The Effect of Compost and Fly Ash Treatment of Contaminated Soil on the Immobilisation and Bioavailability of Lead

Abstract

The study discusses changes in lead contents in soil and crops after application of compost and fly ash. A three-year experiment was conducted on narrow-leaved lupine (Lupinus angustifolius L.), camelina (Camelina sativa L.) and oat (Avena sativa L.), which were grown on medium soil fertilised with compost or fly ash (FA). The lead amounts in various combinations were evaluated using sequential (BCR analysis) and single (DTPA solution) methods. The total contents of lead and amounts of selected macronutrients were assessed in the biomass of plants. The Pb contents in the soil and plants were used to calculate the risk assessment code (RAC), individual contamination factor (ICF), bioconcentration factor (BCF) and contamination coefficient level (CCL). Lower amounts of bioavailable Pb in the soil were observed as a result of compost and FA application. Fly ash immobilised Pb more effectively, as evidenced by the BCF and CCL values. The increase in the Pb contents in the sequentially separated fractions and in plant biomass were caused by applied compost or FA. The Pb contents in exchangeable forms decreased, whereas its contents in residual forms increased.

The Effect of Immobilizing Agents on Zn and Cu Availability for Plants in Relation to Their Potential Health Risks

“…This work presents a fragment of a long-term experiment conducted on medium soil (clay loam) classified as haplic cambisol according to WRB [21]. Detailed information concerning the experimental conditions is given by Jakubus and Graczyk [13]. According to the data presented in Table 1, in comparison to the thresholds established by the Directive [22], the tested soil was characterised by an elevated level of Cu and a permissible level of Zn.…”

“…In practice, organic and inorganic substances are usually used as immobilization agents. The most popular organic immobilizing agent are composts, manure, and biochar [7,9,11,[13][14][15]. In turn, mineral substances proposed for remediation purposes include natural zeolites, lime, phosphorus [15,30], and fly ash [13,14,31].…”

“…The most popular organic immobilizing agent are composts, manure, and biochar [7,9,11,[13][14][15]. In turn, mineral substances proposed for remediation purposes include natural zeolites, lime, phosphorus [15,30], and fly ash [13,14,31]. It is worth emphasizing that the abovementioned substances not only immobilize metals, but also fertilize (especially compost and manure), modifying the physicochemical properties of fertilized soils, first of all pH, OM, TOC and CEC, which consequently mitigates the bioavailability of heavy metals for plants [7,9].…”

“…Regardless of the used materials, the final effect is similar-reduction in heavy metal mobility and bioavailability for plants. The potential application of organic or alkali substances for remediation processes of soils contaminated with heavy metals has been underlined by various authors [7,[9][10][11][12][13][14][15]. Binding of metals by organic matter or formation of insoluble compounds under alkali conditions leads to restricted metal uptake by plants and consequently prevents the bioaccumulation of heavy metals in the food chain.…”

Heavy Metal Pollution and Its Effects on Agriculture

“…Jakubus and Graczyk [18] studied the immobilisation effect of compost and fly ash on Pb uptake by narrow-leaved lupine (Lupinus angustifolius), camelina (Camelina sativa) and oat (Avena sativa). The Pb contents in the soil and plants were used to calculate the risk assessment code (RAC), individual contamination factor (ICF), bioconcentration factor (BCF) and contamination coefficient level (CCL).…”