Evaluation of Mobility, Bioavailability and Toxicity of Pb and Cd in Contaminated Soil Using TCLP, BCR and Earthworms

Abstract

The objective of the present study was to investigate the reduction of mobility, availability and toxicity found in soil contaminated with lead (Pb) and cadmium (Cd) from Santo Amaro Municipality, Bahia, Brazil using two combined methods, commonly tested separately according to the literature: metal mobilization with phosphates and phytoextraction. The strategy applied was the treatment with two sources of phosphates (separately and mixed) followed by phytoremediation with vetiver grass (Vetiveria zizanioides (L.)). The treatments applied (in triplicates) were: T1—potassium dihydrogen phosphate (KH2PO4); T2—reactive natural phosphate fertilizer (NRP) and; T3—a mixture 1:1 of KH2PO4 and NRP. After this step, untreated and treated soils were planted with vetiver grass. The extraction procedures and assays applied to contaminated soil before and after the treatments included metal mobility test (TCLP); sequential extraction with BCR method; toxicity assays with Eisenia andrei. The soil-to-plant transfer factors (TF) for Pb and Cd were estimated in all cases. All treatments with phosphates followed by phytoremediation reduced the mobility and availability of Pb and Cd, being KH2PO4 (T1) plus phytoremediation the most effective one. Soil toxicity however, remained high after all treatments.

Chrysomya megacephala larvae feeding favourably influences manure microbiome, heavy metal stability and greenhouse gas emissions

“…, Cd in CMSM seems to be easier to migrate from swine manure into plants than Pb because the percentage of ResCd was lower than that of Pb. Similar results were found in the contaminated soils that Cd was more labile than Pb (Ptistišek et al ., ; Kede et al ., ). However, we were pleased to see that C .…”

“…Bioactivity and mobility of heavy metals could be evaluated by sequential extraction methods (Ptistišek et al ., ). The BCR (European Communities Bureau of Reference) method is one of the most commonly used methods for heavy metal speciation (Kede et al ., ; Razek, ). Heavy metals are more difficult to be extracted which indicates that they are more settled, less available and have a lower risk to organisms.…”

Suppression of the environmental risks of lead in cropland soil using biomass ash and its modified product

“…The TCLP method is widely used to evaluate the mobility, bioavailability and toxicity of heavy metals in soil and waste. 5,[18][19][20] Depending on the pH value of the soil sample, TCLP extraction was performed as follows. 5.7 mL glacial acetic acid was diluted to 1 liter with Milli-Q water.…”

Lead and Cadmium Ions Mitigation in Soil using Calcium Carbide Waste-Carbonised Lophira Alata Sawdust Composite (CCW-CLAS) as Immobilizing Agent

“…The best-demonstrated technologies (BDATs) for the remediation of heavy metal-contaminated locations, such as immobilization, soil washing, and phytoremediation procedures, are the most regularly used (Kede et al, 2014). The process of decreasing metal mobility, bioavailability, and bioaccessibility of heavy metals in soil by adding immobilizing agents such as an organic and inorganic amendment to the contaminated soils is called immobilization or waste fixation.…”