Remediation Of Polluted Soils Research Articles

Efficacy evaluation of biochar and activated carbon as carriers of bacterial inoculants in the remediation of multi-metal polluted soil

ABSTRACT Application of appropriate organic amendments as the carriers of bacterial consortium may improve the remediation efficiency of HMs-polluted soil. A greenhouse experiment was designed and carried out to investigate the capability of biochar, and activated carbon prepared from ostrich manure and almond husk as the carriers of bacterial inoculants in the phytoremediation of a calcareous soil polluted with Pb, Ni, Cd and Zn by maize. Results showed that the application of biochar and activated carbon prepared from ostrich manure increased root (78–129%) and shoot (72.3–272%) dry weight, as compared to the control. The values of metal accumulation in both maize root and shoot were in the order of Cd>Zn>Ni>Pb. While biochar and activated carbon prepared from ostrich manure significantly increased both root and shoot metals uptake, those prepared from almond husk drastically decreased the uptake of some metals. The foremost mechanism involved in the phytoremediation of Cd, Ni and Pb was phytostabilization while that of Zn was due to the phytoextraction. Results of the present study demonstrated the effectiveness of ostrich manure-derived biochar and activated carbon as an efficient treatment in the phytoremediation of multi-metal-polluted soils and the mitigation of HMs phytotoxicity.

Influence of Pteris vittata-maize intercropping on plant agronomic parameters and soil arsenic remediation

To achieve “production while remediation” in arsenic (As) -contaminated farmlands, a field experiment was conducted to investigate the effects of five Pteris vittata L. (PV) - maize intercropping modes on the growth, nutrient, and As accumulation characteristics of PV and maize. The intercropping increased the As content of PV by 2.9%–132.0% and decreased the As content in maize shoots by 15.5%–37.0%. Total As accumulation in above-ground plant parts reached 202.03–941.97 g hm−2. Intercropping also improved nitrogen and phosphorus content in maize kernels by 27.6%–124.7% and 15.9%–31.5%, respectively. Additionally, intercropping increased maize kernel 100-grain weight by 10.0%–16.6% and resulted in a 1.1%–24.1% increase in maize yield compared to sole cultivation. The intercropping transformed soil As from iron-bound to calcium-bound and aluminum-bound forms. Analysis of soil microbial diversity showed that the intercropping decreases the abundance of Chloroflexi and increases the abundance of Proteobacteria. Among the five modes, the intercropping mode with 4 rows of maize and 4 rows of PV showed the highest remediation efficiency and mechanized operation. These findings contribute to a theoretical framework and technical support for the simultaneous soil pollution remediation and productive farming practices.

Chemical Technology and Development Trend of Contaminated Land Remediation

In recent years, the rapid development of industry and agriculture in China has led to the destruction of soil environmental quality caused by pesticides, heavy metals and other pollutants entering the soil, and the decline of crop yield and quality. Therefore, soil pollution remediation is urgent, and it is urgent to explore the remediation technologies of polluted land with good remediation effect, low cost and popularization. This paper summarizes the relevant technologies in the literature, expounds several practical measures of chemical remediation technology of polluted land in detail, and discusses the development trend of contaminated land remediation technology in the future, in order to provide theoretical support for promoting the remediation technology of polluted land in China.

Study on Physical Remediation Technology of Polluted Land

Cultivated land soil pollution has seriously affected food security and people's living and health level in our country. Therefore, this study discusses how to use engineering technology to restore polluted land into utilizable land. The author analyzed the present situation of soil pollution development in China by summarizing the domestic and foreign literatures on the treatment of polluted land. Based on the engineering and technical experience of polluted land control and restoration for many years, this paper discusses the engineering and technical points of polluted land physical restoration, and how to use physical measures to transform polluted land into utilizable land, and looks forward to the development trend of polluted land restoration in China. This study lays a theoretical foundation for proposing soil pollution remediation technology suitable for China's national conditions and regional characteristics, and provides technical support for national food security and ecological civilization construction.

Recent advances in clay minerals for groundwater pollution control and remediation.

Clay minerals are abundant on Earth and have been crucial to the advancement of human civilization. The ability of clay minerals to absorb chemicals is frequently utilized to remove hazardous compounds from aquatic environments. Moreover, clay-based adsorbent products are both environmentally acceptable and affordable. This study provides an overview of advances in clay minerals in the field of groundwater remediation and related predictions. The existing literature was examined using data and information aggregation approaches. Keyword clustering analysis of the relevant literature revealed that clay minerals are associated with groundwater utilization and soil pollution remediation. Principal component analysis was used to assess the relationships among clay mineral modification methods, pollutant properties, and the Langmuir adsorption capacity (Qmax). The results demonstrated that pollutant properties affect the Qmax of pollutants adsorbed by clay minerals. Systematic cluster analysis was utilized to classify the collected data and investigate the relationships. The pollution adsorption mechanism of the unique structure of clay minerals was investigated based on the characterization results. Modified clay minerals exhibited changes in surface functional groups, internal structure, and pHpzc. This review provides a summary of recent clay-based materials and their applications in groundwater remediation, as well as discussions of their challenges and future prospects.

Nanotechnology Approaches for the Remediation of Agricultural Polluted Soils.

Soil pollution from various anthropogenic and natural activities poses a significant threat to the environment and human health. This study explored the sources and types of soil pollution and emphasized the need for innovative remediation approaches. Nanotechnology, including the use of nanoparticles, is a promising approach for remediation. Diverse types of nanomaterials, including nanobiosorbents and nanobiosurfactants, have shown great potential in soil remediation processes. Nanotechnology approaches to soil pollution remediation are multifaceted. Reduction reactions and immobilization techniques demonstrate the versatility of nanomaterials in mitigating soil pollution. Nanomicrobial-based bioremediation further enhances the efficiency of pollutant degradation in agricultural soils. A literature-based screening was conducted using different search engines, including PubMed, Web of Science, and Google Scholar, from 2010 to 2023. Keywords such as "soil pollution, nanotechnology, nanoremediation, heavy metal remediation, soil remediation" and combinations of these were used. The remediation of heavy metals using nanotechnology has demonstrated promising results and offers an eco-friendly and sustainable solution to address this critical issue. Nanobioremediation is a robust strategy for combatting organic contamination in soils, including pesticides and herbicides. The use of nanophytoremediation, in which nanomaterials assist plants in extracting and detoxifying pollutants, represents a cutting-edge and environmentally friendly approach for tackling soil pollution.

Sustainable remediation of Cr(VI)-contaminated soil by soil washing and subsequent recovery of washing agents using biochar supported nanoscale zero-valent iron

Soil contamination by Cr(VI) has attracted widespread attention globally in recent years, but it remains a significant challenge in developing an environmentally friendly and eco-sustainable technique for the disposal of Cr(VI)-contaminated soil. Herein, a sustainable cyclic soil washing system for Cr(VI)-polluted soil remediation and the recovery of washing agents using biochar supported nanoscale zero-valent iron (nZVI-BC) was established. Citric acid (CA) was initially screened to desorb Cr(VI) from contaminated soil, mobilizing Cr from the highly bioaccessible fractions. The nZVI-BC exhibited superior properties for Cr(VI) and Cr(total) removal from spent effluent, allowing effective recovery of the washing agents. The elimination mechanism of Cr(total) by nZVI-BC involved the coordinated actions of electrostatic adsorption, reduction, and co-precipitation. The contributions to Cr(VI) reduction by Fe0, surface-bound Fe(II), and soluble Fe(II) were 0.6 %, 39.8 %, and 59.6 %, respectively. Meanwhile, CA favored the activity of surface-bound Fe(II) and Fe0 in nZVI-BC, enhancing the production of soluble Fe(II) to strengthen Cr(VI) removal. Finally, the recovered washing agent was proven to be reused three times. This study showcases that the combined soil washing using biodegradable chelant CA and effluent treatment by nZVI-BC could be a sustainable and promising strategy for Cr(VI)-contaminated soil remediation.

Toxicity and biodegradability evaluation of HCHs-polluted soils after persulfate remediation treatments

Soils contaminated with lindane (γ-hexachlorocyclohexane, γ–HCH) wastes are widespread due to its massive production and high persistence. A noticeable case is in the Sardas and Bailín landfills (Spain), where INQUINOSA discharged tons of lindane wastes. The current work evaluates the remediation of polluted surface soil (HCHs = 409 mg kg−1) from these emplacements by two persulfate (PS)-activated on-site treatments: thermal (PS/T) and alkaline activation, the last one also intensified by temperature (PS/NaOH/T). The possible adverse effects of the chemical treatments on acute toxicity (associated with reagents, pH, by-product generation, etc.) of all phases involved (soils, soil organic extracts, reaction supernatants, and soil elutriates) towards Vibrio fischeri and Artemia salina were evaluated. Biodegradability assays were also performed. Both treatments presented high efficiency in pollutant degradation (XHCHs ≥ 90 % and dechlorination degree ≈ 80 %). After PS/T treatment, the soil and organic extract acute toxicity (Vibrio fischeri and Artemia salina) was reduced to the minimum level, and neither the reaction supernatant nor the soil leachate exhibited acute toxicity. Vibrio fischeri-soil acute toxicity remained unaltered after PS/NaOH/T treatment, which was attributed to the high NaOH concentration used. The toxicity of this soil elutriate was low, although that of aqueous reaction supernatant presented non-negligible values. In the case of Artemia salina bioassay, the alkaline treatment leads to a more significant decrease in toxicity than the thermal activation of PS. Finally, the biodegradability of treated soils increased, highlighting the suitability of PS-activated treatments for the remediation of HCHs-polluted soils.

Dichloro Diphenyl Trichloroethane (DDT) Insecticide Polluted Soil Remediation by Bacteria Consortium with Co-Substrate Utilization

Dichloro Diphenyl Trichloroethane (DDT) is an organochlorine insecticide that are largely used on agriculture and health sectors. DDT is an organic pollutant that are difficult to be dissolved and tend to survive in the environment for a long time because it is highly stable and persistent. DDT insecticide residue is still discovered in the soil even though its utilization has been stopped years ago and still negatively impacting human life and the environment through bio accumulation and bio magnification. Bioremediation is a potential method to remove recalcitrance compound such as DDT. The objective of this study is to gather and analyze information on DDT degradation by bacteria consortium with co-substrate addition. Pseudomonas putida and Pseudomonas stutzeri bacteria consortium were utilized to remediate DDT with glucose, sucrose, and yeast extract as cosubstrates. During 72 hours of observation, the three co-substrates namely yeast extract, glucose, and sucrose are able to degrade 75%, 56% and 39.55% of 10 ppm DDT. Yeast is the most ideal co-substrate to assist bacteria consortium growth and to degrade DDT. The implementation of pilot scale land treatment bioremediation is planned to be at 50m3, with dimension of 20m length, 5m wide, and 0.5m high. The efficiency of the removal reached 90% with 67 hours of detention time.

Exploring the remediation potential of Hydrangea macrophylla (Thunb.) Ser. in cadmium-contaminated soil by comparing cultivars and seedling age

The current situation regarding soil cadmium pollution in China is far from optimistic, necessitating the exploration of more viable Cd pollution-remediating plants. Several studies have shown that ornamental plants have excellent potential for application in soil pollution remediation. However, research on the Cd tolerance capacity of Hydrangea remains scarce, and the effects of plant age on heavy metal tolerance has not been thoroughly investigated. In this study, greenhouse pot experiments were conducted with artificially prepared Cd-polluted soil at various concentrations (0–240 mg·kg−1). Two cultivars of H.macrophylla, “Endless Summer” (H.'ES') and “Classic Rood” (H.'CR'), were cultivated in different Cd-contaminated soil levels for 60 d, after which the growth response, physiological changes, mineral element absorption, and Cd concentration of different plant parts were measured. The effect of plant age on the heavy metal absorption capacity of H. macrophylla was also explored. The results showed that under Cd stress, the antioxidant activity and penetration-regulating substance content of H. macrophylla increased, and the absorption of Mg, Mn, and Zn changed. Under all Cd treatments, Cd concentrations in the roots were higher than those in the shoots of the cultivars, with a bioconcentration factor of > 1 and a translocation factor of < 1. The tolerance to Cd of the H.'CR' was stronger than that of the H.'ES'. The Cd tolerance of H. macrophylla increased with seedling age. This study indicated that H. macrophylla is a suitable candidate for Cd phytostabilization and the remediation of Cd-polluted soils to limit harm caused by Cd flow in the ecosystem.

The addition of Glomalin-related soil protein and functional microbial consortium increased bound PAH residue degradation in soil

Bound Polycyclic Aromatic Hydrocarbons (PAHs) residues are the “end point” of soil pollution remediation. However, bound PAH residues can be released and become bioavailable exerting ecological and human health impacts. Remediation of soils contaminated with bound PAHs is a critical pollution control issue that support safe and healthy agricultural production We conducted microcosmic experiments to study the degradation of bound PAH residues in the soil by exogenous functional microbial consortium with and without the addition of glomalin-related soil protein (GRSP). Our results showed limited degradation of bound PAHs by the functional microbial consortium, however, a high concentration of 1000 mg/kg could accelerate the process. The removal rates of low molecular weight PAHs, medium molecular weight PAHs, high molecular weight PAHs, and total PAHs increased by 6.6%–14.2%, 8.2%–14.6%, 5.2%–7.5% and 6.7%–12.0%, respectively. The application of high- concentration GRSP increased the content of PAHs degrading bacteria such as Sphingomonas and Arthrobacter in soil and the abundance of some vital functional genes during PAH biodegradation (phe, nahAc, and nidA) thus promoting the degradation of bound PAHs residues. This study fills the cognitive gap of GRSP in regulating the degradation of bound PAH residues in soil, and provides an important basis for the subsequent development of bound PAH residue removal technology. These findings contribute to our understanding of the role of GRSP in regulating the degradation of soil-bound PAHs.

Technosols Derived from Mining, Urban, and Agro-Industrial Waste for the Remediation of Metal(loid)-Polluted Soils: A Microcosm Assay.

This study evaluated the effectiveness of six Technosols designed for the remediation of polluted soils (PS) by metal(loid)s at physicochemical, biological, and ecotoxicological levels and at a microcosm scale. Technosols T1-T6 were prepared by combining PS with a mix of organic and inorganic wastes from mining, urban, and agro-industrial activities. After two months of surface application of Technosols on polluted soils, we analysed the soil properties, metal(loid) concentration in total, soluble and bioavailable fractions, soil enzymatic activities, and the growth responses of Trifolium campestre and Lactuca sativa in both the Technosols and the underlying polluted soils. All Technosols improved the unfavourable conditions of polluted soils by neutralising acidity, increasing the OC, reducing the mobility of most metal(loid)s, and stimulating both the soil enzymatic activities and growths of T. campestre and L. sativa. The origin of organic waste used in the Technosols strongly conditioned the changes induced in the polluted soils; in this sense, the Technosols composed of pruning and gardening vermicompost (T3 and T6) showed greater reductions in toxicity and plant growth than the other Technosols composed with different organic wastes. Thus, these Technosols constitute a potential solution for the remediation of persistent polluted soils that should be applied in large-scale and long-term interventions to reinforce their feasibility as a cost-effective ecotechnology.

High-temperature electrothermal remediation of multi-pollutants in soil

Soil contamination is an environmental issue due to increasing anthropogenic activities. Existing processes for soil remediation suffer from long treatment time and lack generality because of different sources, occurrences, and properties of pollutants. Here, we report a high-temperature electrothermal process for rapid, water-free remediation of multiple pollutants in soil. The temperature of contaminated soil with carbon additives ramps up to 1000 to 3000 °C as needed within seconds via pulsed direct current input, enabling the vaporization of heavy metals like Cd, Hg, Pb, Co, Ni, and Cu, and graphitization of persistent organic pollutants like polycyclic aromatic hydrocarbons. The rapid treatment retains soil mineral constituents while increases infiltration rate and exchangeable nutrient supply, leading to soil fertilization and improved germination rates. We propose strategies for upscaling and field applications. Techno-economic analysis indicates the process holds the potential for being more energy-efficient and cost-effective compared to soil washing or thermal desorption.

Legal System of Soil Pollution Remediation in China and Its Regulation and Guidance to Soil Pollution Remediation

Faced with increasingly serious soil pollution problems, China has passed the Chinese Soil Pollution Prevention and Control Law (hereinafter referred to as the Law on the Prevention and Control of Soil Pollution) and established a series of soil pollution remediation systems. However, there are still some shortcomings in the current legal system for soil pollution remediation, which cannot fully solve the problems faced in soil remediation activities. The research focuses on the legal system for soil pollution remediation. This study analyzes the development process of relevant systems, focusing on the analysis of the Soil Pollution Prevention and Control Law, including the basic content and process of soil pollution prevention and control work. On this basis, this study summarizes the legal structure and practice of soil pollution control in China and analyzes the problems existing in the implementation of China’s soil pollution remediation legal system, such as imperfect remediation standards and insufficient public participation. Then, the relevant policies of EU countries are summarized and analyzed. Combined with the actual situation of China, suggestions are put forward to improve the legal system of soil pollution remediation in China and strengthen soil remediation.

Characteristics of dissolved organic matter composition in biochar: Effects of feedstocks and pyrolysis temperatures.

Biochar has widely used in soil pollution remediation due to its advantages of high efficiency and environmental sustainability. Dissolved organic matter (DOM) released by biochar plays a non-negligible role in the migration and transformation of pollutants in environment, and its composition was regarded as main impact factor. In this study, 28 biochar were investigated to detect the effect of pyrolysis temperature and feedstock on DOM content and components. Results showed that the content of DOM released from biochar at low pyrolysis temperatures (300-400 ℃) was higher than that from high pyrolysis temperatures (500-600 ℃). In addition, the specific UV-Visible absorbance at 254nm (SUVA254) results expressed that DOM from peanut shell biochar (PSBC), rice husk biochar (RHBC) and bamboo biochar (BBC) had higher humification at high temperatures. Moreover, one fulvic acid-like (C2) and two humic acid-like (C1, C3) substances were main fluorescent components of biochar-derived DOM identified by parallel factor analysis based on excitation emission matrices fluorescence spectroscopies (EEM-PARAFAC). With the increase of pyrolysis temperature, humic acid substances content gradually decreased. The correlation analysis results revealed that pyrolysis temperatures and O/C, H/C, DOM content, the biological index (BIX), humification index (HIX), C1% and C3% was negatively correlated (p < 0.001). Thus, the pyrolysis temperatures take important roles in composition of DOM released from biochar, and this research would provide a reference for the application of biochar in the environment.

Effect of freeze-thaw cycles and biochar coupling on the soil water-soil environment, nitrogen adsorption and N2O emissions in seasonally frozen regions

Freeze-thaw cycles (FTCs) usually occur in the nongrowing season of crops, and the temporal mismatch between soil nitrogen (N) supply and crop N utilization increases the risk of N loss. Crop straw burning is a seasonal air pollution source, and biochar provides new alternatives for waste biomass recycling and soil pollution remediation. To investigate the effect of biochar on N loss and N2O emissions under frequent FTCs, different biochar content treatments (0 %, 1 %, 2 %) were set, and laboratory simulated soil column FTC tests were conducted. Based on the Langmuir and Freundlich models, the surface microstructure evolution and N adsorption mechanism of biochar before and after FTCs were analyzed, and the change characteristics of the soil water-soil environment, available N and N2O emissions under the interactive effect of FTCs and biochar were studied. The results showed that FTCs increased the oxygen (O) content by 19.69 % and the N content by 17.75 % and decreased the carbon (C) content by 12.39 % of biochar. The increase in the N adsorption capacity of biochar after FTCs was related to changes in surface structure and chemical properties. Biochar can improve the soil water-soil environment, adsorb available nutrients, and reduce N2O emissions by 35.89 %–46.31 %. The water-filled pore space (WFPS) and urease activity (S-UE) were the main environmental factors determining N2O emissions. Ammonium nitrogen (NH4+-N) and microbial biomass nitrogen (MBN), as substrates of N biochemical reactions, significantly affected N2O emissions. The interaction of biochar content and FTCs in different treatments had significant effects on available N (p < 0.05). The application of biochar is an effective way to reduce N loss and N2O emissions under the action of frequent FTCs. These research results can provide a reference for the rational application of biochar and efficient utilization of soil hydrothermal resources in seasonally frozen soil areas.

Effect Of Phytoremediation On The Geotechnical Properties Of Heavy Metal Contaminated Soil

&lt;p&gt;The accumulation of heavy metals in soils increases rapidly due to various natural processes. Heavy metal pollution changes the geotechnical properties of soil and poses a serious threat to human health and ecosystems, so soil pollution remediation is particularly important. Phytoremediation is an environmentally friendly approach that can be used as a successful mitigation measure to restore heavy metal-contaminated soils cost-effectively. The plants extract and remove elemental contaminants or reduce their bioavailability in soil and improve the geotechnical properties. In this study, we are conducting a pot experiment with Amaranthus by adding Zn salt as a contaminant and determining the rate of removal of metal.&lt;/p&gt;&#x0D;

Review on Remediation Technology of Heavy Metal Contaminated Soil

With the development of global social economy, there are also problems of soil heavy metal pollution. It will not only destroy the original soil quality, but also cause harm to our health and affect the growth and development of animals and plants. Therefore, the remediation of soil pollution has become an important research field. This paper expounds the current common soil remediation technology, comprehensively evaluates the corresponding remediation technology, and preliminarily puts forward the development suggestions of soil remediation technology in contaminated sites.

Earthworms synergize with indigenous soil functional microorganisms to accelerate the preferential degradation of the highly toxic S-enantiomer of the fungicide imazalil in soil

The roles of soil and earthworm gut microorganisms in the degradation of the chiral fungicide imazalil (IMA) enantiomers were systemically studied in soil-earthworm systems. S-IMA degraded slower than R-IMA in soil without earthworms. After the addition of earthworms, S-IMA degraded faster than R-IMA. Methylibium was the potential degradative bacterium likely related to the preferential degradation of R-IMA in soil. However, the addition of earthworms significantly decreased the relative abundance of Methylibium, especially in R-IMA-treated soil. Meanwhile, a new potential degradative bacterium Aeromonas first appeared in soil-earthworm systems. Compared with enantiomer-treated soil, the relative abundance of indigenous soil bacterium Kaistobacter significantly boomed in enantiomer-treated soil with earthworms. Interestingly, Kaistobacter in the earthworm gut also obviously increased after exposure to enantiomers, particularly in S-IMA-treated soil, which was associated with the significant increase in Kaistobacter in soil. More importantly, the relative abundances of Aeromonas and Kaistobacter in S-IMA-treated soil were obviously higher than those in R-IMA-treated soil after the addition of earthworms. Moreover, these two potential degradative bacteria were also potential bacterial hosts of the biodegradation genes p450 and bph. Collectively, gut microorganisms are important helpers in soil pollution remediation by participating in the preferential degradation of S-IMA mediated by indigenous soil microorganisms.

Degradation of four pesticides by ozonation under field conditions and assessment of its influence on soil microbial activity

The application of pesticides is a common practice for pest control. Either its excessive use or by performing improper farming practices, the occurrence of residual levels of these compounds in soil has become a global issue due to their negative impacts on environment and human health. This work was aimed to assess the effectiveness of ozonation technique for the remediation of soils polluted with boscalid, chlorantraniliprole, flonicamid and metribuzin residues at field conditions and the impact of its application on microorganism activity of the soil. Trial was conducted in plots located in a greenhouse, exposing polluted soil to different treatments during the winter season. Four different treatments were applied: S (soil covered with polyethylene film), SOD (film covering and deep-ozonation), SOSD (film covering and superficial-deep-ozonation) and C (no treatment, control). Better degradation efficiency was found for SOSD treatment (dual ozone application), where remaining percentages ranged from 13.2 % to 33.1 %. The main transformation products (TPs) were monitored through the remediation experiment, showing residual levels of six intermediates in all treatments. Further, the overall activity of the soil microbial community was evaluated through basal respiration, with SOSD showing the greatest microbial activity. The results suggest that ozonation could be proposed as an alternative technical approach for the remediation of pesticide polluted soils.