Biochar remediates cadmium and lead contaminated soil by stimulating beneficial fungus Aspergillus spp.

An in-depth understanding of the micro-ecological mechanisms underlying the remediation of heavy metal-contaminated soils by biochar amendment is crucial for enhancing the efficacy of biochar-microbe combination. Nevertheless, this remediation mechanism remains elusive. Consequently, we performed a pot experiment to investigate the effects of biochar on soil fungal communities in a cadmium (Cd) and lead (Pb) contaminated soil. The results demonstrated that the amendment of biochar derived from rice straw significantly reshaped soil fungal communities, leading to the enrichment of members of the genus Aspergillus, which was found to correlate significantly with the remediation of heavy metal-contaminated soil. A representative of the targeted Aspergillus species (strain F8) was successfully isolated. The results of the pot experiments demonstrated that the inoculation with the isolate F8 can promote plant growth, immobilize soil Cd and Pb, and decrease tomato plant uptake of Cd and Pb. These results indicate that the enrichment of specific taxa induced by biochar amendment is associated with the remediation of heavy metal-contaminated soil. Therefore, this study provides new evidence to support the indirect mechanism of biochar in the remediation of heavy metal-contaminated soil by reshaping the soil microbiome.

Genotype of pioneer plant Miscanthus is not a key factor in the structure of rhizosphere bacterial community in heavy metal polluted sites.

Miscanthus is a common pioneer plant with abundant genetic variation in abandoned mines in southern China. However, the extent to which genetic differentiation among species modulates rhizosphere bacterial communities remains unclear. Miscanthus samples were collected from 26 typical abandoned heavy-metal mines with different soil types in southern China, tested using 14 pairs of simple sequence repeats (SSR) primers, and classified into two genotypes based on Nei's genetic distance. The structure and diversity of rhizosphere bacterial communities were examined using 16 S rRNA sequencing. The results showed that among the factors affecting the rhizosphere bacterial community structure of Miscanthus samples, the role of genotype was not significant, and geographical conditions were the most important factors, followed by pH and total organic carbon (TOC). The process of rhizospheric community assembly varied among different genotypes; however, the recruited species and their abundances were similar. Collectively, we provided an approach based on genetic differentiation to quantify the relative contribution of genotypes to the rhizosphere bacterial community, demonstrating that genotypes contribute less than soil conditions. Our findings provide new insights into the role of host genetics in the ecological processes of plant rhizosphere bacterial communities in abandoned mines and provide theoretical support for microbe-assisted phytoremediation.

Microplastics in heavy metal-contaminated soil drives bacterial community and metabolic changes.

Microplastic (MP) and heavy metal pollution in soil are global issues. When MPs invade the soil, they combine with heavy metals and adversely affect soil organisms. Six common MPs-polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, and polytetrafluoroethylene-were selected for this study to examine the effects of various concentrations and MP types on the physicochemical properties, bacterial community, and soil metabolism of heavy metal-contaminated soil. MP enhanced predation and competition among heavy metal-contaminated soil bacteria. Heavy metal-MPs alter metabolites in lipid metabolism, other pathways, and the bacterial community. MP treatment promotes energy production and oxidative stress of soil bacteria to resist the toxicity of heavy metals and degrade MP pollution. In conclusion, MP treatment changed the metabolism of the microbiome in heavy metal-contaminated soil and increased the abundance of Proteobacteria that responded to MPs and heavy metal pollution by 11.54 % on average. This study explored bacteria for the ecological regeneration and provided ideas for MPs and heavy metal-contaminated soil remediation.

Research Enhancing Acidic Mine Wastewater Purification: Innovations in Red Mud-Loess.

This study investigates the adsorption of cadmium (Cd) by red mud-loess mixed materials and assesses the influence of quartz sand content on permeability. Shear tests are conducted using various pore solutions to analyze shear strength parameters. The research validates solidification methods for cadmium-contaminated soils and utilizes SEM-EDS, FTIR, and XRD analysis to elucidate remediation mechanisms. The findings suggest that the quartz sand content crucially affects the permeability of fine-grained red mud-loess mixtures. The optimal proportion of quartz sand is over 80%, significantly enhancing permeability, reaching a coefficient of 6.7 × 10-4 cm/s. Insufficient quartz sand content of less than 80% fails to meet the barrier permeability standards, leading to a reduced service life of the engineered barrier. Adsorption tests were conducted using various pore solutions, including distilled water, acidic solutions, and solutions containing Cd, to evaluate the adsorption capacity and shear characteristics of the red mud-loess mixture. Additionally, the study examines the behavior of Cd-loaded red mud-loess mixtures in various pore solutions, revealing strain-hardening trends and alterations in cohesiveness and internal friction angle with increasing Cd concentrations. The analysis of cement-red mud-loess-solidified soil demonstrates enhancements in soil structure and strength over time, attributed to the formation of crystalline structures and mineral formations induced by the curing agent. These findings provide valuable insights into the remediation of cadmium-contaminated soils.

Research progress and hotspots on microbial remediation of heavy metal-contaminated soil: a systematic review and future perspectives.

Microbial remediation technology has received much attention as a green, ecological, and inexpensive technology, and there is great potential for the application of microbial remediation technology for heavy metals (HMs) contaminated soil alone and in conjunction with other technologies in environmental remediation. To gain an in-depth understanding of the latest research progress, research hotspots, and development trends on microbial remediation of HMs-contaminated soil, and to objectively reflect the scientific contributions and impacts of relevant countries/regions, institutions, and individuals of this field, in this manuscript, ISI Web of Knowledge's Web of Science™ core collection database, data visualization, and analysis software Bibliometrix, VOSviewer, and HistCite Pro were used to collect and analyze the relevant literature from 2000 to 2022, and 1409 publications were subjected to scientometric analyses. It involved 327 journals, 5150 authors, 75 countries/regions, and 2740 keywords. The current progress and hotspots on microbial remediation of HMs-contaminated soil since the twenty-first century were analyzed in terms of the top 10 most productive countries (regions), high-yielding authors, source journals, important research institutions, and hotspots of research directions. Over the past 22 years, China, India, and the USA have been the countries with the most articles. The institution and author with the most publications are the Chinese Acad Sci and Zhu YG, respectively. Journal of Hazardous Materials is the most productive journal. The keywords showed 6 co-occurrence clusters. These findings revealed the research hotspots, knowledge gaps, and future exploration trends related to microbial remediation of HMs-contaminated soil.

Using restored heavy metal contaminated soil as brick making material: Risk analysis upon different scenarios, considering the completeness of bricks.

Restored heavy metal contaminated soil (RHMCS) can be utilized as building material, but the risks of heavy metal dissolution (HMD) under different scenarios are not clear. This study focused on sintered bricks made from RHMCS and assessed the HMD process and utilization risks of whole bricks (WB) and broken bricks (BB) under two simulated utilization scenarios of leaching and freeze-thaw. Part of the studied bricks were crushed, which increased the surface area (SSA) 3.43-fold and exposed the inner heavy metals, increasing the HMD in BB. However, the HMD in sintered bricks did not exceed the "Groundwater Quality Standard" and "Integrated Wastewater Discharge Standard" under different utilization scenarios, although the dissolution processes were different. In the leaching scenario, the release rate of HMs (As, Cr, Pb) changed from fast to slow over time; the maximum concentration was 17% of the standard limits. In the freeze-thaw scenario, there was no significant correlation between the release of HMs and freeze-thaw time, and the HMD of As was the highest, reaching 37% of the standard limits. Further analysis of health risks of bricks in the two scenarios found that the carcinogenic risks (CR) and the non-carcinogenic risks (NCR) were below 9.56 × 10-7 and 3.21 × 10-2, respectively, which are both lower than the Guidelines for Health Risk Assessment of Groundwater Pollution issued by Ministry of Ecology and Environment of China. These findings suggest that the utilization risks of RHMCS sintered bricks analyzed in this study are low in both scenarios, and higher completeness of bricks leads to higher safety in product utilization. The results provide a reference for the engineering utilization and disposal of building materials made from RHMCS.

Heavy metal contamination affects the core microbiome and assembly processes in metal mine soils across Eastern China.

Mining activities in metal mine areas cause serious environmental pollution, thereby imposing stresses to soil ecosystems. Investigating the ecological pattern underlying contaminated soil microbial diversity is essential to understand ecosystem responses to environment changes. Here we collected 624 soil samples from 49 representative metal mines across eastern China and analyzed their soil microbial diversity and biogeographic patterns by using 16 S rRNA gene amplicons. The results showed that deterministic factors dominated in regulating the microbial community in non-contaminated and contaminated soils. Soil pH played a key role in climatic influences on the heavy metal-contaminated soil microbial community. A core microbiome consisting of 25 taxa, which could be employed for the restoration of contaminated soils, was identified. Unlike the non-contaminated soil, stochastic processes were important in shaping the heavy metal-contaminated soil microbial community. The largest source of variations in the soil microbial community was land use type. This result suggests that varied specific ecological remediation strategy ought to be developed for differed land use types. These findings will enhance our understanding of the microbial responses to anthropogenically induced environmental changes and will further help to improve the practices of soil heavy metal contamination remediation.

Global perspectives for biochar application in the remediation of heavy metal-contaminated soil: a bibliometric analysis over the past three decades.

Herein, 7,308 relevant documents on biochar application for the remediation of heavy metal (HM)-contaminated soil (BARHMCS) from 1991 to 2020 were extracted from the Web of Science Core Collection and subjected to bibliometric and knowledge mapping analyses to provide a global perspective. The results showed that (1) the number of publications increased over time and could be divided into two subperiods, i.e., the slow growth period (SGP) and rapid growth period (RGP), according to whether the annual publication number was ≥300. (2) A total of 126 countries, 741 institutions, and 1,021 scholars have contributed to this field. (3) These studies are mainly published in Science of the Total Environment, Chemosphere, etc., and are mainly based on the categories of environmental science, soil science, and environmental engineering. (4) The top five keyword clusters for the SGP were biochar, biochar, sorption, charcoal, and HMs, and those for the RGP were adsorption, black carbon, nitrous oxide, cadmium, and pyrolysis. (5) The main knowledge domains and the most cited references during the SGP and RGP were discussed. (6) Future directions are related to biochar application for plant remediation, the mitigation of climate change through increased carbon sequestration, biochar modification, and biochar for HMs and multiple organic pollutants.

Biochar application in the remediation of heavy metal-contaminated soil (BARHMCS) has become a popular research topic worldwide. Many excellent papers on this topic have been published, including some valuable reviews. However, there are no reviews including bibliometric and visual analyses. In the present study, bibliometric and visual analyses of relevant literature in the field of BARHMCS based on the Web of Science Core Collection were carried out to outline the development process of this field at a macro level, clarify the research hotspots, identify the knowledge domains that support this field, and explore future research directions. These efforts will no doubt help readers fully understand BARHMCS from a global perspective and provide a reference for future research. HIGHLIGHTSAn overall global perspective of biochar remediation of heavy metal (HM)-contaminated soil was provided.The main popular research topics of each period were discussed.Knowledge domains were discussed.Five main future research directions were identified based on burst keyword analysis.Biochar modification and its effect on HMs and coexisting organic pollutants should be studied in the future for soil remediation purposes.

Plant growth and heavy meal accumulation characteristics of Spathiphyllum kochii cultured in three soil extractions with and without silicate supplementation.

A hydroponic method was conducted to test whether Spathiphyllum kochii is tolerant to multiple HMs as well as to evaluate whether sodium silicate promotes plant growth and alleviates HM stress mainly by assessing biomass, HM accumulation characteristics and antioxidant enzyme activities (AEAs). Three soil extractions from an uncontaminated soil, a comparable lightly HM-contaminated soil (EnSE), and a comparable heavily HM-contaminated soil (ExSE) with or without 1 mM sodium silicate supplementation were used. S. kochii showed no obvious symptoms when cultured in EnSE and ExSE, indicating that it was a multi-HM-tolerant species. The biomass and photosynthesis followed the order: UnSE > EnSE > ExSE, but the opposite order was found for HM concentration, AEAs, and malondialdehyde content. Silicate had no effects on the growth and HM bioaccumulation characteristics of S. kochii cultured in UnSE but exhibited a novel role in decreasing HM uptake by 13.61-41.51% in EnSE and ExSE, respectively, corresponding upregulated AEAs, and reduced malondialdehyde contents, resulting in increased biomass and alleviating HM stress. The activities of peroxidase and superoxide dismutase were upregulated by an increase in soil extraction HM concentration and further upregulated by silicate supplementation, indicating that they were important mechanisms alleviating HM stress in S. kochii.

Phytoremediation is an economical and environmentally friendly technology for the alleviation of heavy metal (HM)-contaminated soil. Improving bioremediation efficiency is crucial for this kind of technology. Many studies have shown that silicon plays a novel role in plant growth and adversity responses, but studies in the field of phytoremediation are limited. In addition, phytoremediation plant species are usually hyperaccumulators or may be tolerant crops, commercial crops, or wild species from mining areas, and the use of landscape species in phytoremediation is limited. This is the first report on the effects of silicate on the multi-HM bioaccumulation characteristics of a garden plant (Spathiphyllum kochii) cultured in uncontaminated and HM-contaminated soil extractions. This study will broaden phytoremediation species screening and enrich our understanding of the mechanisms by which Si supports the bioremediation of HM-contaminated environments.HIGHLIGHTSS. kochii was a multi-heavy metal-tolerant species.Silicon played a novel role in reducing heavy metal concentrations by 14­40% and 14­42% in shoots and roots, respectively.Silicon upregulated antioxidant enzyme activities to alleviate heavy metal stress in plants.

Experimental Study on Solidification and Stabilization of Heavy-Metal-Contaminated Soil Using Cementitious Materials.

In order to solve the shortcomings of the traditional curing agent in the treatment of composite heavy-metal-contaminated soil with the solidification and stabilization method, a new type of cementing material A was used as a curing agent, and the Pb, Cd, Cu composite heavy-metal-contaminated soil was artificially prepared to carry out an experimental study on solidification and stabilization (SS) restoration by the mechanical properties test, leaching performance test, and microscopic test. The results show that in the range of test dosage, with the increase in the curing agent content, the unconfined compressive strength of the solidified body increased, and the resistance to deformation was enhanced. From the perspective of leaching characteristics, the new curing agent A had an excellent curing effect on the composite heavy-metal-contaminated soil. To achieve safe disposal, a curing agent content of 10% applies only for the soil heavily contaminated by heavy metals. The curing agent A could significantly reduce the content of acid-extractable heavy metals after solidifying the heavy metal Pb, Cd, and Cu composite contaminated soil and effectively converted it into a residue state. The solidified phase contained hydrated products such as calcium silicate hydrate (CSH) and ettringite (AFt). These hydrated products can inhibit the leaching performance of heavy metal ions through adsorption, encapsulation, and ion exchange. The study provides a feasible method and reference for the solidification, restoration, and resource utilization of heavy-metal-contaminated soil in the subgrade.

Changes in the Structures and Directions of Heavy Metal-Contaminated Soil Remediation Research from 1999 to 2020: A Bibliometric & Scientometric Study.

The pollution of heavy metals in soil is a problem of great concern to international scholars today. This research investigates the current research activities in the field of soil heavy metal pollution remediation and discusses the current areas of research focus and development trends. We conducted a bibliometric analysis of the literature on soil heavy metal pollution remediation from 1999 to 2020. CiteSpace and Vosviewer were used to conduct document co-citation and cluster analyses on the collected data. The research was mainly carried out based on the following factors: chronological distribution, country and institution distribution, source journal analysis, keyword co-occurrence analysis, and reference co-citation analysis. China (2173, 28.64%) and the United States (946, 12.47%) are the top two countries in terms of the number of articles published, and Environmental Science and Pollution Research (384, 5.06%) and Science of the Total Environment (345, 4.55%) published the most articles. The Chinese Academy of Science (485) is the organization that has contributed the most to the total number of publications. Furthermore, based on a keyword co-word analysis with Vosviewer and CitesSpace, it was concluded that the applications of phytoremediation and biochar in the remediation of heavy metals in soil are current research hotspots. Additionally, future research should focus on repair mechanisms, the development of new repair technology and joint repair systems.

Simultaneous remediation and fertility improvement of heavy metals contaminated soil by a novel composite hydrogel synthesized from food waste.

Soil contamination by heavy metals constitutes a serious global environmental problem, and numerous remediation technologies have been developed. In this study, a novel soil remediation agent, namely composite hydrogel (leftover rice-g-poly(acrylic acid)/montmorillonite/Urea, LR-g-PAA/MMT/urea), was prepared based on free radical polymerization cross-linking technology. Experimental results indicated that the LR-g-PAA/MMT/urea dosage increased from 0% to 10%, the oxidizable state proportions of Cd, Cu, Pb and Zn in contaminated soil increased from 8.3%, 23.7%, 54.0% and 11.4%-71.3%, 61.0%, 76.5%, and 27.9%, respectively. Compared with control experiment, the residue state growth rate were 56.6%, 23.4% and 39.8% for Cu, Pb and Zn respectively with 10% dosage of composite hydrogel. Simultaneously, the LR-g-PAA/MMT/urea was also seen to enhance soil fertility, including organic matter content, cation exchange capacity, and N and P contents. Pot experiments for biological toxicity suggested that the addition of hydrogel weakened the toxic effect of heavy metals on cotton seeds, and the action effect was increasingly visible with the increase of hydrogel dosage. The analysis of the mechanism involved suggested that the organic matter and its possessed characteristic functional groups could weaken the biological toxicity via complexation, adsorption, and ion exchange. Overall, the synthesized composite hydrogel exhibits great potential for the simultaneous remediation and fertility improvement of heavy metal contaminated soil.

Mechanism of cadmium removal from soil by silicate composite biochar and its recycling.

Biochar added to the soil is generally difficult to separate. In order to solve the problem of separating biochar from soil, this paper applies a hydraulic silicate gel material to the preparation of biochar. Non-magnetic silicate bonded biochar (SBC) and magnetic silicate bonded biochar (MSBC) with hydraulic properties were prepared. The new silicate bonded biochar has good adsorption performance, separation and recovery characteristics. The findings are as follows: (1) after three times of soil remediation, the silicate bonded biochar still had good mechanical properties, and the compressive strength was not attenuated, remaining between 210 and 270 N. (2) After three times of SBC and MSBC remediation, total Cd in soil decreased by 29.33% and 31.82% respectively, and available Cd decreased by 60.82% and 62.74% respectively. (3) After three cycles, the recovery rates of SBC and MSBC both exceeded 94.88%, and the highest adsorption regeneration rates of SBC and MSBC reached 83.09% and 92.06%, respectively. (4) The Cd content of wheat after SBC and MSBC repair was reduced by 29.67-37.36% and 47.25-63.74%, respectively.

Pteridophytes in phytoremediation.

Soil contamination by heavy metals and metalloids is a serious problem which needs to be addressed. There are several methods for removal of contaminants, but they are costly, while the method of phytoremediation is eco-friendly and cost-effective. Pteridophytes have been found to remediate heavy metal-contaminated soil. Pteridophytes are non-flowering plant that reproduces by spores. Pteris vittata has been reported as the first fern plant to hyperaccumulate arsenic. The Pteris species belongs to the order Pteridales. Other ferns that are known phytoremediators are, for example, Nephrolepis cordifolia and Hypolepis muelleri (identified as phytostabilisers of Cu, Pb, Zn and Ni); similarly Pteris umbrosa and Pteris cretica accumulate arsenic in leaves. So, pteridophytes have a number of species that accumulate contaminants. Many of them have been identified, while various other are being explored. The present review article describes the phytoremediation potential of pteridophytes plants and suggests as a potential asset for phytoremediation programs.

Assessment of strength and leaching characteristics of heavy metal-contaminated soils solidified/stabilized by cement/fly ash.

Solidification/stabilization technique has been widely adopted to remediate the heavy metal-contaminated sites. In the present work, the strength and leaching characteristics of the contaminated soils solidified/stabilized by cement/fly ash were systemically investigated. Electrical resistivity was also measured to establish empirical relationships for assessment of remediation efficacy. Tests results showed that the unconfined compressive strength increased and the leached ion concentration decreased with increasing curing time. In contrast, the unconfined compressive strength decreased and the leached ion concentration increased with increasing initial heavy metal ion concentration in the specimen. For the strength characteristic, the most notable detrimental effect was induced by Cr3+ and the least was induced by Pb2+. For the leaching characteristic, the trend was reversed. The electrical resistivity of the tested specimen increased significantly with increasing curing time and with decreasing initial ion concentration. The electrical resistivity of the Pb-contaminated specimen was higher than that of the Zn-contaminated specimen, which in turn was higher than that of the Cr-contaminated specimen. Empirical relationships between the strength, leaching characteristic, and electrical resistivity were established, which could be adopted to assess the remediation efficacy of heavy metal-contaminated soil solidified/stabilized by cement/fly ash.

Increased biomass and quality and reduced heavy metal accumulation of edible tissues of vegetables in the presence of Cd-tolerant and immobilizing Bacillus megaterium H3.

A Cd-resistant and immobilizing Bacillus megaterium H3 was characterized for its impact on the biomass and quality and heavy metal uptake of edible tissues of two vegetables (Brassica campestris L. var. Aijiaohuang and Brassica rapa L. var. Shanghaiqing) grown in heavy metal-polluted soil. The impact of strain H3 on the soil quality was also evaluated. The increase in the edible tissue biomass and the contents of soluble proteins and vitamin C of the vegetables inoculated with strain H3 ranged from 18% to 33%, 17% to 31%, and 15% to 19%, respectively, compared with the controls. Strain H3 significantly decreased the edible tissue Cd and Pb contents of the two greens (41-80%), DTPA-extractable Cd content (35-47%) of the rhizosphere soils, and Cd and Pb translocation factors (25-56%) of the greens compared with the controls. Moreover, strain H3 significantly increased the organic matter content (17-21%) and invertase activity (13-14%) of the rhizosphere soils compared with the controls. Our results demonstrated the increased edible tissue biomass and quality, decreased Cd and Pb uptake of the edible tissues, and improved soil quality in the presence of strain H3. The results also suggested an effective bacterial-enhanced technique for decreased metal uptake of greens and improved vegetable and soil qualities in the metal-contaminated soils.

[Enhanced Electrokinetic Remediation of Heavy Metals Contaminated Soils by Stainless Steel Electrodes as well as the Phenomenon and Mechanism of Electrode Corrosion and Crystallization].

Electrode corrosion and salt crystallization are important challenges that restrict the engineering application of electrokinetic technology. In the present study, using stainless steel as an electrode, and deionized water (DW), citric acid (CA) and polyaspartic acid (PASP) as electrolytes, Pb/Cu-contaminated soil was remediated by electrokinetic. All of the EK experiments were conducted in a 2 L soil cell reactor with a moisture level of about 35% blended with 1000 mg·g-1 of Pb and 778 mg·g-1 of Cu under a constant voltage gradient (1 V·cm-1, 2 V·cm-1) for 150 h. The removal efficiency of heavy metals and influencing factors, as well as the phenomenon and mechanism of electrode corrosion and salt crystallization were explored. The experimental results showed under the action of electric field, the Ca in the test soil would move to the cathode, and the crystal was formed in the alkaline condition. Additionally, the conductivity of the electrode was reduced. During the EK process, water at the anode was primarily oxidized, undergoing a reduction reaction at the cathode. Because H+ and OH- were transported through the soil by electromigration and electro-osmotic flow (EOF), changes in soil pH could occur. The concentrations distribution of Pb-Cu appeared to be related to the distribution of soil pH in the cell, which might be associated with the desorption and hydroxide precipitation of Pb-Cu. PASP resulted in obvious inhibitory effect on the corrosion of stainless steel electrode, CA and PASP could clearly destroy the formation of CaCO3 crystal, while barely effectively disrupted the formation of Ca (OH)2 crystal. Both CA and PASP could promote the removal of Pb, but the influence of PASP on the removal of Cu was not obvious, and the effect of CA was very significant. Combined with different corrosion inhibitor and reinforcing agent, stainless steel can be chosen as the engineering application electrode in electrokinetic remediation.

Synergistic effects of plant growth-promoting Neorhizobium huautlense T1-17 and immobilizers on the growth and heavy metal accumulation of edible tissues of hot pepper.

A plant growth-promoting Neorhizobium huautlense T1-17 was evaluated for its immobilization of Cd and Pb in solution. Meanwhile, the impacts of T1-17, immobilizers (vermiculite and peat) and their combination on the fruit biomass and heavy metal accumulation of hot pepper were characterized. T1-17 could significantly reduced water-soluble Cd and Pb in solution. T1-17, vermiculite+T1-17, peat, and peat+T1-17 significantly increased the fruit biomass (ranging from 45% to 269%) and decreased the fruit Cd (ranging from 66% to 87%) and Pb (ranging from 30% to 56%) contents and water-soluble Cd and Pb (ranging from 23% to 59%) contents of the rhizosphere soils compared to the controls. T1-17+vermiculite or peat had higher ability to increase the fruit biomass than T1-17 or vermiculite or peat. Furthermore, T1-17+peat had higher ability to reduce the water-soluble Cd and Pb contents of the rhizosphere soil and the fruit Pb uptake of hot pepper. The results showed that T1-17 and the immobilizers alleviated the heavy metal toxicity and decreased the fruit heavy metal uptake of hot pepper. The results also showed the synergistic effects of T1-17 and the immobilizers on the growth and Cd and Pb accumulation of hot pepper.