Successful Conversion of Pb-Contaminated Soils to Low-Bioaccessibility Plumbojarosite Using Potassium-Jarosite at Ambient Temperature.

Methods promoting lead (Pb) phase transformation in soils are essential for decreasing Pb bioaccessibility/bioavailability and may offer an in situ, cost-efficient process for mitigating contaminant exposure. Recent plumbojarosite (PLJ) conversion methods have shown the greatest potential to reduce soil Pb bioaccessibility, an in vitro bioaccessibility assay measurement of the proportion of Pb solubilized under gastric chemical conditions. Soils tested utilizing the recent PLJ method were found to have a Pb bioaccessibility of <1%, compared to original soils possessing bioaccessibility of >70%.

Plumbojarosite Remediation of Soil Affects Lead Speciation and Elemental Interactions in Soil and in Mice Tissues.

Lead (Pb) contamination of soils is of global concern due to the devastating impacts of Pb exposure in children. Because early-life exposure to Pb has long-lasting health effects, reducing exposure in children is a critical public health goal that has intensified research on the conversion of soil Pb to low bioavailability phases. Recently, plumbojarosite (PLJ) conversion of highly available soil Pb was found to decrease Pb relative bioavailability (RBA <10%).

High Lead Bioavailability of Indoor Dust Contaminated with Paint Lead Species.

House dust and soils can be major sources of lead (Pb) exposure for children. The American Healthy Homes Survey (AHHS) was developed to estimate Pb exposure from house dust and soil, in addition to other potential household contaminants and allergens. We have combined X-ray absorption spectroscopic (XAS) fingerprinting and mouse relative bioavailability (RBA) measurements for a subset of house dust and residential soils collected in the AHHS, with the primary objective of gaining a better understanding of determinants of house dust Pb bioavailability.

Comparison of Zn accumulation and speciation in kernels of sweetcorn and maize differing in maturity.

Background And Aims: Understanding the speciation of Zn in edible portions of crops helps identify the most effective biofortification strategies to increase the supply of nutrients for improving the health and nutrition of consumers.

Methods: Kernels of 12 sweetcorn and three maize (Zea mays) varieties were analysed for Zn concentration and content. The speciation of the Zn in the embryos, endosperms and whole kernels at 21, 28 and 56 days after pollination (DAP) was then examined for one maize and one sweetcorn variety using synchrotron-based X-ray absorption spectroscopy (XAS).

Point of zero charge: Role in pyromorphite formation and bioaccessibility of lead and arsenic in phosphate amended soils.

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.

X-ray Analyses of Lead Adsorption on the (001), (110), and (012) Hematite Surfaces.

Predicting the environmental fate of lead relies on a detailed understanding of its coordination to mineral surfaces, which in turn reflects the innate reactivity of the mineral surface. In this research, we investigated fundamental dependencies in lead adsorption to hematite by coupling extended X-ray absorption fine structure (EXAFS) spectroscopy on hematite particles (10 and 50 nm) with resonant anomalous X-ray reflectivity (RAXR) to single crystals expressing the (001), (012), or (110) crystallographic face. The EXAFS showed that lead adsorbed in a bidentate inner-sphere manner in both edge and corner sharing arrangements on the FeO octahedra for both particle sizes.

The impact of particle size on the adsorption of citrate to hematite.

We investigated the adsorption of citric acid on the surface of two different sized hematite nanoparticles using batch adsorption experiments, Fourier-transform infrared spectroscopy, surface complexation modeling and computational molecular modeling. Citrate adsorption reached a maximum between pH approximately 2.5 and 5.