title: Novel approach for quantitatively estimating element retention and material balances in soil profiles of recharge basins used for wastewater reclamation.
abstract: We investigated changes in element content and distribution in soil profiles in a study designed to monitor the geochemical changes accruing in soil due to long-term secondary effluent recharge, and its impact on the sustainability of the Soil Aquifer Treatment (SAT) system. Since the initial elemental contents of the soils at the studied site were not available, we reconstructed them using scandium (Sc) as a conservative tracer. By using this approach, we were able to produce a mass-balance for 18 elements and evaluate the geochemical changes resulting from 19 years of effluent recharge. This approach also provides a better understanding of the role of soils as an adsorption filter for the heavy metals contained in the effluent. The soil mass balance suggests 19 years of effluent recharge cause for a significant enrichment in Cu, Cr, Ni, Zn, Mg, K, Na, S and P contents in the upper 4m of the soil profile. Combining the elements lode record during the 19 years suggest that Cr, Ni, and P inputs may not reach the groundwater (20 m deep), whereas the other elements may. Conversely, we found that 58, 60, and 30% of the initial content of Mn, Ca and Co respectively leached from the upper 2-m of the soil profile. These high percentages of Mn and Ca depletion from the basin soils may reduce the soil's ability to buffer decreases in redox potential pe and pH, respectively, which could initiate a reduction in the soil's holding capacity for heavy metals.
authors.affiliation: Soil Erosion Research Station, Ministry of Agriculture & Rural Development, HaMaccabim Road, Rishon-Lezion. P.O.B. 30, Beit-Dagan, 50250, Israel. Electronic address: eshelgil@gmail.com.
authors.forename: Gil
authors.initials: G
authors.lastname: Eshel
authors.affiliation: School of Environment, Beijing Normal University, 19 Xinjiekouwaidajie St., Beijing, 100875, China.
authors.forename: Chunye
authors.initials: C
authors.lastname: Lin
authors.affiliation: Department of Soil and Water Sciences, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot, Israel.
authors.forename: Amos
authors.initials: A
authors.lastname: Banin
mesh_terms: D000327:Adsorption; D004784:Environmental Monitoring / Q000379:methods*; D019216:Metals, Heavy / Q000032:analysis; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D014131:Trace Elements / Q000032:analysis*; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D014131:Trace Elements; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Initial elemental contents; Mass-balance; Scandium; Secondary effluent recharge; Soil Aquifer Treatment