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Potassium jarosite seeding of soils decreases lead and arsenic bioaccessibility: A path toward concomitant remediation
Citation:
Sowers, T., M. Blackmon, A. Betts, M. Jerden, K. Scheckel, AND K. Bradham. Potassium jarosite seeding of soils decreases lead and arsenic bioaccessibility: A path toward concomitant remediation. PNAS (PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES). National Academy of Sciences, WASHINGTON, DC, 120(50):e2311564120, (2023). https://doi.org/10.1073/pnas.2311564120
Impact/Purpose:
We showcase the potential for K-jarosite to treat lead-contaminated soils to form plumbojarosite, a Pb mineral of very low bioaccessibility/bioavailability. This study confirms that plumbojarosite significantly decreased Pb and As biocessibility, making this an exceptionally promising remediation technology. A primary barrier to our early research involving plumbojarosite formation was high temperature requirements for the treatment to function (95-100°C); however, our newly developed K-jarosite method may be performed at room temperature conditions. These findings further ORD’s research on development of soil remediation technologies to reduce lead bioavailability at contaminated sites in support of EPA’s OLEM/OSRTI and Regional offices. ORD’s soil remediation research for lead contaminated soils is listed as a high priority research need for OLEM/OSRTI and EPA Regional offices. This work paves the way for field trials that are actively being planned.
Description:
Soils are common sources of metal(loid) contaminant exposure globally. Lead (Pb) and arsenic (As) are of paramount concern due to detrimental neurological and carcinogenic health effects, respectively. Pb and/or As contaminated soils require remediation, typically leading to excavation, a costly and environmentally damaging practice of removing soil to a central location (e.g., hazardous landfill) that may not be a viable option in low-income countries. Chemical remediation techniques may allow for in situ conversion of soil contaminants to phases that are not easily mobilized upon ingestion; however, effective chemical remediation options are limited. Here, we have successfully tested a soil remediation technology using potted soils that relies on converting soil Pb and As into jarosite-group minerals, such as plumbojarosite (PLJ) and beudantite, possessing exceptionally low bioaccessibility [i.e., solubility at gastric pH conditions (pH 1.5 to 3)]. Across all experiments conducted, all new treatment methods successfully promoted PLJ and/or beudantite conversion, resulting in a proportional decrease in Pb and As bioaccessibility. Increasing temperature resulted in increased conversion to jarosite-group minerals, but addition of potassium (K) jarosite was most critical to Pb and As bioaccessibility decreases. Our methods of K-jarosite treatment yielded <10% Pb and As bioaccessibility compared to unamended soil values of approximately 70% and 60%, respectively. The proposed treatment is a rare dual remediation option that effectively treats soil Pb and As such that potential exposure is considerably reduced. Research presented here lays the foundation for ongoing field application.
URLs/Downloads:
DOI: Potassium jarosite seeding of soils decreases lead and arsenic bioaccessibility: A path toward concomitant remediation
https://pubmed.ncbi.nlm.nih.gov/38048468/