Politics of the natural vegetation to balance the hazardous level of elements in marble polluted ecosystem through phytoremediation and physiological responses

Contrasting Responses and Phytoremediation Potential of Two Poplar Species to Combined Strontium and Diesel Oil Stress

The soil pollution caused by diesel oil and heavy metals has become an increasingly serious environmental issue, with negative global-scale impacts. The remediation of contaminated soil requires special attention, in which phytoremediation has emerged as an ecofriendly solution. However, the response of plants to the combined stress of diesel oil and heavy metals remains largely unknown. In this study, the aim was to investigate the potential of Populus alba and P. russkii for phytoremediation by examining their response to combined diesel oil and heavy metal stress. In a greenhouse experiment using soil contaminated with 15 mg kg^-1 of diesel oil and varying concentrations of Sr (0, 10, or 100 mg kg^-1), we studied the physiological and biochemical changes, as well as the Sr absorption, of P. alba and P. russkii. The results showed that at high concentrations of Sr and diesel oil, the growth of both species was substantially inhibited, but P. alba exhibited higher resistance due to its higher antioxidant enzyme activities and increased accumulation of soluble sugar and proline. Additionally, P. alba concentrated Sr in the stem, whereas P. russkii accumulated Sr in the leaf, exacerbating its negative effects. Diesel oil treatments were beneficial for Sr extraction due to cross-tolerance. Our findings indicate that P. alba is more suitable for the phytoremediation of Sr contamination due to its superior tolerance to combined stress, and we identified potential biomarkers for monitoring pollution. Therefore, this study provides a theoretical basis and implementation strategy for the remediation of soil contaminated by both heavy metals and diesel oil.

Detoxifying the heavy metals: a multipronged study of tolerance strategies against heavy metals toxicity in plants

Heavy metal concentrations exceeding permissible limits threaten human life, plant life, and all other life forms. Different natural and anthropogenic activities emit toxic heavy metals in the soil, air, and water. Plants consume toxic heavy metals from their roots and foliar part inside the plant. Heavy metals may interfere with various aspects of the plants, such as biochemistry, bio-molecules, and physiological processes, which usually translate into morphological and anatomical changes. They use various strategies to deal with the toxic effects of heavy metal contamination. Some of these strategies include restricting heavy metals to the cell wall, vascular sequestration, and synthesis of various biochemical compounds, such as phyto-chelators and organic acids, to bind the free moving heavy metal ions so that the toxic effects are minimized. This review focuses on several aspects of genetics, molecular, and cell signaling levels, which integrate to produce a coordinated response to heavy metal toxicity and interpret the exact strategies behind the tolerance of heavy metals stress. It is suggested that various aspects of some model plant species must be thoroughly studied to comprehend the approaches of heavy metal tolerance to put that knowledge into practical use.

Phytoremediation of Potentially Toxic Elements: Role, Status and Concerns

Environmental contamination with a myriad of potentially toxic elements (PTEs) is triggered by various natural and anthropogenic activities. However, the industrial revolution has increased the intensity of these hazardous elements and their concentration in the environment, which, in turn, could provoke potential ecological risks. Additionally, most PTEs pose a considerable nuisance to human beings and affect soil, aquatic organisms, and even nematodes and microbes. This comprehensive review aims to: (i) introduce potentially toxic elements; (ii) overview the major sources of PTEs in the major environmental compartments; (iii) briefly highlight the major impacts of PTEs on humans, plants, aquatic life, and the health of soil; (iv) appraise the major methods for tackling PTE-caused pollution; (v) discuss the concept and applications of the major eco-technological/green approaches (comprising phytoextraction, rhizofiltration, phytostabilization, phytovolatilization, and phytorestoration); (vi) highlight the role of microbes in phytoremediation under PTE stress; and (vii) enlighten the major role of genetic engineering in advancing the phytoremediation of varied PTEs. Overall, appropriate strategies must be developed in order to stop gene flow into wild species, and biosafety issues must be properly addressed. Additionally, consistent efforts should be undertaken to tackle the major issues (e.g., risk estimation, understanding, acceptance and feasibility) in order to guarantee the successful implementation of phytoremediation programs, raise awareness of this green technology among laymen, and to strengthen networking among scientists, stakeholders, industrialists, governments and non-government organizations.

Use of Parthenium hysterophorus with synthetic chelator for enhanced uptake of cadmium and lead from contaminated soils-a step toward better public health

Parthenium hysterophorus L. is a vigorous plant species with cosmopolitan distribution. It can uptake considerable quantities of heavy metals from the soil and accrue these metals in its different tissue. The use of chelating agent i.e., Ethylenediaminetetraacetic acid (EDTA) can boost up metal uptake capacity. Pot experiment was performed to evaluate phytoextraction potential of P. hysterophorus for lead (Pb) and cadmium (Cd) with and without the aid of EDTA chelator. Shoot length, weight of root and shoot (both fresh and dry), leaves number, and chlorophyll contents of P. hysterophorus got reduced with an increase in metal uptake. The results revealed the highest concentration of Cd in shoot without and with EDTA was 283.6 and 300.1 mg kg^-1, correspondingly. Increase in Pb concentration was also boosted up by the EDTA from its maximum concentration in shoot 4.30-9.56 mg kg^-1. Generally, Pb and Cd concentrations were greater in shoots of P. hysterophorus than the roots regardless of EDTA in the treatments. EDTA also impacted positively the accumulation of essential ions K⁺, Na⁺, and Ca⁺² in P. hysterophorus. The capacity of P. hysterophorus to accumulate Pb and Cd found to be increased with EDTA in the soil. Bringing metals level in the soil in accordance to the WHO standards can improve the ecosystem as well as public health.

Environmental, Energy, and Water Footprints of Marble Tile Production Chain in a Life Cycle Perspective

The marble industry is growing in Pakistan, and Khyber Pakhtunkhwa province is the largest producer of marble tiles in Pakistan. Marble production consumes a considerable amount of water during its life cycle stages and impacts various environmental compartments, such as air, water, and soil; therefore, this study aimed to quantify the environmental impacts, water footprint, and cumulative energy demand of one-tonne marble tile manufactured in a small industrial estate Mardan (SIEM), Pakistan, and provide recommendations to improve its environmental impact profile. The study covers water consumption, energy use, and associated environmental impacts of raw materials and processes through different stages of the marble life-cycle during 2017–2018. The cradle-to-gate (extraction to factory gate or store house) life cycle assessment approach was followed in this study. The functional unit for the current study was one tonne of finished marble tile produced. Primary data from the field surveys and secondary data were modeled using the water scarcity index (WSI), CML 2000 v.2.05 methodology, and the cumulative energy demand indicator present by default in SimaPro v.8.3 software. The total water footprint required for one tonne of finished marble tile was 3.62 cubic meters per tonne (m3/t), with electricity consumed at processing units contributing to environmental burdens the most. Similarly, electricity consumed (at processing units and during polishing) and transportation of finished marble tile to the local market were responsible for global warming potential (388 kg CO2 eq/tonne tile), human toxicity (84.34 kg 1,4-DB-eq/tonne), freshwater aquatic ecotoxicity (94.97kg 1,4-DB eq/tonne) and abiotic depletion (7.1 × 10−5 kg Sb eq/tonne). The results of our study follow other marble tile LCA studies conducted globally (such as in Turkey and Italy), which also reported a high contribution to GWP, AP, EP, and HT due to electricity and fossil fuels consumption. The total cumulative energy demand (CED) was calculated as 5863.40 MJ (Mega Joule), with most energy usage associated with non-renewable fossil fuel sources. The results indicated that reducing electricity (using standard automatic machinery) and waste materials, especially paper and plastic wastes, can reduce environmental impacts. Most of the surveyed industrial units did not have wastewater treatment and recycling plants, and wastewater directly flows to nearby freshwater bodies and terrestrial ecosystems. These wastewaters should be adequately treated before being discharged into freshwater aquatic bodies. Environmental impacts must be improved by using the latest automatic machinery, reducing waste materials generation, reducing the distance between processing units and the market, and installing wastewater recycling plants.

Plants predict the mineral mines – A methodological approach to use indicator plant species for the discovery of mining sites

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Plant species predict presence of specific mineral reserves.

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These plants can be used as indicators for economically important mineral reserves.

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Indicator Species and modelling approaches were used for indicators of mineral mines.

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Coal indicators were Olea ferruginea, Gymnosporia royleana and few more.

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These approaches could potentially be applied for exploration of mineral reserves.

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