Short‐Term Effect of Lime, Phosphorus, and Iron Amendments on Water‐Extractable Lead and Arsenic in Orchard Soils

Abstract

Lead arsenate was extensively used to control insects in apple and plum orchards in the 1900s. Continuous use of lead arsenate resulted in elevated soil levels of lead (Pb) and arsenic (As). There are concerns that As and Pb will become solubilized upon a change in land use. In situ chemical stabilization practices, such as the use of phosphate-phosphorus (P), have been investigated as a possible method for reducing the solubility, mobility, and potential toxicity of Pb and As in these soils. The objective of this study was to determine the effectiveness of calcium carbonate (lime), P, and iron (Fe) amendments in reducing the solubility of As and Pb in lead-arsenate-treated soils over time. Under controlled conditions, two orchard soils, Thurmont loam (Hapludults) and Burch loam (Haploxerolls), were amended with reagent-grade calcium carbonate (CaCO 3 ), iron hydroxide [Fe(OH) 3 ], and potassium phosphate (KH 2 PO 4 ) and incubated for 16 weeks at 268C. The experimental results suggested that the inorganic P increased competitive sorption between H 2 PO 4 2 and dihydrogen arsenate (H 2 AsO 4 2 ), resulting in greater desorption of As in both Thurmont and Burch soils. Therefore, addition of lime, potassium phosphate, and Fe to lead-arsenate-contaminated soils could increase the risk of loss of soluble As and Pb from surface soil and potentially increase these metal species in runoff and movement to groundwater.

Arsenic mobility in the amended mine tailings and its impact on soil enzyme activity

“…An alternative explanation regarding the relationships between the soil pH, DOC and enzyme activities involved the masking effect from higher concentrations of As WS fractions in both mine tailings (Bhattacharyya et al 2008). In fact, concentrations of As WS fractions in the present study were higher than those observed in previous studies using As-contaminated agricultural soils (Bhattacharyya et al 2008), As-contaminated landfill site soils (Hartley et al 2004) and As-contaminated orchard soils (Codling and Dao 2007). It was concluded from these statistical analyses that the equation with As WS fraction gave the best prediction of the soil enzyme activities in both mine tailings samples.…”

“…In the present study, treatments with ZVI largely reduced both the As WS and As NSS fractions. Generally, Fe oxide has a high affinity for the adsorption of As; therefore, the mobility of As in soils is markedly associated with the presence of Fe oxide on the soil surface (Codling and Dao 2007). Of the many Fe sources, Fe(II) with SO 4 and ZVI are well known and commonly used as stabilizing agents for As (Koo et al 2011b;Kumpiene et al 2008).…”

“…Of these, the incorporation of various soil amendments, containing adsorptive sources of As, into contaminated soils has been recognized as a cost-effective and environmentally friendly technique (Codling and Dao 2007). Actually, chemical stabilization of As using soil amendments is considered for remediating As-contaminated soils, and possible amendments for reducing the availability of toxic element and improving soil quality have been reported in many investigations (Koo et al 2011b;Subacz et al 2007).…”

Fertilizer‐Borne Trace Element Contaminants in Soils

“…Inorganic As can be relatively mobile in soils in both oxidation states [55,56], particularly in alkaline soils. Arsenic may form insoluble compounds with Fe and Al oxides [56,57], be adsorbed to organic matter or hydroxyl groups on clay minerals [58], and be desorbed from these sites by phosphate fertilizers [57]. However, Huang and Matzner [55] argued that sorption by organic matter was of minor importance in most soils.…”

Uso de fosfato para remoção de arsênio de solo contaminado

“…As formas oxianiônicas de arsênio nos solos ricos em óxidos de ferro, estão envolvidas na adsorção específica desse elemento (Waychunas et al, 1993;Bhattacharya et al, 2007) e competem com os fosfatos (Wasay et al, 2000). A remoção do arsênio por dessorção com soluções de fosfato tem sido usada para lavagem deste elemento em solos contaminados (Codling & Dao, 2007). Nesta técnica, é necessário que, posteriormente, se trate o efluente gerado sendo que a remoção do arsênio de efluentes contaminados tem sido realizada por coagulação, sedimentação e filtração (Nguyen et al, 2006).…”