Assessment of solid phase microfiber extraction fibers for the monitoring of volatile organoarsinicals emitted from a plant-soil system

The role of microbiomes in cooperative detoxification mechanisms of arsenate reduction and arsenic methylation in surface agricultural soil

Microbial arsenic (As) transformations play a vital role in both driving the global arsenic biogeochemical cycle and determining the mobility and toxicity of arsenic in soils. Due to the complexity of soils, variations in soil characteristics, and the presence and condition of overlying vegetation, soil microbiomes and their functional pathways vary from site to site. Consequently, key arsenic-transforming mechanisms in soil are not well characterized. This study utilized a combination of high-throughput amplicon sequencing and shotgun metagenomics to identify arsenic-transforming pathways in surface agricultural soils. The temporal and successional variations of the soil microbiome and arsenic-transforming bacteria in agricultural soils were examined during tropical monsoonal dry and wet seasons, with a six-month interval. Soil microbiomes of both dry and wet seasons were relatively consistent, particularly the relative abundance of Chloroflexi, Gemmatimonadota, and Bacteroidota. Common bacterial taxa present at high abundance, and potentially capable of arsenic transformations, were Bacillus, Streptomyces, and Microvirga. The resulting shotgun metagenome indicated that among the four key arsenic-functional genes, the arsC gene exhibited the highest relative abundance, followed by the arsM, aioA, and arrA genes, in declining sequence. Gene sequencing data based on 16S rRNA predicted only the arsC and aioA genes. Overall, this study proposed that a cooperative mechanism involving detoxification through arsenate reduction and arsenic methylation was a key arsenic transformation in surface agricultural soils with low arsenic concentration (7.60 to 10.28 mg/kg). This study significantly advances our knowledge of arsenic-transforming mechanisms interconnected with microbial communities in agricultural soil, enhancing pollution control measures, mitigating risks, and promoting sustainable soil management practices.

Phytoremediation strategies for mitigating environmental toxicants

In natural environments, persistent pollutants such as heavy metals and organic compounds, are frequently sequestered in sediments, soils, and mineral deposits, rendering them biologically unavailable. This study examines phytoremediation, a sustainable technology that uses plants to remove pollutants from soil, water, and air. It discusses enhancing techniques such as plant selection, the use of plant growth-promoting bacteria, soil amendments, and genetic engineering. The study highlights the slow removal rates and the limited availability of plant species that are effective for specific pollutants. Furthermore, it investigates bioavailability and the mechanisms underlying root exudation and hyperaccumulation. Applications across diverse environments and innovative technologies, such as transgenic plants and nanoparticles, are also explored. Additionally, the potential for phytoremediation with bioenergy production is considered. The purpose of this study is to provide researchers, practitioners, and policymakers with valuable resources for sustainable solutions.

Futuristic advancements in phytoremediation of endocrine disruptor Bisphenol A: A step towards sustainable pollutant degradation for rehabilitated environment

Bisphenol A (BPA) accumulates in the environment at lethal concentrations because of its high production rate and utilization. BPA, originating from industrial effluent, plastic production, and consumer products, poses serious risks to both the environment and human health. The widespread aggregation of BPA leads to endocrine disruption, reactive oxygen species-mediated DNA damage, epigenetic modifications and carcinogenicity, which can disturb the normal homeostasis of the body. The living being in a population is subjected to BPA exposure via air, water and food. Globally, urinary analysis reports have shown higher BPA concentrations in all age groups, with children being particularly susceptible due to its occurrence in items such as milk bottles. The conventional methods are costly with a low removal rate. Since there is no proper eco-friendly and cost-effective degradation of BPA reported so far. The phytoremediation, green-biotechnology based method which is a cost-effective and renewable resource can be used to sequestrate BPA. Phytoremediation is observed in numerous plant species with different mechanisms to remove harmful contaminants. Plants normally undergo several improvements in genetic and molecular levels to withstand stress and lower levels of toxicants. But such natural adaptation requires more time and also higher concentration of contaminants may disrupt the normal growth, survival and yield of the plants. Therefore, natural or synthetic amendments and genetic modifications can improve the xenobiotics removal rate by the plants. Also, constructed wetlands technique utilizes the plant's phytoremediation mechanisms to remove industrial effluents and medical residues. In this review, we have discussed the limitations and futuristic advancement strategies for degrading BPA using phytoremediation-associated mechanisms.

Roles and significance of chelating agents for potentially toxic elements (PTEs) phytoremediation in soil: A review

Phytoremediation is a biological remediation technique known for low-cost technology and environmentally friendly approach, which employs plants to extract, stabilise, and transform various compounds, such as potentially toxic elements (PTEs), in the soil or water. Recent developments in utilising chelating agents soil remediation have led to a renewed interest in chelate-induced phytoremediation. This review article summarises the roles of various chelating agents and the mechanisms of chelate-induced phytoremediation. This paper also discusses the recent findings on the impacts of chelating agents on PTEs uptake and plant growth and development in phytoremediation. It was found that the chelating agents have increased the rate of metal absorption and translocation up to 45% from roots to the aboveground plant parts during PTEs phytoremediation. Besides, it was also explored that the plants may experience some phytotoxicity after adding chelating agents to the soil. However, due to the leaching potential of synthetic chelating agents, the use of organic chelants have been explored to be used in PTEs phytoremediation. Finally, this paper also presents comprehensive insights on the significance of using chelating agents through SWOT analysis to discuss the advantages and limitations of chelate-induced phytoremediation.

Water and soil contaminated by arsenic: the use of microorganisms and plants in bioremediation

Owing to their roles in the arsenic (As) biogeochemical cycle, microorganisms and plants offer significant potential for developing innovative biotechnological applications able to remediate As pollutions. This possible use in bioremediation processes and phytomanagement is based on their ability to catalyse various biotransformation reactions leading to, e.g. the precipitation, dissolution, and sequestration of As, stabilisation in the root zone and shoot As removal. On the one hand, genomic studies of microorganisms and their communities are useful in understanding their metabolic activities and their interaction with As. On the other hand, our knowledge of molecular mechanisms and fate of As in plants has been improved by laboratory and field experiments. Such studies pave new avenues for developing environmentally friendly bioprocessing options targeting As, which worldwide represents a major risk to many ecosystems and human health.

Insights into conventional and recent technologies for arsenic bioremediation: A systematic review

Arsenic (As) bioremediation has been an economical and sustainable approach, being practiced widely under several As-contaminated environments. Bioremediation of As involves the use of bacteria, fungi, yeast, plants, and genetically modified organisms for detoxification/removal of As from the contaminated site. The understanding of multi-factorial biological components involved in these approaches is complex and more and more efforts are on their way to make As bioremediation economical and efficient. In this regard, we systematically reviewed the recent literature (n=200) from the last two decades regarding As bioremediation potential of conventional and recent technologies including genetically modified plants for phytoremediation and integrated approaches. Also, the responsible mechanisms behind different approaches have been identified. From the literature, it was found that As bioremediation through biosorption, bioaccumulation, phytoextraction, and volatilization involving As-resistant microbes has proved a very successful technology. However, there are various pathways of As tolerance of which the mechanisms have not been fully understood. Recently, phytosuction separation technology has been introduced and needs further exploration. Also, integrated approaches like phytobial, constructed wetlands using As-resistant bacteria with plant growth-promoting activities have not been extensively studied. It is speculated that the integrated bioremediation approaches with practical applicability and reliability would prove most promising for As remediation. Further technological advancements would help explore the identified research gaps in different approaches and lead us toward sustainability and perfection in As bioremediation.

Two facets of world arsenic problem solution: crop poisoning restriction and enforcement of phytoremediation

This review provides insights into As toxicity in plants with focus on photosynthesis and sugar metabolism as important arsenic targets and simultaneously defence tools against accompanying oxidative stress. Heavy metal contamination is a great problem all over the world. Arsenic, a metalloid occurring naturally in the Earth's crust, also massively spreads out in the environment by human activities. Its accumulation in crops poses a severe health risk to humans and animals. Besides the restriction of human-caused contamination, there are two basic ways how to cope with the problem: first, to limit arsenic accumulation in harvestable parts of the crops; second, to make use of some arsenic hyperaccumulating plants for phytoremediation of contaminated soils and waters. Progress in the use of both strategies depends strongly on the level of our knowledge on the physiological and morphological processes resulting from arsenic exposure. Arsenic uptake is mediated preferentially by P and Si transporters and its accumulation substantially impairs plant metabolism at numerous levels including damages through oxidative stress. Rice is a predominantly studied crop where substantial progress has been made in understanding of the mechanisms of arsenic uptake, distribution, and detoxification, though many questions still remain. Full exploitation of plant potential for soil and water phytoremediations also requires deep understanding of the plant response to this toxic metalloid. The aim of this review is to summarize data regarding the effect of arsenic on plant physiology with a focus on mechanisms providing increased arsenic tolerance and/or hyperaccumulation. The emphasis is placed on the topic unjustifiably neglected in the previous reviews - i.e., carbohydrate metabolism, tightly connected to photosynthesis, and beside others involved in plant ability to cope with arsenic-induced oxidative and nitrosative stresses.

Removal of 1,2-Dichloroethane from real industrial wastewater using a sub-surface batch system with Typha angustifolia L

1,2-Dichloroethane (1,2-DCA) is widely present in urban wastewaters and can be remediated by green technology. Subsurface batch system constructed wetlands (SSCWs) using macrophyte species of T. angustifolia L. were examined to remove 1,2-DCA using real wastewater from a petrochemical industry with a 1,2-DCA concentration of 390mg/L. We conducted an experiment with four pilot-scale constructed wetlands (0.81m²) in a greenhouse. Three SSCWs (T2, T3 and T4) were fed with real wastewater, and another one (T1) was fed with tap water (as plant control) to assess the role of T. angustifolia L. and their associated rhizobacteria to remediate 1,2-DCA. Tank T2 contained only sand without plants acting as contaminant control, tank T3 contained sand with plants and finally tank T4 contained plants with mixture of sand, soil and compost (3:2:1). The results show that the green technology has improved the removal of 1,2-DCA from the contaminated water through biodegradation with a remediation efficiency of 100% in T4 within 42 days. The removal efficiency was enhanced in T4 with 18% more than in T3 due to the compost addition, giving evidence for the potential application of SSCWs to treat chlorinated hydrocarbon in real field.

Metal phytoremediation: General strategies, genetically modified plants and applications in metal nanoparticle contamination

The accumulation of metals in different environmental compartments poses a risk to both the environment and biota health. In particular, the continuous increase of these elements in soil ecosystems is a major worldwide concern. Phytoremediation has been gaining more attention in this regard. This approach takes advantage of the unique and selective uptake capabilities of plant root systems, and applies these natural processes alongside the translocation, bioaccumulation, and contaminant degradation abilities of the entire plant and, although it is a relatively recent technology, beginning in the 90's, it is already considered a green alternative solution to the problem of metal pollution, with great potential. This review focuses on phytoremediation of metals from soil, sludge, wastewater and water, the different strategies applied, the biological and physico-chemical processes involved and the advantages and limitations of each strategy. Special note is given to the use of transgenic species and phytoremediation of metallic nanoparticles.