(OM,s)] or extracted independently by water\([{\text{F}}_{{ ( {\text{H}}_{ 2} {\text{O)}}}} ]\) or 0.01  mol L−1 CaCl2 solution\([{\text{F}}_{{(0.01{\text{ M CaCl}}_{ 2} )}} ]\). Averaged\({\text{F}}_{{ ( {\text{h, H}}_{ 2} {\text{O,s)}}}}\),\({\text{F}}_{{ ( {\text{MgCl}}_{ 2} , {\text{ s)}}}}\), F(oxides,s) and F(OM,s) accounted for 51, 14, 5 and 30  % of the total sequential extracts, respectively. There were significant correlations among\({\text{F}}_{{ ( 0. 0 1 {\text{ M CaCl}}_{ 2} )}}\),\({\text{F}}_{{ ( {\text{H}}_{ 2} {\text{O)}}}}\) and F(OM,s). Fluoride contents in leaves correlated with\({\text{F}}_{{ ( {\text{H}}_{ 2} {\text{O)}...
Source: Environmental Geochemistry and Health - Category: Environmental Health Source Type: research