Pb In Tailings Research Articles

Positive interaction of trembesi (Samanea saman) and arbuscular mycorrhizae fungi in Pb stabilization of gold-mine tailing media

Abstract. Setyaningsih L, Ramadhani FA, Muttaqin Z, Maslahat M. 2024. Positive interaction of trembesi (Samanea saman) and arbuscular mycorrhizae fungi in Pb stabilization of gold-mine tailing media. Biodiversitas 25: 379-385. This experiment aimed to determine the ability of trembesi (Samanea saman Merr.) seedlings inoculated with AMF (Glomus manihotis) to reduce Pb from gold mine tailings media. Therefore, using plants and Arbuscular Mycorrhizae Fungi (AMF) is an alternative choice that can be considered to support a phytoremediation program to reduce Pb contamination in tailing areas. The experiment was conducted using a completely randomized design in a greenhouse with two factors, i.e., with and without AMF, and four different Pb treatments (0, 0.5, 1, and 1.5 mM). AMF-inoculated seedlings were grown on tailings media and exposed to Pb in different concentrations for 5 weeks. The results showed that the seedlings were still able to grow on the media with Pb up to 1.5 mM with a tolerance index of 91.6%. AMF induced the plant to accumulate Pb dramatically higher, even though this absorption tended to reduce plant biomass. Root tissue stored significantly higher Pb than stem and leaf tissue, with an average concentration was 526.29 mg/kg in the roots of mycorrhizal seedlings. The bioaccumulation level of Pb in mycorrhizal seedlings was significantly higher. The value of the transport factor was below 1, indicating that S. saman seedlings carried out the phytostabilization. The interaction of AMF with S. saman has a big potential to be applied in efforts to remediate Pb in tailings.

Bioremediation potential and primary mechanism of Sporosarcina pasteurii for cadmium (Cd) and lead (Pb) in contaminated tailings

ABSTRACT Efficient bioremediation technology has drawn extensive attention from scholars due to the serious damage caused by heavy metals (HMs) to the environment. This study explored the remediation potential and mechanisms of the S. pasteurii strain in alleviating toxicity of Cd and Pb in tailings. The results showed that the decrease in DTPA-Cd and -Pb was associated with the transfer of exchangeable HMs to carbonate-bound HMs in bacteria-treated tailings. Biomineralization, extracellular adsorption, and intracellular accumulation were observed to result in removal rates above 95% for HMs in tailings solution. Mineralisation products driven-urease were identified as carbonate minerals, including otavite CdCO3, cerussite PbCO3 and hydrocerussite Pb3(CO3)2(OH)2. However, the increased Km in the urease kinetics study indicated that HMs reduced urease activity and biomineralization by minimum inhibitory concentrations (Cd 0.5 mM and Pb 40 mM). The functional groups (-OH, -NH2, -COOH and -PO4 3-) on the bacterial surface were involved in immobilising HMs, while the biosorption capacity (qm) was inhibited by metal ions (Pb2+ > Cd2+) according to Langmuir sorption isotherm. In conclusion, the biomineralization-adsorption of S. pasteurii was the mainstay for stabilising Cd and Pb in tailings, and the contribution of biomineralization was found to be much higher than that of biosorption.

Solidification behavior and environmental risk assessment of toxic elements on tailings from carbothermic reduction-magnetic separation of lead blast furnace slag

Lead blast furnace slag (LBFS) generated during lead smelting is a hazardous solid waste containing potentially toxic elements (Pb, Zn, As, and Cd) with high mobility and solubility. In this study, a process for the utilization of LBFS by carbothermic reduction-magnetic separation method is proposed. Leaching toxicity and Tessier sequential extraction experiments were conducted on LBFS and magnetic separation tailings (TS), and the environmental risk was evaluated using the risk assessment coding index and potential ecological risk index. The obtained results showed that the potentially toxic elements in the TS were solidified in the spinel phase or silicate phase. In addition, the XRD, SEM-EDS, and FTIR results showed the formation of PbCa2Si3O9, ZnAl2O4, and Ca3(AsO4)2 phases. The leaching concentrations of Pb, Zn, As, and Cd in TS were much lower than the toxicity characteristic leaching procedure (TCLP) and China standard leaching test (CSLT) limits. The results of Tessier sequential extraction procedure confirmed that the proportions of the stable residual state of the potentially toxic elements in TS were significantly higher than in LBFS. Furthermore, the ecological environmental risk level for the TS decreased significantly compared to that of LBFS.

Assessment of metals pollution in sediments and tailings of Klein Aub and Oamites mine sites, Namibia

The environmental challenges posed by huge volumes of tailings and tailings dumps are often overshadowed by the economic benefits of mining. Tailings contain harmful quantities of toxic substances that can potentially pose serious health and environmental problems through air dispersion of air-dried tailings, leaching of potentially toxic chemical species, erosion and uptake by the aquatic system and bioaccumulation. The objective of this study was to determine the concentrations of investigated metals (Cr, Cu, Mn, Ni, Pb, Sr, V, Zn, Zr, Rb, Ba, Ca, Fe, K, S and Ti) and assess the pollution and contamination of sediments and tailings from Klein Aub and Oamites mine sites. Klein Aub was a copper mine (chalcocite) and Oamites mined chalcopyrite (Cu), bornite and gold as a byproduct of copper blisters. A total of 58 sediments and tailings samples were collected between January 2018 to January 2019 and analyzed using potable X-ray Fluorescence (XRF). Total concentrations showed high levels of crustal elements and heavy metals, particularly Cu, Zn, Ni and Pb in tailings. These toxic elements have a potential to cause serious human health and environmental impacts through leaching, erosion, air dispersion of tailings, etc. Pollution indices such as geo-accumulation, enrichment factor, contamination factor and PLI were used to assess the extent and degree of contamination. The Geo-accumulation index indicated that all tailings dams in both areas were moderately polluted with Cu, which recorded the highest Igeo values, above 1 but below 2. Sediments samples in both sites recorded Igeo values below 1, suggesting that the quality of sediments is unpolluted to moderately polluted. All tailings dams recorded an EF ≥ 40 for Cu, with the overall highest value in Klein Aub, all of which is indicative of an extremely high enrichment from non-crustal sources. This enrichment was attributed to the primary and secondary mineral ores. The pollution in Oamites tailings was minimal compared to the Klein Aub tailings, owing to the fact that the tailings dams at Oamites are capped. However, the enrichment factor of the sediments at Oamites suggests that the streams are polluted possibly through leaching, erosion and/or seepage. The HPI value for the Klein Aub tailings indicates that the tailings were considerably polluted. Therefore, precautionary measures should be considered for the Klein Aub tailings dam to prevent contamination or pollution of the surrounding environment.

Evolution of the Speciation and Mobility of Pb, Zn and Cd in Relation to Transport Processes in a Mining Environment.

Elements in mining extracts can be potentially toxic if they are incorporated into soils, sediments or biota. Numerous approaches have been used to assess this problem, and these include sequential extractions and selective extractions. These two methods have limitations and advantages, and their combined use usually provides a rough estimate of the availability or (bio)availability of potentially toxic elements and, therefore, of their real potential as toxicants in food chains. These indirect speciation data are interesting in absolute terms, but in the work described here, this aspect was developed further by assessing the evolution of availability-related speciation in relation to the transport processes from the emission source, which are mainly fluvial- and wind-driven. This objective was achieved by characterizing tailings samples as the source of elements in soils and sediments at increasing distances to investigate the evolution of certain elements. The standard procedures employed included a sequential five-step extraction and a selective extraction with ammonium acetate. The results show that the highest percentages of Zn and Pb in tailings, soils and sediment samples are associated with oxyhydroxides, along with a significant presence of resistant mineralogical forms. In the case of Cd, its association with organic matter is the second-most important trapping mechanism in the area. The physicochemical mechanisms of transport did not transform the main mineralogical associations (oxyhydroxides and resistant mineralogical forms) along the transects, but they produced a chaotic evolution pattern for the other minor matrix associations for Zn and a decrease in exchangeable and carbonate-bound forms for Pb in soils. Interestingly, in sediments, these mobile forms showed a decrease in Zn and a chaotic evolution for Pb. The most probable reason for these observations is that Zn2+ can form smithsonite (ZnCO3) or hydrozincite (Zn5(CO3)2(OH)6), which explains the retention of a carbonate-bound form for Zn in the soil transect. In contrast, Pb and Cd can appear as different mineral phases. The order of (bio)availability was Pb > Zn > Cd in tailings but Cd > Pb > Zn in soils. The physicochemical processes involved in transport from tailings to soils produce an increase in Cd (bio)availability. The trend is a decrease in bioavailability on moving away from the source (tailings), with maximum values obtained for Cd near to the source area (200–400 m).

Preliminary Evaluation of Animal Bone Char as Potential Metal Stabilization Agent in Metal Contaminated Soil.

The aim of this study was to evaluate the potential effect of animal bone char (ABC) addition on metal mobility in mine tailings. The mobility of metals after addition of ABC to tailings at four different application rates (0.6 g, 1.2 g, 1.8 g and 3.6 g ABC per 100 g of tailings) was evaluated by Toxicity Characteristic Leaching Procedure (TCLP) one step extraction. The obtained results indicated that the mobility of Pb, Cr and Cd gradually decreased with increasing quantity of added ABC. According to the TCLP, mobile concentrations of Pb in tailings exceeded threshold values for almost eight times. After ABC addition, Pb TCLP-extractable concentrations decreased from 39 mg L-1 in tailings to lower than the TCLP limit values of 5 mg L-1 at all ABC application rates, except in mixtures with the lowest addition of ABC. We concluded that ABC could be a successful metal stabilization agent for multi-metal contaminated soil, although attention should be paid at highly As contaminated soil.

Bioaccessibility of Cd and Pb in tailings from a zinc smelting in Brazil: implications for human health.

Soils and wastes enriched with heavy metals may present ecological and human health risks. A considerable number of mining areas exist in Brazil, where high levels of metals have been found. However, studies of bioaccessibility of metals in soils/tailings from these areas are scarce, despite their potential informational contribution concerning exposure risks of residents near these areas. This study evaluated tailings collected from four sites of a zinc smelting area located in Brazil with aims to: (1) evaluate the presence of metals of potential concern; (2) investigate Cd and Pb bioaccessibility; and (3) determine the desorption kinetics of Cd and Pb. High concentrations of total Cd and Pb (up to 1743mgCdkg(-1) and 8675mgPbkg(-1)) and great variability were found in the tailings, indicating the importance of adequate planning for their final disposal, in order to avoid contamination in the surrounding environment. Cadmium and Pb bioaccessibility percentages in the intestinal phase were less than 47 and 4%, respectively, which represents significant fractions not available for absorption in the intestinal tract. However, this material has to be monitored since its bioaccessibility may increase with eventual physicochemical changes, releasing Cd and Pb. Desorption kinetics experiments revealed that Pb in the samples remained in less labile fractions, whereas Cd was found in more labile fractions, which is in accordance with the bioaccessibility results.

Vegetation Response to Lime and Manure Compost Amendments on Acid Lead/Zinc Mine Tailings: A Greenhouse Study

AbstractLand disturbed by mining in China is a serious problem and lead/zinc (Pb/Zn) mine tailings constitute the majority of the metal mine tailings produced in Guangdaong Province, China. A greenhouse study was therefore conducted to evaluate the effects of lime (40, 80, 120, and 160 t/ha) and manure compost (50 and 100 t/ha) amendment on the revegetation of the Pb/Zn mine tailings using Cynodon dactylon (Bermuda grass) and Agropyron elongatum (tall wheatgrass). The results showed that a combination of lime and manure compost amendment together with deionized water leachating was able to increase pH, reduce electrical conductivity and diethylenetraminepentaacetic acid (DTPA)‐extractable concentrations of Zn and Pb in tailings. Using 80 t/ha lime amendment with the supplement of fertilizer or manure compost was able to effectively improve germination of both C. dactylon and A. elongatum. The highest dry weight yields were obtained in tailings receiving 80 t lime/ha and 100 t manure compost/ha for both plant species. Plant tissue analysis showed that lime amendment at 120–160 t/ha reduced Zn accumulation in both shoot and root of C. dactylon. However, this trend was not observed for Pb.