Abandoned Mine Lands Reclamation by Plant Remediation Technologies

The scientific landscape of phytoremediation of tailings: a bibliometric and scientometric analysis

This article seeks to evaluate the scientific landscape of the phytoremediation of mine tailings through a series of bibliometric and scientometric techniques. Phytoremediation has emerged as a sustainable approach to remediate metal-contaminated mine waste areas. A scientometric analysis of 913 publications indexed in Web of Science from 1999 to 2023 was conducted using CiteSpace. The results reveal an expanding, interdisciplinary field with environmental sciences as the core category. Keyword analysis of 561 nodes and 2,825 links shows a focus on plant-metal interactions, microbial partnerships, bioavailability, and field validation. Co-citation analysis of 1,032 nodes and 2,944 links identifies seminal works on native species, plant-microbe interactions, and amendments. Temporal mapping of 15 co-citation clusters indicates a progression from early risk assessments and native plant inquiries to integrated biological systems, economic feasibility, and sustainability considerations. Recent trends emphasize multidimensional factors influencing adoption, such as plant-soil-microbe interactions, organic amendments, and field-scale performance evaluation. The findings demonstrate an intensifying translation of phytoremediation from scientific novelty to engineering practice. This quantitative and qualitative analysis of research trends aids in understanding the development of phytoremediation for mine tailings. The results provide valuable insights for researchers and practitioners in this evolving field.

Microbial inoculants using spent mushroom substrates as carriers improve soil multifunctionality and plant growth by changing soil microbial community structure

Peat is typically used as a carrier for microbial inoculants; however, due to its non-renewable nature alternatives need to be identified as reliable and renewable carriers for mineral-solubilizing inoculants. In pot experiments, solid microbial inoculants were comprised of peat (P), biochar (BC), and spent mushroom substrates (SMS) using Medicago sativa L. as experimental materials, and the purpose of this study is to assess the effect of solid microbial inoculants on soil multifunctionality and plant growth. The results revealed that the SMS microbial inoculant had the greatest positive impact on plant biomass and significantly stimulated soil multifunctionality which is typically managed or assessed based on various soil functions or processes that are crucial for sustaining productivity, in contrast to the peat microbial inoculant, particularly at a supply level of 100 g/pot. There was no significant correlation between soil multifunctionality and bacterial/fungal microbial diversity. However, according to the co-occurrence network of bacteria and fungi, soil multifunctionality was intimately correlated with the biodiversity of the main ecological clusters (modules) of bacteria and fungi, rather than to the entire soil microbial community structure. The keystone species of module hubs and connectors play critical roles in maintaining the stability of ecological clusters of microbial co-occurrence networks and linkages between ecological clusters. Soil pH is a major predictor of changes in plant biomass, and leads to changes therein by affecting the major ecological clusters of bacterial and fungal co-occurrence networks. These results suggested that SMS may serve as a good alternative to peat as a carrier of mineral-solubilizing microorganisms to maintain soil multifunctionality and promote plant growth.

A comprehensive review on phytoremediation of fly ash and red mud: exploring environmental impacts and biotechnological innovations

Fly ash (FA) and red mud (RM) are industrial byproducts generated by thermal power plants and the aluminum industry, respectively. The huge generation of FA and RM is a significant global issue, and finding a safe and sustainable disposal method remains a challenge. These dumps contain harmful trace elements that have a significant impact on the environment and human health. It contributes to air, water, and soil pollution, disrupting the delicate balance of the ecosystems. It also introduces toxins into the food chain through biomagnification. Utilizing a vegetation cover can assist in addressing environmental health concerns associated with FA and RM dumps. Nevertheless, the presence of alkaline pH, toxic metals, the absence of soil microbes, and the pozzolanic properties of both FA and RM pose challenges to plant growth. Taking a comprehensive approach to the ecological restoration of these dumps through phytoremediation is crucial. This review examines the role of various factors in the ecological restoration of FA and RM dumps, specifically the use of naturally occurring plants. However, the issue of slow plant growth due to a lack of nutrients and microbial activities is being resolved through various advances, such as amendments in conjunction with organic matter, microbial inoculants, and the use of genetically modified plants. Research has demonstrated the benefits of using amendments to stimulate vegetation growth on FA and RM dumps. In this review, we explore various approaches to restoring FA and RM dumps and transforming them into productive sites that enhance the ecosystem services.

The social and environmental responsibility of informal artisanal and small-scale mining in Ghana: An Akan philosophical perspective

Informal artisanal and small-scale mining (ASM) continues to grow globally, raising both challenges and opportunities in terms of economic, social, and environmental impacts. The ASM literature explores the formalization and transfer of corporate social responsibility (CSR) practices from larger firms as the pathway to minimize negative impacts and maximize benefits. But we know very little about environmental and social responsibilities of informal mining operations (and informal economy actors in general, who are often portrayed as devoid of these responsibilities). This paper aims to theorize and empirically explore principles and practices of social and environmental responsibility in informal mining. We combine elements of relational stakeholder theory with Ghana's Akan philosophy to develop our theoretical framework. Through a qualitative research process involving thematic analysis - of field notes from field observations and 81 interviews with ASM miners, community leaders/residents and executive members of Small-Scale Mining Association-Prestea Branch in Ghana - and pattern-matching technique, we find that: a) informal ASM is culturally and relationally motivated to be socially and environmentally responsible, b) there is a model of informal social and environmental responsibility (ISER) that is characterized by commonality, solidarity, tradition, and human-nature interdependencies, and c) social and environmental responsibilities are interpreted in a distinctive, non-Western way and comply with two main informal norms: gifting for social responsibilities and taboos for environmental responsibility. We conclude by suggesting that governments should collaborate with traditional authorities to promote ISER practices as cultural norms.

Impact of Biotic/Abiotic Stress Factors on Plant Specialized Metabolites

Plants are a group of organisms that have developed remarkable adaptations to merely exist in the environment [...].

Revitalizing contaminated lands: A state-of-the-art review on the remediation of mine-tailings using phytoremediation and genomic approaches

The mining industry has historically served as a critical reservoir of essential raw materials driving global economic progress. Nevertheless, the consequential by-product known as mine tailings has consistently produced a substantial footprint of environmental contamination. With annual discharges of mine tailings surpassing 10 billion tons globally, the need for effective remediation strategies is more pressing than ever as traditional physical and chemical remediation techniques are hindered by their high costs and limited efficacy. Phytoremediation utilizing plants for remediation of polluted soil has developed as a promising and eco-friendly approach to addressing mine tailings contamination. Furthermore, sequencing of genomic DNA and transcribed RNA extracted from mine tailings presents a pivotal opportunity to provide critical supporting insights for activities directed towards the reconstruction of ecosystem functions on contaminated lands. This review explores the growing prominence of phytoremediation and metagenomics as an ecologically sustainable techniques for rehabilitating mine-tailings. The present study envisages that plant species such as Solidago chilensis, Festuca arundinacea, Lolium perenne, Polygonum capitatum, Pennisetum purpureum, Maireana brevifolia, Prosopis tamarugo etc. could be utilized for the remediation of mine-tailings. Furthermore, a critical evaluation of the organic and inorganic ammendments that optimize conditions for the remediation of mine tailings is also provided. The focus of this review extends to the exploration of environmental genomics to characterize microbial communities in mining sites. By delving into the multifaceted dimensions of phytoremediation and genomics for mine tailings, this study contributes to the ongoing efforts to revitalize contaminated lands for a sustainable and environmentally friendly future.

Management of excessive soil H+ ion induced toxicities by application of organic seaweed amendment enhances photosynthesis and resource use efficiencies in rice (Oryza sativa)

Globally, soil acidification is a serious environmental issue that reduces commercial agricultural production. Rice is subjected to nutritional stress due to acidic soil, which is a major impediment to rice production. Since acid soil threatens rice plants with soil compaction, nutrient loss, and plant stress-induced oxidative cell damage that results in affecting the photosynthetic system, restricting the availability of water, and reducing overall plant growth and productivity. Since contemporary soil acidification management strategies provide mediocre results, the use of Sargassum wightii seaweed-based biostimulants (BS) and soil amendments is sought as an environmentally friendly alternative strategy, and therefore its potential isevaluated in this study. BS was able to mediate soil quality by improving soil pH and structure along with facilitating nitrogen phytoavailability. BS also increased the activity of the antioxidant enzyme system, superoxide dismutase ((48%), peroxidase (76.6%), and ascorbate peroxidase (63.5%), aggregating the monaldehyde-mediating accumulation of osmoprotective proline in roots, that was evident from rapid initiation of root hair growth in treated seedlings. BS was also able to physiologically modulate photosynthetic activities and chlorophyll production (24.31%) in leaves, maintaining the efficiency of plant water use by regulating the stomatal conductance (0.91 mol/m/s) and the transpiration rate (13.2 mM/m/s). The BS compounds were also successful in facilitating nitrogen uptake resulting in improved plant growth (59%), tiller-panicle number, and yield (52.57%), demonstrating a resourceful nitrogen use efficiency (71.96%) previously affected by stress induced by acid soil. Therefore, the study affirms the competent potential of S. wightii-based soil amendment to be applied not only to improve soil quality, but also to increase plant production and yield.

The efficient applications of native flora for phytorestoration of mine tailings: a pan-global survey

Mine tailings are the discarded materials resulting from mining processes after minerals have been extracted. They consist of leftover mineral fragments, excavated land masses, and disrupted ecosystems. The uncontrolled handling or discharge of tailings from abandoned mine lands (AMLs) poses a threat to the surrounding environment. Numerous untreated mine tailings have been abandoned globally, necessitating immediate reclamation and restoration efforts. The limited feasibility of conventional reclamation methods, such as cost and acceptability, presents challenges in reclaiming tailings around AMLs. This study focuses on phytorestoration as a sustainable method for treating mine tailings. Phytorestoration utilizes existing native plants on the mine sites while applying advanced principles of environmental biotechnology. These approaches can remediate toxic elements and simultaneously improve soil quality. The current study provides a global overview of phytorestoration methods, emphasizing the specifics of mine tailings and the research on native plant species to enhance restoration ecosystem services.

Extraction of heavy metals from copper tailings by ryegrass (Lolium perenne L.) with the assistance of degradable chelating agents

Heavy metal contamination is an urgent ecological governance problem in mining areas. In order to seek for a green and environmentally friendly reagent with better plant restoration effect to solve the problem of low efficiency in plant restoration in heavy metal pollution soil. In this study, we evaluated the effects of three biodegradable chelating agents, namely citric acid (CA), fulvic acid (FA) and polyaspartic acid (PASP), on the physicochemical properties of copper tailings, growth of ryegrass (Lolium perenne L.) and heavy metal accumulation therein. The results showed that the chelating agent application improved the physicochemical properties of copper tailings, increased the biomass of ryegrass and enriched more Cu and Cd in copper tailings. In the control group, the main existing forms of Cu and Cd were oxidizable state, followed by residual, weak acid soluble and reducible states. After the CA, FA or PASP application, Cu and Cd were converted from the residual and oxidizable states to the reducible and weak acid soluble states, whose bioavailability in copper tailings were thus enhanced. Besides, the chelating agent incorporation improved the Cu and Cd extraction efficiencies of ryegrass from copper tailings, as manifested by increased root and stem contents of Cu and Cd by 30.29-103.42%, 11.43-74.29%, 2.98-110.98% and 11.11-111.11%, respectively, in comparison with the control group. In the presence of multiple heavy metals, CA, FA or PASP showed selectivity regarding the ryegrass extraction of heavy metals from copper tailings. PCA analysis revealed that the CA-4 and PASP-7 treatment had great remediation potentials against Cu and Cd in copper tailings, respectively, as manifested by increases in Cu and Cd contents in ryegrass by 90.98% and 74.29% compared to the CK group.

Health risk assessment of potentially toxic elements (PTEs) concentrations in soil and fruits of selected perennial economic trees growing naturally in the vicinity of the abandoned mining ponds in Kuba, Bokkos Local Government Area (LGA) Plateau State, Nigeria

This study was designed to determine the level of potentially toxic elements (PTEs) contamination in soil and selected fruits and assesses the health risk of inhabitants in the abandoned tin mining community in Kuba, Bokkos LGA. Samples of the abandoned mine soil and selected fruits mango (Magnifera indica), guava (Psidium guajava), avocado pear (Persea americana), and banana (Musa spp)) from the vicinity of the abandoned mine were analyzed for the presence of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the levels of all the PTEs analysed in the abandoned mine soil samples were significantly (p < 0.05) higher than their corresponding values in the control soil from the non-mining area. Except for Cd, the mean concentrations of As, Cr, Cu, Mn, Ni, and Pb were significantly higher than the FAO/WHO maximum permissible limit. Except for Zn in guava fruits and Cd in avocado fruits, the mean concentration of PTEs in fruits from abandoned mines was significantly (p < 0.05) higher than their corresponding control values. In contrast, the mean levels of As, Cr, Cu, Mn, Ni, and Pb in the investigated fruits were significantly (p < 0.05) higher than FAO/WHO maximum permissible limits established for fruits. The studied fruits remarkably took up and bioaccumulated PTEs from the abandoned mine soil. Mango fruit significantly bioaccumulated As (5.40), Cd (3.40), and Zn (2.81). Guava fruit bioaccumulated As (1.50) and Cd (4.60), while avocado bioaccumulated As (3.53), Cd (3.80), and Zn (6.48). Banana bioaccumulated As (0.96), Cd (0.80), and Zn (6.78). The hazard quotient values for PTEs investigated in fruits for adults, and children were several folds greater than 1. The hazard index (HI) for the PTEs through consuming fruits for children and adults was greater than 1, indicating that possible health risks exist for both local children and adults. However, the HI values for the children were higher than those for adults, implying that children were exposed to more potential noncarcinogenic health risks from PTEs than adults. The total cancer risk (TCR) values for Cr and Ni for all the fruits studied were within 10-3-10-1, which is several-fold higher than the permissible limits (10-6 and < 10-4), indicating high carcinogenic risk. TCR values for Cd and Pb in all the fruits, except for Cd in guava and avocado fruits for children, were within the range of 10-5-10-4, indicating that they are associated with moderate risk. The CR values for all the PTEs in all the fruits for adults and children except for mango fruit adults were within 10-2-10-1, indicating high carcinogenic risk. In conclusion, the results and risk assessment provided by this study indicate that human exposure to fruits from abandoned mines suggests a high vulnerability of the local community to PTE toxicity. Long-term preventive measures to safeguard the health of the residents need to be put in place.

Comprehensive evaluation of land reclamation schemes in mining areas based on linguistic intuitionistic fuzzy group decision-making

Schemes to protect the geological environment and reclaim land are core requirements for an application for mining rights and complying with mining regulations. Mining enterprises must be supervised to ensure they fulfill their obligations. To guide oversight of such schemes and to provide references for their compilation and review, this study evaluates land reclamation schemes in mining areas using a multi-attribute group decision-making method. First, linguistic intuitionistic fuzzy numbers are used to describe the evaluation information. Considering the authority and preferences of experts, methods for determining expert weights in four cases are established. Max-min deviation then determines the attribute weights, and a method for linguistic intuitionistic fuzzy group decision-making is proposed. Finally, the practicability of this method is verified through a comparative analysis of land reclamation schemes for four mining areas in Sichuan Province, China. The results show the proposed method to give simple and effective evaluation, making it reasonably applicable to the compilation and review of land reclamation schemes.

Bentonite as a Functional Material Enhancing Phytostabilization of Post-Industrial Contaminated Soils with Heavy Metals

Growing awareness of the risks posed by pollution of the soil environment is leading to the development of new remediation strategies. The technique of aided phytostabilization, which involves the evaluation of new heavy-metal (HM)-immobilizing amendments, together with appropriately selected plant species, is a challenge for environmental protection and remediation of the soil environment, and seems to be promising. In this study, the suitability of bentonite for the technique of aided phytostabilization of soils contaminated with high HM concentrations was determined, using a mixture of two grass species. The HM contents in the tested plants and in the soil were determined by flame atomic absorption spectrometry. The application of bentonite had a positive effect on the biomass of the tested plants, and resulted in an increase in soil pH. The concentrations of copper, nickel, cadmium, lead and chromium were higher in the roots than in the above-ground parts of the plants, especially when bentonite was applied to the soil. The addition of the analyzed soil additive contributed significantly to a decrease in the levels of zinc, copper, cadmium and nickel in the soil at the end of the experiment. In view of the above, it can be concluded that the use of bentonite in the aided phytostabilization of soils polluted with HMs, is appropriate.

Mobilization of contaminants: Potential for soil remediation and unintended consequences

Land treatment has become an essential waste management practice. Therefore, soil becomes a major source of contaminants including organic chemicals and potentially toxic elements (PTEs) which enter the food chain, primarily through leaching to potable water sources, plant uptake, and animal transfer. A range of soil amendments are used to manage the mobility of contaminants and subsequently their bioavailability. Various soil amendments, like desorbing agents, surfactants, and chelating agents, have been applied to increase contaminant mobility and bioavailability. These mobilizing agents are applied to increase the contaminant removal though phytoremediation, bioremediation, and soil washing. However, possible leaching of the mobilized pollutants during soil washing is a major limitation, particularly when there is no active plant uptake. This leads to groundwater contamination and toxicity to plants and soil biota. In this context, the present review provides an overview on various soil amendments used to enhance the bioavailability and mobility of organic and inorganic contaminants, thereby facilitating increased risk when soil is remediated in polluted areas. The unintended consequences of the mobilization methods, when used to remediate polluted sites, are discussed in relation to the leaching of mobilized contaminants when active plant growth is absent. The toxicity of targeted and non-targeted contaminants to microbial communities and higher plants is also discussed. Finally, this review work summarizes the existing research gaps in various contaminant mobilization approaches, and prospects for future research.

Sustainable amelioration of fly ash dumps linking bio-energy plantation, bioremediation and amendments: A review

Disposal of fly ash in dumps is posing serious environmental problem causing air pollution, groundwater contamination, and loss of valuable land making it unproductive dumpsites. Cultivation of plants using bioremediation technique is looked upon as one of the sustainable remedial solution to these fly ash dumpsites. In recent years, researches on the plantation of bio-energy crops over the fly ash dumpsites is creating renewed interest, as it serves remediation along with distinct energy outcomes creating a win-win situation. The issue of the slow growth of plants, due to lack of nutrients and microbial activities is being resolved through advances in bioremediation research done in conjunction with organic matter, microbial inoculants, and inclusion of wastewater. New researches are being done with different plants and microbes in the matrix combination and use wastewater to supplement nutrients requirement to find eco-friendly & sustainable solutions. The present paper critically reviews the research on bioremediation and amendments with specific to bio-energy plantation on fly ash dumps.

Assessment of the Transfer of Trace Metals to Spontaneous Plants on Abandoned Pyrrhotite Mine: Potential Application for Phytostabilization of Phosphate Wastes

The abandoned Kettara pyrrhotite mine (Marrakech region, Morocco) is a real source of acid mine drainage (AMD) and heavy metal pollution from previous mining operations-which has spread, particularly because of wind erosion. A store-and-release cover system made of phosphate wastes was built on the site for preventing AMD. To ensure the integrity of this cover and its durability, it is desirable to revegetate it (phytostabilization) with plants adapted to the edaphoclimatic conditions of the region. In this paper, a study was carried out on the spontaneous vegetation around the phosphate cover in order to consider the selection of plants to promote the stabilization of the Kettara mine tailings pond. Nine species of native plants with their rhizospheric soils growing in agricultural soils and tailings from the Kettara mine were collected, and metals (As, Cd, Co, Cu, Pb, Zn, Ni, Cr) were analyzed. The soil analysis showed that the tailings contained high concentrations of Cu (177.64 mg/kg) and Pb (116.80 mg/kg) and that the agricultural soil contained high concentrations of As (25.07 mg/kg) and Cu (251.96 mg/kg) exceeding the toxicity level (Cu > 100 mg/kg, Pb > 100 mg/kg, As > 20 mg/kg). The plant analysis showed low trace metal accumulation in Scolymus hispanicus, Festuca ovina, Cleome brachycarpa, Carlina involucrata and Peganum harmala. These species had a bioconcentration factor (BCF) greater than 1 and a translocation factor (TF) less than 1, demonstrating a high tolerance to trace metals. Therefore, they are good candidates for use in the phytoremediation of the Kettara mine tailings. These species could also potentially be used for the phytostabilization of the phosphate waste cover of the Kettara mine, thus completing the rehabilitation process of this area.

Hydrothermally-altered feldspar reduces metal toxicity and promotes plant growth in highly metal-contaminated soils

Novel green technologies for soil remediation have been focusing on altering soil properties and improving soil health. Hydrothermally-altered feldspar (HYP, HydroPotash), recently developed, is being related as both an efficient amendment to immobilize heavy metals in soils and a plant nutrients source, consisting in a promising technology for revegetation of contaminated sites. In order to evaluate the effectiveness of using HYP for phytostabilization programs, two different soils (Technosol and Oxisol) collected from a smelting site were amended with increasing doses of HYPs (HYP-1 and HYP-2): 15, 30, 60, and 120 Mg ha^-1. For comparison, a control (soil without amendment) and a soil amended with zeolite (clinoptilolite) were also included as treatments. After 90 days of incubation, HYPs decreased up to 83.8 % of Cd availability and reduced exchangeable Al up to 100 %. HydroPotash increased pH, cation exchange capacity, and contents of potassium, calcium, and phosphorus, as well as microbial biomass carbon, and fluorescein diacetate hydrolysis of soils. Andropogon gayanus, Eucalyptus grandis, and Heterocondylus vitalbae started growing from the dose of 15 Mg ha^-1 HYPs in the Oxisol and 60 Mg ha^-1 HYPs in the Technosol. Principal component analysis indicates that plant shoot dry weight was negatively correlated with extractable Cd and Zn and positively with pH, CEC, and Ca content. Besides promoting plant growth, HYPs reduced heavy metals (Cd and Zn) absorption by plants, indicating that HYP has potential use as an amendment in phytostabilization programs.

Bioavailability, Accumulation and Distribution of Toxic Metals (As, Cd, Ni and Pb) and Their Impact on Sinapis alba Plant Nutrient Metabolism

This study presents the behavior of white mustard seedlings Sinapis alba grown for three months in laboratory polluted soil containing As, Cd, Ni and Pb. Four different experiments were performed in which As was combined with the other three toxic metals in different combinations (As, AsCd, AsCdNi, AsCdNiPb), keeping the same concentrations of As and Cd in all tests and following the national soil quality regulations. The effects of these metals were monitored by the analytical control of metal concentrations in soil and plants, bioavailability tests of mobile metal fractions using three different extracting solutions (DTPA + TEA + CaCl₂-DTPA, DTPA + CaCl₂-CAT, and CH₃COONH₄ + EDTA-EDTA) and calculation of bioaccumulation and translocation factors. Additionally, micro, and macro-nutrients both in soil and plant (root, stem, leaves, flowers and seeds) were analyzed in order to evaluate the impact of toxic metals on plant nutrient metabolism. Metals were significantly and differently accumulated in the plant tissues, especially under AsCdNi and AsCdNiPb treatments. Significant differences (p < 0.05) in the concentration of both As and Cd were highlighted. Translocation could be influenced by the presence of other toxic metals, such as Cd, but also of essential metals, through the competition and antagonism processes existing in plant tissues. Significantly, more Cd and Ni levels were detected in leaves and flowers. Cd was also detected in seeds above the WHO limit, but the results are not statistically significant (p > 0.05). The extraction of metallic nutrients (Zn, Cu, Mn, Ni, Mg, K, Fe, Ca, Cr) in the plant was not influenced by the presence of toxic metal combinations, on the contrary, their translocation was more efficient in the aerial parts of the plants. No phytotoxic effects were recorded during the exposure period. The most efficient methods of metal extraction from soil were for As-CAT; Cd-all methods; Pb and Ni-DTPA. The Pearson correlations (r) between applied extraction methods and metal detection in plants showed positive correlations for all toxic metals as follows: As-CAT > DTPA > EDTA, Cd-DTPA > CAT > EDTA, Ni-EDTA = DTPA > CAT, Pb-EDTA = DTPA = CAT). The results revealed that Sinapis alba has a good ability to accumulate the most bioavailable metals Cd and Ni, to stabilize As at the root level and to block Pb in soil.

Influence of crude oil pollution on the content and electrophoretic spectrum of proteins in Carex hirta plants at the initial stages of vegetative development

The role of proteins in the general adaptive response of Carex hirta plants to soil pollution by crude oil has been studied. It was established that a possible element of the process of adaptation of C. hirta plants to combined stress – conditions of soil polluted by crude oil – may be the synthesis of stress proteins – high molecular weight of more than 60 kD and low molecular weight, not exceeding 22–45 kD. The synthesis of all 5 HSP families was detected in the leaves and rhizomes, and only sHSP (starting from Mr 32 kD), Hsp 60 and Hsp 100 proteins were synthesized in the roots under the influence of crude oil pollution. The development of C. hirta adaptation syndrome under the influence of crude oil pollution of the soil was promoted by enhanced synthesis of proteins with Mr 85, 77, 64, 60 and 27 kD in the leaves, 118 and 41 kD in the rhizomes and proteins with Mr 105, 53, 50 and 43 kD in the roots of the plants. The decrease in the amount of proteins with Mr 91, 45, 28 kD in the leaves, proteins with Mr 85, 76 and 23 kD in rhizomes and proteins with Mr 64 and 39 in the roots of C. hirta plants under conditions of crude oil polluted soil could be a consequence of inhibition of synthesis or degradation of protein molecules providing the required level of low molecular weight protective compounds in cells. The root system and rhizomes of C. hirta plants undergo a greater crude oil load, which leads to increased protein synthesis in these organs and decreased in the leaves, correspondingly. However, a decrease in protein content in the leaves may indicate their outflow in the roots and rhizomes. Сrude oil contaminated soil as a polycomponent stressor accelerated the aging of leaves of C. hirta plants, which could be caused by increased synthesis of ABA. ABA in its turn induced the synthesis of leaf-specific protein with Mr 27 kD. These proteins bind significant amounts of water with their hydrate shells maintaining the high water holding capacity of the cytoplasm under drought conditions. ABA inhibits the mRNA synthesis and their corresponding proteins, which are characteristic under normal conditions, and induces the expression of genes and, consequently, the synthesis of specific proteins including 27 kD protein. By stimulating the expression of individual genes and the synthesis of new polypeptides, ABA promotes the formation of protective reactions and increases the resistance of plants to crude oil pollution.