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Updated: Jan 29, 2026

Monitoring Pedogenic Inorganic Carbon Accumulation Due to Weathering of Amended Silicate Minerals in Agricultural Soils.
Published on: June 4, 2021
Point of zero charge: Role in pyromorphite formation and bioaccessibility of lead and arsenic in phosphate amended
Ranju R Karna1,2, Matthew R Noerpel1,2, Todd P Luxton2
1Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, USA.
Abstract:
Soluble lead (Pb) can be immobilized in pure systems as pyromorphite by adding sources of phosphorus (P), but uncertainties still remain in natural systems. Knowledge of PZC is important to predict the ionization of functional groups and their interaction with metal species in solution. This study utilized the Pb- and As-contaminated soils to determine the combined effect of pH with respect to PZC and different rates of P-application on pyromorphite formation, and Pb and arsenic (As) bioaccessibility as impacted by speciation changes. Solution chemistry analysis along with synchrotron-based Pb- and As-speciation, and bioaccessibility treatment effect ratios (TERs) were conducted. Results indicated no significant effect of PZC on pyromorphite formation in P-amended soils; however, the TERPb appeared significantly lower at pH>pHPZC and higher at pH
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