Abstract
The distribution of total and labile Zn, and the Zn2+-pH isotherms of arable urban fields were evaluated to determine the fate of Zn under long-term Zn loading from untreated wastewater irrigation. At the three sites, total Zn concentration in the surface layer had attained pollution level in the topsoil, but the concentration of total, mobile and the potentially labile Zn decreased rapidly with depth, suggesting limited movement within the profiles. The soils were spiked with Zn(NO3)2 solution at the pH range of 4-8 and allowed to react for 25 days, results indicated that the soil attained maximum Zn adsorption at pH ≥ 7.5. Free cationic Zn2+ activities accounted for between 69 and 88% of soluble Zn while Zn-inorganic complexes accounted for just about 1-5% of the total dissolved Zn in soil solution as compared to the Zn-fulvate complex that ranged from 11 to 22% of total soluble Zn. The linear -log Zn2+-pH isotherms had slopes that approached the solubility isotherm of hopeite, (Zn3(PO4)2 especially at pH ≥ 7.0. Given the increasing tendency of pH and the attendant Zn loading of the soils due to irrigation with untreated wastewater, precipitation of Zn-solid phases having solubility similar to hopeite will likely control Zn2+ activities and availability in the soils in the long-term.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
