Evaluation of Chloropyromorphite Stability in the Rhizosphere of Brassica juncea and Medicago sativa in a Sand Culture
- Ali Abbaspour *a and
- Joselito M. Arocenab
Chloropyromorphite (Pb5(PO4)3Cl), CP, is the most stable lead (Pb) mineral under normal environmental conditions and precipitates in Pb-contaminated soils by addition of phosphorous (P). A sand culture experiment was conducted to evaluate the efficiency of Brassica juncea and Medicago sativa roots to dissolve CP in the presence and in the absence of P source. The results showed that the rhizosphere of the plants had lower soluble P and Pb compared with the bulk, which can be attributed to a higher pH in the rhizosphere. Mineralogical transformations of CP in the root surface of the plants including lanarkite (PbSO4.PbO) has been confirmed by X-ray diffraction and scanning electron microscopy techniques. Decrease in soluble P in the rhizosphere as a consequence of P uptake by the plant roots may be a reason for CP dissolution. This study indicates that the dissolution of CP can be promoted by rhizosphere processes.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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